Dissertations / Theses: 'Antagonistic Control'

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Thompson, Rebecca Jane. "Control of Pythium ultimum by antagonistic fungal metabolites." Thesis, University of Kent, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329388.

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Saijonma-Koulumies, Leena E. M. "Bacterial interference in the control of canine pyoderma." Thesis, Royal Veterinary College (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368117.

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Knox, Oliver Gimli Gunning. "Exploiting nitrate respiration to optimise antagonistic control of root disease in soil." Thesis, University of Aberdeen, 2000. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU602312.

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In soils of high matric potential, low oxygen conditions often develop that favour disease development by many soil-borne plant pathogens. The introduction of a third party, or biocontrol agent, to suppress disease development would require that the agent remains metabolically active under such conditions. In the rhizosphere, plant roots not only supply carbon as an electron donor but cause a localised lowering of oxygen concentrations, conditions favourable for nitrate respiration. The effect of the addition of nitrate on the activity of antagonistic strains of Bacillus subtilis, Pseudomonas fluorescens and P. corrugata was studied in vitro on agar plates, but no significant (P 0.05) quantitative effect was observed . A sealed plate method, using aerobic, anoxic, and anaerobic conditions with 0, 1, 2.5, 5, 10 and 100mM nitrate concentrations was investigated using the B. subtilis strains. This assay tested the activity of antifungal volatiles (AFV) produced by the bacteria. The results indicated that nitrate led to an increased AFV production and/or activity against fungal pathogens under anoxic conditions with nitrate at or above 10 mM. To investigate root colonisation and the establishment of biocontrol colonies in the rhizosphere, lux marking of the biocontrol bacterial strains was undertaken. The transformed bioluminescent B. subtilis strains lost the ability to antagonise the test fungi on agar plates. This loss of antagonism appeared to be due to luciferase utilising metabolites involved in antibiosis and producing a low, but significantly different (P ?0.05) from background and parental strains level of luminescence. The effects of nitrate on a soil based biocontrol system were studied in greenhouse trials. Unfortunately, disease failed to develop, and the effects of the addition of nitrate could not be assessed. The potential involvement of nitrate in maintaining certain biocontrol aspects under conditions that favour pathogen attack seems likely from in vitro based studies. The removal of the antagonistic phenotype, from lux marked B. subtilis strains, raised questions as to the suitability of luciferase for use in this system and highlighted the need for careful monitoring and screening of genetically modified organisms.

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Mahdy, Magdy. "Biological control of plant parasitic nematodes with antagonistic bacteria on different host plants." Bonn : Rheinische Friedrick-Wilhelms-Universität, Institut für Pflanzenkrankheiten, 2002. http://hss.ulb.uni-bonn.de/ulb_bonn/diss_online/landw_fak/2002/mahdy_magdy/0203.pdf.

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Obici, Luciana Villanova. "Efeito do cultivo de plantas leguminosas sobre a população de nematoides em solos naturalmente infestados." Universidade Estadual do Oeste do Paraná, 2009. http://tede.unioeste.br:8080/tede/handle/tede/1414.

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Made available in DSpace on 2017-07-10T17:37:45Z (GMT). No. of bitstreams: 1 Luciana Villanova Obici.pdf: 1177002 bytes, checksum: 01dddf93e43aa5c55d8bd97f82de407d (MD5) Previous issue date: 2009-08-26
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The aim of this study was to evaluate Arachis pintoi, Canavalia ensiformis and Stylosanthes Campo Grande legumes cultivation over nematodes in naturally infested soils with a history of sugarcane crop. For this, naturally infested silt loam and clay loam soils were distributed into pots being transplanted two maize seedlings in order to facilitate nematode multiplication. After 60 days, plants aerial part was discarded and initial nematode population determined by assessing nematodes number (in the soil and roots). Legume seedlings were transplanted into the pots where remained for three or four months, analyzing again, the same nematodes populations. Maize was used as susceptible control. Finally, two sugarcane seedlings were transplanted into each pot, in order to assess the residual effect of the plants over nematodes in soil, by using the same parameters. Pratylenchus zeae and Helicotylenchus dihystera were present in analyzed samples. The results obtained showed that, regardless of soil type and cultivation time spent in pot, the three legume species were efficient for controlling P. zeae, with an outstanding effect even after 120 days of subsequent sugarcane cultivation. Canavalia ensiformis allowed increasing of H. dihystera population, whereas the other legumes caused its reduction. The conducted work allowed concluding that the three tested legumes may be used to P. zeae control. However, more studies need to be performed in relation to its effect, and in particular for C. ensiformis, over H. dihystera
O presente estudo foi realizado com o objetivo de avaliar o cultivo das leguminosas Arachis pintoi, Canavalia ensiformis e Stylosanthes Campo Grande sobre os nematoides em solos naturalmente infestados com histórico de cultivo de cana-de-açúcar. Para isto, um solo franco siltoso e um solo franco argiloso, naturalmente infestados, foram distribuídos em vasos, nos quais foram transplantadas duas plântulas de milho, para possibilitar a multiplicação dos nematoides. Após 60 dias, a parte aérea das plantas foi descartada e determinou-se a população inicial, por contagem dos nematoides (no solo e raízes). Plântulas das leguminosas foram transplantadas para vasos, onde permaneceram durante três ou quatro meses, avaliando-se novamente as populações de nematoides. Foi utilizado milho como testemunha suscetível. Por fim foram transplantadas duas plântulas de cana-de-açúcar para cada vaso, com o intuito de avaliar o efeito residual das leguminosas sobre os nematoides no solo, analisando-se os mesmos parâmetros. Nas amostras avaliadas registrou-se a presença de Pratylenchus zeae e Helicotylenchus dihystera. Os resultados obtidos mostraram que, independente do tipo de solo e do tempo de cultivo, as três espécies de leguminosas foram eficientes na redução de P. zeae, com efeito ainda pronunciado após 120 dias do cultivo subsequente da cana-de-açúcar. Canavalia ensiformis possibilitou o aumento populacional de H. dihystera, enquanto as outras duas leguminosas promoveram a sua redução. O trabalho realizado permitiu concluir que as três leguminosas testadas poderão ser utilizadas no controle de P. zeae. No entanto, mais estudos terão que ser realizados relativamente ao seu efeito, e em particular de C. ensiformis sobre H. dihystera

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Gillespie, Morgan Thomas. "Comparing Efficacy of Different Dynamic Models for Control of Underdamped, Antagonistic, Pneumatically Actuated Soft Robots." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5996.

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Research in soft robot hardware has led to the development of platforms that allow for safer performance when working in uncertain or dynamic environments. The potential of these platforms is limited by the lack of proper dynamic models to describe or controllers to operate them. A common difficulty associated with these soft robots is a representation for torque, the common electromechanical relation seen in motors does not apply. In this thesis, several different torque models are presented and used to construct linear state-space models. The control limitations on soft robots are induced by natural compliance inherent to the hardware. This inherent compliance results in soft robots that are commonly underdamped and present significant oscillations when accelerated quickly. These oscillations can be mitigated through model-based controllers which can anticipate these oscillations. In this thesis, multiple model predictive controllers are implemented with the torque models produced and results are presented for an inflatable single-DoF pneumatically actuated soft robot. Larger, multi-DoF, soft robots present additional issues with control, where flexibility in one joint impacts control in others. In this thesis a preliminary method and results for controlling multiple joints on an inflatable multi-DoF pneumatically actuated soft robot are presented. While model predictive controllers are capable, their control commands are defined by solving an optimization constrained by model dynamics. This optimization relies on minimizing the cost of a user-defined objective function. This objective function contains a series of weights, which allow the user to tune the importance of each component in the objective function. As there are no calculations that can be performed to tune model predictive controllers to achieve superior control performance, they often need to be tuned tediously by a skilled operator. In this thesis, a method for automated discrete performance identification and model predictive controller weight tuning is presented. This thesis constructs multiple state-space models for single- and multi-DoF underdamped, antagonistic, pneumatically actuated soft robots and shows that these models can be used with model predictive control, tuned for performance, to achieve accurate joint position control.

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Chidburee, Siripun. "Biological control of soil-borne disease in soybean by denitrifying antagonistic bacteria : the possible role of reduced nitrogen compounds for control of plant pathogens." Thesis, University of Aberdeen, 1998. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU602299.

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A number of experiments were carried out to study the potential of denitrifying bacteria and reduced nitrogen compounds for control of soil-borne damping-off pathogens. Measurement of the rhizosphere pH of growing soybean roots was carried out in soil adjusted to different pH states and packed into sheet microcosms. The results showed that the rhizosphere pH of soybean was lower than the bulk soil. Nitrate reductase activity and nitrite production was then characterised for the rhizosphere of intact 14 day-old soybean roots that were incubated in nitrate substrates adjusted to different pH values under water-logged conditions. The results showed that the rate and the quantity of nitrite production increased with increasing nitrate concentration and pH in the solution. A growth room experiment was carried out to determine root colonization by denitrifying bacteria in relation to disease caused by soil-borne pathogens, which are favoured by high soil moisture (approximately -5 KPa) and low oxygen levels. Nitrite producing bacteria were isolated from soybean roots grown in Grampian (Insch) soils which had not been cropped with soybean and Thai (Phitsanulok) soils which previously had been cropped with soybean. In the first pot experiment, the nitrite producing bacteria were isolated from different root sections of 12 and 19 day-old soybean plants after 8 weeks of continuous cropping of soils with soybean (a new crop was planted every week), and using different isolation media in order to determine the genus/species composition of the denitrifying bacteria on the rhizoplane. The results showed that continuous cropping of Thai soil and Insch soil with soybean increased pre-emergence damping-off disease and decreased fresh weight yields in seedlings that did emerge. ANOVA showed significant differences between root sections for most bacterial groups monitored {Bacillus spp., Pseudomonas and Enterobacteriaceae), with regression analysis generally showing densities increasing with root age or toward the shoot base. All nitrite producing bacterial isolates were screened for antifungal activity against Macrophomina phaseolina on agar plates and between 10 and 25% of nitrite producing bacteria were found to show in vitro antagonism. In a second pot experiment, the nitrite producing bacteria were isolated from root tissue below the crown (5 cm in length) every 2 weeks of continuous cropping of soils with soybean (a new crop was planted every 2 weeks). Plate-counting was carried out to determine the population of nitrite producing bacteria while a liquid culture MPN method was used for determination of NO, N2O and N2 producing bacteria. Linear regression analysis of the incidence of pre-emergence damping-off and soybean yields in seedling that did emerge showed a highly significant negative correlation between these parameters for both soils. ANOVA showed that there was a significant difference between soil type, with the Thai soil showing higher population densities of antagonistic bacteria on soybean roots. All nitrite producing bacterial isolates were screened for antifungal activity, but the plant pathogenic fungus, Pythium ultimum, was used in this experiment. The results showed that between 10 and 40% of nitrite producing bacteria showed in vitro antagonism. However, regression analysis showed that there was no significant increase or decrease in the nitrite producing antagonistic bacterial population with continuous soybean cropping. All 900 isolates of nitrite producing bacteria isolated from the soybean rhizoplane were screened for antagonistic activity towards Pythium ultimum based on a pot trial assay in the greenhouse. As expected, very low numbers of nitrite producing bacteria showed activity against P. ultimum and only one isolate gave a significant reduction in disease incidence in pot trials. The interactive effects of nitrite producing antagonist and an Arbuscular Mycorrhizal fungus (Glomus mosseae) and Bradryrhizobium japonicum, on control of the fungal pathogens, P. ultimum or M. phaseolina were investigated in the greenhouse. The results showed that improved plant growth was obtained with certain combined inocula involving nitrite producing bacterial antagonists, Glomus mosseae and Bradryrhizobium japonicum.

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Volkmann, Anette (Anette Sigrid). "Suppression of Botrytis cinerea by antagonists in living, moribund and dead grapevine tissue." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52472.

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Thesis (MScAgric)--University of Stellenbosch, 2001.
ENGLISH ABSTRACT: Several attempts have been made to reduce Botrytis cinerea grey mould in vineyards and in storage by means of biological control. However, the so called "silver bullet" approach in utilising a single antagonist, has its limitations when compared with synthetic fungicides. Often the antagonist has a limited spectrum of activity and the duration of its effectiveness is less than that provided by synthetic fungicides. Furthermore, antagonists are more likely to be effective in preventing initial infection rather than resumption of latent infection. Therefore, due to the various infection sites in grape bunches utilised by B. cinerea and the fact that the pathogen can remain latent in the grapevine tissue, it may be possible to obtain effective control of the pathogen by integrating fungicides and different biological control agents each aimed at a different site in grape bunches, protecting the bunch at the various phenological stages of growth and under different micro climatic conditions. In this study the potential of three fungal antagonists (Glioc/adium roseum, Uloc/adium atrum and Trichoderma harzianum) and one yeast (Trichosporon pullulans) to colonise different sites in grape bunches, and to reduce B. cinerea infection, was investigated in commercial vineyards. As the biological control agents were used in an integrated system, the effect of various fungicides frequently applied to local vineyards on the organisms was also investigated. Fungicide trials were conducted taking into account two possible scenarios. Firstly, the possible effect of fungicides applied to the vineyard after an application of the biological control agent or shortly before the application of the biocontrol agent. This entailed exposing the biocontrol agents to relatively low concentrations of the active ingredient of the fungicides, similar to the residue levels to which these organisms would be exposed under field conditions. Secondly, the possibility of applying the organisms and the fungicides at the same time by making use of spray tank mixtures. This meant exposing the biocontrol agents to relatively high doses of the active ingredient of the various fungicides. Mycelial growth and germination tests were performed on agar in Petri dishes to determine the effect of fungicides. It was assumed that if the fungicide effectively inhibits the antagonist at 2.5 !-lg a.Uml, the fungicide and antagonist can not be used in an integrated programme. Based on this criterium, T harzianum can not be applied to vineyards with penconazole, mancozeb/metalaxyl, pyrifenox or mancozeb. In addition T harzianum can not be applied as tank mixtures with iprodione. However, T harzianum can be used in conjunction with pyrimethanil, folpan, iprodione, fosetyl-Al and copperhydroxide, provided the chemicals and the antagonist are applied alternately. Gliocladium roseum can not be applied in a tank mixture with pyrimethanil and penconazole, but can be used on grapevine in conjunction with penconazole, pyrifenox, pyrimethanil, iprodione and fosetyl-Al. Ulocladium atrum can not be applied with pyrimethanil and iprodione. Ulocladium atrum can be applied in conjunction with penconazole, pyrifenox, pyrimethanil, iprodione, fosetyl-Al and mancozeb. The fungus can be applied in a tank mixture with penconazole and pyrifenox. The antagonists were applied as conidial suspensions to bunches at various phenological stages in commercial vineyards planted with the wine grape cultivar Chardonnay in the Stellenbosch region, or the table grape cultivar Dauphine planted in Paarl region. Bunches were collected 2 wk after application, surface-sterilised and used for determining antagonist colonisation and B. cinerea infection at specific sites in the bunches. In Chardonnay, the antagonists colonised the different sites, but colonisation during the three seasons was inconsistent and sporadic. Ulocladium atrum and G. roseum colonised floral debris to a degree in the 1996 season. However, in the 1997 season these two antagonists did not develop from floral debris. Trichoderma harzianum colonised floral debris extensively in the 1996 season. In the 1997 season colonisation by T harzianum dropped, but unlike G. roseum and U atrum, T harzianum occurred at a low level in flowers. Ulocladium atrum only colonised bunches during bloom, and was not found in bunches monitored from pea-size stage to véraison. This finding suggests that the saprophyte colonised moribund and dead flower parts occurring in bunches during full bloom to the pre-pea size stage, and is not likely to be found in living tissue. Gliocladium roseum colonised grape berries and pedicels to some degree and T harzianum colonised these grape parts extensively. Botrytis cinerea occurred inconsistently and at low frequencies in the different sites in bunches. It was therefore not possible to comment on the effectivity of the various antagonists in the three seasons during which the trials were performed. However, it was noted that, during the peasize stage in 1996, when high levels of B. cinerea were recorded, T harzianum controlled these infections in the pedicels more effectively than any other treatment.
AFRIKAANSE OPSOMMING: ONDERDRUKKING VAN BOTRYTIS CINEREA DEUR ANTAGONISTE IN LEWENDE, AFSTERWENDE EN DOOIE WINGERDWEEFSEL Die benadering om Botrytis cinerea verrotting van wingerd met behulp van 'n enkele biologiese beheeragent in plaas van met sintetiese fungisiede te beheer, het sekere beperkinge. Antagoniste het dikwels 'n beperkte spektrum van aktiwiteit, en die duur van hul effektiwiteit is minder as dié van fungisiede. Antagoniste is gewoonlik ook minder effektief in die beheer van latente infeksie. Die patogeen het verder die opsie om druiwetrosse deur verskillende infeksieweë te koloniseer. Fungisiede kan druiwetrosse beter teen infeksie deur veelvuldige infeksieweë beskerm as 'n enkele antagonis. In die lig hiervan is die beheer van die patogeen deur 'n kombinasie van fungisiede en verskillende biologiese beheeragente, wat elk gemik is om 'n ander infeksiepunt in die druiwe te beskerm, ondersoek. Drie swamagtige antagoniste (Glioc/adium roseum, Uloc/adium atrum en Trichoderma harzianum) en een gis (Trichosporon pullulans) is in die ondersoek gebruik. Voorloper ondersoeke, waar twee moontlike scenarios in ag geneem is, is met fungisiede uitgevoer. In die eerste scenario is die effek van fungisiede, aangewend op wingerd kort vóór aanwending van die biologiese beheeragent, of kort ná aanwending, ondersoek. Hierdie proef het die blootstelling van die biologiese beheeragent aan relatief lae konsentrasies van die aktiewe bestanddeel van die fungisied, vergelykbaar met residuvlakke waaraan die organismes onder veldtoestande blootgestel sou word, behels. Tweedens is die moontlikheid om antagoniste en fungisiede gelyktydig as spuitpompmengsels toe te dien, ondersoek. In hierdie proef is die biologiese beheeragente aan relatief hoë dosisse van die aktiewe bestanddeel van verskillende fungisiede blootgestel. Miseliumgroei en ontkiemingstoetse is op agar in Petribakkies uitgevoer om die effek van die fungisiede te bepaal. As kriterium is aanvaar dat indien 'n fungisied die antagonis effektief by 2.5J..lglml aktiewe bestanddeel inhibeer, die fungisied en antagonis nie in 'n geïntegreerde program gebruik kan word nie. Gebaseer op hierdie kriterium kan T harnzianum nie aangewend word in 'n wingerd wat met penconazole, mancozeb/metalaxyl, pyrifenox of mancozeb behandel is nie. Ook kan T harzianum nie in 'n spuitpompmengsel met iprodione aangewend word nie. Trichoderma harzianum kan egter saam met pyrimethanil, folpan, iprodione en fosetyl-Al gebruik word, mits dié chemikalieë en die antagonis afwisselend aangewend word. Glioc/adium roseum kan nie in 'n spuitpompmengsel met pyrimethanil en penconazole aangewend word nie, maar kan saam met penconazole, pyrifenox, pyrimethanil, iprodione en fosetyl-Al gebruik word. Uloc/adium atrum kan nie saam met pyrimethanil, iprodione en fosetyl-Al gebruik word nie. Die swam kan wel in 'n spuitpompmengselmet penconazole en pyrifenox aangewend word. In verdere proewe is die antagoniste as spoorsuspensies op trosse op verskillende groeistadia in kommersiële wingerde, wat met die wyndruitkultivar Chardonnay of die tafeldruifkultivar Dauphine aangeplant is, ondersoek. Trossies is twee weke na toediening versamel, oppervlakkig gesteriliseer en gebruik om vlakke van antagoniskolonisasie en B. cinerea infeksie op spesifieke nisse in die trosse te bepaal. In die geval van Chardonnay het die antagoniste die verskillende nisse gekoloniseer, maar die kolonisasie was sporadies en nie konstant gedurende die drie seisoene van ondersoek nie. Uloc/adium atrum en G. roseum het blomdeeltjies tot 'n beperkte mate in die 1996 seisoen gekoloniseer, maar nie in die daaropvolgende seisoen nie. Daarteenoor het T. harzianum blomdeeltjies ekstensief in die 1996 seisoen gekoloniseer, en in 'n beperkte mate in die daaropvolgende seisoen. Uloc/adium atrum kon nie trosse van ertjiekorrelgrootte tot deurslaan vestig nie. Hierdie bevinding dui daarop dat die saprofiet afsterwende en dooie blomdeeltjies, wat van volblom tot ertjiekorrelstadium in die trosse voorkom, koloniseer, maar dat dit nie in lewende weefsel voorkom nie. Daarteenoor het T. harzianum die verskillende trosdele ekstensief gekoloniseer. Botrytis cinerea het gedurende die drie seisoene wisselvallig en teen lae frekwensies in die verskillende nisse in die trosse voorgekom. Dit was gevolglik nie moontlik om 'n konkrete afleiding oor die effektiwiteit van die verskillende antagoniste as biobeheeragente van B. cinerea te maak nie. In die geval van Dauphine was die onderskeie organismes swak koloniseerders van blomdeeltjies. Trichoderma harizanum kon egter die lewende trosdele koloniseer. Kolonisasievlakke was laag en was nooit meer as 50% nie. In beide seisoene het die kolonisasievermoë van T. harzianum drasties ná trostoemaak gedaal. Daarteenoor het beide G. roseum en U atrum tydens al die ontwikkelingstadia die lewende trosdele swak gekoloniseer. Botrytis cinerea het ook uiters sporadies en teen baie lae vlakke voorgekom. Die bevindinge het getoon dat klimaatsomstandighede wat in tafeldruifwingerde in die Wes-Kaap heers, nie geskik is vir die vestiging van die biologiese beheeragente wat in die studie ondersoek is nie.

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Sultan, Muna [Verfasser]. "Biological control of leaf pathogens of tomato plants by Bacillus subtilis (strain FZB24) : antagonistic effects and induced plant resistance / Muna Sultan." Bonn : Universitäts- und Landesbibliothek Bonn, 2012. http://d-nb.info/1043055711/34.

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Kumar, Pratheesh [Verfasser]. "Study on Antagonistic and Growth Promotion Potential of Certain Exo and Endophytic Bacteria of Mulberry (Morus SPP.) : Biological control / Pratheesh Kumar." München : GRIN Verlag, 2019. http://d-nb.info/118869961X/34.

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Vries, Filicity Ann. "Synergistic effects of mixtures of fungicides and medicinal plant extracts against Botrytis cinerea." Thesis, University of the Western Cape, 2008. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_6798_1372423235.

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We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill&trade
, Rovral&trade
, Terminator&trade
and Teldor&trade
at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral&trade
significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit.

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Marquardt, Daniel [Verfasser]. "Field assessment of the influence of a seed treatment with the antagonistic bacterium Serratia plymuthica on the control of major rapeseed pathogens in Brassica napus / Daniel Marquardt." Kiel : Universitätsbibliothek Kiel, 2012. http://d-nb.info/102387041X/34.

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Migliore, Shane A. "Role of passive joint stiffness and active knee control in robotic leg swinging applications to dynamic walking /." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22684.

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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.
Committee Chair: DeWeerth, Stephen; Committee Member: Butera, Robert; Committee Member: Howard, Ayanna; Committee Member: Kemp, Charlie; Committee Member: Ting, Lena.

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Gontijo, Luciana Nunes. "Meloidogyne exigua: distribuição espacial, nível de infestação, mortalidade de seringueiras e controle com plantas antagonistas." Universidade Federal de Uberlândia, 2017. https://repositorio.ufu.br/handle/123456789/19442.

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A infestação de áreas com Meloidogyne exigua é um dos principais fatores limitantes ao desenvolvimento da heveicultura brasileira. Estudos anteriores demonstraram que o nematoide afeta o crescimento da seringueira, reduzindo o desenvolvimento de árvores que estão em fase produtiva podendo comprometer até mesmo a sua sobrevivência. Nesse contexto, o objetivo do presente estudo foi avaliar a distribuição espacial e nível populacional de M. exigua em um seringal e seu controle com plantas antagonistas. Para tanto, foram montados dois experimentos. O primeiro avaliou a distribuição espacial e o nível populacional do nematoide de galha em um plantio comercial de seringueira no Triângulo Mineiro, Minas Gerais. Constatou-se que o nível populacional de M. exigua, na área estudada, concentrou-se em focos elípticos – reboleiras – e sua distribuição espacial era do tipo agregada. O segundo experimento avaliou o efeito das plantas antagonistas Arachis repens, Brassica juncea, Brassica napus, Crotalaria spectabilis, Tagetes sp. consorciadas com mudas de seringueira no controle de Meloidogyne exigua. As plantas Arachis repens, Brassica juncea, Brassica napus e Tagetes sp. demonstraram efeito antagônico sobre a população do nematoide. Os resultados obtidos evidenciam a importância do manejo para expansão da heveicultura brasileira.
The infestation of nematodes of the genus Meloidogyne is one of the main limiting factors for the expansion of Brazilian rubber tree plantations. Previous studies have shown that this root-knot nematode affects growth of the rubber tree, thus reducing the development of trees in the production phase and even jeopardizes its survival. In this context, the objective of this study was to evaluate the spatial distribution of Meloidogyne exigua in a rubber tree plantation and its control with antagonistic plants. In order to perform this, two experiments were done. The first one evaluated the population density of the root-knot nematode in a commercial rubber tree plantation in Triângulo Mineiro, Minas Gerais. The population density of M. exigua, in the studied area, was concentrated in elliptic foci with a clustered spatial distribution. The second experiment evaluated the effect of the antagonistic plants Arachis repens, Brassica juncea, Brassica napus, Crotalaria spectabilis, and Tagetes sp. on the management of M. exigua in rubber tree seedlings. Both Brassica juncea and Arachis repens showed antagonistic effect on nematode population. The results obtained highlight the importance of proper nematode management for the expansion of Brazilian rubber tree plantations.
Dissertação (Mestrado)

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15

Chagas, Haroldo Antunes [UNESP]. "Controle de mofo-cinzento (amphobotrys ricini) da mamoneira (ricinus communis l.) por métodos químico, biológico e com óleos essenciais." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/86345.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
A mamoneira (Ricinus communis L.) é uma espécie oleaginosa tropical, sendo o óleo extraído de suas sementes um dos mais versáteis da natureza e com inúmeras aplicações industriais. Embora ainda seja uma espécie rústica, ela está sujeita a diversas doenças, dentre elas o mofo-cinzento, causada pelo fungo Amphobotrys ricini. O melhoramento genético seria a melhor alternativa para o controle da doença, mas demanda tempo para se obter cultivares resistentes. Dessa Maneira, o uso de métodos de controle baseado em métodos químicos, alternativos ou biológicos mostra-se viável em curto prazo. O objetivo do trabalho foi estudar a eficiência de controle do mofocinzento, na cultura da mamoneira, utilizando-se de métodos químico, alternativo e biológico. Para tanto, foram verificados, in vitro, a eficiência de diferentes meios de cultura na esporulação do patógeno e do antagonista C. rosea. Verificou-se, também, a produção de escleródios do patógeno nos meios. Quanto à eficiência dos métodos, verificou-se, in vitro, a eficiência deles na inibição do crescimento micelial e da germinação dos conídios do patógeno. Após desenvolver e validar uma escala diagramática de avaliação de severidade da doença em racemos de mamoneira, verificou-se a eficiência de aplicação do antagonista C. rosea em frutos destacados da mamona inoculados com o patógeno. Em plantas submetidas a condições de estufa e em campo, verificou-se a eficiência dos métodos no controle da doença causada por A. ricini Quanto à esporulação, o melhor meio de cultura para o patógeno foi V8-20%, obtendo 5,7 x 106 conídios/mL. Para o antagonista C. rosea, o melhor meio foi o TJ- 5% (Suco de Tomate), produzindo 4,41 x 106 conídios/mL. O único meio que propiciou abundante produção de escleródios de A. ricini foi o aveia-ágar. Quanto a inibição do crescimento micelial do patógeno...
The castor bean (Ricinus communis L.) is a tropical oily species, and the oil extracted of its seeds is one of most versatile of the nature, with many industrial applications. Even being a rustic species, it still subjects to several diseases, between them the gray mold, caused by the fungus Amphobotrys ricini. The genetic breeding would be the best alternative for the disease control, but spend time to get a resistant cultivar. In this way, the use of methods of control based on chemical, alternative or biological methods shows viable in short time. The aim of this work was to study the efficiency of the control of gray mold, on castor bean crop, using chemical, alternative and biological methods. Therefore, they had been verified, in vitro, the efficiency of different culture medium in the pathogen sporulation and the antagonist C. rosea. The sclerotia production in the culture medium can be also verified. About the efficiency of the methods, in vitro, the inhibition of the mycelial growth and germination of conidia was verified. After to develop and to validate a diagrammatic scale of evaluation of severity of the disease in racemes of castor bean, the efficiency of application of the antagonist C. rosea in inoculated fruits detached of castor bean with the pathogen was verified. In plants submitted to greenhouse and field conditions, the efficiency of the methods in the control of the disease caused by A. ricini was verified About the sporulation, the optimum culture medium for the pathogen was V8-20%, getting 5,7 x 106 conidia/mL. For the antagonist... (Complete abstract click electronic access below)

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Santos, Paula Leite dos 1985. "Manejo de macrophomina phaseolina (tassi) goid. em sementes de feijoeiro (phaseolus vulgaris l.) com óleos essenciais e antagonistas /." Botucatu, 2018. http://hdl.handle.net/11449/154999.

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Orientador: Adriana Zanin Kronka
Banca: Danila Comelis Bertolin
Banca: Marileia Regina Ferreira
Banca: Martha Maria Passador
Banca: Silvia Renata Siciliano Wilcken
Resumo: O feijoeiro comum (Phaseolus vulgaris L.) está sujeito à ocorrência de doenças, cujos agentes causais podem ser transportados e transmitidos via sementes, além de comprometer o potencial fisiológico destas. Dentre os patógenos que influenciam negativamente, se presentes nas sementes de feijão, está o fungo Macrophomina phaseolina (Tassi) Goid., que pode ser transmitido às plantas, causando a podridão cinzenta da haste do feijoeiro, uma doença com sérios impactos na cultura. Apesar do tratamento químico de sementes ser uma prática eficiente no controle de patógenos, o emprego de substâncias naturais com ação fungicida e de antagonistas de fitopatógenos surge como uma opção de manejo sustentável. Diante do exposto, o objetivo desta pesquisa foi avaliar o efeito do tratamento de sementes de feijão com óleos essenciais (Capítulo I) e antagonistas (Capítulo II) sobre a incidência do fungo M. phaseolina e o potencial fisiológico das sementes tratadas. No primeiro capítulo, inicialmente, investigou-se a ação in vitro dos óleos essenciais de cravo da índia, pimenta preta e gerânio sobre o crescimento micelial e a esporulação do fungo. Dois tratamentos testemunha foram incluídos: fungicida tiofanato metílico + fluazinam e BDA puro. Verificou-se inibição total do crescimento micelial pelos óleos essenciais de cravo da índia e pimenta preta, com ação semelhante ao fungicida. O óleo essencial de gerânio não apresentou efeito inibitório satisfatório sobre o fungo. Os óleos essenciais de c... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Common bean crop (Phaseolus vulgaris L.) is subject to diseases occurrence, whose causal agents can be transported and transmitted through seeds, besides compromising their physiological potential. Macrophomina phaseolina (Tassi) Goid. is one of the pathogens that negatively influences this potential, if present in common bean seeds. This fungus can be transmitted to the plants, causing charcoal rot of common bean, a disease with serious impacts on this crop. Although the chemical treatment of seeds is an efficient practice in the pathogens control, the use of natural substances with fungicidal action and antagonists of phytopathogens appears as a sustainable management option. This research aimed to evaluate the effect of common bean seeds treatment with essential oils (Chapter I) as well as antagonists (Chapter II) on the incidence of M. phaseolina and the physiological potential of the treated seeds. In the first chapter, the in vitro action of clove, black pepper and geranium essential oils on mycelial growth and fungal sporulation was investigated. Two control treatments were included: methyl thiophanate + fluazinam fungicide and pure potato-dextrose-agar (PDA). Total inhibition of mycelial growth was verified by clove and black pepper essential oils, which showed a fungicide-like action. The geranium essential oil had no satisfactory inhibitory effect on the fungus. Clove and black pepper essential oils were used in the common bean seeds treatment in order to determine their potential for M. phaseolina control and possible effects on the physiological quality of treated seeds. The essential oils treatments were compared with the methyl thiophanate + fluazinam fungicide one. Inoculated and uninoculated seeds were also evaluated. The essential oils reduced the fungus incidence in the seeds, however, clove essential oil caused a germination reduction. In spite of this, there was no negative ...
Doutor

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Fialho, Mauricio Batista. "Efeito in vitro de Saccharomyces cerevisiae sobre Guignardia citricarpa, agente causal da pinta preta dos citros." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/11/11138/tde-25042005-154547/.

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Devido à percepção dos consumidores sobre o impacto da utilização de pesticidas sobre o ambiente e saúde humana, além da aquisição de resistência por parte dos fitopatógenos, a sociedade tem exercido pressões que levaram ao estabelecimento de políticas governamentais que restringem a utilização de fungicidas levando agricultores e pesquisadores a considerar a aplicação de técnicas de controle biológico de fitopatógenos fúngicos. Guignardia citricarpa é o agente causal da pinta preta dos citros, que é de grande importância econômica, pois interfere na produção e causa depreciação estética dos frutos, acarretando em prejuízos principalmente na comercialização de frutos in natura para o mercado externo. Neste contexto, o objetivo deste trabalho foi a avaliação in vitro do potencial de linhagens de Saccharomyces cerevisiae, utilizadas em processos fermentativos, como agentes de biocontrole contra G. citricarpa. Através de ensaio em placa, foi evidenciado que entre as linhagens de S. cerevisiae testadas (BG-1, CR-1, CAT-1, KD-1, K-1 e PE-2), a CR-1 demonstrou a maior atividade antagônica contra o fitopatógeno, causando 73% de inibição do crescimento micelial. Também foi demonstrado que as linhagens são capazes de produzir voláteis de ação fungistática inibindo em até 83% o desenvolvimento do patógeno. O filtrado de cultura autoclavado e não autoclavado, bem como as células inativadas termicamente, obtidas a partir do crescimento da linhagem CR-1 por 24 h em meio YEPD, não causaram redução do crescimento vegetativo do fungo. A produção de enzimas hidrolíticas extracelulares (quitinases, β-1,3-glucanases e proteases) pela levedura não foi detectada em meio YEPD contendo glicose ou preparação de parede celular de G. citricarpa, nos tempos de cultivo avaliados. Baseado nas informações obtidas, foi possível constatar que as linhagens de S. cerevisiae, em especial a linhagem CR-1, são potenciais antagonistas para o controle de G. citricarpa. O possível mecanismo utilizado para inibição pela levedura é a produção de voláteis, no entanto, outros mecanismos não podem ser descartados. Desta forma, o presente trabalho mostra o potencial de S. cerevisiae no controle de G. citricarpa em frutos de laranja na pós-colheita.
Due to the consumers perception about the impact caused by pesticides utilization over the environment and human health, besides the acquisition of resistance for part of the phytopathogens, the society has exercised pressures that had led to the establishment of governmental politics that restrict the use of fungicides leading agriculturists and researchers to consider the application of techniques of biological control of plant pathogenic fungi. Guignardia citricarpa is the causal agent of citrus black spot that has a great economic importance, therefore interfering in production and causing aesthetic depreciation of the fruits that can interfere with commercialization of fresh-fruit in the external market. In this context, the aim of this work was to evaluate in vitro the potential of Saccharomyces cerevisiae strains, used in fermentative process, as biocontrol agents against G. citricarpa. Through plate assay it was evidenced that among the tested strains of S. cerevisiae (BG-1, CR-1, CAT-1, KD-1, K-1 and PE-2), the strain CR-1 was the one that demonstrated the greatest antagonic activity against the phytopathogen, causing 73% of micelial growth inhibition. It was also demonstrated that the strains were able to produce volatile compounds with fungistatic action inhibiting up to 83% the development of the pathogen. The autoclaved and not autoclaved culture filtrate, as well as the termical inactivated cell obtained from the growth of strain CR-1 in YEPD medium for 24 h, did not cause reduction in the fungal vegetative growth. The production of extracellular hydrolytic enzymes (chitinases, β-1,3-glucanases and proteases) by the yeast was not detected in YEPD medium with glucose or cell wall preparation of G. citricarpa at the evaluated times. Based upon the obtained information it was possible to evidence that the strains of S. cerevisiae, specially the strain CR-1, are potentials antagonists for the control of G. citricarpa. The possible mechanism used for inhibition by yeast is the volatile production, however other mechanisms cannot be discarded. Thus, the present work shows the potential of S. cerevisiae to control G. citricarpa in orange fruits in postharvest.

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Santos, Inaura Patrícia da Silva. "Controle alternativo da podridão radicular (Sclerotium rolfsii Sacc.) em feijão-caupi [Vigna unguiculata (L.) Walp.] (Fabaceae)." Universidade Federal de Alagoas, 2010. http://repositorio.ufal.br/handle/riufal/250.

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The cowpea, Vigna unguiculata (L.) Walp., is known as feijão-de-corda and feijão-verde , among others, is one of the main cultures exploited by small producers of the Northeast region of Brazil. Among the phytopathogens that affects its productivity, Sclerotium rolfsii Sacc. is noteworthy, causing the stem rot in several cultures around the world. The objective of this work was to evaluate the alternative control of S. rolfsii Sacc. in saplings of V. unguiculata (L.) Walp. trough the biocontrol of antagonists, organic residues incorporation to the soil, utilization of essential oils, plant extracts and mineral nutrition. The work was developed in the Laboratory de Phytopathology and in the vegetation house of CECA/UFAL. The pathogen was obtained trough the isolations of cowpea with symptoms of the disease and, afterwards, it was cultivated in sterilized rice. For in vitro control, the antagonists isolates were matched with the pathogen in PDA medium, for the purpose of evaluating the reduction of growth and the hyperparasitism. For the biofumigations of the soil, the organic materials poultry litter, mussel, sugar cane bagasse, bean residue, cassava scuff were dehydrated in stove at 55ºC for 96h, grinded in the concentrations of 10% and 20% (v/v) and incorporated to the substrate, infested for 20 days and compared to the group treated with methyl thiophanate and to the control. After thirty days, the seedlings were evaluated about the incidence and the suppression of the disease. In the in vivo control the seeds were microbiolized with antagonists (C110, C21, ENF24, R14 and Trichoderma harzianum), the fungicide and saline solution for the control. The substrate was infested with the pathogen, two days after the sow, and after 30 days were evaluated. For the natural substances, 21 days old seedlings were pulverized with cassava flour wastewater extract (40%), eucalyptus oil (1%), peppermint (1%), Ecolife® (2%), methyl thiophanate (0,7 g/L) and water for the control and after two days, the substrate was infested with the pathogen. Six days after the inoculation, a new pulverization was done. The mineral fertilization was done in the sow trough Sarruge solution and doses of calcium silicate and sodium, 50, 100, 500 and 1000mg/L-1 and water for the control. The substrate was infested two days after that and a second fertilization was done 10 days after the sow. After 30 days the evaluations took place. The antagonists R14, C16, ENF 24 and T. harzianum inhibited the pathogen with RC from 42 up to 57%. Trichoderma has the hyperparasitic capacity. The incorporation of organic material was not efficient in the control of the disease. The in vivo antagonists reduced the incidence of the disease, but it was effective in the suppression. The oils and plant extracts were not efficient in reduced the incidence. The mineral fertilizations was not able to suppress the disease.
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O feijão-caupi, Vigna unguiculata (L.) Walp., é conhecido como feijão-de-corda e feijão-verde sendo uma das principais culturas exploradas pelos pequenos produtores no Nordeste brasileiro. Dentre os fitopatógenos que afetam sua produtividade, destaca-se Sclerotium rolfsii Sacc. que causa a podridão de colo em diversos cultivos do mundo. O objetivo do trabalho foi avaliar o controle alternativo de S. rolfsii Sacc. em mudas de V. unguiculata (L.) Walp. através do uso de antagonistas, incorporação de resíduos orgânicos ao solo, utilização de óleos essenciais, extratos vegetais e ecolife® e nutrição mineral. O trabalho foi desenvolvido no Laboratório de Fitopatologia e em casa de vegetação do CECA/UFAL. O patógeno foi obtido pelo isolamento de folhas de feijão-caupi com sintomas da doença e depois cultivados em arroz esterilizado. Para controle in vitro , os isolados de antagonistas foram pareados com o patógeno em meio de BDA, para avaliar a redução de crescimento micelial (RC) e o hiperparasitismo. Para a biofumigação do solo, as matérias orgânicas cama de frango, marisco, bagaço de cana, resíduo de feijão, raspa de mandioca foram desidratadas em estufa 55ºC por 96h, moídas e incorporadas ao substrato infestado, em concentrações de 10% e 20% (v/v) por 20 dias e comparadas ao tiofanato metílico e a testemunha. Após 30 dias, as plantas foram avaliadas quanto à incidência da doença e desenvolvimento da planta. No controle in vivo as sementes foram microbiolizadas com os antagonistas (C110, C21, ENF24, R14 e Trichoderma harzianum), o fungicida e água salina para testemunha. O substrato foi infestado com o patógeno, dois dias após o semeio foram avaliadas com 30 dias. Para as substâncias naturais, plantas de feijão-caupi, com 21 dias de idade foram pulverizadas com extrato de manipueira (40%), óleo de eucalipto (1%), hortelã pimenta (1%), Ecolife® (2%), tiofanato metílico (0,7 g/L) e água para a testemunha. Após dois dias, o substrato foi infestado com o patógeno. Ao completar seis dias da infestação, uma nova pulverização foi realizada. A adubação mineral foi realizada no semeio através de solução de Sarruge e doses de silicato de cálcio e sódio, 50, 100, 500 e 1000mg/L-1 e água para testemunha. O substrato foi infestado dois dias depois e uma segunda adubação foi feita 10 dias após o semeio. Os antagonistas R14, C16, ENF 24 e T. harzianum inibiram o patógeno com RC de 42 a 57%. Trichoderma teve capacidade hiperparasitária. A incorporação da matéria orgânica não foi eficiente no controle da doença. Os antagonistas in vivo reduziram a incidência da doença e contribuiu para o desenvolvimento das plantas. Os óleos e extratos vegetais não foram eficientes em reduzir a incidência da doença. A adubação mineral não foi capaz de suprimir a doença.

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Siedel, Torsten. "Hybride Steuerung parallel gekoppelter Aktoren am Beispiel des humanoiden Roboters Myon." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17368.

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Die motorischen Fähigkeiten humanoider Roboter werden häufig von antriebsbedingten Nichtlinearitäten und Reibungseffekten negativ beeinflusst. Zur deren Kompensation werden üblicherweise modellbasierte Regelkreise genutzt, die i.d.R. von einer hochfrequenten Signalverarbeitung und mehreren Sensorqualitäten abhängen. Entgegen solch modellbasierten Techniken werden in der vorliegenden Arbeit modellfreie Steuerungsmethoden auf Basis parallel gekoppelter Antriebe entwickelt. Zur Entwicklung und Untersuchung dieser Steuerungsmethoden wird nach der von Pfeifer in seinem Werk “How the body shapes the way we think” beschriebenen synthetischen Methodik vorgegangen. Entgegen modellbasierten Untersuchungen auf Basis von Simulationen stehen bei der synthetischen Methodik empirische Untersuchungen am realen System im Vordergrund. Als Ausgangspunkt dienen konventionelle elektromechanische Antriebe mit deren bekannten leistungseinschränkenden Nichtlinearitäten und Reibungseffekten. Durch die parallele Kopplung mehrerer Antriebe an einem einzelnen Gelenk wird das Spektrum der Steuerungsmöglichkeiten deutlich erweitert. Es zeigt sich, dass (1) durch eine konstante antagonistische Vorspannung das Arbeitsverhalten von konventionellen Proportionalreglern optimiert werden kann, (2) durch dynamische asymmetrische Änderung der Vorspannung Nichtlinearitäten bei niedrigen Geschwindigkeiten ausgeglichen werden können und (3) getriebebedingte Reibungseffekte mit einer phasenverschobenen Pulsmodulation der Steuersignale kompensiert werden können. Weiterhin wird gezeigt, wie die erarbeiteten Steuerungsmethoden auf beliebig viele parallel gekoppelte Antriebe übertragen werden können. Für den praktischen Einsatz der Steuerungsmethoden werden diese in einer hybriden Steuerung zusammengeführt. Diese wird durch eine weitere Funktion, den Energiesparmodus beim Halten statischer Positionen, ergänzt und am humanoiden Roboter Myon implementiert und experimentell evaluiert.
Motor functions of humanoid robots are often negatively influenced by nonlinearities and friction effects of the actuators. The popular means of compensation are control circuits based on modelling, which rely on powerful HF Signal processing and various sensor qualities. In contrast, this thesis develops non-modelling control methods based on parallel coupled actuators. Development and exploration of these control methods follow Pfeifer’s synthetic methodology as described in his work “How the body shapes the way we think”. In contrast to the analysis based on emulation as used in modelling, the synthetic methodology focuses rather on empirical tests within the real system. The present work explores control methods for parallel coupled actuators for use in robot points. It starts from conventional electromechanical actuators with their known power limiting nonlinearities and frictional effects. Linking several parallel coupled actuators to a single joint significantly expands the spectrum of control capabilities. Using two parallel coupled actuators as an example, it is examined to which extent undesirable properties of single actuators can be compensated. The results show that (1) the Performance of conventional proportional controllers can be optimized by a constant antagonistic bias voltage, (2) nonlinearities at low velocities can be balanced out by a dynamic asymmetrical adjustment of the bias, and that (3) gear related frictional effects can be compensated by a phase shifted pulse modulation of the control signals. In addition, it is shown how the developed control methods can be applied to a random number of parallel coupled actuators. For practical use, the various control methods are combined in a hybrid control, which is supplemented by an energy saving mode when maintaining static positions. The hybrid control is being implemented into the humanoid robot Myon and evaluated by experiment.

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Brandão, Dayson Fernando Ribeiro. "Isolamento de micro-organismos antagonistas de solo para o controle de Bipolaris oryzae, agente causal da mancha parda em arroz." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11135/tde-15052018-150256/.

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O arroz (Oryza sativa L.) está entre as culturas mais importantes do mundo, tanto em valores de produção quanto em contribuição para a alimentação humana. A mancha parda, causada pelo fungo Bipolaris oryzae, destaca-se entre as principais doenças que afetam o arroz por reduzir a produtividade das lavouras e a qualidade dos grãos colhidos, colocando em risco a segurança alimentar de mais da metade da população mundial. O biocontrole de doenças como a mancha parda apresenta-se como uma alternativa mais sustentável em comparação ao controle químico que, por sua vez, apresenta elevados custos financeiro e ambiental. Os objetivos desse trabalho foram isolar micro-organismos antagonistas de solo com potencial de utilização no biocontrole da mancha parda, elucidar alguns dos mecanismos de ação ocorrentes no antagonismo entre os micro-organismos isolados e B. oryzae, avaliar os efeitos dos filtrados de cultivos dos micro-organismos isolados sobre o desenvolvimento do fitopatógeno e avaliar a eficácia dos micro-organismos isolados no controle da mancha parda em folhas de arroz. Dois micro-organismos antagonistas foram selecionados pela capacidade de produzirem metabólitos que inibem o crescimento de outros micro-organismos. Os antagonistas foram identificados como Paecilomyces lilacinus e Bacillus amyloliquefaciens ou B. methylotrophicus (o fragmento sequenciado de gDNA apresentou nível idêntico de similaridade para ambas as espécies), micro-organismos já utilizados na formulação de produtos biológicos para o controle de doenças de plantas. Bacillus spp. e P. lilacinus inibiram o crescimento micelial de B. oryzae em 52,5% e 37,3%, respectivamente, em ensaio de pareamento de culturas. Ambos os micro-organismos isolados foram capazes de inibir, também, o crescimento de outros importantes fitopatógenos como Magnaporthe oryzae, Sclerotinia sclerotiorum e Phytophthora infestans. Além dos metabólitos dissolvidos no meio de cultivo, foi verificada a produção de compostos orgânicos voláteis (COVs) pelos antagonistas. Bacillus spp. e P. lilacinus produziram COVs que reduziram o crescimento de B. oryzae em 19,3% e 20,6% respectivamente. Os filtrados de cultivo de Bacillus spp. e P. lilacinus apresentaram efeito fungistático sobre o desenvolvimento de B. oryzae. O filtrado da bactéria inibiu o crecimento, a esporulação e a germinação daquele patógeno em 74,7%, 94,2% e 100% respectivamente. O filtrado do fungo, por sua vez, foi capaz apenas de reduzir o crecimento micelial do patógeno (39,4%). Os metabólitos produzidos por Bacillus spp. demonstraram ser foto e termoestáveis; enquanto que os produzidos por P. lilacinus perderam sua atividade inibitória na presença de luz ultravioleta de comprimento longo. O biocontrole da mancha parda foi avaliado em segmentos de folhas de arroz tratadas, separadamente, com suspensão de células e esporos de Bacillus spp. e P. lilacinus respectivamente, e em seguida inoculadas com esporos de B. oryzae. Não houve redução da incidência e da severidade da doença através do tratamento de segmentos de folhas de arroz com suspensões de células e esporos dos antagonistas. No presente estudo, os micro-organismos antagonistas isolados de solo foram capazes de inibir in vitro o crescimento de B. oryzae e outros 3 fitopatógenos; porém, nas condições experimentais avaliadas, não foram eficazes no controle in vivo da mancha parda.
Rice (Oryza sativa L.) is one of the most important crops in the world in terms of total production and contribution to human diet. Brown spot of rice, caused by the fungus Bipolaris oryzae, is among the diseases that most affect this crop, reducing both yield and grain quality, and threatening food security for millions of people across the world. Biological control is considered a more sustainable approach to control plant diseases since pesticides application presents higher economical and environmental costs. The objectives of this study were: isolating antagonistic microorganisms from soil which show potential for use in the biocontrol of brown spot; elucidating some of the antagonistic mechanisms of the interaction among the plant pathogen and the isolated microorganisms; assessing the effect of cell-free culture filtrates from the antagonists on the development of B. oryzae; and evaluating the efficacy of the antagonistic microorganisms on the biocontrol of brown spot in rice leaves. Two microorganisms were selected because of the production of metabolites wich showed inhibitory effects on other microorganisms. The selected antagonists were identified as Bacillus amyloliquefaciens or B. methylotrophicus (gDNA sequenced fragments presented high similarity to both species), and Paecilomyces lilacinus, which are already used as commercial biocontrol products. Bacillus spp. and P. lilacinus inhibited mycelial growth of B. oryzae in 52.5 and 37.3%, respectively, in dual plate assays. Both microorganisms also inhibited mycelial growth of other important plant pathogens such as Magnaporthe oryzae, Phytophthora infestans and Sclerotinia sclerotiorum. Besides the production of metabolites dissoveld in the culture medium, the antagonism among B. oryzae and the isolated microorganisms also involves volatile organic compounds (VOCs). Bacillus spp. and P. lilacinus produced VOCs which reduced mycelial growth of that pathogen in 19.3 and 20.6% respectively. The cell-free culture filtrate from both antagonists showed fungistatic effetcs on the development of B. oryzae. The filtrate obtained from Bacillus spp. inhibited mycelial growth (74.7%), spore formation (94.2%) and germination (100%) of the plant pathogen. On the other hand, the antagonistic fungus filtrate was only effective on the reduction of the mycelial growth of B. oryzae (39.4%). While the metabolites produced by Bacillus spp. remained stable after heat and light treatments, the ones produced by P. lilacinus lost their inhibitory activity under near-ultraviolet light exposure. Brown spot biocontrol was assessed in detached rice 5-cm leaf segments treated, simultaneously, with a spore suspension of B. oryzae and cell suspension of Bacillus spp. or spore suspension of P. lilacinus. No reduction in disease incidence and severity was observed in leaves treated with the antagonists in comparison to control (water). In the present study, the antagonistic microorganisms isolated from soil inhibited in vitro the mycelial growth of B. oryzae and other three plant pathogens; however, they were not able to control brown spot in rice leaves in the experimental conditions used.

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21

Travaglini, Raphael Vacchi. "Bases para o controle microbiano de formigas cortadeiras." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/152256.

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O controle biológico tem recebido atenção dos pesquisadores, principalmente devido aos movimentos, de preservação do ambiente. Têm sido amplamente aplicado em espécies consideradas importantes pragas agrícolas, porém não indicado para as formigas cortadeiras. Tais formigas apresentam um conjunto de estratégias físicas, químicas e comportamentais que as operárias realizam a fim de evitar a própria contaminação e da colônia. Entretanto alguns microorganismos conseguem causar mortalidade de alguns membros da colônia, como os fungos entomopatogênicos. Pretende-se fornecer conhecimentos básicos para desenvolvimento de novas estratégias de controle microbiano das formigas cortadeiras em um futuro próximo. Para tanto estudamos quatro fungos com grande potencial patogênico, Metarhizium anisopliae, Beauveria bassiana, Aspergillus flavus e Trichoderma asperellus. Primeiramente foram estudados a patogenicidade dos fungos (entomopatogeno e oportunista) em operarias isoladas da colônia. Estudou-se a susceptibilidade de larvas e adultos de formigas cortadeiras Atta sexdens rubropilosa a conídios de B. bassiana, por meio de técnicas histológicas e de microscopia. Finalmente encapsulados com conídios foram veiculados para o jardim de fungo simbionte visando o controle de mini colônias em laboratório. Propomos a elaboração de novas alternativas aos manejos existentes.

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22

Na, Lampang Acharaporn. "Study on interactions between Sclerotium rolfsii Sacc. and selected antagonists." Title page, table of contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phn165.pdf.

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23

Fabry, Cléia de Fátima Silva. "Controle de Meloidogyne javanica por rizobactérias de plantas antagonistas a fitonematóides." Universidade Federal de Viçosa, 2002. http://www.locus.ufv.br/handle/123456789/11307.

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Uma amostra de solo com alto teor de matéria orgânica foi dividida em frações de 1 kg e estas foram submetidas ao tratamento térmico em autoclave (120°C/1 h), em forno de microondas (4min) ou não tratadas (natural). Raízes de Mucuna aterrima, Crotalaria juncea, Tagetes erecta e Lycopersicon esculentum foram maceradas em liquidificador, peneiradas e os sucos resultantes foram adicionados, separadamente, aos três tipos de solo, aguardando-se 24h a 28°C. Isolados bacterianos foram obtidos por diluição serial como descrito por ROMEIRO (2001), a partir de suspensão aquosa de cada substrato, obtendo-se 78 isolados de rizobactérias. As rizobactérias foram submetidas à seleção massal em que sementes de tomate foram microbiolizadas por imersão em suspensão de propágulos de cada uma das culturas, semeadas e o solo foi infestado com M. javanica. Dos 78 isolados, 56 reduziram o número de galhas e 22 não apresentaram diferença significativa em relação ao controle. Quanto ao número de ovos presentes nas raízes, 26 isolados ocasionaram a redução, 43 não diferiram do controle e nove estimularam a formação. O isolado UFV-6 reduziu o número de galhas em maior proporção (80%) ao passo que o isolado UFV-8 foi o mais eficiente na redução do número de ovos (83%). Ambos os isolados foram provenientes do tratamento térmico de solo em microondas acrescidos do suco de raízes de T. erecta e de M. aterrima, respectivamente. Em contraposição, o isolado UFV-48 foi o mais deletério. Os dez isolados mais promissores foram reavaliados, em recipientes maiores pela inoculação com 1000 ovos de M. javanica por tubete e com 10 repetições. Não foi encontrada diferença no que tange ao número de galhas, mas os isolados UFV-41 e UFV-8 foram os mais eficientes em reduzir o número de ovos (35,3% e 35,0%, respectivamente). Os isolados UFV-29 e UFV-31 permitiram o aumento do número de ovos. Para investigar se o tipo de substrato pode potencializar a capacidade antagonista dos isolados UFV-8 e UFV-57 a M. javanica, comparou-se solo de terriço de mata com solo de barranco, com 15 repetições por tratamento. Os isolados reduziram galhas em 34,9% e 36,4% no solo de terriço e 41,5% e 35,3% em solo de barranco, respectivamente, não apresentando diferença significativa quanto ao tipo de substrato. Avaliou-se também a inibição da eclosão de juvenis in vitro. Os isolados mais eficientes na inibição de eclosão foram UFV-6 e UFV-53 reduzindo a eclosão em 64,9% e 85,7% respectivamente.
Five 1-kg samples of organic soil were autoclaved at 120°C for 1 hour, five were microwaved in a 660 watts and 2450Hz microwave oven at full power for 4 minutes, and five were not heat-treated. Roots of Mucuna aterrima, Crotalaria juncea, Tagetes erecta and Lycopersicon esculentum were macerated, separately, in 1000 mL of tap water in a blender at low speed for 30 seconds, sieved, and each of the resulting juices, or just tap water (control treatment) was poured on one of the treated and non-treated soil, inside of a plastic bag (5x3 factorial design). Each plastic bag was closed and vigorously shaken to mix the juice with the soil, and placed in the incubator at 28°C for 24 hours. Seventy eight bacterial isolates were obtained from all the soils by serial dilution. The screen of isolates for the biocontrol of Meloidogyne javanica was made by allowing tomato seeds to soak in water suspension of each bacterial isolate sowing them in substrate inside plastic tubes in the greenhouse, and inoculating the resulting seedlings with nematode eggs. Fifty six isolates promoted reduction of the number of root galls compared to the control treatment (seeds soaked in distilled water). Twenty six isolates promoted reduction of the number of nematode eggs per root system. The isolate UFV-6 was the most effective in reducing the number of galls (80% less than the control), and UFV-8 was the most effective in reducing egg numbers (83% reduction). Both isolates came from microwaved soil, but the UFV-6 was isolated from soil amended with T. erecta root juice and the UFV-8 from soil amended with M. aterrima root juice. The UFV-48, isolated from non-heated soil amended with tomato root juice was the most deleterious, increasing the number of eggs in 134,3% compared to the control treatment. The ten most effective isolates were re-evaluated in larger recipients (400 mL plastic pots) by the inoculation with 1,000 M. javanica eggs per plant (one plant/pot) and 10 replicates per treatment. There was no statistical difference among treatments for the number of galls, but the number of eggs was reduced in 35,3% and 35% by the UFV-41 and the UFV-8, respectively. The isolates UFV-29 and UFV-31 promoted increase in the number of eggs. In order to investigate if the substrate type has influence in the performance of the rhizobacteria, two effective isolates, the UFV-8 and the UFV-57 were tested in a highly organic soil and in a B horizon soil, with 15 replicates. They promoted gall reductions of 34,9% and 36,9% in the organic soil and 41,5% and 35,3% in the B horizon soil, respectively. Both treatments differed from the control, but did not differ from each other. The effect of ten good candidates and ten deleterious ones on the M. javanica egg hatch was evaluated in vitro. The UFV-6 and UFV-53 were the most effective, reducing egg hatch in 64,9% and 85,7%, respectively.

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24

Stefanelo, Daniela Rossato. "Doses, ambiente e forma de infecção causada por fusarium solani f.sp. chrysanthemi em crisântemo (dendranthema grandiflora) cv. calabria e seu controle por trichoderma virens." Universidade Federal de Santa Maria, 2004. http://repositorio.ufsm.br/handle/1/5138.

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Fusarium wilt has been damaging the chrysanthemum crop in the central region of Rio Grande do Sul, especially in those cultivated in greenhouse. Four experiments were done with the objective of studying the effect of doses, environment, and forms of infection of Fusarium solani f. sp. chrysanthemi in chrysanthemum and its control by Trichoderma virens. In the first experiment, the objective was to select the inoculum quantity of F. solani f. sp. chrysanthemi needed to infect chrysanthemum plants cv. Calabria and 6g/600 g of soil was found to be the most damaging to the plants. In the second experiment, the inoculation of the pathogen by soil infestation or root immersion, with and without physical damage of the roots, was tested. There was no difference between the inoculation forms and the plants with damaged roots showed less growth. In the third and fourth experiments six isolates and five doses of biological powders of Trichoderma virens were tested in the control of the Fusarium wilt and the growth of plants. Since the plants did not show symptoms of Fusarium, it was not possible to determine the best doses of Trichoderma to control the disease and the utilization of the biological powders interfered negatively in the growth of chrysanthemum plants cv. Calabria.
A murcha de Fusarium tem causado danos à cultura do crisântemo na região central do Rio Grande do Sul, especialmente nos cultivos em ambiente protegido. Quatro experimentos foram desenvolvidos com o objetivo de estudar o efeito de doses, ambiente e formas de inoculação de Fusarium solani f. sp. chrysanthemi em crisântemo, e seu controle por Trichoderma virens. No primeiro experimento, objetivou-se selecionar a quantidade de inóculo de F. solani f. sp. chrysanthemi necessária à infecção de plantas de crisântemo cv. Calabria, sendo que 6g/600g de solo foi considerada a mais prejudicial às plantas. No segundo experimento, foi testada a inoculação do patógeno por infestação do solo ou imersão de raízes, em presença ou não de dano nas raízes. Não houve diferença entre as formas de inoculação e as plantas com dano nas raízes apresentaram menor desenvolvimento. No terceiro e quarto experimentos, foram testados seis isolados e cinco doses de pós contendo inóculo de Trichoderma virens no controle da murcha de Fusarium e no desenvolvimento das plantas. Em decorrência da ausência de sintomas de Fusarium, não foi possível determinar a melhor dose de Trichoderma para o controle da murcha e a utilização dos pós de Trichoderma interferiu negativamente no crescimento das plantas de crisântemo cv. Calabria.

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25

Ordon, Violetta. "Field evaluation of fungal antagonists for the reduction of inoculum of Venturia inaequalis (Cke.) Wint." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21616.

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The use of a biofungicide on the perfect stage of V. inaequalis on leaf litter is one potential way to reduce the number of fungicides used to control apple scab. The previous in vitro screenings of Quebec mycoflora have shown that several isolates are able to significantly reduce the primary inoculum of the pathogen. Among the screened fungi, P176A and P130A, reduced over 98% of the ascospore production and were as effective as Athelia bombacina. However, because in vitro tests are generally poor predictors of in vivo assays a re-evaluation of the antagonists was done under field conditions. Eight fungal isolates, leaf shredding, and two comparative treatments (A. bombacina, 5% urea) were applied to intact scabbed leaves in October 1994 and 1995. After the treatments, the leaves overwintered on the orchard ground until the next spring. In April, samples of treated leaves were randomly selected and placed in spore traps to collect the ejected ascospores during rainfall. Since the primary inoculum was ejected during a four-month period, antagonism was based upon ratings taken throughout the whole ejection season. To evaluate the effect of incubation conditions on the antagonistic performance we incubated separately, in vitro and in vivo, sterile leaf disks which were artificially inoculated with V. inaequalis and fungal isolates. (Abstract shortened by UMI.)

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26

Philion, Vincent. "The screening of potential fungal antagonists of pseudothecial formation by the apple scab pathogen : Venturia inaequalis." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22791.

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In 1992, a research program was initiated to select suitable antagonists against the saprophytic (or winter) phase of the apple scab pathogen, Venturia inaequalis. An improved method for the mass screening of a vast collection of fungi was developed for this purpose. Some of the previously reported criteria such as leaf rheology and overwintering structure production proved unreliable or fastidious and cannot be used for in vitro antagonist selection. The main antagonism selection criterium retained was the in vitro inhibition of ascospore formation. To measure ascospore production, a simplified method of in vitro pseudothecia production was devised. This new method eliminates the need for prior conidia production by using a mycelial suspension and greatly reduces the risks of sterile mating by using a cocktail of Venturia inaequalis strains of different origins. Finally, the production cycle duration was reduced by varying the incubation temperature during the simulated winter. Moreover, a quick and efficient method of ascospore collection was developed. Ascospores were forcibly ejected in a large scale bubbler type apparatus in only one hour. This bubbler can be used for other studies including axenically produced ascospores. This new method compared favourably to the previously reported method and was used to screen a collection of about forty-two fungi. Six proved to significantly reduce the ascospore production of Venturia inaequalis. Two were as effective as Athelia bombacina, a previously reported antagonist of pseudothecia formation and inhibited over 98% of the ascospore production. These new organisms are now available for future field tests. Future selections from a large collection of saprophytes can now be based on a reliable and simple in vitro screening methodology.

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Santos, Deise Regina dos. "Isolamento e seleção de bactérias antagonistas a fitopatógenos e detecção de genes associados à produção de compostos bioativos." Universidade Federal de Sergipe, 2014. https://ri.ufs.br/handle/riufs/3037.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Soil is a structurally complex environment and an important reservoir of microbial diversity. Only a small portion of this diversity has been recovered and cultured by conventional techniques, which limits the access to genetic and metabolic information in such microorganisms. Soil bacteria synthesize a wide variety of secondary metabolites, particularly of antibiotics. Polyketide synthase (PKS) and non-ribosomal peptide synthetase have been highlighted as important enzymatic systems for the biosynthesis of these compounds. The detection of genes associated with these two biosynthetic systems in bacterial isolates has become a strategy to screening for antagonists with high biological control activity. Therefore, the objective of this study was to evaluate bacterial isolates for their in vitro antagonistic activity against plant pathogens of agricultural interest and to analyze their genomes for the presence of genes associated with the synthesis of bioactive compounds activity. Methods of soil sample pre-treatment with chloramine-T and phenol were used for selective isolation and followed by preliminary qualitative antibiosis tests of isolates against the fungal pathogens Thielaviopsis paradoxa and Plenodomus destruens. Extracellular extracts from isolates selected in this previous step were further evaluated for the in vitro antagonist potential against Thielaviopsis paradoxa, Plenodomus destruens and Xanthomonas campestris and compared with the active ingredient of a commercial biofungicide. The taxonomic affiliation of the antagonistic isolates was assessed by sequencing of 16S rDNA gene. For the detection of PKS and NRPS genes, degenerate primers described in the literature were used. Two hundred and fifty-seven bacterial isolates, in their majority belonging to the genus Bacillus or similar, were obtained. Out of those, 84 (33%) were simultaneously bioactive for both fungi in qualitative tests. Fourty-eight bacterial isolates had extracellular extracts with inhibitory effects against Thielaviopsis paradoxa, with eight of these with inhibition ≥80%, when compared to the control. Plenodomus destruens was inhibited by the extracellular extracts of 63 isolates, of which 10 inhibited ≥80% of this pathogen growth. The extract of a Bacillus isolate from a commercial biofungicide strongly inhibited P. destruens (95%), but had no effect on T. paradoxa. Thirty antagonistic isolates from this study did not differed from this commercial isolate regarding in vitro growth inhibition of P. destruens by their extracts of 27 isolates inhibited X. campestris (inhibition rates varying from 45 to 100%), of which six completely suppressed the growth of this bacteria. There was no relationship between either the presence of PKS genes or the joined occurrence of NRPS and PKS and the inhibitory action of the strains on the relative growth of the pathogens. Only the presence of NRPS genes was associated with the effect on the relative growth of Thielaviopsis paradoxa. The isolation of bacteria with promising bioactive potential associated with experiments at greenhouse and field attesting to the feasibility of its use, will enable the achievement of new biocontrol agents.
O solo é um ambiente estruturalmente complexo e um importante reservatório da diversidade microbiana. Somente uma pequena proporção desta diversidade tem sido recuperada e cultivada por técnicas convencionais, o que limita o acesso às informações genéticas e metabólicas desses micro-organismos. Bactérias do solo sintetizam uma ampla variedade de metabólitos secundários, em particular de antimicrobianos. Sintases de policetídeo (PKS) e da sintetases de peptídeo não-ribossomal (NRPS) têm se destacado como importantes sistemas enzimáticos para a biossíntese destes compostos. A detecção de genes associados com estes dois sistemas biossintéticos em isolados de bactérias é uma estratégia para a seleção de antagonistas com alta atividade de controle biológico. Diante disso, o objetivo deste estudo foi isolar e avaliar o potencial dos isolados quanto à atividade antagônica in vitro frente a fitopatógenos de interesse agrícola, e analisar em seus respectivos genomas a presença de genes associados à síntese de compostos bioativos. Métodos de pré-tratamentos das amostras de solo com cloramina T e fenol foram utilizados para o isolamento e seguidos por testes de antibiose qualitativos frente aos fitopatógenos fúngicos Thielaviopsis paradoxa e Plenodomus destruens. Filtrados extracelulares dos isolados selecionados nesta etapa foram quantitativamente avaliados a seguir quanto à capacidade de inibição de T. paradoxa, P. destruens e Xanthomonas campestris, e comparados com o ingrediente ativo de um biofungicida comercial. A afiliação taxonômica dos isolados antagonistas foi realizada com base nas sequências parciais do gene DNAr 16S. Para a detecção dos genes PKS e NRPS foram utilizados primers degenerados descritos na literatura. Dos 257 isoladas bacterianos obtidos, a grande maioria foi pertencente ao gênero Bacillus ou outros proximamente afiliados. Destes, 84 (33%) foram inibitórios de ambos os fungos nos testes qualitativos. Quarenta e oito isolados bacterianos apresentaram filtrados extracelulares com efeitos inibitórios contra T. paradoxa, com oito destes com inibições de mais de 80% comparativamente ao controle sem filtrado. P destruens foi inibido pelo filtrado extracelular de 63 isolados, dos quais 10 inibiram mais de 80% do crescimento deste patógeno. O extrato do isolado de Bacillus do biofungicida comercial apresentou forte inibição sobre P. destruens (95%), mas não afetou T. paradoxa. Trinta isolados antagonistas deste estudo não diferiram deste isolado comercial com relação à inibição do crescimento in vitro de P. destruens pelos extratos. Extratos de 27 isolados inibiram X. campestris (inibições entre 45 e 100% do crescimento), dos quais seis suprimiram totalmente o crescimento desta bactéria. A presença dos genes PKS ou a presença conjunta de genes de NRPS e PKS não foram associadas à ação inibitória dos isolados em relação ao crescimento relativo dos três fitopatógenos. Somente a presença do NRPS associou-se ao efeito sobre o crescimento relativo do Thielaviopsis paradoxa. O isolamento de bactérias com potencial bioativo promissor associado a experimentos em casa-de-vegetação e em campo que atestem a viabilidade do seu uso possibilitará a obtenção de novos agentes de biocontrole.

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Kabir, Nasreen Zahan. "Selection of effective antagonists against Rhizoctonia solani (AG-3), the causal agent of Rhizoctonia disease of potato." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27351.

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Rhizoctonia solani (AG-3), the causal agent of Rhizoctonia disease of potato, overwinters as sclerotia on potato tubers. To develop a biocontrol strategy based on the prevention of the sclerotial germination, an isolation of microorganisms colonizing sclerotia of infected potato tubers (cultivars Norland, Atlantic and Souris), was conducted. In vitro screening was used to select effective antagonistic fungi against Rhizoctonia solani. Fifty fungal isolates were selected in order to cover all identified genera and potato variety and examined for their ability to inhibit germination of sclerotia which were incubated with the test fungus for 14 days. Twenty-four (24) fungal isolates were retained based on their ability to reduce sclerotial viability by more than 50% as compared with 100% viability of untreated sclerotia. These 24 isolates were further examined for their ability to protect Table beet seedlings against the pathogen in greenhouse soils. Based on their ability to protect Table beet seedlings from Rhizoctonia infections and to increase the number of secondary roots and root length isolates, F2, F11, F132, F158, and F258 were screened and test their efficacy to increase beet seed germination in field soils. (Abstract shortened by UMI.)

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Podestá, Guilherme Silva de. "Interação entre Pochonia chlamydosporia e rizobactérias no controle de Meloidogyne javanica." Universidade Federal de Viçosa, 2015. http://www.locus.ufv.br/handle/123456789/6316.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Fitonematoides são patógenos de difícil manejo, extremamente importantes para a agricultura mundial. Entre as medidas de manejo utilizadas, o controle biológico tem ganhado espaço, principalmente pela maior conscientização acerca dos malefícios causados pelos nematicidas químicos à saúde humana e ao meio ambiente. No presente trabalho, avaliou-se a compatibilidade entre o fungo nematófago Pochonia chlamydosporia e isolados bacterianos obtidos em raízes de plantas antagonistas no manejo de Meloidogyne javanica em casa de vegetação, bem como a utilização de substrato sólido para a multiplicação do isolado bacteriano selecionado para o controle de nematoides. Testando o efeito de Pochonia chlamydosporia, Gracilibacillus dipsosauri e de um condicionador de solo organo-mineral no controle de Meloidogyne javanica em tomateiro, observou-se que na interação dos três tratamentos, e na interação entre G. dipsosauri e P. chlamydosporia, a redução no número de galhas radiculares causadas pelo nematoide foi de 48 e 41% respectivamente. Os tratamentos com G. dipsosauri e P. chlamydosporia + Ribumin proporcionaram redução de 26 e 21% no número de ovos respectivamente. A interação entre o fungo nematófago e a rizobactéria foi positiva para o controle do nematoide, apesar do fato de G. dipsosauri ter inibido o crescimento do fungo P. clamydosporia em até 30% em teste in vitro. Avaliando o controle de M. javanica em tomateiro com bactérias endofíticas, observou-se que dos 51 isolados obtidos, 18 foram eficientes em reduzir o número de galhas de M. javanica, resultando em 51 a 75% de controle em relação à testemunha. Cinco isolados reduziram o número de massas de ovos de 65 a 75% em relação ao tratamento testemunha. Os tratamentos com os isolados Cs-2, Cs-12 e Mc-3 causaram 22, 24 e 27% de imobilidade nos J2 de M. javanica respectivamente. Os isolados Cs-2, Cp-5 e Mc-3, quando aplicados via irrigação do solo, reduziram em até 46% o número de galhas de M. javanica. Além disso, o isolado Mc-3 mostrou-se eficiente também na microbiolização de sementes, reduzindo grandemente a multiplicação do nematoide no interior das raízes. O fungo P. chlamydosporia não produziu compostos antibióticos contra os isolados bacterianos testados e os isolados Cs-2, Cs-12, Cp-1 e Mc-3 foram os que apresentaram maior compatibilidade nos testes de antibiose, efeito dos compostos voláteis e confrontação direta realizados in vitro. Quando aplicados via microbiolização de sementes, observou-se que o tratamento com a bactéria Mc-3 proporcionou redução de 23% no número de ovos do nematoide. A combinação da bactéria Cs-2 com Pc-10 proporcionou redução de 31% e a combinação das três bactérias com P. chlamydosporia proporcionou redução de 37%. Na aplicação via irrigação, Pc-10 isoladamente reduziu o número de galhas em 33% e quando associado a Mc-3, em 30%. Já quanto ao número de ovos por sistema radicular, as reduções foram de 64, 60 e 49% quando o solo foi tratado com Mc-3, Pc-10 e na interação de ambos, respectivamente. Por fim, nos testes para produção de esporos do isolado Mc-3 (Bacillus sp.) em meio sólido, observou-se que a aplicação de 100 mL de água nos sacos contendo 300g de arroz em pré autoclavagem, seguido da aplicação de suspensão bacteriana e incubação por 5 dias a 30° é eficiente em produzir C esporos de Mc-3, gerando em média 1 x 109 esporos por grama de arroz. A adição de meios de cultura líquidos à suspensão bacteriana pós autoclavagem não resultou em aumento da produção. Já a aplicação de doses crescentes de farelo de soja ao arroz, mostrou que a aplicação de 10-20 g de farelo de soja por saco, proporciona aumento da produção de esporos de Mc-3.
Plant-parasitic nematodes are unwieldy pathogens, extremely important for global agriculture. Among the management measures used, biological control has gained ground, mainly due to increased awareness of the harm caused by chemical nematicides to human health and the environment. In this study, were evaluated the compatibility between the nematophagous fungus Pochonia chlamydosporia (Pc-10) and bacteria isolated from nematode-antagonistic plant roots in the management of Meloidogyne javanica in the greenhouse, and the use of solid substrate for multiplication of selected bacterial isolate for the control of nematodes. Testing the effect of Pochonia chlamydosporia, Gracilibacillus dipsosauri and an organo-mineral soil conditioner in the control of Meloidogyne javanica in tomato plants, it was observed that the interaction of the three treatments, and the interaction between G. dipsosauri and P. chlamydosporia, reduction the number of root galls caused by the nematode was 48 and 41%, respectively. Treatments with G. dipsosauri and P. chlamydosporia + soil conditioner resulted in the reduction of 26 and 21% of the number of eggs, respectively. The interaction between the nematophagous fungi and rhizobacteria was positive for controlling nematode, despite the fact that G. dipsosauri inhibited the growth of the fungus P. clamydosporia by 30% in vitro test. Evaluating the control of M. javanica in tomato with endophytic bacteria, it was observed that from the 51 isolates obtained, 18 were effective in reducing the number of galls caused by M. javanica, resulting in 51-75% control when compared to the control treatment. Five isolates reduced the number of egg masses from 65 to 75% when compared to the control treatment. The treatments with the isolates Cs-2, Cs-12 and Mc-3 caused 22, 24 and 27% in immobility J2 of M. javanica respectively. The isolates Cs-2, Cp-5 and Mc-3, when applied via irrigation of the soil, reduced the number of galls of M. javanica by 46%. Furthermore, the isolate Mc-3 was also efficient when used through seed treatment, greatly reducing nematode multiplication in the roots. The fungus P. chlamydosporia did not produce antibiotic compounds against the bacterial isolates, and Cs-2, Cs-12, Cp-1 and Mc-3 isolates had the highest compatibility with the fungus in antibiosis, effect of volatile compounds and direct confrontation tests, performed in vitro. When applied to seeds, it was observed that treatment with Mc-3 bacterium gave 23% of reduction in the number of nematode eggs. The combination of Cs-2 bacteria and Pc-10 gave a reduction of 31%, and combining the three bacteria with P. chlamydosporia gave 37% reduction. When the antagonists where applied through soil irrigation, the number of galls caused by M. javanica was reduced by 33 and 30% for Pc- 10 alone and in combination with Mc-3, respectively. As for the number of eggs per root system, the reductions were 64, 60 and 49% when the soil was treated with Mc-3, Pc-10 and the interaction of both, respectively. Finally, in tests for the production of the Mc-3 (Bacillus sp.) spores in solid state fermentation, we observed that the application of 100 ml of water in bags containing 300g of pre- autoclaved rice, followed by the application of bacterial solution and incubated for 5 days at 30° is effective in producing Mc-3 spores, generating an average C of 1 x 109 spores per gram of rice. The addition of liquid culture media after autoclaving the bacterial solution did not result in increased production. The application of increasing doses of soybean meal into the rice showed that the application of 10-20 g of soybean meal provides increases in the production of Mc-3 spores.

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Fialho, Mauricio Batista. "Mecanismos de ação de compostos orgânicos voláteis antimicrobianos produzidos por Saccharomyces cerevisiae sobre o desenvolvimento de Guignardia citricarpa, agente causal da pinta preta dos citros." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11138/tde-12022009-085637/.

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A pinta preta dos citros tem como agente causal o fungo G. citricarpa. A doença causa depreciação estética dos frutos e praticamente inviabiliza a exportação de laranja in natura principalmente para a União Européia, por ser considerada uma doença quarentenária. Frutos colhidos contendo infecções quiescentes, embora sem sintomas, podem desenvolvê-los durante o processo de exportação. A utilização de fungicidas é o principal método de controle utilizado em pré e pós-colheita. No entanto, o custo do controle químico é significativamente alto e já foi relatado o surgimento de isolados resistentes. A levedura S. cerevisiae é capaz de inibir o desenvolvimento in vitro de G. citricarpa e o antagonismo se deve a produção de compostos orgânicos voláteis de ação fungistática. Em virtude da procura por novos métodos de controle menos danosos à saúde humana e meio ambiente, dos prejuízos causados pela doença e do potencial dos compostos voláteis no controle da doença na pós-colheita, o trabalho visou identificar os compostos voláteis produzidos pela levedura e elucidar os mecanismos envolvidos na inibição do fitopatógeno. Esse conhecimento é fundamental para o desenvolvimento de técnicas inovativas de controle. A produção de compostos voláteis antimicrobianos por S. cerevisiae foi dependente do substrato utilizado para o seu cultivo, sendo a glicose, sacarose e maltose fontes de carbono favoráveis. Foi verificado através da análise em SPME-GC-MS que a levedura produziu em meio BDA, principalmente compostos pertencentes ao grupo dos álcoois, constituindo 95% da composição total, além de ésteres em menor proporção. A mistura artificial de voláteis mimetizou os efeitos dos voláteis produzidos pela levedura, sendo os valores de MIC50 e MIC100 de 0,48 µL mL-1 e 2,84 µL mL-1, respectivamente. A exposição do fitopatógeno aos compostos voláteis reduziu a síntese de proteínas e inibiu a atividade de enzimas associadas à morfogênese (quitinase, b-1,3-glucanase, lacase e tirosinase). Os compostos voláteis desencadearam o processo de estresse oxidativo no fungo, fato observado através da elevação da atividade de enzimas (superóxido dismutase e catalase) associadas a mecanismos de detoxificação de espécies ativas de oxigênio. A análise das proteínas diferencialmente expressas de G. citricarpa, através de eletroforese bidimensional, indicou que os compostos voláteis alteraram a expressão de 40 proteínas, sendo 29 inibidas e 11 superexpressas. A mistura artificial de voláteis também foi ativa contra fungos de diversos grupos taxonômicos, no entanto, não apresentou atividade sobre as bactérias testadas. Os compostos 3-metil-1-butanol e 2- metil-1-butanol foram os mais ativos quando utilizados isoladamente contra Colletotrichum gloesporioides, Penicillium digitatum, Sclerotinia sclerotiorum e Fusarium oxysporum. Sementes de feijão fumigadas com a mistura artificial de voláteis exibiram redução na incidência de S. sclerotiorum. A mistura também exibiu efeito nematicida sobre Meloidogyne javanica. Portanto, os resultados demonstram que os voláteis identificados em S. cerevisiae afetam a síntese de proteínas e a atividade de enzimas associadas ao crescimento vegetativo de G. citricarpa. Finalmente, fumigação utilizando compostos voláteis apresenta potencial no controle de G. citricarpa em pós-colheita, bem como de outros organismos de importância agronômica. O trabalho também contribuiu com novos elementos sobre o papel dos voláteis na interação entre microrganismos na natureza.
The citrus black spot has as causal agent the fungus G. citricarpa. The disease causes aesthetic depreciation of fruits and practically makes them unviable for exportation mainly to European Union where the disease is considered a quarantine pest. Harvested fruits can have quiescent infections although without symptoms and can develop them during the exportation process. The use of fungicides is the main chemical control method used in pre and post-harvest, however the cost is significantly high and it was already described the development of fungicide resistant strains. The yeast S. cerevisiae is able to inhibit the in vitro G. citricarpa growth, and the antagonism is due to production of volatile organic compounds (VOCs) of fungistatic effect. Because of the search for new control methods less harmful for human health and environment, the losses caused by the disease and the potential of the VOCs in the control of the pathogen in the post-harvest, the aim of this work was to identify the VOCs produced by the yeast and to elucidate the mechanisms involved in the inhibition of the fungus. This knowledge is essential for the development of innovative control techniques. The results showed that the production of antimicrobial VOCs by S. cerevisiae was dependent on the substrate used, being glucose, sucrose and maltose favorable carbon sources. It was verified through analysis in SPME-GC-MS that the yeast, grown on PDA medium, produced mainly compounds belonging to the group of alcohols (95% of the total composition), besides esters in smaller proportion. An artificial volatile mixture reproduced the effects of the VOCs produced by the yeast, being the values of MIC50 and MIC100 of 0.48 µL mL-1 and 2.84 µL mL-1, respectively. The phytopathogen exposition to the VOCs reduced protein synthesis and inhibited the activity of morphogenesis associated enzymes like chitinase, b-1,3-glucanase, laccase and tyrosinase. The VOCs initiated the oxidative stress process, which was observed through the increase in the activity of superoxide dismutase and catalase, enzymes associated to the detoxification of active oxygen species. The analysis of the differentially expressed proteins of G. citricarpa, through two-dimensional gel electrophoresis, indicated that the VOCs modified the expression of 40 proteins, being 29 down regulated and 11 up regulated. The artificial mixture of VOCs was also active against fungi of several taxonomic groups, however, there were no activity against bacteria. The compounds 3-methyl-1-butanol and 2-methyl-1-butanol were the most active when tested alone against Colletotrichum gloesporioides, Penicillium digitatum, Sclerotinia sclerotiorum and Fusarium oxysporum. Bean seeds fumigated with the artificial mixture of VOCs showed reduction in S. sclerotiorum incidence. In addition, the VOCs exhibited nematicidal effect against Meloidogyne javanica. The results demonstrate that the VOCs produced by S. cerevisiae affect protein synthesis and the activity of enzymes associated to the vegetative growth in G. citricarpa. Thus, the fumigation using VOCs presents potential in the control of citrus black spot disease in post-harvest as well as of other organisms of agronomic importance. The present workalso contributed with new information regarding the role of the VOCs in the interactions among microorganisms in nature.

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Maia, Cláudio Belmino. "Supressão da murcha-vascular do feijoeiro por microrganismos antagonistas." Universidade Federal de Viçosa, 2004. http://www.locus.ufv.br/handle/123456789/10174.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O presente trabalho objetivou investigar o potencial de uso do controle biológico no patossistema F. oxysporum f. sp. phaseoli e feijão a partir das seguintes etapas: 1-Selecionar um isolado de F. oxysporum não-patogênico (FO), um isolado de Trichoderma sp. (TR) e outro de Pseudomonas fluorescentes (PF) mais competentes e com alta competitividade rizosférica. 2-Estudar o efeito do tratamento de sementes de feijão com isolados selecionados de Pseudomonas fluorescentes, no desenvolvimento da murcha-vascular. 3-Estudar a relação entre a densidade de inóculo de F. oxysporum f. sp. phaseoli e de F. oxysporum não- patogênicos adicionada no solo para supressão da forma patogênica. 4-Estudar, em solo infestado com F. oxysporum f. sp. phaseoli, o efeito combinado de sementes de feijão tratadas com a bactéria e plantadas em solo infestado com F. oxysporum não-patogênico em casa de vegetação, no desenvolvimento da murcha-vascular. 5-Estudar, em solo infestado com F. oxysporum f. sp. phaseoli, o efeito combinado de sementes de feijão tratadas ou não-tratadas com a bactéria e plantadas em solo infestado com F. oxysporum não-patogênico ou Trichoderma sp. e o efeito de cada potencial antagonista sozinho, no campo, no desenvolvimento da murcha-vascular. Foram testados três isolados de FO, 11 de TR e 150 de PF, obtidos da rizosfera (80), rizoplano (30) e internamente as raízes (40). Nos testes de antibiose “in vitro” foram selecionados 22 isolados de PF e nos testes posteriores de competência e competitividade selecionou-se o isolado PF22 (Pseudomonas putida). Testando-se a competência e competitividade de FO e TR foram selecionados os isolados TR11 de Trichoderma (T harzianum) e FO3 de Fusarium não patogênico. Observou-se que não teve diferença entre as concentrações de FO para um mesmo isolado, no entanto, foi observada diferença entre os isolados e destes com o controle. O isolado FO3 teve uma maior área abaixo da curva de decréscimo da clorofila (AACDCL) para as clorofilas A, B e total (5,38, 1,71 e 7,10, respectivamente), menor severidade da doença (2,37) e maior produção de grãos (6,65g) em relação ao FOPm sozinho, com AACDCL de 2,41, 0,87 e 3,25, respectivamente, severidade 4,25 e produção de grãos de 2,23g. O isolado PF22 sozinho não reduziu a severidade da doença. Quando FO3 e PF22 foram usados em conjunto obteve-se uma maior AACDCL paras as clorofilas A, B e total (4,52, 1,05 e 5,57, respectivamente), maior produção de grãos (12,59g) e redução da severidade da doença (2,50) enquanto que FOPm sozinho teve AACDCL de 0,92, 0,23 e 1,16, respectivamente, severidade de 4,30 e produção de 5,71g de grãos. No campo, os isolados TR11 e FO3 sozinhos ou em conjunto com PF22, não diferiram entre si quanto a AACDCL, mas diferiram do FOPm sozinho. Quanto à produção, observou-se que a associação dos microrganismos FO3 + PF22 e TR11 + PF22 não diferiram entre si, com uma produção de 15 e 14 vagens e 14,7 e 13,1 g de grãos, respectivamente. A produção do tratamento apenas com FOPm foi de 8,3 vagens e 4,5 g de grãos. Esses valores mostram um aumento de aproximadamente 200% na produção de grãos quando utilizados os microrganismos em conjunto no controle da doença no campo. A ação conjunta dos microrganismos usados neste trabalho mostrou-se uma estratégia de controle biológico promissora para a redução no solo da densidade de inóculo de F. oxysporum f. sp. phaseoli e, com isso, propiciar uma redução da ocorrência e dos danos causados por essa doença.
This study aimed to investigate the potential of the biological control upon the pathosystem F. oxysporum f. sp. phaseoli and bean, by the following procedure: 1) Selecting an isolate of non-pathogenic F. oxysporum (FO), an isolate of Trichoderma sp. (TR) and one of fluorescent Pseudomonas (FP), which should be more competent and have a higher degree of rhizosphere competitiveness; 2) Studying the effect of the seed treatment with those selected fluorescent Pseudomonas isolates upon the development of the vascular wilt; 3) Studying the relationship between the inoculum densities of the non-pathogenic F. oxysporum and pathogenic F. oxysporum f. sp. phaseoli added to the soil in order to suppress the pathogenic form. 4) Studying the combined effect of bean seed treatment with F. oxysporum f. sp. phaseoli and sowing in a non-pathogenic F. oxysporum-infested soil upon the development of the vascular wilt, under greenhouse conditions. 5) Comparing the combined effect of bean seed treatment with F. oxysporum f. sp. phaseoli or no treatment followed by sowing in soil infested by either non-pathogenic F. oxysporum or Trichoderma sp., as well as the effect of each antagonistist alone upon the development of the vascular wilt under field conditions. The following isolates were tested: three from FO, 11 from TR and 150 from PF [which were obtained from the rhizosphere (80), rhizoplane (30) and internally from the roots (40)]. In the in vitro antibiosis test, twenty two PF isolates were selected, whereas in the following tests for competence and competitiveness the isolate PF22 (Pseudomonas putida) was selected. When testing FO and TR for competence and competitiveness, the isolates TR11 from Trichodema (T. harzianum) and FO3 from the non-pathogenic Fusarium were selected. No differences were observed among the FO concentrations for the same isolate, but differences between the isolates as well as between these and the control were significant. The FO3 isolate occupied a higher area below the chlorophyll decreasing curve (AACDCL) for A, B and total chlorophylls (5.38, 1.71 and 7.10, respectively), as well as a lower disease severity (2.37) and higher bean yields (6.65g) in relation to FOPm alone, with the respective values of 2.41, 0,87 and 3,25 for AACDCL, 4.25 severity, and 2.23g for bean yield. The isolate PF22 did not reduce by itself the severity of the disease. When using FO3 and PF22 together, a higher AACDCL was obtained for the chlorophylls A, B and total (4.52, 1.05 and 5.57, respectively), as well as higher bean yields (12.59g) and reduced severity of the disease (2.50), whereas FOPm alone showed an AACDCL of 0.92, 0.23 and 1.16, respectively, 4.30 severity, and bean yield of 5.71g. Under field conditions, both the isolates TR11 and FO3 by themselves or combined with PF did not differ from each other for AACDCL, but from the FOPm alone. In relation to the yield, no differences were found for the combination of the microorganisms FO3 + PF22 and TR11 + PF22, since a total of 15 and 14 pods and 14.7 and 13.1 beans were yielded, respectively. In the treatment with FOPm alone, a total of 8.3 pods and 4.5 beans were yielded. These values show an increase of around 200% in bean yield, when the microorganisms were used in combination to control the disease in the field. In this study, the combined action of the microorganisms showed to be a promising biological control strategy for reducing the density of the F. oxysporum f. sp. phaseoli inoculum in the soil providing a reduction in both occurrence and damages caused by this disease.
Tese importada do Alexandria

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Mekbib, SB, TJC Regnier, and L. Korsten. "Efficacy and mode of action of yeast antagonists for control of Penicillium digitatum in oranges." Tropical Plant Pathology, 2011. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000688.

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Three yeast antagonists (two strains of Cryptococcus laurentii and one of Candida sake) from orange trees reduced incidence of green mold by 80 to 95% when tested in wounded orange fruits inoculated with Penicillium digitatum and incubated at 7ºC for 30 days. The yeasts inhibited conidial germination of the pathogen, but did not kill the spores. Effectiveness of the three yeasts as antagonists was associated in part with their ability to rapidly colonize wound sites, despite low nutrient availability. Observations suggested that production of extracellular matrix by the yeasts may have facilitated rapid wound colonization. Germination of P. digitatum conidia was significantly inhibited when the pathogen and antagonists were in direct physical contact in a culture suspension. The results supported the view that competition for nutrients is also a mode of action of yeasts against P. digitatum.

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Pimenta, Rute Emanuel Pita. "Pesquisa de fungos endofíticos presente em videira (Vitis vinifera L.) com capacidade antagonista contra os principais agentes causadores da doença do lenho da videira no Alentejo." Master's thesis, Universidade de Évora, 2018. http://hdl.handle.net/10174/23695.

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O trabalho teve como objetivo testar o potencial antagonista de fungos presentes em videiras do Alentejo, contra fungos patogénicos responsáveis por doenças do lenho. Foram identificados 14 isolados provenientes de ramos de videiras aparentemente saudáveis, 12 dos quais pertencentes aos géneros Alternaria, Epicoccum e Cladosporium, sendo considerados fungos endofíticos, dos quais foi testada a capacidade antagonista, e dois identificados como Botryosphaeria dothidea e Phomopsis viticola, fungos patogénicos responsáveis por doenças do lenho. Todos os isolados apresentaram capacidade antagonista contra B. dothidea nos três testes realizados. No caso de P. viticola todos os fungos apresentaram capacidade antagonista no teste de antagonismo direto e compostos voláteis, enquanto que no teste de compostos não voláteis apenas um não apresentou capacidade antagonista. Os resultados apresentados mostram o potencial antagonista dos fungos endofíticos como agentes de luta biológica; ABSTRACT: Antagonistic activity of endophytic fungi of Vitis vinifera L. against the most important grapevine trunk diseases in Alentejo The objective of this work was to test the potential antagonism of fungi present in Alentejo vines against pathogenic fungi responsible for trunk diseases. 14 isolates from apparently healthy grapevines were identified, 12 were considered endophytic fungi belonging to the genera Alternaria, Epicoccum and Cladosporium, and two were identified as Botryosphaeria dothidea and Phomopsis viticola, pathogenic fungi responsible for trunk diseases. All the isolates presented antagonistic capacity against to B. dothidea, in the direct antagonism test, the volatile compounds test and the non-volatile compounds test. In the case of P. viticola all fungi in the test of direct antagonism and volatile compounds presented antagonistic capacity, whereas in the test of non-volatile compounds only one did not present antagonistic capacity. The results presented show the potential antagonism of endophytic fungi as biological control agents.

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Casteliani, Ana Gabriele Barbosa. "Estrutura e diversidade das comunidades bacterianas associadas à Triticum aestivum L. e potencial antagonista contra os fitopatógenos Pyricularia grisea e Fusarium graminearum." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11138/tde-18042017-103056/.

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A cultura de trigo (Triticum aestivum L.) é a segunda maior do mundo e o Brasil ocupa o segundo lugar de produção na América do sul. Entretanto, a produtividade desta cultura pode ser limitada devido à ocorrência de doenças como a brusone, causada pelo fungo Pyricularia grisea e a doença denominada giberela, causada pelo fungo Fusarium graminearum Populações bacterianas associadas à rizosfera de trigo podem apresentar potencial como agentes de controle biológico de diferentes fitopatógenos. Neste contexto, esta pesquisa foi direcionada ao estudo da composição da comunidade bacteriana rizosférica do trigo e a busca por micro-organismos com potencial para o controle biológico da brusone e da giberela. Assim, para melhor compreensão das comunidades associadas ao trigo, foram realizadas coletas em duas regiões diferentes no Brasil, sendo possível a obtenção de 606 estirpes entre bactérias e actinobactérias da rizosfera do trigo e de solo de cultivo da mesma cultura. Destas, 16 apresentaram, em testes in vitro, potencial antagonista diante dos fungos fitopatogênicos Pyricularia grisea e Fusarium graminearum com diferentes porcentagens de inibição. Dez dos isolados selecionados apresentaram similaridade com a família Streptomycetaceae, porém, quatro linhagens necessitam de estudos mais detalhados, pois a similaridade foi baixa, podendo indicar uma espécie ainda não descrita; quatro linhagens demonstraram similaridade com a família Bacillaceae e dois com a família Paenibacillaceae. Na avaliação de produção de metabólitos secundários com efeito inibitório, apenas dez apresentam potencial, porém estudos mais detalhados se fazem necessários para a confirmação deste mecanismo. A análise de diversidade bacteriana demonstrou uma maior abundância do filo Actinobacteria, seguido pelo filo Proteobacteria e Acidobacteria em ambas as áreas amostradas, entretanto, o filo Acidobacteria foi o que demonstrou a maior variação entre as classes presentes nas diferentes regiões estudadas, indicando uma seleção da comunidade de acordo com a variedade do cultivar e o estádio de desenvolvimento do vegetal. A comunidade bacteriana de trigo apresenta micro-organismos com potencial para a inibição dos fungos causadores da brusone e da giberela, porém o efeito destas linhagens deve ser melhor investigado em condições de campo. A compreensão das comunidades bacterianas associadas ao trigo pode se apresentar como uma importante ferramenta para direcionar a busca por antagonistas.
Wheat (Triticum aestivum) is the second largest crop in the world and Brazil is in the second position in the ranking of production in South America. However, its productivity can be limited due to the occurrence of diseases like wheat blast, caused by the fungus Pyricularia grisea and the disease called Fusarium head blight (FHB), caused by the fungus Fusarium graminearum. Bacterial populations associated to wheat rhizosphere may have potential to act as biological control agents of different plant pathogens. In this context, this research aimed to look at wheat rhizosphere bacterial community and the pursuit of microorganisms with potential for the biological control of wheat blast and FHB. Given this, in order to study wheat bacterial communities, data collection was carried out in two different regions in Brazil, returning 606 bacterial and actinomycetes isolates from wheat rhizosphere and bulk soil. Among these,, 16 strains revealed antagonistic potential against both plant pathogens Pyricularia grisea and Fusarium graminearum, with different percentages of inhibition. Ten strains were selected out of the 16 and showed similarity with the family Streptomycetaceae, whereas four of them displayed a low similarity, requiring a deeper analysis and might indicate new species. Four isolates showed similarity with the family Bacillaceae and two with the family Paenibacillaceae. On the assessment of production of secondary metabolites with inhibitory effects, only ten strains were positive, but more detailed studies are necessary to confirm this mechanism. The analysis of bacterial diversity revealed a larger abundance of the phylum Actinobacteria, followed by the phylum Proteobacteria and Acidobacteria in both areas, however, the phylum Acidobacteria revealed more variation among its classes when both araes were compared, indicating a selection of the community according to the cultivar and the developmental stage. Wheat bacterial community presents microorganism with inhibition potential against fungi responsible for wheat blast and FHB, yet the effect of such strains should be investigated closely under field conditions. The understanding of bacterial communities associated to wheat may be seen as an important tool to help in the search for antagonists.

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Fagundes, Inaia Rhavene Freire. "Seleção de isolados de Trichoderma spp. antagonistas a Sclerotinia sclerotiorum." Universidade Federal de Viçosa, 2015. http://www.locus.ufv.br/handle/123456789/7511.

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Trichoderma spp., antagonistas a vários fitopatógenos, são comumente isoladas do solo, da rizosfera, e como endofíticos. Nosso objetivo foi selecionar isolados de Trichoderma spp. nas culturas do feijão e da soja em Minas Gerais e avaliar o antagonismo a S. sclerotiorum, agente causal do mofo-branco de ambas as culturas. Obtiveram-se 48 isolados, sendo 30 da rizosfera, 11 epifíticos, quatro endofíticos e três de restos culturais. Com base no sequenciamento das regiões ITS, TEF1-α e RPB2, incluíram-se os isolados em oito espécies de Trichoderma: 29 como T. harzianum; 5 como T. koningiopsis; 4 como T. hamatum; 4 como T. atroviride; 2 como T. asperelloides; 2 como T. longibrachiatum; 1 como T. asperellum e 1 como T. neokoningii. Oito isolados inibiram completamente o crescimento do patógeno em teste de pareamento. Oito isolados foram os mais eficientes no crescimento em meio de cultura. Vinte e quatro isolados foram os mais eficientes em parasitar escleródios no solo, com 79-99% de eficiência. Em ágar-água, 31 isolados inibiram a germinação miceliogênica entre 78-100%, e sete isolados inibiram a germinação carpogênica em mais de 85%. Sete isolados inibiram 100% a infecção em folíolos destacados e um isolado inibiu em 79% a infecção em hastes destacadas. Dois isolados de T. harzianum, UN34 e IM2, foram os mais promissores: UN34 por reduzir a sobrevivência e as germinações miceliogênica e carpogênica de escleródios; e IM2 por reduzir a infecção em folíolos e hastes destacados. De acordo com os resultados, existe um potencial dos isolados de Trichoderma spp. no controle biológico de S. sclerotiorum.
Trichoderma spp., antagonists to plant pathogens, are commonly isolated from soil, rhizosphere, and as endophytic. We aimed to select Trichoderma spp. isolates from bean and soybean crops in Minas Gerais and to evaluate their antagonism to S. sclerotiorum, the causal agent of white mold on both crops. We got 48 isolates: 30 rhizospheric, 11 epiphytic, four endophytic, and three isolates from crop debris. Based on the sequencing of ITS, TEF1-α, and RPB2 regions, the isolates were classified in eight Trichoderma species: 29 as T. harzianum, 5 as T. koningiopsis, 4 as T. hamatum, 4 as T. atroviride, 2 as T. asperelloides; 2 as T. longibrachiatum, 1 as T. asperellum, and 1 as T. neokoningii. Eight isolates completely inhibited pathogen growth in dual culture test. Eight isolates were the most efficient in growing in culture medium. Twenty-four isolates were the best in parasitizing sclerotia in soil, with 79-99% of efficiency. In water-agar, 31 isolates inhibited miceliogenic germination from 78-100%, and seven isolates inhibited the carpogenic germination by more than 85%. Seven isolates inhibited 100% infection on detached leaflets and one isolate inhibited 79% infection on detached stems. Two isolates of T. harzianum, UN34 and IM2, were the most promising: UN34 for reducing the survival and both miceliogenic and carpogenic germination of sclerotia; and IM2 for reducing infection in both leaflets and stems. According to the results, there is a potential of the isolates of Trichoderma spp. in the biocontrol of S. sclerotiorum.

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Silva, Rafael Salomão da. "Bactérias de solos supressivos com atividade antimicrobiana sobre Xanthomonas campestris pv. campestris." Universidade Federal de Sergipe, 2016. https://ri.ufs.br/handle/riufs/3021.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Xanthomonas campestris pv. campestris is a phytopathogenic bacterium, the causative agent of black rot in crucifers. For the control of plant pathogens diseases, there is the use of bacteria with activity antagonistic to the pathogen. Recent studies show that Bacillus species have on X. campestris a strong biological control. One of the mechanisms of this control is the production of secondary metabolites by these species. The objective of this work was to select bacteria X. campestris and antagonists to evaluate the antimicrobial activity of extracellular filtered bacteria (FEB) antagonist activity. To this, 257 bacteria isolated from a suppressive soil. They were evaluated in vitro antagonist activity by the technique of double layer. Ninety-two isolates (44.6%) were able to inhibit growth of the target pathogen (X.campestris). Of the 92 isolates selected on double layer of the test, 51 (55.43%) showed inhibition of growth of X. campestris on the inhibition assays with FEB in liquid medium. Thirteen of 50% or more inhibited the growth of the target pathogen, and the FEB-8, FEB-31-FEB 68, FEB 74-FEB-87 and were able to inhibit 100% growth of X. campestris. The FEB isolated TC-DT08, belonging to the genus Paenibacillus, it was used for in vivo tests in plant farming kale. The artificial inoculation kale with X. campestris pretreated with FEB-08 showed that the bacterium loses the ability to colonize and cause the cabbage black rot, indicating the potential use of this isolate to protect kale butter infection by X. campestris.
Xanthomonas Campestris. pv campestris é uma bactéria fitopatogênica, agente causal da podridão negra em crucíferas. Dentre os mecanismos para o controle de doenças de fitopatógenos, destaca-se o uso de bactérias com atividade antagonista ao patógeno. Estudos recentes mostram que espécies de Bacillus exercem sobre X. Campestris um forte controle biológico. Um dos mecanismos deste controle é a produção de metabólitos secundários por essas espécies. O objetivo deste trabalho foi selecionar bactérias antagonistas a X. campestris e avaliar a atividade antimicrobiana dos filtrados extracelulares das bactérias (FEB) com atividade antagonista. Para isso, 257 bactérias isoladas de solos supressivos foram avaliadas quanto a atividade antagonista in vitro pela técnica da dupla camada. Noventa e dois isolados (44,6%) foram capazes de inibir o crescimento do fitopatógeno alvo (X.campestris). Dentre os 92 isolados selecionados no teste da dupla-camada, 51 (55,43%) apresentaram inibição do crescimento da X. campestris nos ensaios de inibição com os FEB em meio líquido. Treze destes inibiram 50% ou mais do crescimento do fitopatógeno-alvo, sendo que os FEB-08, FEB-31, FEB-68, FEB-74 e FEB-87 foram capazes de inibir 100% do crescimento de Xanthomonas campestris. O FEB do isolado TC-DT08, pertencente ao gênero Paenibacillus, foi utilizado para testes in vivo em plantas de couve-manteiga, em condições de casa de vegetação. A inoculação artificial de couve-manteiga com X. campestris pré-tratada com o FEB-8 demonstrou que a bactéria perde a habilidade de colonizar a couve e causar a podridão negra, o que indica o potencial do uso deste isolado para proteger a couve-manteiga da infecção por X. campestris.

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Borel, Filipe Constantino. "Metabólitos de Clonostachys rosea inibidores a Botrytis cinerea, sobrevivência do antagonista e efeito sobre o microbioma foliar de tomateiro." Universidade Federal de Viçosa, 2018. http://www.locus.ufv.br/handle/123456789/21853.

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Fundação de Amparo à Pesquisa do Estado de Minas Gerais
Clonostachys rosea é eficaz no biocontrole de várias doenças fúngicas. Ao longo dos anos, constatou-se a eficiência de isolados obtidos no Brasil no biocontrole do mofo cinzento do tomateiro, causado por Botrytis cinerea. Há evidências de que o isolado NCR61/F produza compostos supressivos ao patógeno, mas desconhecia-se a bioatividade e a natureza desses compostos. Assim, estudou-se a bioatividade de compostos de filtrados e extratos do cultivo de C. rosea em meio líquido a B. cinerea e se caracterizaram os metabólitos secundários produzidos. Filtrados e extratos do crescimento do isolado inibiram o crescimento micelial e a germinação de conídios de B. cinerea. O antagonista produziu 51 metabólitos, como peptaibols, glisopreninas e bissorbicilinoides e alguns inderterminados, principalmente após 10 dias de cultivo. Clonostachys rosea é adaptado a diferentes ecossistemas e pode colonizar tecidos de raízes e folhas, mas a dinâmica de sobrevivência nesses tecidos é pouco compreendida. Estudou-se a sobrevivência do isolado NCR61/F como epífita em folhas, na rizosfera e no rizoplano de tomateiros, até 48 dias após a aplicação. A sobrevivência do antagonista diminuiu ao longo do tempo nas superfícies foliares e radiculares, mas sua população permaneceu estável na rizosfera de tomateiros. Um aspecto fundamental e inédito quanto a aplicações de C. rosea é seu efeito na microbiota de folhas de tomateiro, o que foi, também, estudado. O efeito deletério de C. rosea no microbiota foi de curta duração e transiente. O efeito foi maior nas comunidades epifítica e endofítica de fungos, com maior redução em diversidade e riqueza de comunidades até 3 dias após a aplicação. A abundância de filos e alguns gêneros, como Cladosporium e Alternaria, e Cercospora foi menor nas plantas tratadas com o antagonista que nas não tratadas. Em bactérias epifíticas, houve maiores alterações na diversidade aos 3 e 12 dias, e gêneros como Bacillus, Arthrobacter and Enterobacter foram menos abundantes nos dias iniciais após a aplicação. Ao final das avaliações (24 dias), houve resiliência da microbiota foliar de plantas tratadas com o antagonista e aumento gradual das populações. Em conclusão, constatou-se que C. rosea produz compostos inibitórios a B. cinerea, pode sobreviver em folhas e raízes e rizosfera de tomateiro e altera de forma transitória as comunidades fúngicas e bacterianas da solanácea. As informações aqui geradas são relevantes para compreender os mecanismos de antagonismo de C. rosea NCR61/F, sua capacidade de sobrevivência e o efeito perturbador da sua aplicação no microbiota do tomateiro. O conhecimento gerado é importante para traçar estratégias de uso do antagonista e, até mesmo, para validar o seu uso sustentável como agente de biocontrole.
Clonostachys rosea is effective in biocontrol of several fungal diseases. Over the years, we studied the efficiency of isolates obtained in Brazil in the biocontrol of gray mold of tomato, caused by Botrytis cinerea. There is evidence that the C. rosea isolate NCR61/F produces compounds suppressive to the pathogen, but the bioactivity and nature of these compounds was unknown. Thus, the bioactivity of filtrate compounds and extracts of C. rosea culture in liquid medium against B. cinerea was studied and the secondary metabolites produced were characterized. Filtratess and extracts from the growth of the isolate inhibited the mycelial growth and conidial germination of B. cinerea. The antagonist produced 51 metabolites, such as peptaibols, glisoprenins and bissorbicilinoids and some undetermined, mostly after 10 days of culture. Clonostachys rosea is adapted to different ecosystems and can colonize tissues of roots and leaves, but the dynamics of survival in these tissues is little understood. The survival of the isolate NCR61/F isolate was studied as epiphyte in leaves, rhizosphere and rizoplane of tomato plants, up to 48 days after application. The survival of the antagonist decreased over time on leaf and root surfaces, but its population remained stable in the tomato rhizosphere. A fundamental and new aspect of the applications of C. rosea is its effect on the microbiota of tomato leaves, which was also studied. The deleterious effect of C. rosea on the microbiota was transient. The effect was higher in the epiphytic and endophytic communities of fungi, with greater reduction in diversity and richness of communities until 3 days after application. The abundance of phyllum and some genera, such as Cladosporium, Alternaria and Cercospora was lower in plants treated with the antagonist than in plants not treated. Regarding epiphytic bacteria, there were major changes in diversity at 3 and 12 days, and genera such as Bacillus, Arthrobacter and Enterobacter were less abundant in the initial days after application. At the end of the evaluations (24 days), there was resilience of the foliar microbiota of plants treated with the antagonist and gradual increase of the populations. In conclusion, it was found that C. rosea produces inhibitory compounds to B. cinerea, can survive in leaves, roots and rhizosphere of tomato and transiently changes the fungal and bacterial communities of tomato plants. The information generated here is relevant to understand the mechanism of antagonism of C. rosea NCR61/F, its ability to survive and the disturbing effect of its application on the tomato microorganism. The generated knowledge is important to draw strategies of antagonist use and even to validate its sustainable use as biocontrol agent.

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Wehr, Pitt Paul. "Biofertilizantes, a base de esterco bovino, no controle de Phytophthora nicotianae em citros." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/179.

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The objective of this study was to evaluate the effect of two organic liquid fertilizeres made from fresh cattle manure, produced under anaerobic digestion or forced oxygenation, for the control of Phytophthora nicotianae. Furthermore, we aimed to investigate separately the effect of the components in these products over the pathogen. For so, we tested the effect of cultivable microorganisms and the filtered fraction over the pathogen, targeting to identify the role of this factors in the disease control. It was found that biofertilizers have substances and microorganisms present in its composition capable of operating in the pathosystem in question, highlighting the role of baciliform heat resistant bacteria. It was observed that the effect of the filtered fraction of the anaerobic biofertilizer was effective on the mycelial growth of the pathogen and significantly higher than the filtered fraction of the aerobic biofertilizer, and had higher levels of some nutrients, especially calcium, copper and iron. The aerobic biofertilizer showed greater quantity and diversity of microorganisms antagonistic to P. nicotianae. The application of both biofertilizers reduced the number of infected roots of two citrus rootstocks (Citrus limonia and Citrus sunki) Both biofertilizers also reduced the amount of pathogen inoculum in the soil. In high concentrations biofertilizers cause phytotoxicity on young citrus plants, but in moderate concentrations, the products increased the number of germinated seeds of Rangpur lime and mandarin Sunki sown on soil inoculated with the pathogen. This makes the use of biofertilizers an option to be integrated in the disease management of P. nicotianae in citrus, however, more studies are require to investigate other issues, such as the risks related to the application of this products.
O objetivo deste trabalho foi avaliar o efeito de um biofertilizante feito à base de esterco bovino, produzido sob digestão anaeróbica ou oxigenação forçada, no controle de Phytophthora nicotianae, mediante técnicas de avaliação in vitro e in vivo. Além disso, buscou-se investigar separadamente o efeito dos componentes presentes nestes produtos sobre o patógeno. Para tal, testou-se o efeito de microrganismos cultiváveis e da fração filtrada, visando identificar o papel dos fatores responsáveis pelo controle da doença. Verificouse que os biofertilizantes possuem substâncias e microrganismos presentes em sua composição capazes de atuar no patossistema em questão, havendo destaque para bactérias baciliformes termorresistentes. Observou-se que, o efeito da fração filtrada do biofertilizante anaeróbico foi efetivo sobre o crescimento micelial do patógeno e significativamente superior à fração filtrada do biofertilizante aeróbico, este, apresentou teores mais elevados de alguns nutrientes minerais, com destaque para cálcio, cobre e ferro. Já o biofertilizante aeróbico apresentou maior quantidade e diversidade de microrganismos antagônicos à P. nicotianae. A aplicação de ambos os biofertilizantes reduziu o número de raízes de porta-enxerto de citros (Citrus limonia e Citrus sunki) infectadas, assim como, a quantidade de inóculo do patógeno no substrato de plantio utilizado. Em concentrações elevadas os biofertilizantes causaram fitotoxicidade em plantas jovens de citros, mas em concentrações moderadas, os biofertilizantes elevaram o número de sementes germinadas de limão Cravo e tangerina Sunki, semeadas em substrato inoculado com o fitopatógeno. Isso faz do uso de biofertilizantes, uma opção para o manejo de P. nicotianae em citros, contudo novas pesquisas são necessárias para elucidar questões referentes ao seu uso prático e riscos referentes à sua aplicação.

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Biganski, Sarah [Verfasser], Johannes A. [Akademischer Betreuer] Jehle, and Gerhard [Akademischer Betreuer] Thiel. "Evaluation of Natural Antagonists for Biological Control of Drosophila suzukii / Sarah Biganski ; Johannes A. Jehle, Gerhard Thiel." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2020. http://d-nb.info/1218692383/34.

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Memenza, Zegarra Miriam Estela. "Control biológico in vitro de Botrytis cinerea (Pers) mediante el uso de hongos antagonistas, en vid (Vitis vinifera)." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2009. https://hdl.handle.net/20.500.12672/877.

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En el cultivo de la vid, se reporta a Botrytis cinerea Pers como el hongo patógeno causante de lesiones cancrosas, necrosamiento de brotes y racimos de flores, y pudrición de frutos y semillas, que ocasionan grandes pérdidas económicas a los agricultores. El control de este patógeno se realiza hasta nuestros días con sustancias de origen químico: plaguicidas; los cuales son aplicados al follaje, a las semillas y al suelo, ocasionando problemas en el ambiente. En el presente trabajo, se colectaron 56 muestras de hojas de vid, infectadas con Botrytis cinerea Pers, en un viñedo del caserío La Huaca, en el distrito de San Benito, provincia de Contumaza, departamento de Cajamarca, durante el verano del 2006; de las cuales se aislaron e identificaron 12 cepas de Trichoderma viride. En la evaluación de la actividad antagonista de las 12 cepas de T. viride sobre B. cinerea mediante el método Precolonizado de Placas a 24° C y 28° C, se seleccionó a las cinco cepas: CH-13, CH-25, CH-30, CH-38 y CH-52 que presentaron los mayores porcentajes de área ocupada sobre el patógeno. Estas cepas presentaron actividad antagonista del tipo micoparasitismo, observándose enrollamiento y penetración de las hifas de las cepas de T. viride sobre las hifas de B. cinerea. De las cinco cepas seleccionadas de T. viride, la cepa CH-30 presentó el mayor porcentaje de área ocupada sobre B. cinerea a 24° C y 28° C con un 54.67% y 98% respectivamente. Por los resultados obtenidos, las cinco cepas nativas de Trichoderma viride pueden ser consideradas como una alternativa ecológica para su evaluación como agentes potenciales de control biológico del patógeno B. cinerea.
--- In the culturing of grapevine, there is reported Botrytis cinerea Pers as the fungus pathogenic causative of canker injuries, necrotizing of outbreaks and clusters of flowers, and rotting of fruits and seeds, which cause big economic losses to the farmers. The control of this pathogenic is realized actually by substances of chemical origin: pesticides; which are applied to the foliage, to the seeds and to the soil, causing environment problems. In this present work, there were collected 56 samples of leaves of grapevine, infected with Botrytis cinerea Pers, in a vineyard of The Huaca hamlet, in San Benito district, Contumaza province, Cajamarca department, during the summer of 2006; from these ones, there were isolated and identified 12 strains of Trichoderma viride. In the evaluation of the antagonist activity of these 12 strains of T. viride on B. cinerea by the method of Plates pre-colonized in 24° C and 28 °C, was selected five strains: CH-13, CH-25, CH-30, CH-38 and CH-52 that presented the major percentages of occupied area over the fungus pathogenic. These strains showed antagonist activity of mycoparasitism kind, being observed rolling and penetration of mycelium of T. viride strains on the mycelium of B. cinerea. From 5 T. viride strains selected, the CH-30 one showed the major percentage of occupied area on B. cinerea in 24° C and 28 °C with 54.67% and 98% respectively. For the results obtained, five native strains of Trichoderma viride can be considered as an ecological alternative for its evaluation as potential agents of biological control of the pathogenic B. cinerea.
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Mateo, Tuesta Claudia Estefania, and Tuesta Claudia Estefania Mateo. "Actinomicetos nativos de la rizosfera de Solanum tuberosum subespecie andigena con potencial actividad antagonista a Pectobacterium carotovorum." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2017. http://cybertesis.unmsm.edu.pe/handle/cybertesis/6865.

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Evalúa la capacidad antagonista de actinomicetos nativos de la rizosfera de la papa frente a Pectobacterium carotovorum subsp. atrosepticum. Se utilizaron 49 actinomicetos de la colección del laboratorio de Ecología Microbiana - UNMSM, aislados de rizosfera de Solanum tuberosum subespecie andigena. Del total, 13 actinomicetos (26,5%) resultaron tener actividad antagonista. Las cepas AND 12 y AND 30 presentaron la mayor actividad antagonista. Sin embargo, sólo los extractos orgánicos de diclorometano, etil acetato y butanol de la cepa AND 12 evidenciaron actividad antimicrobiana. El extracto butanólico alcanzó una concentración mínima inhibitoria de 0,775 mg/ml, teniendo la mejor actividad de los extractos. El actinomiceto AND 12 fue identificado como Streptomyces pactum. Este actinomiceto por su capacidad antagonista podría ser considerado como potencial controlador biológico de la “pudrición blanda” y “pierna negra” de la papa.
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Ngugi, Michael Kahato [Verfasser]. "Foraging decision of aphidophagous predators and conservation biological control : a case study with syrphid antagonists / Michael Kahato Ngugi." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2013. http://d-nb.info/1032791284/34.

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Gomes, Nei Sebastiao Braga. "Seleção de antagonistas para o controle de Cylindrocladium spathulatum, agente causal da pinta-preta em erva-mate." reponame:Repositório Institucional da UFPR, 2013. http://hdl.handle.net/1884/25122.

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A erva-mate, IIex paraguariensis St. Hil., como qualquer espécie vegetal está sujeita á doenças, que podem provocar prejuízos ou até mesmo inviabilizar seu cultivo. Entre estas, encontra-se a pinta-preta causada por Cylindrocladium spathulatum El GholI, Kimbrough, Barnard, Alfieri & Schoulties, principal doença foliar desta cultura. Ela pode causar perdas significativas, tanto em viveiro, quanto em plantios e, até o momento, tem sido controlada com fungicida mesmo sem existir produtos registrados. O principal objetivo deste trabalho foi selecionar e avaliar antagonistas visando o controle biológico da pinta-preta. Em uma primeira fase, foi feito o isolamento de antagonistas, em seguida foram feitos testes em laboratório, in vitro, e, após a seleção inicial, fez-se a avaliação do potencial antagônico dos melhores isolados em testes com folhas destacadas e em mudas, na casa-de-vegetação. Os experimentos foram conduzidos na Embrapa Florestas, Colombo/PR. Os microrganismos antagônicos residentes utilizados foram isolados de (1) solo infectado com o patógeno, proveniente de plantio comercial em São Mateus do Sul/PR; (2) lavagem de folhas de erva-mate nativa em Colombo/PR e (3) purificação de colônias de microrganismos surgidas em isolamento de lesões de pinta-preta. Os outros microrganismos foram procedentes de Jaguariúna/SP (isolados de Baclilus subtilis) e Bento Gonçalves/RS (isolados de Trichoderma). O experimento inicial foi executado em placas de Petri, acondicionadas em câmara de germinação "BOD" à temperatura de 22 ± 0,5°C e luz fria alternada (12/12 h), utilizando-se 30 isolados de fungos e bactérias, residentes ou não em erva-mate. Posteriormente, foram selecionados 3 isolados de bactérias e 3 de Trichoderma, que apresentaram maior percentual de inibição, em teste de produção de antibióticos e no teste de hiperparasitismo, respectivamente. Esses 6 isolados foram empregados nos testes subseqüentes com papel celofane, placas sobrepostas e inibição de germinação de esporos e, ainda, em folhas destacadas (laboratório) e em mudas (casa-de-vegetação). Concluiu-se que os métodos in vivo foram considerados mais adequados para a seleção de antagonistas que os métodos in vitro. Os isolados de bactérias, de um modo geral, foram mais eficientes que de Trichoderma. Os melhores resultados foram obtidos com o isolado AP-49 (B. subtilis) com 10% de incidência da doença, contra 90% de incidência na testemunha, em mudas. Estes resultados indicam a possibilidade do uso de antagonistas no controle da pinta-preta da erva-mate.

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Bujold, Isabelle. "The use of a fungal antagonist to reduce the initial inoculum of Gibberella zeae on wheat and corn debris /." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31199.

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Gibberella zeae (anamorph: Fusarium graminearum) is the causal agent of fusarium head blight (FHB) and maize ear rot, two major diseases of wheat and corn in Eastern Canada.
In Quebec, Microsphaeropsis sp., an antagonist of Venturia inaequalis, the causal agent of apple scab, was isolated from the apple leaf litter. This fungus, well adapted to Quebec climate, can reduce the initial inoculum of V. inaequalis. FHB and Gibberella ear rot are similar to apple scab because the major inoculum source comes from melanized structures produced on crop residues. Consequently, we evaluated the potential of Microsphaeropsis sp. (isolate P130A) to inhibit ascospore production of G. zeae when applied to crop residues as post harvest or pre-planting applications. Under in vitro conditions, the antagonist significantly reduced ascospore production on wheat and corn residues, when applied prior to (82% and 92% respectively) or at the same time as the pathogen (36% and 58% respectively). Under field conditions, the antagonist had no effect on the pattern of perithecia maturation but significantly reduced the number of ascospores produced on two sampling dates, May 1998 and July 1999. (Abstract shortened by UMI.)

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Hattabou, Anas. "Pilotage de la performance globale entre logique de conformation et logique d'innovation : une approche par les systèmes ago-antagonistes : cas de deux entreprises pionnières au Maroc." Thesis, Bordeaux 4, 2011. http://www.theses.fr/2011BOR40050/document.

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Cette thèse s’intéresse à la dynamique actuelle du développement durable dans l’entreprise et la prise en compte de la responsabilité sociale dans les processus stratégiques. En particulier, elle vise à caractériser les logiques de conception des systèmes de pilotage de la performance globale au sein d’entreprises pionnières au Maroc et la manière dont ces dernières cherchent à articuler exigence de conformation et logique d’innovation en matière de développement durable. La première partie de cette thèse est consacrée à l’élaboration du cadre conceptuel de la recherche, abordant les fondements du concept de la performance globale et analysant la portée et les limites des modèles conçus pour son pilotage. La deuxième partie de la thèse aborde empiriquement la problématique de la recherche. Après une première analyse des démarches des entreprises en matière de développement durable dans le contexte des pays en développement, sont présentés les résultats de deux études de cas multi-sites, réalisées au sein de deux entreprises pionnières au Maroc : Lafarge Maroc et Accor Maroc. Les modalités de déploiement de la démarche de développement durable et les caractéristiques des systèmes de pilotage de la performance globale sont analysées au plan de la stratégie, des structures organisationnelles et de l’instrumentation de gestion. La recherche met en évidence les contraintes spécifiques au contexte marocain qui rendent plus complexe le déploiement stratégique du développement durable. Ces contraintes impliquent un étalement et une gradation des engagements dans le temps permettant à l’encadrement intermédiaire et opérationnel de développer la capacité organisationnelle à porter les projets sociaux et environnementaux du sommet stratégique. On observe par ailleurs un renforcement des structures fonctionnelles et la mise en place de nouvelles démarches qui s’accompagnent d’un décloisonnement organisationnel interne et externe. La mobilisation du cadre d’analyse de la systémique ago-antagoniste a permis de concevoir le pilotage de la performance globale comme un processus d’équilibration sous tension de trois ensembles expansifs de couples ago-antagonistes : performance financière/performance sociale, contrôle/autonomie, routinisation/innovation, relevant respectivement de deux sphères de référence : financière et durable
This thesis focuses on the current dynamics of sustainable development in the company and the inclusion of social responsibility in strategic processes. In particular, it aims to characterize the logical system design for controlling the overall performance of the pioneers in Morocco and how the latter seek to articulate and logical requirement conformation of innovation in sustainable development. The first part of this thesis is devoted to developing the conceptual framework of research, addressing the foundations of the concept of overall performance and analyzing the scope and limitations of models for its management. The second part of the thesis addresses the problem of empirical research. After an initial analysis of business processes for sustainable development in the context of developing countries, are presented the results of two case studies of multi-site, performed in two pioneering companies in Morocco: Morocco Lafarge and Accor Morocco. The arrangements for the deployment of sustainable development and characteristics of systems for controlling the global performance is analyzed in terms of strategy, organizational structures and management instrumentation.The research highlights the constraints to the Moroccan context that complicate the strategic deployment of sustainable development. These constraints imply a spreading and a gradation of the commitments in time for middle management and operational levels to develop the organizational capacity to carry the social and environmental projects of strategic summit. Moreover, there is a strengthening of the functional and the implementation of new approaches that are accompanied by an opening up our internal and external. The mobilization of the analytical framework of ago-antagonist systems has helped design the global performance management as a process of balancing power of three sets of expansive ago-antagonistic couples: financial performance / social performance, control / autonomy , routinization / innovation, falling within two reference spheres: financial sustainability

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Mateo, Tuesta Claudia Estefania. "Actinomicetos nativos de la rizosfera de Solanum tuberosum subespecie andigena con potencial actividad antagonista a Pectobacterium carotovorum." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2017. https://hdl.handle.net/20.500.12672/6865.

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Evalúa la capacidad antagonista de actinomicetos nativos de la rizosfera de la papa frente a Pectobacterium carotovorum subsp. atrosepticum. Se utilizaron 49 actinomicetos de la colección del laboratorio de Ecología Microbiana - UNMSM, aislados de rizosfera de Solanum tuberosum subespecie andigena. Del total, 13 actinomicetos (26,5%) resultaron tener actividad antagonista. Las cepas AND 12 y AND 30 presentaron la mayor actividad antagonista. Sin embargo, sólo los extractos orgánicos de diclorometano, etil acetato y butanol de la cepa AND 12 evidenciaron actividad antimicrobiana. El extracto butanólico alcanzó una concentración mínima inhibitoria de 0,775 mg/ml, teniendo la mejor actividad de los extractos. El actinomiceto AND 12 fue identificado como Streptomyces pactum. Este actinomiceto por su capacidad antagonista podría ser considerado como potencial controlador biológico de la “pudrición blanda” y “pierna negra” de la papa.
Tesis

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Berndt, Oliver. "Entomopathogenic nematodes and soil dwelling predatory mites suitable antagonists for enhanced biological control of Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)? /." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=96851930X.

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Mendoza, Luna Alexander Rafael. "Interrelationships between microbial antagonists having divergent modes-of-action and their influence on biological control of plant-parasitic nematodes." Göttingen Cuvillier, 2008. http://d-nb.info/989139182/04.

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Hollywood, Jane Constance. "Biological control of late blight of potatoes : in vivo and in vitro evaluation of microbial antagonists against tuber blight." Thesis, University College London (University of London), 2004. http://discovery.ucl.ac.uk/1446592/.

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The cost of losses and control measures attributed to late blight of potatoes caused by Phytophthora infestans, are estimated to exceed $5 billion annually. Breeding for resistance is difficult owing to the tetraploid genotype of potato and current strains of the pathogen have developed resistance to chemical control. Consequently the search for biological control has assumed greater importance. In this investigation an in vivo bioassay was used to select soils antagonistic to late blight of potatoes, caused by Phytophthora infestans. Four out of eight samples demonstrated reproducible antagonism as determined by a reduction in the volume of tuber tissue rotted. A total of 292 bacterial and yeast samples and 20 fungal samples were recovered from suppressive soils using a variety of non-selective and selective media. When these organisms were tested individually against P. infestans in the assay, 15 isolates suppressed tuber rotting by >85% in at least three out of four assays. The antagonists were characterised as Pseudomonas spp. (3 strains), Enterobacter spp. (4 strains), Bacillus spp. (1 strain), Pantoea spp. (2 strains), Citrobacter spp. (1 strain), Buttiauxella spp. (1 strain), Trichosporon spp. (2 strains) and Geotrichum spp. (1 strain) by routine bacteriological tests, fatty acid profiling and partial sequencing of the gene encoding 16S or 18S (where appropriate) ribosomal RNA. Subsequently the possible mechanisms by which the potential biocontrol agents inhibited the disease were examined. Nine isolates showed some evidence of antibiotic production with a Pantoea spp. producing a compound that caused the hyphae of P. infestans to kink and permanently cease growth. Three isolates colonised hyphae of the pathogen and eleven produced siderophores in liquid culture. Hydrogen cyanide, proteolytic, cellulolytic and beta-1,3-glucanase activity was also evident in some species. Significant promotion of axenically grown tomato seedlings, as determined by increased stem and main root elongation, was achieved by ten of the isolates. Three population levels of the isolates were retested for disease inhibition at the end of the investigation. Isolates 3, 7 and 14 exhibited the highest levels of consistent inhibition at the lowest population levels and were therefore tested in combination. This achieved disease suppression that, at an antagonist concentration of 25 cfu/nL, was more consistent than isolate 3 alone and was over 30% greater than either isolate 7 or 14.

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Lopez, Susana Pascual. "Studies on production and ecophysiology of fungal antagonists for improved biological control of Fusarium oxysporum f.sp. Iycopersici and Monilinia laxa." Thesis, Cranfield University, 1998. http://dspace.lib.cranfield.ac.uk/handle/1826/4663.

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This work investigated the production of the biocontrol agents: Penicillium oxalicum to control Fusarium oxysporum f.sp. Iycopersici in the rhizosphere; and Epicoccum nigrum and Penicillium frequentans to control Monilinia laxa in the phyllosphere. Ecophysiological studies were carried out to categorise different inoculum types, and to test their biocontrol efficacy. A method was developed for the induction of submerged conidiation of P.oxalicum for the first time. This was achieved by transferring 24 h cultures to a nitrogen free medium, and further stimulated by a high C:N ratio with 20 mM calcium. Optimum submerged conidial concentrations obtained were 35x10 6 spores mr1. The hydrophobicity of submerged and aerial conidia of P.oxalicum was similar. However, different results were obtained depending on the method used. Appearance of both spore types under the SEM was similar in size and shape. However, submerged spores were covered by a filamentous matrix, absent in aerial ones. Viability of aerial and submerged P.oxalicum spores was higher than 80% after 27 weeks, when stored fresh at either 4 or 25°C, but aerial spores survived slightly better. Freeze-drying severely affected viability, especially of submerged spores. Aerial spores effectively colonised sterile soil in tomato seedbeds with water potentials in the range 1-7 (-MPa), and this was further favoured by the addition of nutrients. Aerial conidia of P.oxalicum applied to seedbeds were able to significantly (P<0.05) reduce Fusarium wilt of tomato at concentrations as low as 6x10 4 spores mr 1 substratum, indicating that the amount of the antagonist needed is not a limiting factor for the practical application of this antagoniSt. Aerial spores were slightly more effective than submerged ones in the control of the disease. However, mycelium was ineffective. Coating of tomato seeds with formulations of aerial spores of P.oxalicum in alginate or methyl cellulose significantly (P<0.05) enhanced the growth promotion effect of the antagonist in vitro, which may be related to the ability of the fungus to control the disease. E.nigrum spores were produced by solid fermentation on wheat grains at different water activities (aw). Maximum levels of sporulation (7-11x10 6 spores g-1 grain) were obtained at high aw (0.996) or reduced aw (0.98) adjusted with a mixture glycerol/water. E.nigrum and P.frequentans were both produced in culture medium at reduced aw, to improve their ecological competence in the phyllosphere and therefore their biocontrol ability. E.nigrum produced at reduced aw showed improved germ tube extension and in some cases colony growth rate when placed on medium at reduced aw, showing water stress tolerance of such modified inocula. Furthermore, such inocula showed an enhanced ability to compete with the pathogen, M.laxa, at reduced aw, shown by a higher Niche Overlap Index (the proportion of the carbon compounds utilised by M.laxa that were also utilised by E.nigrum). E.nigrum spores produced at reduced aw had improved survival when stored fresh at 4 or 25°C. Freeze-drying severely affected the viability of both spore types (produced at high or reduced aw). E.nigrum and P.frequentans produced at reduced aw accumulated low molecular weight polyols as compatible solutes. Improvement of biocontrol of peach twig blight was obtained in the case of E.nigrum, which is more sensitive to conditions of low water availability than the xerotolerant P.frequentans. However, both fungi accumulated glycerol as the main compatible solute, indicating that different accumulation mechanisms may be responsible for the different tolerance to low water availability. Glycerol was also the main compatible solute in E.nigrum spores produced by solid fermentation at reduced aw. E.nigrum produced at high or reduced aw was also able to control brown rot of cherries, under optimum conditions for the development of the disease. The results presented in this work show that the conditions during the production of biocontrol agents are critical in determining their efficacy. Therefore, when developing mass-production systems it is necessary to aim not only for high propagule numbers but also for inoculum quality, defined by parameters such as ecological competence or survival during storage.

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Dissertations / Theses on the topic 'Antagonistic Control'

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