Academic literature on the topic 'Pyrethrum'

Six pyrethrin esters were separated from whole pyrethrum by using high performance liquid chromatography on a silica column. Dilutions of individual esters were applied topically to house flies (Musca domestica L.) and compared to whole pyrethrum and transpermethrin. LD50's averaged from two significant dosage-mortality regressions per chemical were in ascending toxicity: Cinerin I (1.77 μjg/fly), jasmolin I (1.28 μjg/fly), pyrethrin II (0.49 μg/fly), jasmolin II (0.46 μg/fy). cinerin II (0.43 μg/fly), pyrethrin I (0.20 μg/fly)> 25% pyrethrin extract (0.11 μg/fly) and trans-permethrin (0.0072 μg/fly).

Pyrethrin is a specialized metabolite of Dalmatian pyrethrum (Tanacetum cinerariifolium (Trevir.) Sch. Bip.), Asteraceae, known worldwide as an effective bioinsecticide. It consists of six active compounds: Pyrethrin I and II, cinerin I and II, and jasmolin I and II. Pyrethrin accumulates mainly in the flower heads and its content depends on numerous factors, such as the flower developmental stage. This study aims to investigate the accumulation patterns of six pyrethrin compounds in the flower heads of Dalmatian pyrethrum over the eight developmental stages (FS1 to FS8), and to make a comparison in six natural populations. Ultrasound assisted extraction was used to extract the pyrethrin, while qualitative and quantitative analysis was performed by High performance liquid chromatography. The accumulation patterns of different pyrethrin compounds were generally similar and also synchronous between different populations, while the pyrethrin I/pyrethrin II ratio showed irregular patterns. In all populations studied, the highest increase of all compounds was observed from FS1 to FS2. Their concentration continuously increased, reaching the highest values at FS4 stage (2–5 rows of open disc flowers), and generally decreased gradually towards FS6 or FS7 and then stagnated until the FS8 stage. Despite the very similar accumulation pattern of pyrethrin compounds in the different populations, the significant differences in their content suggest a different genetic background. Knowledge of the dynamics of pyrethrin compounds accumulation across flower development stages is valuable for determining the optimal harvest time of pyrethrum flower heads.

Nowadays, immediate environmental friendly solutions such as the use of biopesticides and other methods to control and manage pests are well needed. They are imperative due to the continuous accumulation of toxic residues from synthetic insecticides into the environment, the contamination of global agro-ecosystem and resistance of certain insects and pathogens. The global renewed interest of botanical pesticides does not leave aside Turkey. Thus, many environmental reports pointed out contaminations in different regions of Turkey by chemical pesticide residues, like lambda-cyhalothrin in some conventional grapes farming in the Aegean region. The use of botanical pesticides like Pyrethrin extracted from Pyrethrum’s flowers (Chrysanthemum cinerariifolium) is part of sustainable agriculture goals to reduce the incidence of pests and diseases without any alteration to the natural balance. The purpose of this review is to analyse and identify the possibilities of Pyrethrum production in Turkey. Various research works around the world were compiled and some key informants were correlated to existing researches in Turkey. Subsequently, it was found that the Black-Sea region of Turkey has great potential in the growing and industrial production of Pyrethrum by its weather patterns (temperatures, pluviometry and humidity) and soil characteristics. The region has a similar climate with the East-African high-lands well-known for Pyrethrum production. Thus, the country has shown great technological advances and the capacity to produce vegetative and disease-free clones for other ornamental plants by using tissue culture techniques. Therefore, the multiplication of high-quality vegetative clones of Chrysanthemum cinerariifolium and their maintenance can sustain commercial and long term production of Pyrethrum in Turkey.

The main chemical compounds in pyrethrum flower extract obtained by supercritical fluid extraction (SFE) were identified by GC-MS. Peak area normalization was used to determine relative percentage content of the compounds. The results showed that the main chemical compounds in pyrethrum flower extract were β-farnesene, β-cubebene, ethyl palmitate and ethyl linoleate, besides six pesticidal active compounds of pyrethrins that were cinerin I, jasmin I, pyrethrin I, cinerinII, jasminIIand pyrethrinII.

Pyrethrum (Tanacetum cinerariifolium) is one of the most important industrial crops for the extraction of pyrethrins, which are natural insecticidal compounds. Progress in pyrethrum molecular breeding with the objective of increasing pyrethrin content has been slow for lack of a suitable gene transfer system. Regeneration recalcitrance is a crucial barrier to establishing a genetic transformation system in pyrethrum. Therefore, in this study, an Agrobacterium-mediated transformation system in pyrethrum was developed using shoot apical meristems from germinated seedlings. Factors affecting transformation efficiency were optimized. Optimal conditions included explants at the “no true leaf” stage with a half apical meristem, an Agrobacterium tumefaciens cell density of OD600 = 0.5, two days of cocultivation, and the incorporation of 1.5 mg L−1 6-BA and 30 mg L−1 kanamycin into the selection medium. Under the optimized conditions, two expression cassettes (proTcCHS-GUS and proRbcS-TcCHS) were successfully transformed into pyrethrum. Polymerase chain reaction (PCR), Southern blotting, reverse-transcription quantitative PCR (RT-qPCR), and histochemical staining confirmed the identity of proTcCHS-GUS transgenic plants. PCR and RT-qPCR analyses confirmed the identity of proRbcS-TcCHS transgenic plants. The transformation efficiency was 0.83% (5 transgenic lines/600 infected explants). The relative concentration of pyrethrins in proRbcS-TcCHS transformants (OX T0-1: 1.50% or OX T0-2: 1.24%) was higher than that in nontransformed plants (WT: 0.76%). Thus, the genetic transformation system overcame the low regeneration efficiency and integrated a foreign gene into the pyrethrum genome. The new system is a suitable and effective tool for creating high-yielding cultivars of pyrethrum.

Pyrethrum (Tanacetum cinerariifolium) is commercially cultivated for the extraction of natural pyrethrin insecticides from the oil glands inside seed. Yield decline has caused significant yield losses in Tasmania during the last decade. A new pathogen of pyrethrum causing crown rot and reduced growth of the plants in yield decline affected fields of northern Tasmania was isolated from necrotic crown tissue and described as Paraphoma vinacea. Multigene phylogenetic identification of the pathogen also revealed that P. vinacea was a new species different from other Paraphoma type strains. Glasshouse pathogenicity experiments showed that P. vinacea significantly reduced belowground and total biomass of pyrethrum plants 2 months after inoculation. Dull-tan to reddish-brown discoloration of the cortical and subcortical crown tissue was observed in 100% of the infected plants. P. vinacea infected 75% of the plants inoculated with root dip and soil drench inoculation techniques in an inoculation optimization experiment. P. vinacea, the causal agent of Paraphoma crown rot disease, represents an important pathogen that will negatively impact the commercial cultivation of pyrethrum in Tasmania.

Abstract Six biologically active insecticidal compounds in pyrethrum extract—pyrethrin I (Py I), jasmolin I (J I), cinerin I (C I), pyrethrin II (Py II), jasmolin II (J II), and cinerin II (C II)—have been identified and quantitated using a procedure combining the modified version of the AOAC mercury reduction Method 936.05 and capillary gas chromatography with flame ionization detection (GC-FID), GC with mass selective detection, and GC with infrared detection. This method involves hydrolysis of pyrethrum extract and subsequent measurement of monocarboxylic and dicarboxylic acids. Mass and infrared spectra are used to identify the 6 active compounds, and GC-FID is used to determine their purities. The use of this characterized standard is limited to a proposed capillary GC AOAC method that quantitates AAoctyl bicycloheptene dicarboximide (MGK264), pyrethrin, and butylcarbityl 6- propylpiperonyl ether (BPE) in technical materials, concentrates, and certain finished products.

The implementation of the objectives of the Federal Scientific and Technological Program for the Development of Agriculture for 2017-2025, aimed at reducing the level of dependence on imports through the production of biological products, with an expected increase in their output by at least 20% by 2025, has determined the relevance of our research. The aim of the work was to develop compositions of plant insecticides, including natural pyrethrins contained in Dalmatian chamomile (Pyrethrum cinerariaefolium Trev) and neem oil, to confirm the effectiveness of their combinations against insect pests of protected soil. The research was conducted in the greenhouse of the Agrobiotechnological Department of the Patrice Lumumba Peoples' Friendship University of Russia's Agrarian and Technological Institute in 2023-2024. The scientific article presents the results of research on the effectiveness of plant insecticides based on pyrethrums and neem oil against aphids on tomatoes of protected soil. It has been established that pyrethrum essential oil based on Dalmatian chamomile is effective in controlling aphids, but its effectiveness is lower than that of neem oil in the same application rates. In the variant with Pyrethrin, at a consumption rate of 0.5 liters/ha, the effectiveness was significantly lower, which was insufficient to protect tomatoes from aphid-carrying viruses. By day 21, the average number of aphids in the control was 41.0 individuals/100 leaves. On day 21, in the 3 variant with the insecticide Pyrethrin, BP + Neem oil (50 g/l of natural pyrethrin extract +50 g/l neem oil) and the reference, the biological efficacy was high and amounted to: 100-96.6% (Pyrethrin + neem)) and 100 - 99.4%. Thus, the results of the study indicate the effectiveness of treatment with biological preparations from plant extracts of pyrethrin and neem, which help reduce the number of aphids on tomatoes in protected soil, and further increase fruit yields. Among the studied options, option 3 is the most optimal, providing high efficiency comparable to the effectiveness of chemical preparations. The data obtained confirm the possibility of plant extracts based on essential oils as an alternative to chemical insecticides.

Purpose: A favorable environment is available for the cultivation of Pyrethrum in the hilly regions of India, as well as in some mountainous areas of India. In view of the demand for Pyrethrin, it is very necessary to promote the huge cultivation of Pyrethrum. There is no misconception that research work has not been done to promote Pyrethrum, but the data related to the assessment of the right amount of nutrients required for the crop is not available in research related to agrotechnology. If the crop is to be taken as a ratoon crop, then it is very important to estimate the amount of nutrients for single recommendation of crop cultivation. Research Method: A research experiment was conducted in the year 2021 at the CSIR-Central Institute of Medicinal and Aromatic Plant Research, Centre Purara, Bageshwar (Uttarakhand) to study the flower yield potential of Pyrethrum under various NPK levels in the lower hills of Uttarakhand. The experiment was carried out in Complete Randomized Block Design. The six different levels of NPK (kg ha-1) were taken as treatments, i.e., control, 60:60:20, 80:70:30, 100:80:40, 120:90:50, and 150:100:60. Various plant growth and yield parameters considered in the study include plant height (cm), plant diameter (cm), number of flower heads, fresh flower weight plant-1 (g), dry flower weight plant-1(g), fresh flower yield (kg ha-1), dry flower yield (kg ha-1), Pyrethrin concentration (%) and yield (kg ha-1). Findings: Based on the research findings, it seems that the NPK level of 120:90:50 is the best combination to obtain the highest dry flower yield (310.49 kg ha-1) in the lower hills of Uttarakhand. However, the fresh flower weight obtained was the highest under the NPK level of 100:80:40 i.e., 840.47 kg ha-1, but it’s dry flower yield estimated was 301.93 kg ha-1 which was the second highest yield after 310.49 kg ha-1. This could be due to the difference in moisture levels in fresh flowers at the time of harvesting.Research Limitation: Considering the climate of the hilly regions of Uttarakhand, not much work has been done to assess and standardize the proper amount of nutrients required for Pyrethrum crop cultivation, which needs to be done.Originality/ Value: In the hilly areas of Uttarakhand, farmers are interested in the cultivation of Pyrethrum, but if farmers will adopt this crop cultivation as a ratoon crop, then in such a situation it is absolutely necessary to assess the proper amount of nutrients. This research will prove helpful in promoting the cultivation of Pyrethrum in the hilly areas of Uttarakhand.

Six novel green extraction techniques were evaluated and optimized to extract pyrethrin from dried Dalmatian pyrethrum (Tanacetum cinerariifolium (Trevir./Sch.Bip.). This approach offers a promising natural alternative to conventional chemotherapeutics. Four methods are presented for the first time in this study: microwave-assisted extraction (MAE), high-voltage electric discharge (HVED) extraction, subcritical water extraction (SWE), and deep eutectic solvent (DES) extraction, together with supercritical CO2 extraction (SC-CO2) and ultrasound-assisted extraction (UAE), for pyrethrin extraction from Dalmatian pyrethrum. The study revealed that supercritical CO2 extraction was the most effective method for extracting all six pyrethrins, yielding the highest total amount of 124.37 ng/mg. This approach offers a “natural” insecticide produced with a clean, environmentally friendly technology that can contribute to the development of sustainable and effective insecticide strategies that are in line with environmental safety and organic production standards. In addition, this research highlights the potential application of pyrethrins as antiparasitic agents, emphasizing their role in environmentally friendly and ecological practices.

Aneuploid plants are often used to locate genes or establish linkage, but first, they must be available. In Chrysanthemum cinerariaefolium Vis., a plant that produces pyrethrin, a relatively safe natural insecticide, aneuploids had not been categorized before. This research proposed to characterize aneuploids by morphology, cytology, nuclear DNA content, and pyrethrin composition. Aneuploid progeny of triploid parents were examined cytologically and morphologically. HPLC was used to establish pyrethrin composition and nuclear DNA content was calculated from flow cytometry. Five distinct phenotypes were found that may indicate aneuploid status, but not exact chromosome number. Exact chromosome number could only be distinguished cytologically, and ranged from 17 to 36, (2n = 18 for the diploid). Three trisomics were located. Nuclear DNA content indicated diploid or triploid status but not aneuploidy. Some of the aneuploids categorized may be useful in further research to locate pyrethrin genes or their linkages.

Resistance to the root-knot nematode, Meloidogyne hapla, was systemically induced on tomato and pyrethrum plants by advance inoculations with mildly virulent M. incognita and M. javanica, respectively. The reproduction of M. hapla was reduced by 84% on tomato (var. Celebrity), and by 72% on pyrethrum (clone 223) in greenhouse experiments, and by 55% on pyrethrum plants on field-plot experiments, relative to the non-induced controls. The magnitude of induced resistance increased with increasing intervals between the applications of resistance inducer and challenge nematode inocula, from 0 to 10 day intervals, then levelled off, for both tomato and pyrethrum. Induced resistance increased also with increasing levels of inducer inoculum, from 0 to 5,000 infective juveniles per plant in 500 ml pots, for both tomato and pyrethrum. Advance inoculation of one halves of partially-split root systems with resistance-inducing nematodes resulted in protection of the other halves from challenge nematodes. The observation indicated the systemic translocation of induced resistance factors from sites of induction to remote plant parts. Advance inoculations of host plants with the virulent M. hapla increased susceptibility in the plants to secondary nematode inocula, such that the originally non-virulent M. incognita and M. javanica subsequently attained enhanced reproduction rates comparable to M. hapla. Pyrethrum seedlings which received advance inoculation with M. javanica prior to challenge with M. hapla had growth rates comparable to those of nematode-free controls, while the unprotected M. hapla-infected plants were stunted up to 33%, in greenhouse experiments. In field plot experiments, the unprotected pyrethrum seedlings were stunted up to 36%, relative to plants with induced resistance. These results suggest that initial incompatible or compatible plant-nematode interactions conditioned the plants to increased resistance or susceptibility, respectively, against subsequent invading nematodes. As such, advance inoculations of plants with incompatible or mildly virulent nematodes, could be a prospective method of protecting plants against virulent nematodes.

Master of Science<br>Department of Entomology<br>Frank H. Arthur<br>Kun Yan Zhu<br>Experiments were conducted to assess the effects of direct and indirect exposure scenarios, different degrees of residual flour, open and obstructed positions, and seasonal temperature variations on the efficacy of synergized pyrethrin against the red flour beetle, Tribolium castaneum (Herbst) and the confused flour beetle, Tribolium confusum Jacquelin du Val. To evaluate effects of direct and indirect exposures of T. castaneum and T. confusum eggs, larvae, pupae, or eggs to the insecticide aerosol within a flour mill, the following treatments were made to each life stage: insects treated with aerosol and transferred to treated or untreated flour, untreated insects transferred to treated flour, and insects and flour combined and treated together. Different degrees of harborage or sanitation levels were created by exposing T. confusum larvae, pupae, and adults to pyrethrin aerosol in Petri dishes containing 0, 0.1, 1, 5, and 10 g of wheat flour. Effects of pyrethrin dispersal in open and obstructed positions and seasonal temperature variations were assessed by exposing T. confusum pupae and adults in open positions and inside wooden boxes (1 m long, 20 cm wide, and 5, 10, or 20 cm high) inside experimental sheds maintained at target temperatures of 22, 27, and 32 °C. Results showed that when T. castaneum and T. confusum were directly exposed to aerosol without the flour source, or with a low amount of flour at open exposed areas, the aerosol provided good control against all life stages of T. castaneum and T. confusum. However, when insects were indirectly exposed (treated together with flour or untreated insects were transferred to treated flour), or treated together with deeper flour amounts, and exposed inside the boxes, the efficacy was greatly reduced. Eggs and pupae of both the species were more susceptible compared to larvae and adults. Additionally, the moribund adults initially observed in indirect exposure treatments, or at the deeper flour depth and exposure positions insides the boxes, were better able to recover. Generally, temperatures in the range of 22-32 °C had no significant effects on overall efficacy of pyrethrin aerosol.

O desenvolvimento da agricultura, a modernização dos meios dos cultivos, buscando atender a um mercado exigente, tem-se baseado no uso de insumos agrícolas para garantir a produção de alta qualidade e de quantidade. Tais culturas demandam o uso de pesticidas, cujos resíduos, principalmente em hortaliças e frutas, são motivo de preocupação com a saúde dos consumidores e de operários que necessitam retornar às culturas tratadas com esses agrotóxicos. Os objetivos deste estudo foram: a) estudar o comportamento dos resíduos de deltametrina, de diferentes formulações, em frutos, folhas e solo; b) avaliar os resíduos deslocáveis do inseticida nas folhas, como ponto de partida para estudos de exposição ocupacional; c) correlacionar os teores de deltametrina nos frutos com o controle da broca-das-cucurbitáceas e d) correlacionar os resíduos nos frutos com o limite máximo de resíduo (LMR) e o intervalo de segurança (período de carência) estabelecidos pela legislação. Os tratamentos foram: a) testemunha; b) três aplicações da formulação em concentrado emulsionável Decis 25 CE na dosagem de 30 mL p.c.100 L-1 de água (0,75 g i.a. deltametrina.100 L-1 de água); c) três aplicações da formulação em concentrado emulsionável Decis Ultra 100 CE na dosagem de 7,5 mL p.c.100 L-1 de água (0,75 g i.a. deltametrina.100 L-1 de água); e d) três aplicações da formulação em suspensão concentrada Decis 200 SC na dosagem de 3,75 mL de p.c.100 L-1 de água (0,75 g i.a. deltametrina 100 L-1 de água). As amostras de fruto e de solo foram colhidas a (-1); zero; 1; 3; 5 e 7 dias após a última aplicação; as amostras de folhas e as de para estudos de resíduos deslocáveis nestas foram tomadas a (-1); zero; 1; 3; 5; 7 e 14 dias. O método analítico constou da extração dos resíduos de deltametrina de acetato de etila, limpeza dos extratos por técnica de cromatografia de permeação em gel (GPC), com eluição feita com uma mistura de acetato de etila/ciclohexano. A determinação quantitativa por cromatografia de gás. Para a avaliação da eficiência do inseticida, foram feitas seis levantamentos de infestação, determinando-se a porcentagem de frutos brocados. Os resultados indicaram que os resíduos de deltametrina no fruto, embora em baixos níveis, encontravam-se acima do LMR (0,03 mg.kg-1), mesmo um dia após o término do intervalo de segurança (2 dias) para as formulações do inseticida. Nas folhas, os resíduos resultantes das aplicações da formulação SC foram sempre maiores do que ambas CE (10-20 vezes), sendo de 15-80 vezes mais altas do que nos frutos. No solo, os resíduos foram também baixos (0,01-0,05 mg.kg-1), e semelhantes nas três formulações, entretanto, com baixa dissipação. Os resíduos deslocáveis de deltametrina nas folhas foram muito elevados quando de aplicações em SC, comparadas com as formulações CE (4-20 vezes), com valores de meias-vida de 2,8; 3,8 e 32,2 dias, respectivamente para as formulações Decis 25 CE, Decis Ultra 100 CE e Decis 200 SC. O inseticida, nas formulações em que foi aplicado, foi eficiente no controle da praga durante todo o período de avaliação.<br>The agriculture development, the modernization of cultivation means, trying to meet a demanding market, has been based on the use of agricultural supplies to assure a high quality and quantity production. Such crops demand the use of pesticides, whose residues, especially in fruit and vegetable production, raise worries about the consumers’ health and of the workers who need to return to the treated crop with these pesticides. The objectives of this study were: a) to study the behavior of deltamethrin residues applied in different formulations in fruits, leaves and soil; b) to evaluate the dislodgeable residues of the insecticide in leaves, as a starting point for occupational exposure studies; c) to correlate deltamethrin concentration in fruit with the pickleworm control and d) to correlate residues in fruit with the maximum residue level (MRL) and the safety interval established by the legislation. The treatments were: a) control ; b) three applications of the emulsifiable concentrate formulation Decis 25 CE.100-1 at the dosage of 30 mL of c.p.100 L-1 water (0.75 g a.i. deltamethrin.100L-1 water); c) three applications of the emulsifiable formulation of Decis Ultra 100 CE at the dosage of 7.5 mL of p.c.100 L-1 water (0.75 g a.i. deltamethrin.100. L-1 water) and d) three applications of the concentrate suspension formulation Decis 200 SC at the dosage of 3.75 mL of c.p.100.L-1 water (0.75 g a.i. deltamethrin 100L-1 water). The fruit and soil samples were taken at (-1); zero; 1; 3; 5 and 7 days after the last application; leaf samples and also those for the studies of dislodgeable residues on them were collected at (-1); zero; 1; 3; 5; 7 and 14 days after the last application. The analytical method consisted of the extraction of deltamethrin residues in ethyl acetate, clean-up of the extracts by gel permeation chromatography (GPC), with elutition made with a mixture of ethyl acetate/cyclohexane. The quantitative determination was made by gas chromatograph. To evaluate the insecticide efficacy six infestation surveys were carried out, based on the percentage of infested fruit . The results indicate that the deltamethrin residues in fruit, though in low levels, were found higher than the MRL (0.03 mg.kg-1), for the three insecticide formulations, even a day after the end of the safety interval (2 days). In the leaves the resulting residues of the applications of SC formulation were always bigger than both CE (10-20 times), being 15-80 times higher in the fruits. In the soil, the residues were also low (0.01-0.05 mg kg-1), and similar in the three formulations, however with low dissipation. The dislodgeable residues of deltamethrin in leaves were higher in SC as compared to both CE (4-20 times), with half-life values of 2.8; 3.8 and 32.2 days, respectively for the formulation Decis 25 CE, Decis Ultra 100 CE and Decis 200 SC. The insecticide in the formulations applied was efficient in the pest control during the whole evaluation period.

Drying technology is being more and more used in chemical industry, food industry, processing agricultural products, and fibber industry. In the majority of processing industries, drying is carried out for one or more reasons: 1)To offer ease dealing in further processing. For example; drying sweet chrysanthemum in order to increase sweet agents. It can be instead of the cane sugar. The sweet taste is nearly 200 times of that of the cane sugar. Generally, after picking up the fresh leaves of the sweet chrysanthemum, it is necessary to send them to drying equipment at the temperature about 80 C° ---100 C°. With the help of the drying their fresh leaves, their volume will be reduced to one of seventh or one of eighth of fresh leaves volume. Then it is through chemical processing them to get sweet ingredients. Finally, these sweet ingredients are dried at the temperature nearly 140 C° to get the final white products. 2) To supply the final product with satisfactory moisture, such as tea, tobacco. The moisture of fresh tea leaves is about 70%. After drying the final moisture of tea is about 6 %. 3) To preserve the products during storage. For example, drying rice, corn, and other agricultural products are to impede the enzyme to oxidation of these agricultural products, because the final lower moisture of the dried agricultural can limit the enzyme to grow. 4) To avoid the presence of the moisture which may lead to corrosion as in drying some metal products. The drying process includes moisture migration and evaporation. The heat and mass transfer are always key controls for any drying processes in designing the dryer. The drying energy efficiency and drying cost should be considered firstly. Currently high density industrial drying technology is developing quickly based on a deeper understanding of the drying process and the character of wet objects. The purpose of the paper is to analyse the drying process, including heat and mass transfer, moisture movement and moisture evaporation, and the air flow situation in the drying chamber through discussing the practical drying pyrethrum. A moisture moving model in capillaries is set up to study the moisture movement inside the pyrethrum, which will influence the drying rate because the moisture in the wet pyrethrum exists mainly in the capillaries. A mathematical model of Heat and Mass transfer has been developed to explaining the drying principle and to design a suitable dryer for drying pyrethrum. Psychrometric chart and other charts are introduced to understand the change of warm air conditions during drying pyrethrum. The drying curve predicts the moisture changes in the wet materials and the characteristics of the dryer. Analysis of the air flow patterns in the air duct leads to improvement in the air velocity distribution in the drying chamber. After studying the whole drying theory, the forced convection multiple continuous dryer is recommended for drying pyrethrum. In this dryer, the heat energy necessary for moisture evaporation is supplied through the convection of warm air. The vapour is carried away by the warm air. The continuous drying will result in higher drying efficiency. This dryer offers some outstanding features as follows: (1) This dryer offers a larger output for a given floor area. (2) The drying conditions can be easily controlled. (3) Higher heat efficiency can be obtained in this dryer due to the continuous drying process. (4) Automatic loading and discharging save some labour costs. (5) Compared with other dryers, lower operation costs and lower manufacture costs are obtained in selecting this dryer. High density drying should produce the top quality dried products at the lowest cost. In drying plants or agricultural products, the top drying quality has some specification as follows. (1) The final moisture contents of the dried products should be in equilibrium with that of the air in which it is to be stored so that further changes in moisture are small. This conditions is called the equilibrium moisture content. For most organic plants, the EMC is in the ranges 9-15% of oven dry weight. (2) The oxidation of ingredients should be lower than 15% by weight. (3) The broken volume should be lower than 15% by the total volume. (4) Odour and colour should be maintained. For example drying tobacco, the colour should be the golden yellow. For drying some vegetables, the natural green colour should be kept during the drying process. It is hoped that this study may lead to improved drying technology in drying Chinese tea, tobacco, vegetables, mushrooms, agricultural products and food.

Pyrethrum oil sourced from Tanacetum cinerariifolium is the main commercial source of the natural pesticide, pyrethrum oil with the active components being pyrethrin esters. Pyrethrum oil also contains sesquiterpene lactones (STLs) with pyrethrosin being the major STL. Following the refining process, pyrethrins are diluted from 80% to 53% with paraffinic naphthenic (LPA) carrier oil and pyrethrosin, which makes up 0.2-0.4% of the final product, is less soluble in the diluted oil and precipitates during storage. These crystals have been reported to block the nozzles during insecticide application. In addition, it has been reported that exposure of humans to pyrethrosin elicits an allergenic response. The solubility of pyrethrosin in pyrethrin oil diluted with a carrier oil is a major factor that compromises the quality of pyrethrin oil. This study focuses on two aspects: pyrethrosin solubility in stored pyrethrin oil in the presence of carrier oils and the investigation of the biosynthetic pathway for the production of STLs. Firstly, pyrethrum STLs were characterised and quantified using different techniques, including X-ray crystallography, polarised light microscopy and nuclear magnetic resonance (NMR). The precipitate was found to be pyrethrosin, despite the tentative identification of seven other STLs in the oil including cyclo-pyrethrosin, β-cyclo-pyrethrosin, dihydro-β-cyclopyrethrosin, C7-C8 guaianolides, tatridin A and dihydro-tatridin A and C7-C8 eudesmanolide, chrysanin. A method for quality control prior to distribution of the commercial product using polarised micoscopy was developed. Quantitative analytical methods developed in this study to analyse pyrethrum oil firstly trialled the use of liquid chromatography, as the pyrethrin esters are thermally labile however, coupling this with detection using Mass Spectrometry (MS) with Electrospray Ionisation (ESI) was non quantitative as the esters were found to degrade in the electrospray ionisation (ESI) chamber at high temperatures (400°C), whilst pyrethrosin condensed at lower temperatures (120°C, 200°C). Photo Diode Array (PDA) detection was also unsuitable for the simultaneous analyses of pyrethrosin and pyrethrin esters as co-eluting peaks required the specificity of Single Ion Monitoring (SIM). Similarly, when analysed by Gas Chromatography with detection by Flame Ionisation Detection (GC/FID), degraded pyrethrin I coeluted with pyrethrosin, resulting in an elevated baseline on the GC chromatogram. An optimal temperature gradient for GC was established which minimised the degradation of pyrethrin esters allowing for the quantification of pyrethrosin in the trials undertaken in this study. With a view to selectively remove pyrethrosin from pyrethrum oil prior to distribution, the application of silica and octadecane columns were trialled. Silica was found to effectively retain 94% solubilised pyrethrosin in reverse phase chromatography using hexane as the mobile phase while normal phase chromatography using octadecane as the matrix was less effective. Centrifugation was a superior method for removing precipitated pyrethrosin crystals when compared to filtration (0.45μm). The precipitation of pyrethrosin from oil is facilitated in the industry by storage of refined oil, diluted with carrier oil at -10°C, for a period of months, incurring significant costs to commercial operations. This study established the rate of precipitation under different storage conditions in several time series trials. The agitation of oil during storage to provide nucleation sites only slightly increased the rate of crystallisation. The study showed that the majority of the crystals were formed within the first 10 days at -10°C. Subsequent trials confirmed that the rate of precipitation was independent of storage temperature and predominantly occurred within the first 5 to 10 days of storage at both -10°C and 4°C. Larger-scale storage trials of pyrethrin oil at -10°C, 4°C, and room temperature showed that no significant difference in the rate of crystal formation was found for up to 90 days between the treatments. The blockage of spray nozzles by crystals could be alleviated by keeping pyrethrosin in solution. As such, the solubility of pyrethrosin in pyrethrin oil that had been diluted with different carrier oils was established. The solubility of pyrethrosin in mineral oil was found to be 9.4, 6.6, 5.93, 5.27, 5.1, 4.4 and 3.4 mg/g in 100, 90, 85, 80, 73, 70 and 55% diluted oil, respectively. A faster rate of precipitation was recorded for increasing amounts of carrier oil. The use of Isopar-M oil, mineral oil, and canola oil as alternative carrier oils were trialled at dilutions of 100, 80, 70, 55, 45, and 38 % relative to pyrethrum oil. All of the oils formed a partition except canola oil. Pyrethrosin concentration remained constant over time in all of the different dilution ratios of canola oil in pyrethrum oil. The localisation of STLs in the trichomes of pyrethrum flowers was confirmed by the selective extraction of the lactones by dipping the complete pyrethrum flower head in DCM. Only trace levels of esters were co-extracted, with the exception of cinerin 1. Environmental Scanning Electron Microscope (ESEM) images confirmed that the trichomes were emptied of oil without damaging the epidermis. An alternative to the removal of pyrethrosin from pyrethrum oil was to selective breed out the genetics for the production of STLs. Two seed lines named ‘Evil’ and ‘Virtuous’ had been selectively bred to produce high and low levels of pyrethrosin, respectively. Examples of each were propagated, vernalised and the flowers screened. The lowest level of pyrethrosin was 0.06%, detected in Virtuous, which was 24 times less than that recorded for Evil at 1.42%. Peaks tentatively identified as cyclopyrethrosin and dihydro-B-cyclopyrethrosin, on average, were more concentrated in Virtuous plants. ESEM was used to determine the size, density, and distribution of trichomes in both seed lines. On average, there was no significant difference in the trichomes number, although the spatial distance between organelles was found to be significantly different between the two seedlines. The genetic difference between Evil and Virtuous presented the opportunity to investigate the biosynthetic pathway of STLs. Three enzymes, TcGAS, TcGAO, and TcCOS, previously identified as providing the precursors to STLs, were compared by analysing the Gene Expression Ratio (GER) of these enzymes. The entire methodology of GER analysis was optimised for Tasmanian pyrethrum seedlines. Primers to allow for DNA amplification by Polymerase Chain Reaction (PCR) were designed along with the primers for two reference genes TcGAPDH and TcActin7, using a nucleotide sequence database GenBank of National Centre for Biotechnology Information (NCBI), and a public database for primer design Primer 3 of Free Software Foundation USA. The PCR program was optimised for primers specificity for all five genes. The amplified DNA of TcGAS, TcGAO, and TcGAPDH showed a single band on the gel with the expected number of base pairs (bp) when referenced to a ‘ladder’ of known gene fragment sizes, however, a double band was observed for TcCOS, and this may have been due to the formation of primer dimers. Real-time quantitative PCR (RT-qPCR) was used to establish a DNA standard curve with good linear regression efficiency of TcGAS (efficiency:1.00, R\(^2\)=0.9995), TcGAO (efficiency:0.97, R\(^2\)=0.9996), TcGAPDH (efficiency:1.01, R\(^2\)=0.9997), and TcCOS (efficience:0.99, R\(^2\)=0.9994). Melt curves analysis confirmed the purity of DNA for all the genes except for TcCOS, which showed a double peak. Each gene was sequenced, and the BLAST database showed the TcGAPDH sequence matched 93% with the related species Helianthus annuus. The sequences for TcGAS, TcGAO, and TcCOS matched 100%, 97%, and 100% respectively with Tanacetum cinerariifolium and TcActin7 matched 96% with Chrysanthemum morifolium, which is a plant species closely related to pyrethrum in Asteraceae. The relative rate of expression for the three genes in Evil and Virtuous was compared using the technique known as GER analysis. The RNA of six Biological Replicates (BRPS) from stage 3 flowers of each seedline were extracted. The RNA Integrity Number (RIN) for each BRP was >7, confirming the quality of the RNA. The Reverse Transcriptase qPCR (RT-qPCR) of TcGAPDH showed good Cq differences for both seedlines but the melt curve of the cDNA from the Evil seedline presented two peaks rather than a single DNA amplicon. Sequence analysis of the TcGAPDH revealed that the two peaks of the amplicon were due to nucleotide degeneracy of the sequence in Evil BRPS. In GER analysis by RT-qPCR, the cDNA segments of the 12 BRPS were amplified, and the expression ratio of each gene was calculated against two reference genes using the Relative Expression Software Tools (REST) method. The results showed TcGAS expression is down-regulated (p=0.025), while TcGAO (p=0.59) and TcCOS (p=0.14) were at the same level in Virtuous relative to Evil plants. The down-regulated expression of TcGAS correlated with lower pyrethrosin concentrations but did not correlate with the overall increased levels of other STLs, which were higher in Virtuous compared to Evil. Down-regulation of TcGAS, and the implied decrease in the biosynthesis of germacrene A, a precursor to STLs early in the biosynthetic pathway, may provide for the redirection of resources to other secondary metabolites in Virtuous plants such as flavonoids or other minor bioactives. This study provides knowledge to reconsider existing processes for the production of quality pyrethrum oil in terms of pyrethrosin solubility and storage. Investigations undertaken into the biosynthetic pathway for STLs contributes to the understanding of enzyme activity to inform pyrethrum breeding programs.

The study is focused on the field of introduction, research and use of aromatic and medicinal plants. This article presents the results of some investigations, regarding the biological, morphological and ecological peculiarities of development, propagation and cultivation of the aromatic species with insecticidal properties – Pyrethrum cinerariaefolium Trev. – species introduced and researched in the “Plant Resources” Laboratory. The results obtained suggest the need to continue further studies to establish and explore the insecticidal properties, which open new prospects for the use of this species in the biological protection of plants.

Abstract Agropyrum repens is a perennial plant from the grass family (Poaceae). In this paper, the use of Agropyrum repens in soil protection and phytoremediation of degraded areas, and as a medicinal and decorative plant is analyzed. The fact that Agropyrum repens can be grown even in marginal agro-ecological conditions gives us the opportunity to establish perennial grass areas on unused and degraded areas. Thanks to the development of new technologies for the processing of biological waste into energy products, the rate of increase in the use of alternative fuels is growing significantly, and tall mash, thanks to its modest requirements for water and heat, can be classified as a desirable energy crop. Agropyrum repens is one of the best crops for soil protection against all types of erosion, then for phytoremediation, absorption of harmful gases from the atmosphere, and it is valued as a decorative and ornamental plant. In order to ensure security in the supply of necessary energy sources, most countries in the world direct their research in the direction of finding the most rational way of using renewable energy sources. In folk medicine, pyrethrum is used in the prevention of gout, rheumatism, and inflammation of the urinary tract and renal stones. Key words: Biological waste, biofuels, Agropyrum repens, renewable resources, phytoremediation, medicine.Abstract Agropyrum repens is a perennial plant from the grass family (Poaceae). In this paper, the use of Agropyrum repens in soil protection and phytoremediation of degraded areas, and as a medicinal and decorative plant is analyzed. The fact that Agropyrum repens can be grown even in marginal agro-ecological conditions gives us the opportunity to establish perennial grass areas on unused and degraded areas. Thanks to the development of new technologies for the processing of biological waste into energy products, the rate of increase in the use of alternative fuels is growing significantly, and tall mash, thanks to its modest requirements for water and heat, can be classified as a desirable energy crop. Agropyrum repens is one of the best crops for soil protection against all types of erosion, then for phytoremediation, absorption of harmful gases from the atmosphere, and it is valued as a decorative and ornamental plant. In order to ensure security in the supply of necessary energy sources, most countries in the world direct their research in the direction of finding the most rational way of using renewable energy sources. In folk medicine, pyrethrum is used in the prevention of gout, rheumatism, and inflammation of the urinary tract and renal stones. Key words: Biological waste, biofuels, Agropyrum repens, renewable resources, phytoremediation, medicine.