Doses Of Pesticides Research Articles

Contributions on Lindane Degradation by Microcystis aeruginosa PCC 7806

Cyanobacteria are able to tolerate, and even metabolize, moderate doses of organochlorine pesticides, such as lindane (γ-hexachlorocyclohexane), one of the most persistent and widely used in recent decades. Previous work showed that Microcystis aeruginosa PCC 7806 degrades lindane and that, in the presence of the pesticide, microcystin synthesis is enhanced. In this work, using in silico approaches, we have identified in M. aeruginosa putative homologues of the lin genes, involved in lindane degradation in Sphingobium japonicum UT26S. Real-time RT-PCR assays showed that the putative linC gene was induced in the presence of 7 mg/L of lindane. Additionally, prxA, encoding a peroxiredoxin, and involved in oxidative stress response, was also induced when lindane was present. Taking into account these results, M. aeruginosa PCC 7806 may degrade lindane through a metabolic pathway involving a putative 2,5-dichloro-2,5-cyclohexadiene-1,4-diol dehydrogenase encoded by a linC homologue. However, the low similarity of the other potential lin homologues suggest the existence of an alternative pathway different to that of heterotrophic microorganisms such as S. japonicum.

Microfluidic preparation of a novel phoxim nanoemulsion pesticide against Spodoptera litura

With continuous development of pesticide dosage forms, emulsifiable concentrates using large amounts of organic solvents are gradually obsoleted. Nanoemulsions with high water content have been developed and the preparation processes also evolved, but these processes still exist some problems, such as poor controllability and high energy consumption. Microfluidic is a controllable nanoemulsion preparation system which mainly applied to pharmaceutical synthesis. In this study, the pesticide phoxim nanoemulsion was prepared by microfluidic technology. The optimized formulation of phoxim nanoemulsion was composed of Tween 80 and pesticide emulsifier 500 as surfactant, hexyl acetate as oil, and n-propanol as co-surfactant. Moreover, when the flow rates of water and oil in the microfluidic system were adjusted to 5 μL/min and 20 μL/min, phoxim nanoemulsion was obtained with a cloud point/boiling point of 109°C, a particle size of 21.5 ± 0.8nm and a potential value of - 18.7 ± 0.6mV. Furthermore, the nanoemulsion had a rapid release effect in vitro which could be fitted by the Ritger-Peppas model. The feeding toxicity of the phoxim nanoemulsion was higher than that of commercial formulation while the contact killing effect was higher than that of the active ingredient. Therefore, pesticide dosage was reduced and the insecticidal effect was enhanced by using phoxim nanoemulsions. These results also confirm the potential of microfluidics as a green process to produce pesticide nanoemulsions.

Hygienic assessment of the risk of development of metabolic disorders associated with pollution of drinking water with organic chlorinous compounds

Introduction. High morbidity rates of diseases of the endocrine system and the existing features of drinking water pollution with organochlorine compounds (OCCs) make it necessary to study the mechanisms of the influence of low doses of organochlorine pesticides on public health. The purpose of the study is to study the features of the formation of non-carcinogenic risk in the population associated with exposure to OCCs in drinking water and endocrine disorders, using the example of 2,4-dichlorophenoxyacetic acid (2,4-D) under conditions of chronic oral exposure in small doses in the experiment. Materials and methods. According to the results of a comparative hygienic assessment of more than 10 thousand samples of drinking water from centralized water supply in 41 municipalities of the Orenburg region, a rural area with the highest content of OCCs and 2,4-D was identified. There was executed an analysis of the incidence of diseases of the endocrine system, digestive system and metabolic disorders (E00-E90) in the population. The experimental part of the work was carried out on 2 groups of Wistar rats: the 1st group was control, the 2nd group consumed water containing 2,4-DA (ammonium salt of 2,4-dichlorophenoxyacetic acid) at a concentration of 0.015 mg/l (0 .5 MPC). In the blood serum of animals, an analysis was made of the level of hormones: triiodothyronine (T3) and thyroid hormone (T4), testosterone and insulin, with an assessment of body weight and epididymal fat. Results. The observation area was established to be characterized by a high level of contamination of drinking water with OCCs and mainly with 2,4-D. Non-carcinogenic risk for the endocrine system (0.005), corresponding to an acceptable level, is significantly higher by 2-4 times (p < 0.05) for adults and children than in the comparison area. The primary incidence of diseases of the endocrine system, digestive system and metabolic disorders (E00-E90) in the observation area (34.88±5.9) is by 2 times higher than the average regional value and 6 times in the comparison area, which indicates the manifestation of disruptive properties 2,4-D and OCCs. The experiment showed that in animals of the experimental group, body weight on day 135 is 10% higher than the control one. An increase in the level of insulin in animals of the experimental group by 70% on day 45 and by 25% on days 90 and 135 of the experiment was established. In the experimental group, on the 45th, 90th and 135th days, the concentrations of T3 decreased by 22%, 5% and 6%, and T4 - by 13%, 12% and 38%, respectively. By the end of the experiment, the testosterone content in the experimental group was lower by 36%. Limitations. The limitations of the study are related to the transfer of the results of experimental data to the studied exposed population and the assessment of only OCCs and 2,4-dichlorophenoxyacetic acid (2,4-D) in drinking water without taking into account other environmental factors. Conclusion. The conducted study testifies to the manifestation of the disruptive properties of 2,4-D in an animal experiment, which is expressed by a violation of the mechanisms of metabolism regulation. The results of the experiment showed the intake of small doses (0.5 MPC) of 2,4-D into the body to have an obesogenic effect, manifested in a gain in total body weight and epididymal fat, accompanied by a decrease in the level of testosterone and thyroid hormones in the blood serum.

Using tank-mix adjuvant improves the physicochemical properties and dosage delivery to reduce the use of pesticides in unmanned aerial vehicles for plant protection in wheat.

Unmanned aerial vehicles (UAVs) are widely used to improve the efficiency of pesticide applications. Low-volume spraying operations require more efficient deposition of droplets on the target surface. Therefore, pesticide deposition and retention on plant surfaces is a serious challenge for modern precision agriculture. Tank-mix adjuvants have been used to improve spray dilutions performance; however, their effects on the physicochemical properties of spray dilutions, dosage delivery, and pesticide dosage are unclear. Tank-mix adjuvant 8860 significantly improved the physicochemical properties of spray dilutions, inhibited spray droplets rebound, improved the wetting and spreading performance of spray dilutions on wheat leaves, and increased the effective deposition of tebuconazole on wheat leaves. Even when its dosage was reduced by one-third, the spray solution still showed excellent disease control and effective deposition of the active ingredient on wheat leaves. The use of appropriate tank-mix adjuvants in UAV-based plant protection for wheat can significantly improve the performance of spray dilutions, increase the efficiency of pesticide dosage delivery, and improve disease control. These adjuvants can also help reduce the pesticide use while ensuring their effectiveness. © 2022 Society of Chemical Industry.

Awareness of Safe Plant Protection Measures among Vegetable Growers in Prayagraj District of Uttar Pradesh

Vegetable producers are often less knowledgeable about pest and disease identification, pesticide doses, application times, and health impacts of pesticides. As a result, it was thought that the research would be very useful in determining the level of perception of safe plant protection techniques among vegetable producers. The study was conducted in Prayagraj District of Uttar Pradesh to measure the awareness of safe plant protection measures among the vegetable growers in Prayagraj district of Uttar Pradesh. A total number of 120 respondents were selected randomly from ten villages under Chaka block because productivity, production and area under vegetable cultivation were found to be maximum. The data were collected by personnel interview method by using pre structured interview schedule and descriptive research design was used for this study. The findings of the study revealed that 47.50 per cent of the respondents belonged to the middle- aged group, majority of the respondents (55.84%) belong to the OBC caste and majority of the respondents belongs to medium level of annual income i.e. 50,000 – 1 lakh. The findings also revealed that 49.16 per cent of the respondents had medium level of awareness towards safe plant protection measures followed by 23.34% and 27.50% of the respondents with low and high levels of awareness respectively. It was found that independent variables like age, caste, economic motivation were positively and significantly correlated with awareness of safe plant protection measures. It is suggested that government should organized awareness camps, campaigns and demonstrations about safe plant protection measures.

EFFECT OF THE PESTICIDE TREATMENT DOSE ON THE BIOCHEMICAL RESPONSE OF THE POTATO PLANTS (SOLANUM TUBEROSUM L.)

In order to enhance and protect crop yields from different pests, the use of pesticides has increased. In Algeria, most often farmers do not respect the recommended dose of pesticides. The aim of this study is to investigate the dose effect of applying pesticides in field conditions at standard and double doses (agronomic dose, AD; agronomic double dose, ADD) on the morphological and biochemical responses of potato plants (Solanum tuberosum L.). Our result showed significant effect of pesticide application on the biochemical and antioxidant properties of the plant. Higher contents of phenolic and flavonoid were noticed in plants treated with AD and ADD. The accumulation of malondialdehyde increases lipid peroxidation due to the excessive reactive oxygen species production. The significant increase of catalase, ascorbate peroxidase and phenylalanine ammonia lyase activities were recorded in the final growth stage compared with control. AD increases proline content in the final growth stage, but a decrease for chlorophylls and carotenoids. In addition, the decrease in thiols level was observed for both growth stages. In conclusion, the results demonstrated that treatments with pesticides at higher doses than recommended caused oxidative disturbances in potato plants and lead to an enhanced capacity of antioxidant enzymes.

Assessment of the integrated palinotoxic effect of ecotoxicants on microhametophyte Vitis vinifera L.

The article presents information of the study of the complex effects of heavy metals and residual dose of pesticides on the male generative organs of populations of Vitis vinifera L. growing in agricultural areas of Crimea with varying degrees of pollution and located along highways with different road traffic. The control possibility is populations growing up on plantations which located at a considerable distance from highways. In the soil samples of these areas, residual amounts of pesticides (baileton, BI-58, insegar) were found, the content of which didn’t exceed the established sanitary and hygienic standards. A microgametophyte test of V. vinifera L. populations growing in agricultural areas whose soils are contaminated with heavy metals and pesticide residues revealed reduced production of fertile pollen compared to the control zone and background, significantly decreasing with increasing concentrations of ecotoxicants. Morphometric analysis of abortive pollen grains revealed an increase in their size, with the largest number found in more polluted areas. Increased production of large sterile pollen may indicate an adverse effect of heavy metals and pesticides on the generative organs of grapes and microsporogenesis occurring in them. It was found that pollutants in the background and in the Bakhchisarai district (low load) had a mildly toxic effect, in Alushta (medium load) and Simferopol district (high load) – a medium toxic effect of microgametophyte V. vinifera L. Thus, heavy metals and pesticide residues can form more toxic combine.

High Doses of Pesticides Induce mtDNA Damage in Intact Mitochondria of Potato In Vitro and Do Not Impact on mtDNA Integrity of Mitochondria of Shoots and Tubers under In Vivo Exposure.

It is well known that pesticides are toxic for mitochondria of animals. The effect of pesticides on plant mitochondria has not been widely studied. The goal of this research is to study the impact of metribuzin and imidacloprid on the amount of damage in the mtDNA of potato (Solanum tuberosum L.) in various conditions. We developed a set of primers to estimate mtDNA damage for the fragments in three chromosomes of potato mitogenome. We showed that both metribuzin and imidacloprid considerably damage mtDNA in vitro. Imidacloprid reduces the rate of seed germination, but does not impact the rate of the growth and number of mtDNA damage in the potato shoots. Field experiments show that pesticide exposure does not induce change in aconitate hydratase activity, and can cause a decrease in the rate of H2O2 production. We can assume that the mechanism of pesticide-induced mtDNA damage in vitro is not associated with H2O2 production, and pesticides as electrophilic substances directly interact with mtDNA. The effect of pesticides on the integrity of mtDNA in green parts of plants and in crop tubers is insignificant. In general, plant mtDNA is resistant to pesticide exposure in vivo, probably due to the presence of non-coupled respiratory systems in plant mitochondria.

Amyloid-Like Protein Aggregation Toward Pesticide Reduction.

Pesticide overuse is a major global problem and the cause of this problem is noticeable pesticide loss from undesired bouncing of sprayed pesticide droplets and rain erosion. This further becomes a primary source of soil and groundwater pollution. Herein, the authors report a method that can enhance pesticide droplet deposition and adhesion on superhydrophobic plant leave surfaces by amyloid‐like aggregation of bovine serum albumin (BSA). Through the reduction of the disulfide bond of BSA by tris(2‐carboxyethyl) phosphine hydrochloride (TCEP), the amyloid‐like phase transition of BSA is triggered that rapidly affords abundant phase‐transitioned BSA (PTB) oligomers to facilitate the invasion of the PTB droplet into the nanostructures on a leaf surface. Such easy penetration is further followed by a robust amyloid‐mediated interfacial adhesion of PTB on leaf surface. As a result, after mixing with pesticides, the PTB system exhibits a remarkable pesticide adhesion capacity that is more than 10 times higher than conventional fixation of commercial pesticides. The practical farmland experiments show that the use of PTB aggregation could reduce the use of pesticides by 70–90% while ensuring yield. This work demonstrates that current pesticide dosage in actual agriculture production may be largely reduced by utilizing eco‐friendly amyloid‐like protein aggregation.

Research progress on pesticide residues of Panax ginseng

Panax ginseng, a perennial herb, is prone to diseases and insect pests in the growth process, which are primarily prevented and treated by pesticides. However, due to the lack of standardization in the types, frequencies, and doses of pesticides, pesticide residues have become the main exogenous pollutants of P. ginseng. To explore the risk of pesticide residues in P. ginseng, this paper summarized and analyzed the common pesticide residues in P. ginseng, detection techniques, and pesticide residue limit stan-dards based on the published literature in recent years. The results revealed that the main pesticide residues in P. ginseng were organochlorine pesticides, such as tetrachloronitrobenzene, pentachloronitrobenzene, and hexachlorobenzene, and the detection techniques were dominated by gas chromatography(GC), liquid chromatography(LC), or those combined with mass spectrometry(MS). Because of the long half-life and difficulty in degradation, organochlorine pesticides have become the main factor affecting the export of P. ginseng. It is worth mentioning that P. ginseng has been classified as food in Japan, South Korea, the European Union, and other countries, and the standards of pesticide residues and limits are stricter than those in China. The quality and safety of P. ginseng are prerequisites for the efficacy of Chinese medicine and the development of traditional Chinese medicine. The formulation of scientific and effective standards for pesticide application and limits would promote the high-quality development of the P. ginseng industry.

Pesticide dose based on canopy characteristics in apple trees: Reducing environmental risk by reducing the amount of pesticide while maintaining pest and disease control efficacy

Although many different designed air-assisted sprayers can be used for pesticide application in apple orchards, the lack of adequate adjustments according to specific crop characteristics leads to application inefficiencies and failures. To evaluate the spray coverage and biological efficacy of different application techniques combined with an alternative dosage adjustment based on tree row volume (TRV), field tests with five different techniques were carried out at three crop stages on a commercial apple orchard. The results showed that conventional mist-blower with a high application volume (800 L ha−1) exhibited an excessive coverage with a high risk of contamination at the early crop stage (BBCH19), whereas other treatments using different application techniques, with a reduced volume rate and pesticide dose of 75%, were equivalent with good uniformity, revealing the great importance of suitable adjustment for the sprayers. For the middle and late stages (BBCH64 and 75), the orchard sprayer equipped with vertical booms provided the maximum coverage, and the pneumatic sprayer achieved significantly higher impacts density, which revealed their advantages and high efficiency for dense apple trees. The newly developed multi-fan sprayer and pneumatic sprayer achieved consistent coverage during the entire crop stage, independent of the changes in canopy structure (TRV). This indicates that a suitable setting and adjustment of the sprayer can contribute to a consistent spray quality. In general, benefiting from these new spraying technologies, an average reduction of 60.7% in pesticide dose and volume rate were achieved within the entire season, maintaining the same threshold of pest and disease control as that of the higher reference dose normally applied. These results demonstrate the importance of an alternative dose adjustment method to meet the requirements of the Farm to Fork strategy.

An Autonomous Pesticide Sprayer Robot with a Color-based Vision System

The usage of robots has been due to cost reduction and increasing operation accuracy. Furthermore, employing robots in farming can decrease human tasks in hard and dangerous duties such as plowing, spraying pesticides, etc. Spraying chemicals is a common operation in agriculture crop protection. This operation is essential, but it can create some problems such as human and environmental damages by overdosing using pesticides. Recently, researchers focused on precision agriculture to make this smart. Sensors are employed to detect leaves of plants on the ground and spray them as much as required. Thus, pesticide dose will be under control. The current paper aims to introduce a wheeled robot that is developed to detect plants by color sensor and spray them. This robot can move between planting rows and detect weeds based on the leave color. A microcontroller-based board was used as the main controller, which sends spray commands to the sprayer nozzle. Outdoor and indoor tests were carried out to study the accuracy of this system. Results of experiments showed that this robot could work with acceptable accuracy in identifying weeds in the field. Thus, this robot can be commercialized for applying in the field to spray pesticides.

Risk Factors Related To Pesticide Exposure In Banjar Horticultural Farmers

Agriculture in Indonesia is the driving force for the country's economy. Farmers in an effort to improve the quality and productivity of agricultural products use pesticides. The use of pesticides to control pests is growing rapidly. Banjar farmers from the Dasong Department are active pesticide users, so there is a potential for pesticide exposure. This study aims to determine the relationship between risk factors and complaints on horticultural farmers in Banjar Dinas Dasong, Pancasari Village, Sukasada District, Buleleng Regency. This study is an analytical observational study with a cross-sectional approach using 46 respondents. Data were analyzed by SPSS using chi-square test and logistic regression. The results of the Chi-Square test showed that there was no significant relationship between age, pesticide dose, duration of spraying, time of spraying, and frequency of spraying with complaints from farmers (p>0.05). While there is a significant relationship between the use of PPE with complaints to farmers (p <0.05). The results of the logistic regression test showed that the duration of spraying, spraying time, frequency of spraying, and use of PPE with complaints to farmers was not significant (p>0.05). This is due to other external factors. This research can be concluded that there is no correlation between the duration of spraying, spraying time, frequency of spraying, and the use of PPE with the complaints of farmers in Banjar Dinas Dasong, Pancasari Village, Sukasada District, Buleleng Regency.

Risk Factors Related To Pesticide Exposure In Banjar Horticultural Farmers

Agriculture in Indonesia is the driving force for the country's economy. Farmers in an effort to improve the quality and productivity of agricultural products use pesticides. The use of pesticides to control pests is growing rapidly. Banjar farmers from the Dasong Department are active pesticide users, so there is a potential for pesticide exposure. This study aims to determine the relationship between risk factors and complaints on horticultural farmers in Banjar Dinas Dasong, Pancasari Village, Sukasada District, Buleleng Regency. This study is an analytical observational study with a cross-sectional approach using 46 respondents. Data were analyzed by SPSS using chi-square test and logistic regression. The results of the Chi-Square test showed that there was no significant relationship between age, pesticide dose, duration of spraying, time of spraying, and frequency of spraying with complaints from farmers (p>0.05). While there is a significant relationship between the use of PPE with complaints to farmers (p <0.05). The results of the logistic regression test showed that the duration of spraying, spraying time, frequency of spraying, and use of PPE with complaints to farmers was not significant (p>0.05). This is due to other external factors. This research can be concluded that there is no correlation between the duration of spraying, spraying time, frequency of spraying, and the use of PPE with the complaints of farmers in Banjar Dinas Dasong, Pancasari Village, Sukasada District, Buleleng Regency.

Fabrication of iron nanoparticles from tea waste as an efficient adsorbent towards the removal of profenofos pesticide from aquatic environment

ABSTRACT Pesticide contamination has led to serious environmental issues that pose a significant threat to living organisms throughout the world. Therefore, the significant removal of pesticides from aquatic environments has attracted the attention of environmental scientists and academicians in recent decades. Hence, in the present investigation, the iron nanoparticles (INPs) from tea waste were fabricated as an efficient adsorbent towards the removal of profenofos (PF) from aqueous solution. The as-synthesised INPs were systematically characterised by various analytical techniques such as Ultra Violet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (PXRD) and dynamic light scattering (DLS). Various influencing factors such as contact time, adsorbent dosage, solution pH and initial concentration of pesticide were systematically optimised for the maximum adsorption efficiency of PF by the prepared INPs. Based on the obtained results, the INPs showed greater adsorption efficiency towards the removal of PF. The kinetic data were analysed using various adsorption kinetic models such as pseudo-first-order, pseudo-second-order and intra-particle diffusion. Further, the interaction between prepared INPs and PF was evaluated using various adsorption isotherm models such as Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) models. The monolayer Langmuir adsorption capacity of 43.67 mg g−1 was obtained with a minimum contact time of 15 min. According to the kinetic and isotherm data, the pseudo-second-order kinetic and Langmuir isotherm models were found to be well fitted for PF adsorption using the prepared INPs. The obtained findings of this study clearly demonstrated that the fabricated INPs are an efficient material towards the removal of pesticide molecules from aquatic environments.

SENSITIVITY ANALYSIS OF PESTICIDE DOSE ON PREDATOR-PREY SYSTEM WITH A PREY REFUGE

<abstract> A type of predator-prey model with refuge and nonlinear pulse feedback control is established. First, we construct the Poincar$ \acute{\rm{e}} $ map of the model and analyse its main properties. Then based on the Poincar$ \acute{\rm{e}} $ map, we explore the existence, uniqueness and global stability of the order-1 periodic solution, and also the existence of order-$ k $($ k \geq $2) periodic solutions of the system. These theoretical analysis gives the relationship between pesticide dosage and spraying cycle and economic threshold, and the relationship between the pesticide dose $ D $ and threshold $ ET $. The results show that choosing the appropriate spraying period and finding the corresponding pesticide dose under the certain economic threshold can control the number of pests and the healthy growth of crops could be controlled. Moreover, we study the influence of refuge on population density. The results show that with the increase of refuge intensity, the population of predators decreases or even becomes extinct. The parameter sensitivity analysis shows that the change of control parameters and pesticide dosage is very sensitive to the critical condition of the stability of the boundary periodic solution. </abstract>

Removal of imidacloprid and acetamiprid in tea (Camellia sinensis) infusion by activated carbon and determination by HPLC

Activated carbons were applied to the removal of imidacloprid and acetamiprid from tea infusion and both pesticides were determined by HPLC in this study. Results presented that the YQFB, an activated carbon with large BET surface area and more mesopores was effective for the removal of both pesticides from tea infusion. The removal rates were significantly ( p ≤ 0.05) affected by absorbent dosage, adsorption time, temperature, tea concentration and initial concentration of pesticide. Removal rates of both pesticides were improved with the dosage increased and the adsorption time prolonged, while decreased as the increase of tea concentration and initial concentration of pesticides. The maximum removal rates were 85.0% for imidacloprid and 85.7% for acetamiprid. The adsorption of both pesticides by YQPB followed the pseudo-second-order kinetics model well. The quality of tea infusion after activated carbon treatment was analyzed and results revealed that the retention rates of most components were higher than 85% and the stability of tea infusion was not significantly ( p > 0.05) affected by activated carbon treatment. The present study found a low-cost and effective way to remove imidacloprid and acetamiprid from te a infusion, and it has the potential to be applied to the ready-to drink tea beverages production in industrial scale.

The Effect of Increasing the Dose of Acetamiprid and Dichlorvos Pesticides on the Reproductive Performance of Laboratory Mice.

Pesticides are widely used around the world. However, these chemicals are being used more frequently and at increased doses in underdeveloped and developing countries. Although the hazard of pesticides has been studied in ecological fields, the effect of residual amounts of these compounds on the physiological processes of the body has always been debated. In this experimental study, 45 greenhouse cucumber plants were sprayed with dichlorvos and acetamiprid pesticides in concentrations of twofold (acetamiprid 500 g/1000 L and dichlorvos 4 L/1000 L) and threefold of the recommended dose. After 24 h, the residual amount was obtained. To evaluate the residual effect of the mentioned pesticides, an equivalent of this residue was added to the drinking water of 105 mice. Pesticide residues were obtained for twofold and threefold concentrations of the recommended dose, 1.5 and 2.5 (mg/kg cucumber) for acetamiprid and 0.5 and 1 (mg/kg cucumber) for dichlorvos, respectively. Application of these chemicals at higher doses not only significantly reduced the body weight, food consumption, testosterone production, testicular germ cells and embryo numbers, but also increased the levels of follicle-stimulating hormone and luteinizing hormone in mice. The emergence of biological disorders and reducing reproductive potential in male mice can be attributed to the addition of pesticides to their drinking water. Therefore, to reduce the hazards caused by insecticides, it is recommended to familiarize farmers with the harmful effects of overdose of pesticides and monitoring the residuals in agricultural products.

Diversity and Genetic Structuration of Populations of &amp;lt;i&amp;gt;Plutella xylostella&amp;lt;/i&amp;gt; (Lepidoptera, Plutellidae), Cabbage Farming Destroyer in Senegal

Plutella xylostella, pointed out as the most dangerous destroyer of cabbage (Brassica olerarea), is a cosmopolitan species. In fact, owing to its large capacity of adaptation, P. xylestella colonizes any kind of area. This insect can bring about up to 90% of losses on cabbage farming. To control the insect, Senegalese farmers, very often, resort to high dose of chemical pesticides which are repetitively sprayed. The use of these chemical products gives rise to different varieties of resistant insects, which results in the emergence of different haplotypes between populations. It is in such a context that this study has been undertaken. Our objective is then to contribute to the knowledge of the genetic diversity of P. xylostella populations in Senegal. To hit the target, PCR- Sequencing method has been applied on samples from the five following localities: Diofior, Malika, Mboro, Santh Ndong, and Sebikotane. P. xylostella from Mboro is genetically different from the other populations. This fact could be due to a different way of using pesticides in this area vis-à-vis of the other localities. On the other hand, between populations of P. xylostella from Diofior, Malika, Santh Ndong, and Sebikotane, there is no significant genetic difference. In other respects, phylogenetic trees reveal the existence of two clades: one with individuals from Mboro and the other one with individuals from the other four localities. P. xylostella from Mboro distinguishes itself from other populations and then, can be regarded as a sub-population. Thus, the phylogenetic trees reveal the existence of two groups of P. xylostella in Senegal.

Pesticide Exposure Levels and Risk Assessment in Operators Involved in the Cashew Production in C&amp;#244;te d’Ivoire

To assess the level of producers’ exposure and the health risk in relation to phytosanitary practices in cashew crops in C?te d’Ivoire, a descriptive longitudinal toxicological study was conducted in 2018-2019 with 76 cashew producers in the areas of Mankono, Dabakala and Bondoukou. The data collected permitted the assessment of phytosanitary risks on the health of producers according to the Quebec-IRPeQ pesticide risk indicators. Field observations translated into scenarios were used to determine the exposure levels of producers via the UK-POEM predictive model. The main active substances used were glyphosate, 2,4-D, cypermethrin, acetamiprid, lambdacyhalothrin, profenofos, imidacloprid, deltamethrin, mancozeb and metalaxyl. The risk indicators showed that 2,4-D (TRI = 1332.25; SRI = 432.98), profenofos (TRI = 2550.25; SRI = 637.56) and mancozeb (TRI = 841; SRI = 147.18) among herbicides, insecticides and fungicides respectively could have more adverse health effects after exposure. These findings translated into scenarios specifically showed high exposure of producers to herbicides, with exposure levels ranging from 1.31 mg/kg bw/day to 1.67 mg/kg bw/day, well above the acceptable operator’s exposure levels (AOEL). These health risks could be significantly reduced if the required personal protective equipment is worn. But, recommended doses of pesticides should be reconsidered, because in some cases, applicators exposure remained high despite the protective equipment.