Academic literature on the topic 'Weed control methods'

This article provides the results of harmonized weed control measures, which annual and biennial weeds in cotton and autumn wheat fields have been reduced by 80.2-82.7% in cotton fields and by 93.5% in autumn wheat fields.

SUMMARYThe effects of weeds on coffee productivity and the methods used for their control are discussed. The more common weeds are listed, together with the control methods that can be used at various phases of coffee production.Malezas y control de las mismas en el café

One of the most challenging duties in an agricultural field is weed control. Weed control is a major problem for peasant framers everywhere. This paper's objectives are to reviewing and reporting the weed management practices utilized in Ethiopian agriculture and to recommend the viability of mechanizing weeding operations for the further research. In agriculture, three weed management techniques are frequently used. These are chemical, mechanical, and manual control. Farmers that are convinced of its benefits quickly adopt mechanical weed control. In addition to pulling weeds out from between the rows of crops, mechanical weed management maintains the soil's top loose, improving soil aeration and water absorption. Mechanical weeding saves time and labor while lowering labor costs also. Some weeding tools that are powered by animals are effective in terms of time and money savings. Herbicides are occasionally used by farmers; however, they are not often used in farming. In conclusion, weed control is one of the most essential and expensive operation in agriculture. Weeding by mechanical device reduces the cost of labour and also saves time than any other methods of weed control. Therefore, instead of manual weeding and using chemicals, the use of a mechanical weeding machine should be given priority.

Weed control is necessary to ensure success in early stages of juneberry (Amelanchier alnifolia) orchard development; however, juneberry growers have limited chemical weed control options. A field trial was initiated at Prosper, ND, to evaluate the efficacy of physical and chemical weed control methods and their effects on juneberry growth. Woven landscape fabric most effectively eliminated weed emergence, whereas winter rye (Secale cereale) cover crop allowed the most weeds to emerge throughout the study. During both years, a hairy vetch (Vicia villosa) companion crop provided poor early- to midseason weed control, but weed suppression increased over time as hairy vetch grew to cover open areas. However, hairy vetch was very competitive with juneberry, reducing crop height, width, and overall growth. Plants within the herbicide treatments (glyphosate at 0.75 lb/acre plus oryzalin at 2 lb/acre and linuron at 1.7 lb/acre followed by flumioxazin at 1 oz/acre) and the hand-weeded control, which was weeded three times each year, had the greatest growth.

Nursery growers estimate that they spend $500 to $4000/acre ($1235 to $9880/ha) of containers for manual removal of weeds, depending upon weed species being removed. Economic losses due to weed infestations have been estimated at about $7000/acre ($17,290/ha). Herbicide treated bark nuggets were found extremely effective for weed control in studies during 1998, regardless of whether oxyfluorfen, oryzalin, or isoxaben were applied to the bark. A study conducted in 2000 compared 24 treatments of novel nonchemical alternatives, conventional chemical practices and herbicide treated barks. Four of the best treatments were herbicide treated douglas fir bark, specifically, small [<1 inch (2.5 cm) length] douglas fir nuggets treated with oryzalin at the 1× rate, large (>1 inch length) douglas fir nuggets treated with oryzalin at the 0.5× rate, small douglas fir nuggets treated with oryzalin at the 0.5× rate and large douglas fir nuggets treated with flumioxazin at the 1× rate. The four bark treatments indicated above provided equivalent efficacy and phytotoxicity to Geodiscs. Penn Mulch and Wulpack provided poor weed control. Mori Weed Bag, a black polyethylene sleeve, and Enviro LIDs, a plastic lid provided less control than herbicide treated bark. Compared to the bark alone, herbicide treated bark provides a 1.8-fold increase in efficacy and a 2.8-fold extension in duration of efficacy. Compared to the herbicide alone, herbicide treated bark provides a 1.5-fold increase in efficacy and a 2.2-fold reduction in phytotoxicity. Of the innovative weed control products tested herbicide treated bark provided the most promising results. The data support that the bark nuggets are possibly acting as slow release carriers for the herbicides or reducing the leaching potential of the herbicides. Recent studies have indicated that the controlled release of herbicides using lignin as the matrix offers a promising alternative technology for weed control.

The experiment was conducted in the years 2004-2006 in a private farm in the village of Frankamionka in Zamość district. There were two experimental factors: I. Cultivation methods - sole cropping and strip intercropping; and II. Tending methods - mechanical, mechanical-chemical, and chemical weed control. The subject of the study was weed infestation of the Mela variety of common bean. Beans were sown between 30 April and 5 May. Weed infestation was assessed in the last week before harvesting by determining its floristic composition and the frequency of occurrence of particular weed species, as well as the air-dry weight of weeds. The dominant weed species were <i>Galinsoga parviflora</i>, <i>Echinochloa crus-galli</i>, <i>Chenopodium album</i>, and <i>Amaranthus retroflexus</i>, which comprised 84.7% of the total number of weeds. Strip intercropping markedly reduced the number of weeds per unit area (by 50%), as well as the dry weight of their aerial parts. The most effective method of weed control was the mechanical-chemical method, which resulted in the lowest occurrence of weeds. It also significantly reduced the weight of weeds.

Master of Science
Department of Horticulture, Forestry, and Recreation Resources
Steven Keeley
Common dandelion (Taraxacum officinale Weber) is an important perennial weed in turfgrass. Fall is considered the optimal time for postemergence herbicidal control of dandelions; however, applications in spring, when volatility damage to surrounding plants is an additional concern, are often needed. Therefore, we conducted research to determine the volatility of common broadleaf herbicides, and their efficacy when applied at spring and fall application timings. Volatility was determined by applying herbicides to turfgrass and using potted tomatoes as indicator plants. Tomatoes exposed to turfgrass treated with Trimec Classic, Confront, Surge, Escalade 2, and Imprelis exhibited little or no volatility damage, while exposure to Speedzone, 4 Speed XT, and Cool Power caused significant damage. In general, herbicides causing little or no damage were amine formulations. Two field studies determined the effect of spring and fall application timing on dandelion control with several herbicides. Herbicide applications in the spring coincided with dandelion anthesis stages: pre-bloom, peak bloom, and post-bloom. Results were dependent on dandelion pressure in the studies. In 2010, with lower pressure, there were no differences among herbicides at any spring timing when dandelion control was evaluated after one year; all herbicides gave ≥ 80% control. In 2011, with higher dandelion pressure, Imprelis SL and 4 Speed XT provided ≥ 96% dandelion control at the spring pre- and post-bloom timings, which was better than Surge, Escalade 2, Cool Power, and Confront. The best choices for spring efficacy combined with minimal to no volatility were Escalade 2 and Trimec Classic. Finally, because interest in organic dandelion control is increasing, we compared several organic weed control tactics with a conventional herbicide. In a two-year field study, the conventional herbicide gave much better control (> 96%) than any organic method. Horticultural vinegar corn gluten meal, and fertilizer-only gave < 25% control, while hand-weeding gave 58 to 71% control. While hand-weeding was the best of the organic tactics, the time required was considered prohibitive for turfgrass managers, unless initial weed levels were very low.

Field experiments were conducted in Virginia to evaluate the efficacy of AEF-130060 03 plus AEF-107892 applied postemergence (POST) for the control of Italian ryegrass [Lolium multiflorum (Lam)] in barley [Hordeum vulgare (L.)] in comparison to other herbicides currently registered for use in wheat [Triticum aestivum (L.)] and barley. Laboratory experiments were also conducted to evaluate absorption, translocation and metabolism of AEF-130060 03 plus AEF-107892 in wheat, barley, and Italian ryegrass with or without the addition of dicamba. AEF-130060 03 plus AEF-107892 was applied alone at three POST timings. All of these applications were effective in controlling Italian ryegrass. The third application timing of AEF-130060 03 plus AEF-107892 commonly resulted in lower yields than the first or second application timing, due to increased duration of Italian ryegrass competition, increased barley injury and insufficient time for barley recovery from this injury. In the field experiment, significantly greater barley injury was observed when AEF-130060 03 plus AEF-107892 was combined with 2,4-D and dicamba. Early postemergence (EP) treatments of AEF-130060 03 plus AEF-107892 provided control of Italian ryegrass equivalent to that of delayed preemergence (DPRE) applications of flufenacet plus metribuzin when rainfall was received. However, when rainfall was not received AEF-130060 03 plus AEF-107892 provided superior control. Because the efficacy of AEF-130060 03 plus AEF-107892 is not dependant on rainfall, it should provide more consistent control of Italian ryegrass than DP treatments. Laboratory experiments indicated that Italian ryegrass absorbed greater than 2.5, 2.0, and 1.5 times the amount of applied radioactivity at 24, 48, and 96 hours after treatment (HAT), respectively, than wheat or barley. Metabolism experiments indicated that quantity of parent compound in the three species was greatest in Italian ryegrass, followed by barley and then wheat. However, the sum total of metabolites was not different between species. A higher rate of metabolism of AEF-130060 03 plus AEF-107892 was also observed in wheat and barley than in Italian ryegrass. Thus, lower absorption of herbicide by wheat and barley, coupled with a more rapid rate of metabolism, most likely accounts for differential selectivity between these plant species. No differences in absorption, translocation or metabolism were observed within the three plant species due to the addition of dicamba. An additional experiment was conducted in 2000 and 2001 to evaluate the efficacy of preemergence (PRE) and EP applications of DPX-R6447 for the control of Italian ryegrass in wheat and barley in comparison to other herbicides currently registered for use in these crops. Barley and wheat injury and yield were similar with treatments of DPX-R6447 at rates below 176 g ai/ha and treatments of flufenacet plus metribuzin applied alone in both years. Consistent Italian ryegrass control with DPX-R6447 occurred only with rates of 176 g ai/ha or greater in both years. However, these rates resulted in variable injury in both wheat and barley between years. Rates higher than 176 g ai/ha of DPX-R6447 resulted in unacceptable barley and wheat injury. The lack of consistency with regard to barley and wheat injury could limit the utility of this compound in these crops. Field trials were conducted in Virginia to evaluate herbicide programs for control of Italian ryegrass in no-till corn [Zea mays (L.)] establishment. Herbicide programs using transgenic corn hybrids were compared to standard programs that utilize non-selective herbicides in combination with high rates of triazine herbicides. Italian ryegrass control and corn yields similar to those provided by standard programs could be attained through the use of paraquat plus atrazine, and glyphosate applied in combination with atrazine or rimsulfuron plus thifensulfuron-methyl. In glyphosate-tolerant corn, EP applications of glyphosate controlled Italian ryegrass, but yield did not differ from yields of corn treated with standard PRE applications of glyphosate plus atrazine. The use of glufosinate, imazethapyr plus imazapyr, or sethoxydim with appropriate herbicide-tolerant hybrids did not demonstrate potential for improved control of Italian ryegrass. Field experiments were also conducted to investigate the incidence and severity of maize chlorotic dwarf virus (MCDV) and maize dwarf mosaic virus (MDMV) in response to POST johnsongrass control in two corn hybrids. Recent observations have indicated a lack of virus-tolerance in glyphosate-tolerant corn hybrids in Virginia. The rapidity of virus disease development in corn resulting from application of glyphosate or nicosulfuron was also investigated. The virus-susceptible glyphosate-tolerant hybrid developed significantly higher levels of virus incidence three weeks after treatment than the virus-tolerant, non-transgenic hybrid, and virus incidence and severity increased throughout the duration of the growing season. Little or no disease incidence occurred in the virus-tolerant hybrid. The virus-susceptible hybrid exhibited significant increases in disease incidence in response to any herbicide treatment applied to johnsongrass-containing plots relative to the same treatment applied to weed free plots. Johnsongrass control with nicosulfuron or glyphosate caused similar disease incidence and severity in the virus-susceptible hybrid, regardless of application method. Results of these experiments indicated that growers' choice of hybrid should focus primarily on disease resistance rather than herbicide resistance.
Ph. D.

Riparian zones lie at the interface between aquatic and terrestrial ecosystems and usually have fertile soils, which play a crucial role in maintaining ecosystem productivity and biodiversity. Riparian zones are currently subject to vegetation loss and degradation due to human activities, intensification of agricultural practices, weed invasion, and global climate change. Therefore, there is an urgent need to revegetate and/or maintain the current vegetation of riparian zones. Soil nitrogen (N) is one of the most important growth-limiting nutrients and plays a crucial role in plant growth and productivity. Various management practices such as revegetation establishment, weed control methods, fertiliser applications, and/or organic amendments are practiced to sustain vegetation in riparian zones. However, management practices can alter soil N cycling. It is essential to understand the effect of different land management practices on soil N transformations, to maintain the long-term functional stability of riparian zones ecosystems. Revegetation of degraded riparian zones is considered one of the most effective measures in riparian management, which may influence soil N cycling. To date, no systematic literature review (meta-analysis) exists to assess the effects of different vegetation types and age on soil N pools regarding the revegetation of riparian zones (Chapter 2). Vegetation types along the riparian zones can be both native tree species and/or horticultural trees. The success of riparian revegetation projects with tree species currently depends on weed control to reduce the non-target vegetation competing over nutrients. I, hence, investigated the effects of chemical weed control on N cycling using glyphosate (commonly used herbicide) and organic-based herbicides including the registered products BioWeedTM, Pelargonic acid (Slasher®), and horticultural vinegar (acetic acid) compared with mulching. Additionally, there is a lack of information on how different herbicides could affect soil N dynamics and microbial community structure even after the application was ceased for at least one year (Chapter 3). Horticultural crops established within riparian zones are also one of the major land-use practices requiring large quantities of fertiliser, particularly N, and herbicide inputs. Glyphosate is commonly applied in horticultural lands and glyphosate interactions with organic amendments (e.g., biochar) remain uncertain. I explored the long-term interactions between biochar-amended soil and repeated application of glyphosate even after the application has ceased for over two years on soil microbial communities and soil N transformations are not well understood (Chapter 4). Glyphosate application is likely to be resumed even after stopping for a period of time and usually, very short-term N pools in response to glyphosate application in the presence of soil organic amendments like biochar are overlooked. Short-term N pools may have implications for long-term N management and hence it is important to understand short-term N pools with respect to treatments (Chapter 5). Therefore, my thesis specifically aimed to: (1) Examine the influence of riparian zone revegetation with different revegetation types and age on soil N pools by conducting a quantitative literature review (meta-analysis) (Chapter 2). (2) Assess and compare the effects of different organic-based herbicides (BioWeedTM, Slasher®, and acetic acid) and the commonly used herbicide glyphosate with mulch, on soil N dynamics and microbial community structure at two riparian revegetation sites up to two years repeated application of herbicides followed by one year after stopping herbicides applications (in total three years since the revegetation establishment) (Chapter 3). (3) Investigate the impacts of long-term repeated application of glyphosate (12 years) interacted with biochar (for three years) on soil N cycling, more specifically abundance of nitrifying populations such as the ammonia-oxidizing bacteria and archaea (AOB and AOA) as well as the overall soil microbial diversity and community structure (both fungi and bacteria) after two years following the cessation of herbicide applications (Chapter 4). (4) Explore how the interaction of biochar and glyphosate would immediately affect soil N transformations in short-term (in a 5-day laboratory incubation) using the 15N pool dilution techniques (Chapter 5) In Chapter 2: A meta-analysis was undertaken using a categorical mixed effect model to synthesise the results from 52 published articles. This study aimed to explore how different revegetation types (woodland, shrubland, and grassland) and revegetation age (< 3 years, 3-10 years, 10-20 years, 20-40 years, or > 40 years) would affect soil N pools. This meta-analysis revealed that revegetation of riparian zones significantly increased soil total nitrogen (TN) particularly in woodlands, which was associated with the presence of N fixing species and high litter inputs. Soil TN increased in revegetation ages between 10 and 40 years following revegetation, which might be associated with the increased soil organic carbon (SOC) inputs within those ages following establishment. Of the revegetation types considered in this study, NO3--N concentration in soil followed the order of grassland < shrubland < woodland, suggesting that woodland might be more efficient in soil NO3--N retention than grassland. However, revegetation significantly decreased soil moisture by 7.6% compared with the corresponding control, which might be associated with the selection of exotic species as dominant vegetation in riparian zone revegetation. This study provides insight into the influence of different revegetation types and age on soil N pools and soil moisture. This study also highlights the importance of revegetating riparian zones to increase soil TN, particularly in woodlands. Therefore, in Chapter 3, I used two newly established revegetation sites at (Kandanga and Pinbarren sites), planted with native wood species to investigate how different weed control methods including organic-based herbicides (BioWeedTM, Slasher®, and acetic acid) and the commonly used herbicide, glyphosate with mulch would affect soil N dynamics and microbial community structure over three years following revegetation establishment(two years repeated application of herbicides followed by one year after stopping herbicides applications). Soil samples were collected three times following revegetation establishment at months 2, 14, and 26 at the Kandanga site and at months 10, 22, and 34 at the Pinbarren site. The last sampling at the Pinbarren site (at month 34) occurred one year after the last herbicide was applied. In this study, I found that soil microbial biomass carbon (MBC) was significantly higher in response to mulch compared with glyphosate and organic-based herbicide treatments at months 26 at the Kandanga site and months 10 at the Pinbarren site following the revegetation establishment. However, soil MBC at month 34 at the Pinbarren site was only significantly higher in the mulch treatment than glyphosate and BioWeedTM. The level of MBC in glyphosate and BioWeedTM was also lower than the acceptable threshold at month 34 at the Pinbarren site. I also found that soil nitrate (NO3--N) was significantly higher in the soil treated with mulch than only glyphosate treatment at months 22 and 34 after revegetation at the Pinbarren site. Higher soil NO3--N in mulch compared with that of glyphosate could be partly explained by decreased denitrifying bacteria (Candidatus solibacter and Candidatus koribacter). However, there were no significant differences in soil NO3--N between mulch and other organic-based herbicides despite the fact that C. solibacter and C. koribacter were still lower under mulch than those of other herbicides. My study suggested that the application of mulch in the riparian revegetation projects would be beneficial for soil microbial functionality, particularly soil MBC as compared with [glyphosate and other organic-based herbicides. Additionally, this study suggested that some herbicides like glyphosate and BioWeedTM may have long-lasting effects on soil 125 microbial biomass even if they do not necessarily change microbial diversity. Hence, the long-term use of glyphosate and BioWeedTM needs to be considered with caution. Some woodlands within riparian zones are also horticultural sites where intensive weed control management practices are applied (Chapter 4). Therefore, an established horticultural site (Macadamia orchard) located in a riparian zone, with a history of repeated application of glyphosate (up to four times per annum for 12 years) was chosen to understand the impacts of repeated application of glyphosate interacted with biochar on soil N cycling. Wood-based biochar was first applied at this site in 2012 (64 months before my sampling time) at two different rates of 10 dry t ha-1 (B10) and 30 dry t ha-1 (B30) and the glyphosate had not been applied for two years before my sampling. Therefore, biochar and glyphosate applications coincided for three years before glyphosate was ceased. The results showed that soil TN was significantly higher in the glyphosate applied areas compared with those of no glyphosate, which may suggest that glyphosate may have stimulated N transformations in this study through increasing soil carbon (C) substrate resulting from the degradation of glyphosate and dieback of weeds. Similarly, no effect of glyphosate on soil microbial diversity and community structure was observed two years after glyphosate application had been ceased. However, glyphosate-treated soil had significantly higher AOB abundance than no glyphosate areas, which might be potentially associated with increased total carbon (TC). Conversely, biochar did not affect soil TN in this study, potentially due to the low TN content of the biochar used in this study (wood-based biochar), but had also significantly higher AOB abundance than those of no biochar plots, potentially through stimulated N cycling. In summary, neither glyphosate nor biochar impacted soil microbial diversity or community structure, but both increased AOB abundance with possible long-term implications on soil N cycling even after two years since the last glyphosate was applied. In Chapter 5, I then investigated the short-term N pools in response to the immediate interaction of glyphosate in an amended soil with biochar. I conducted an incubation study (5-day) to understand the short-term and immediate effects of glyphosate interacted with biochar on soil N transformations (ammonification, nitrification, and N mineralisation) using the 15N pool dilution techniques. Soil samples were collected from the same horticultural site used in Chapter 4. My 5-day incubation study showed that δ15N of NO3--N was not affected by any of the factors assessed including glyphosate, biochar, nd moisture content, nor were their interactions significant. However, this study showed that both nitrification and N mineralisation were stimulated by biochar. My results also showed that application of glyphosate significantly decreased δ15N of NH4+-N in soil following 3- and 5-day incubation, indicating that N mineralisation occurred, which could be related to stimulation of soil microbes due to the addition of C as a source for soil microbes resulting from the decomposition of glyphosate. In summary, my work highlighted the importance of revegetating riparian zones to increase soil N retention particularly using woodland species and showed that glyphosate and organic-based herbicides may not necessarily alter soil microbial diversity but there were long-lasting effects on soil microbial biomass observed about one year after the application being terminated. In the horticultural site, there was also an indication of both glyphosate and biochar having affected soil microbial abundance. This long-lasting effect of herbicides on soil N cycling may have implications for the long-term sustainability of riparian zones. Therefore, my work suggested that the application of mulch should be an alternative for chemical weed control when possible.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
Full Text

The methods currently used to evaluate cultivator weed control are imprecise and often biased. A new method was tested. An experiment was carried out at two sites in 1993 and again in 1994, using a split-plot design with four repetitions. Cultivation was carried out on weed populations simulated with rye grass (Lolium spp L.) and mustard (Sinapis alba L.) in 1993 and on both simulated and natural weed population in 1994 with Rabe Werk, Hiniker and Kongskilde cultivators. Weed control was assessed by the effective weed kill and the percentage of the area of the simulated weed population which was affected, and by counts and visual observations on the natural weed population. The new method provided an objective assessment of the cultivation treatments, especially by the effective weed kill index. The area affected approach was not suitable for all cultivation treatments. There was agreement between the proposed method and the conventional methods. This validated the proposed new method. Overall, the Hiniker with ridgers performed the best. The Hiniker without ridgers, and the Kongskilde with or without ridgers performed similarly. The Rabe Werk without goosefoot attachment resulted in the poorest weed control. The degree of weed displacement varied among the cultivators and was associated with weed density. The degree of weed displacement onto the crop row from the inter-row area was low ($<$1% in 1993 and up to 3.4 in 1994). The weed displacement distance was related to weed density and the degree of weed uprooting produced by cultivation.

Aquatic weeds transform and degrade the ecosystems which they invade, impacting various aspects of their surroundings ranging from the community level to disrupting important processes affecting ecosystem services. All of the major aquatic weeds of South Africa are found in the Cape Town Metropolitan Area. Landowners, whether private or public, are legally obliged to manage the listed invasive species through applying environmentally acceptable methodologies. This thesis provides an overview of the strategic management options, prevention, early detection, rapid response and eradication of new invasions, and containment and control species of established species. It discusses the different control methods available for managing aquatic weeds, namely mechanical, manual, chemical and biological, and the integration of different methods to improve their effectiveness. Although various studies have shown that biological control is the most cost–effective, environmentally-friendly and sustainable method, it is not yet fully integrated into weed management programmes in South Africa. In addition, the successes achieved in other parts of the world with the control of water hyacinth through biological control have not been repeated in the urban environment, despite the fact that South Africa has the highest number of biological control agents available for the weed. Urbanisation puts pressure on the natural environment and ecosystem functioning. Nutrient-enriched waters support aquatic weed growth and pose a challenge to the management thereof, in particular with regard to integrating biological control into management programmes. The aims of this study were to determine the reasons for the lack of integration of biological control into weed management programmes in South Africa, to determine the feasibility of integrating biological control in aquatic weed management programmes in a complex urban environmental and socio-political landscape by means of three case studies in the Cape Town Metropolitan Area, which showed that biological control is feasible in urban environments and should be considered. Two surveys were conducted to determine the reasons for the lack of integration of biological control into weed management programmes. The surveys showed that there is a gap between research and implementation as a result of poor communication, non-supporting institutional arrangements and a lack of appropriate capacity and skills at the implementation level. Recommendations were offered to address these issues.

A series of experiments were conducted to determine the potential of a new method of steam treatment for the control of soil-borne diseases, insects and weeds in sustainable crop production.  The new method involved rapidly heating a bed of prepared soil on a porous base by passing an upward flow of steam through it.  The aim was to determine whether the new method would be suitable for use in a field machine, making large-scale field steaming practically and economically viable. In the first experiments, the feasibility of the new method was tested.  It was shown that it was an effective and rapid way in which a soil bed could be steamed.  However, for some soils at, or near, permanent wilting point, the entrainment of aggregates in the steam flow was shown to be a problem.  The second series of experiments showed that the key factor determining the flow rate at which aggregate entrainment occurred was the mean aggregate diameter of the soil being treated.  The third series of experiments examined the rate at which heated soil would cool when placed in the field.  It was shown that where there was contact with unheated field soil, cooling was very rapid.  The final series of experiments investigated the effects of the new steaming method on the soil.  A three minute steaming time was used to account for the short time it had been shown some of the heated soil would remain at steam temperature when replaced in the field.  The effects of the new method, including the effectiveness of disinfection, were shown to be similar to those of a conventional steam treatment. It was concluded that the new steaming method was an effective way to steam treat soil and should be suitable for use in a field machine.

Cette étude s’inscrit dans le cadre de l’inspection en service des soudures des réacteurs nucléaires de génération IV, en vue de contribuer à la démonstration de sûreté. La structure anisotrope et hétérogène des soudures multipasses en acier inoxydable austénitique rend leur contrôle ultrasonore difficile. Ainsi, afin d'interpréter correctement les signaux mesurés et de caractériser les défauts potentiels, une description de la soudure est utilisée. Elle constitue la connaissance a priori introduite dans la méthode de l'Energie Topologique. L’étude réalisée se décline en deux temps : le développement de la méthode en milieu borné et sa comparaison avec le Matched Field Processing, puis son application au cas de soudures réelles. L'extension de la méthode de l'Energie Topologique aux milieux bornés isotropes et homogènes vise à tirer parti des réflexions multiples. Plusieurs solutions du problème numérique de propagation, obtenues pour différentes conditions aux frontières, sont judicieusement associées afin de sélectionner les échos de diffraction porteurs d'information. Selon le type de défaut à imager des énergies topologiques spécifiques sont définies. La technique est introduite analytiquement avant d'être validée numériquement puis expérimentalement.Dans un second temps, la méthode est appliquée au milieu complexe de la soudure. La procédure est testée expérimentalement sur des soudures réelles afin d'évaluer les performances en localisation. Cependant, en raison de la variabilité de la structure, la qualité de l'image peut se dégrader selon les cas d'étude. La possibilité de générer des sources arbitraires permet de pallier en grande partie cette difficulté
The present study has been done as part of the in-service inspection of weld structure belonging to generation IV nuclear reactors. It aims at checking both the safety and integrity of these components. The anisotropic and heterogeneous structure of austenitic stainless steel welds disturbs the ultrasonic non destructive testing. Thus, a weld description model is necessary to properly analyze the ultrasonic measured signals and to characterize potential flaws. The weld model makes a priori knowledge up in the Topological Energy method. The study is divided into two parts: development of the method in a bounded medium and comparison with the Matched Field Processing method, and then its application to real weld structures.The work firstly focuses on expanding the Topological Energy method to isotropic and homogeneous bounded medium to take advantage of multiple reflections between the flaw and edges. For that, different conditions are numerically applied to boundaries. By adding up these conditions it becomes possible to select the appropriate scattering signal. Modified topological energies are defined according to the type of analyzed flaws. The approach is analytically demonstrated before being validated firstly from synthetical data and then from experimental data.The second part deals with the application of the method to the complex weld structure. The process is experimentally tested on welds in order to evaluate efficiency of flaws localization. However, the image's quality can be deteriorated because of variability of the structure. By generating arbitrary ultrasonic source this difficulty is mostly overcame

When conducting precision operations, such as disease detection, weed removal, yield prediction, and harvesting, on plants such as strawberries and blueberries, it is necessary to know the exact location of each plant. To date, GPS and LiDAR based methods have been proposed, however these methods either cannot routinely store position data, are labor intensive, expensive, or bulky. In this study, a low cost and lightweight localization approach is proposed using relative pixel information of adjacent plants. The kinematic information of a scouting robot carrying the camera and the relative position information of adjacent plants are modeled. The centroids of strawberry plants are identified one by one via image processing technologies. An extended Kalman filter is then developed to estimate the relative positions of adjacent plants. The proposed strawberry plant localization algorithm is validated in a commercial farm. The method is low cost and can be used in routine localization operations in agricultural fields.

During the study, we found that 2019 was favourable for pests’ growth, development and spread. Cicadellidae and Aphidoidea were the most harmful and numerous ones that damaged essential oil plants. Salvia sclarea was the most susceptible among the studied plants. We also found that the number of pathogens did not exceed the economic injury level thanks to timely monitoring and weed control methods.

In part I of this study an optimum NURBS curve fitting by two evolutionary optimization techniques was successfully designed. These methods were implemented to optimize the location of a set of NURBS control points for the measured point cloud of four segments of a gas turbine compressor airfoil shape. The purpose of the optimization was to demonstrate the good ability of evolutionary techniques, in particular Genetic Algorithms, in optimizing such curve fitting problems. The objective of part II is to examine two alternative solutions for NURBS curve fitting of the same airfoil point cloud with swarm intelligence optimization technique. Indeed, the same work has been done by applying two basically different optimization approaches that is Particle Swarm Optimization and Invasive Weed Optimization. Results allow seeing a number of advantages as well as some disadvantages in this optimum curve fitting approach in comparison to the previous techniques applied by authors.

Computational weld modeling is challenging because many of the processes of welding are highly nonlinear. Material melts and re-solidifies, very high transient thermal gradients are experienced, non-linear temperature dependent plastic straining and phase transformations can occur, among other sources of nonlinearity. Moreover, for weld modeling to have practical advantages in industrial production, computational solution times must be manageable since an optimum weld design of large, complex fabrications requires numerous separate analyses. Weld modeling technology is now advanced to where it can have an important impact on numerous fabricated structures. These include nuclear power plant components in commercial nuclear plants and nuclear ship structures, including Aircraft Carriers, Submarines, and Destroyers. The benefits of weld modeling include: • Significantly reduced Fabrication Costs. • Life cycle cost reduction from improved corrosion, and fatigue performance and damage reduction enhancement. • Elimination of non-valued added re-work fabrication costs. • Improve readiness by speeding the time from conception to service for new designs. • Outreach program to continue paradigm shift improvements in welded fabrications. Weld distortion control must be performed on three dimensional models. Here, extensive full-scale experiments have validated the accuracy and predictive power of models. It can be used to reduce fabrication cost and improve quality by minimizing and controlling distortions. Several application examples are presented to illustrate how to apply this tool in welded structure design and manufacture.

This presentation reviews few different applications of Concrete Canvas and Concrete Canvas Hydro material. Concrete Canvas is a flexible, concrete filled fabric which provides a thin durable concrete layer when hydrated or fully waterproof layer in it's Hydro variant. It's possible to apply concrete Canvas in many different ways, some of them are slope protection, weed suppression, canal lining, lagoon lining and erosion control. We are going to present our application of material at 3 different projects: securing waterproofness of area around gas tanks in luka Ploče, preventing fire outbreaks along railway in Slovenia and water drainage at hardly accessible locations in Serbia. Each project had it's problems where we found Concrete Canvas suitable replacement for conventional concrete solutions. In that way we delivered Investor faster and high quality solution which in the end resulted in lower expanses. We will show comparison between Concrete Canvas and standard methods that are usually used.

Orobanche is an important parasitic weed. For developing novel methods for its control, a thorough understanding of crucial stages of its development is needed. Therefore, the objectives of this project were characterization of Orobanche germination stimulants, analysis of mechanisms of haustorial penetration, and characterization and isolation of penetration enzymes. The first highly potent natural germination stimulant for Orobanche was isolated from sunflower and identified by high-field 1D (1H and 13C), 2D (1H-1H COSY, HMQC, HMBC)-NMR, GC.FT-IR, and GC.MS as costuslactone, a guaiane type sesquiterpene lactone that resembles strigol only in possessing a lactone moiety that is required for activity. The first direct in situ evidence for the enzymatic nature of the infection process of a parasitic angiosperm was established. Pectin deesterification and depletion of pectins in host cell walls were shown adjacent to haustorial cells. Pectin methyl esterase and polygalacturonase were immunocytochemically detected in intrusive cells and in adjacent host apoplast. Orobanche tissues contain inhibitors of PGase activity. PME and three PGases were isolated from Orobanche calli. PME was characterized and purified, and antibodies were prepared against it. This study presents novel findings regarding parasitism in Orobanche, which may help to open up new approaches for controlling broomrapes.

Broomrapes (Orobanche/Phelipanchespp.) are holo parasitic plants that subsist on the roots of a variety of agricultural crops and cause severe losses to the yield quality and quantity. Effective methods for controlling parasitic weeds are scarce, with only a few known cases of genetic resistance. In the current study, we proposed an improved strategy for the control of parasitic weeds based on trans-specific gene-silencing of three parasite genes at once. We used two strategies to express dsRNA containing selected sequences of three Phelipancheaegyptiacagenes PaACS, PaM6PR and PaPrx1 (pma): transient expression using Tobacco rattle virus (TRV:pma) as a virus-induced gene-silencing (VIGS) vector and stable expression in transgenic tomato Solanumlycopersicum(Mill.) plants harboring a hairpin construct (pBINPLUS35:pma). siRNA-mediated transgene-silencing (20–24 nt) was detected in the host plants. Our results demonstrate that the quantities of PaACSand PaM6PR transcripts from P. aegyptiacatubercles grown on transgenic tomato or on Tobacco rattle virus-infected Nicotianabenthamianaplants were significantly reduced. However, only partial reductions in the quantity of PaPrx1 transcripts were observed in the parasite tubercles grown on tomato and on N. benthamianaplants. Concomitant with the suppression of the target genes, there were significant decreases in the number and weight of the parasite tubercles that grew on the host plants, in both the transient and the stable experimental systems. The results of the work carried out using both strategies point to the movement of mobile exogenous siRNA from the host to the parasite, leading to the impaired expression of essential parasite target genes. In light of the importance of parasitic weeds to world agriculture and the difficulty of obtaining resistance by conventional methods, we assume that genetic resistance based on the silencing of key metabolic genes in the parasite is now feasible. BARD Report - Project4622 Page 2 of 60

The specific objectives of this research were the study of the physical and nutritional properties of the In Ovo Feeding (IOF) solution (i.e. theosmostic properties and the carbohydrate: protein ratio composition). Then, using the optimal solution for determining its effect on hatchability, early nutritional status and intestinal development of broilers and turkey during the last quarter of incubation through to 7 days post-hatch (i.e. pre-post hatch period) by using molecular, biochemical and histological tools. The objective for the last research phase was the determination of the effect of in ovo feeding on growth performance and economically valuable production traits of broiler and turkey flocks reared under practical commercial conditions. The few days before- and- after hatch is a critical period for the development and survival of commercial broilers and turkeys. During this period chicks make the metabolic and physiological transition from egg nutriture (i.e. yolk) to exogenous feed. Late-term embryos and hatchlings may suffer a low glycogen status, especially when oxygen availability to the embryo is limited by low egg conductance or poor incubator ventilation. Much of the glycogen reserve in the late-term chicken embryo is utilized for hatching. Subsequently, the chick must rebuild that glycogen reserve by gluconeogenesis from body protein (mostly from the breast muscle) to support post-hatch thermoregulation and survival until the chicks are able to consume and utilize dietary nutrients. Immediately post-hatch, the chick draws from its limited body reserves and undergoes rapid physical and functional development of the gastrointestinal tract (GIT) in order to digest feed and assimilate nutrients. Because the intestine is the nutrient primary supply organ, the sooner it achieves this functional capacity, the sooner the young bird can utilize dietary nutrients and efficiently grow at its genetic potential and resist infectious and metabolic disease. Feeding the embryo when they consume the amniotic fluid (IOF idea and method) showed accelerated enteric development and elevated capacity to digest nutrients. By injecting a feeding solution into the embryonic amnion, the embryo naturally consume supplemental nutrients orally before hatching. This stimulates intestinal development to start earlier as was exhibited by elevated gene expression of several functional genes (brush border enzymes an transporters , elvated surface area, elevated mucin production . Moreover, supplying supplemental nutrients at a critical developmental stage by this in ovo feeding technology improves the hatchling’s nutritional status. In comparison to controls, administration of 1 ml of in ovo feeding solution, containing dextrin, maltose, sucrose and amino acids, into the amnion of the broiler embryo increased dramatically total liver glycogen in broilers and in turkeys in the pre-hatch period. In addition, an elevated relative breast muscle size (% of broiler BW) was observed in IOF chicks to be 6.5% greater at hatch and 7 days post-hatch in comparison to controls. Experiment have shown that IOF broilers and turkeys increased hatchling weights by 3% to 7% (P<0.05) over non injected controls. These responses depend upon the strain, the breeder hen age and in ovo feed composition. The weight advantage observed during the first week after hatch was found to be sustained at least through 35 days of age. Currently, research is done in order to adopt the knowledge for commercial practice.

The Center for Plant Health Science and Technology (CPHST) provides scientific support for the regulatory decisions and operations of the Animal and Plant Health Inspection Service’s (APHIS) Plant Protection and Quarantine (PPQ) program in order to safeguard U.S. agriculture and natural resources. CPHST is responsible for ensuring that PPQ has the information, tools, and technology to make the most scientifically valid regulatory and policy decisions possible. In addition, CPHST ensures that PPQ’s operations have the most scientifically viable and practical tools for pest exclusion, detection, and management. This 2009 CPHST Annual Report is intended to offer an in-depth look at the status of our programs and the progress CPHST has made toward the Center’s long-term strategic goals. CPHST's work is organized into six National Science Programs: Agricultural Quarantine Inspection and Port Technology; Risk and Pathway Analysis; Domestic Surveillance, Detection, and Identification; Emergency Response; Response and Recovery Systems Technology - Arthropods; and Response and Recovery Systems Technology - Plant Pathogens and Weeds. the scientists of CPHST provide leadership and expertise in a wide range of fields, including risk assessments that support trade, commodity quarantine treatments, pest survey and detection methods, molecular diagnostics, biological control techniques, integrated pest management, and mass rearing of insects. Some highlights of significant CPHST efforts in 2009 include: Establishment of the National Ornamentals Research Site at Dominican University of California, Established LBAM Integrated Pest Management and Survey Methods, Continue to develop Citrus Greening/Huanglongbing Management Tools, and further European Grapevine Moth (EGVM) Response.