Action Of Pesticides Research Articles

Assessing the stereoselective bioactivity and biotoxicity of penthiopyrad in soil environment for efficacy improvement and hazard reduction

Penthiopyrad, a chiral pesticide, has been widely used in agricultural production. However, systematic evaluation of stereoselective bioactivity and biotoxicity of penthiopyrad in soil environment is insufficient. In this study, the stereoselective bioactivity of penthiopyrad against three soil-borne disease pathogens and its stereoselective biotoxicity to soil non-target organisms were investigated. The present results showed that the bioactivities of S-penthiopyrad were 546, 76 and 1.1-fold higher than those of R-penthiopyrad due to their different interaction modes with SDH in different target pathogens. S-penthiopyrad was more persistent in the soil environment and had stronger bioaccumulation than R-penthiopyrad. The accumulation of penthiopyrad in earthworms induced the response of detoxification system, resulting in the significant increases in the activity of detoxifying enzymes, such as GST, CarE, and CYP450. Additionally, both S-penthiopyrad and R-penthiopyrad induced cell apoptosis, intestinal damage and differentially expressed genes in earthworms, especially S-penthiopyrad. Furthermore, S-penthiopyrad has stronger binding capacity with COL6A and ACE proteins, while R-penthiopyrad has stronger binding capacity with CYP450 family proteins, which may be the main reason for the differences in biotoxicity between PEN enantiomers. Considering the differences in bioactivity and biotoxicity of penthiopyrad enantiomers, as well as the modes of action of pesticides on target and non-target organisms, S-penthiopyrad has greater potential for future development.

Anwar Fazal-A Breastfeeding Advocate Extraordinaire.

Anwar Fazal has been a driving force in the founding of several civil society organizations in the areas of health, human rights, environment, and peace, that have been at the forefront of activism locally, nationally, and globally. In this interview, he shares his journey of 6 decades, involving a multiverse of public interest issues, which led him into the breastfeeding movement. It began with the setting up of the International Baby Food Action Network (IBFAN), a pioneering action that triggered the formation of Health Action International (HAI), Pesticide Action Network (PAN), and the World Alliance for Breastfeeding Action (WABA). Each of these resulted in several unique frameworks and codes relating to the marketing of infant foods, pharmaceuticals, and pesticides. They also led to the formation of World Breastfeeding Week, now being celebrated globally. Anwar studied Economics at the University of Malaya and did his postgraduate studies in Education. Anwar has served as a visiting professor at the University of Science Malaysia and the International Islamic University Malaysia (IIUM). He is the recipient of the Right Livelihood Award, popularly known as the "Alternative Nobel Prize," for his work on breastfeeding and infant nutrition and other health, environmental, and consumer issues. La Leche League International (LLLI) and the United Nations Development Programme (UNDP) have honored him with the International Health Award and the Millennium Development Goals Award. He has written extensively on breastfeeding. He is currently Chairperson Emeritus of the World Alliance for Breastfeeding Action (WABA) and continues to speak out actively on protecting, promoting, and supporting breastfeeding.

Renewal of an active substance found in an insecticide: How to articulate risk assessment and risk management?

In Pesticide Action Network Europe v Commission (Case T-536/22), Pesticide Action Network Europe (PAN Europe) contested the renewal by the European Commission of the active substance cypermethrin. This substance is used or is marketed as an insecticide in large-scale commercial agricultural applications as well as in consumer products for domestic purposes (ant and cockroach killer). PAN Europe sought the annulment of the European Commission's decision of 23 June 2022 by which the latter rejected the request for internal review made by PAN Europe in accordance with Regulation (EC) No. 1367/2006 on the application of the provisions of the Aarhus Convention on Access to Information, Public Participation in Decision-making and Access to Justice in Environmental Matters. The applicant argued, in essence, that where a risk is established with sufficient certainty by the European Food Safety Authority (EFSA), the Commission could not disregard the conclusions of the scientific assessment by relying on its powers as risk manager. In stressing the discretion enjoyed by the Commission, the General Court dismissed the action of PAN Europe. This casenote suggests that the General Court applied the precautionary principle too formally.

Influence of Artemisia dubia Wall and Pig Manual Digestate on Winter Wheat Productivity and Grain Quality

Sustainable agriculture aims to use biological resources to improve crop quality and productivity. This approach promotes alternatives, such as replacing synthetic pesticides with biological ones and substituting mineral fertilizers with organic fertilizers. Field trials were conducted using two different factors: fertilizer treatments (ammonium nitrate and pig manure digestate) and plant protection treatments (pesticides, Artemisia dubia Wall biomass mulch, and strips). After harvesting the winter wheat, the productivity and quality (weight of 1000 grains, protein, gluten, starch, sedimentation of grains) were evaluated. The two-year studies showed that pig manure digestate positively affected winter wheat grain quality. Mugwort biomass outperformed other plant protection options in three key grain quality indicators (protein, gluten, and sedimentation). Furthermore, in 2023, the highest grain yield of 5798 ± 125 kg ha−1 was observed in the pesticides and pig manure digestate treatment. The quick impact and mode of action of vegetation pesticides were more easily felt over the two years of study, leading to the highest yield of wheat grains compared to other plant management measures. This study shows that mugwort biomass can positively influence wheat grain quality, a significant milestone in utilizing nonfood crops as alternatives for agricultural productivity.

Geospatial share of fungicide resistant Botrytis cinerea mutations in the Tokaj and Eger wine regions according to local pest management strategies

AbstractBotrytis cinerea is one of the fungal pathogens with the widest host plant spectrum, causing serious yield losses and significant economic damage in vineyards from year to year. As an ubiquitous, polyphagous fungal pathogen, with both saprophytic and parasitic lifestyle. The sequential use of active substances belonging to the same chemical family to protect vineyards can lead to an increase in fungal chemical resistance, which is reflected in the enrichment of point mutations in the genomic regions coding proteins involved in the mechanism of action of different pesticides. The aim of our studies was to compare the sensitivity to different fungicides of B. cinerea populations in two wine regions with different pest management practices: the Tokaj region, where the presence of B. cinerea is necessary to produce noble rot wines, and the adjacent Eger Region, where a total protection against B. cinerea is desired. Our study is the first Hungarian report of some previously studied resistance mutations in ERG27 and SDHB protein-coding genes. We identified point mutations in ERG27 transmembrane domain that have not been previously described but may affect the emergence of resistance to certain fungicides. Our study shows that the B. cinerea population of the Northern Hungary region is consistently characterized by an increase in fenhexamid resistance.

Bacterial Pesticides: Mechanism of Action, Possibility of Food Contamination, and Residue Analysis Using MS.

As Sustainable Development Goals (SDGs) and the realities of climate change become widely accepted around the world, the next-generation of integrated pest management will become even more important for establishing a sustainable food production system. To meet the current challenge of food security and climate change, biological control has been developed as one sustainable crop protection technology. However, most registered bacteria are ubiquitous soil-borne bacteria that are closely related to food poisoning and spoilage bacteria. Therefore, this review outlined (1) the mechanism of action of bacterial pesticides, (2) potential concerns about secondary contamination sources associated with past food contamination, and, as a prospective solution, focused on (3) principles and methods of bacterial identification, and (4) the possibility of identifying residual bacteria based on mass spectrometry.

Development of K-Maryblyt for Fire Blight Control in Apple and Pear Trees in Korea.

K-Maryblyt has been developed for the effective control of secondary fire blight infections on blossoms and the elimination of primary inoculum sources from cankers and newly emerged shoots early in the season for both apple and pear trees. This model facilitates the precise determination of the blossom infection timing and identification of primary inoculum sources, akin to Maryblyt, predicting flower infections and the appearance of symptoms on various plant parts, including cankers, blossoms, and shoots. Nevertheless, K-Maryblyt has undergone significant improvements: Integration of Phenology Models for both apple and pear trees, Adoption of observed or predicted hourly temperatures for Epiphytic Infection Potential (EIP) calculation, incorporation of adjusted equations resulting in reduced mean error with 10.08 degree-hours (DH) for apple and 9.28 DH for pear, introduction of a relative humidity variable for pear EIP calculation, and adaptation of modified degree-day calculation methods for expected symptoms. Since the transition to a model-based control policy in 2022, the system has disseminated 158,440 messages related to blossom control and symptom prediction to farmers and professional managers in its inaugural year. Furthermore, the system has been refined to include control messages that account for the mechanism of action of pesticides distributed to farmers in specific counties, considering flower opening conditions and weather suitability for spraying. Operating as a pivotal module within the Fire Blight Forecasting Information System (FBcastS), K-Maryblyt plays a crucial role in providing essential fire blight information to farmers, professional managers, and policymakers.

Coupling input and output intensity to explore the sustainable agriculture intensification path in mainland China

Sustainable intensification (SI) of agriculture is widely regarded as an important way to alleviate the contradiction between the food gap and ecosystem health. Correlate input intensity and output intensity have been regarded as an important dimension in most estimation frameworks of SI. But in practice, this correlation is generally expressed in terms of efficiency metrics and calculated as the ratio of output intensity to input intensity, which cannot quantitatively explain the impact of input intensity on output intensity and provide a threshold value for estimating the suitability of SI. This study's goals are to propose an input—output coupled method to explain the impact of input intensity on output intensity and thereby estimate the suitability of provincial SI. Provincial annual input intensity and output intensity were estimated from an emergy-based perspective by taking China as a case study. The K-means algorithm was used to identify the structural pattern of arable land input intensity. A sliding window-based partial correlation index method was proposed and applied to reveal the interaction process between input intensity and output intensity. The results show that there are two main change paths in the pattern of input intensity: one path in the western irrigation regions and the other path in the eastern northeast China Plain and middle-lower Yangtze Plain. The former path can be expressed as a small increase in fertilizer and agro-machinery input intensity with a decrease in labour force input intensity. The latter path shows a larger increase in fertilizer and pesticide input intensity. For each type of input intensity except mulching film, its correlation to output intensity has experienced a similar coupling—decoupling—recoupling process in both plain provinces and mountainous or plateau provinces. According to Landau's theory of phase transition, the complex coupling of input and output undergoes a phase transition process from order to disorder and then to order, depicted by the sliding window-based partial correlation coefficient as the order parameter from a holistic perspective. The inflection points of coupling relation changes show that the phenomenon of fertilizer and pesticide overuse has steadily occupied most provinces in eastern China and is spreading westwards. Although the “zero growth action for fertilizers and pesticides” has made considerable achievements in reducing the input intensity of fertilizer and pesticides since 2015, the situation of superfluous fertilizer and pesticide input has not changed substantially. The input intensity of fertilizer and pesticides still needs to be further reduced. This study can contribute to the estimation method system of SI. The input—output coupled method is applicable for other spatial scales and regions (or countries) to estimate the suitability of SI.

Microbial Pesticides: A Nigerian Perspective on Sustainability of Health and Agriculture

The concerns on the use of insecticides have been in areas of agriculture and human health. Insect pests populating the farms damage crops leading to food insecurity. The use of chemical insecticides to treat insect infestation is quite popular in Nigeria in area of food crop production and in animal and human health management. These chemical insecticides often pose some health challenges to man and animals hence the need for safer bio-pesticides. Microbial insecticides consist of living cells of microorganisms Research method employed was by collection of secondary data from literatures on previous research works done. These include reports, journal articles, seminars, symposia, and conference papers. Literatures were collected online using the Dennis Osadebay University e-library. These organisms are reared using basic microbiological techniques. Mode of action of microbial pesticides is by contact, which is by entering the host through the outer protective covering or the intestine of the insect. These microbes act on the host (insects) either by elimination or by altering some of their physiological functions. They may act directly on the insects or by the action of their toxins. The toxins can be used independently as bioactive substances in place of the microbial species. Microbial insecticides can be applied as sprays, dusts, liquid drenches, liquid concentrates, wet-table powders or granules. The bio-insecticides have the capacity to ensure the safety of humans and other non-target organisms. They leave less or no residue deposits in food and are ecologically friendly.

Impact of pesticide regulations on mortality from suicide by pesticide in China: an interrupted time series analysis.

Pesticide bans and regulatory restrictions have been shown to be effective strategies for preventing suicide in several countries. Suicide and suicide by pesticides have decreased significantly in China over the past two decades. However, whether the reduction was associated with pesticide regulation is unknown. The monthly data on suicide and suicide by pesticide from 2006 to 2018 were obtained from China's Disease Surveillance Point (DSP) system. Information on China's pesticide regulations since 1970 was obtained from Pesticide Action Network International (PAN International), Joint Meeting on Pesticide Management Highly Hazardous Pesticides (JMPM HHP) lists, the website of the Ministry of Agriculture of China, Pesticide Information Network of China, and the Wan Fang database. Change point detection and policy analysis were combined to identify the time of any trend change breakpoint of suicide and suicide by pesticide. Interrupted time series analysis was used to investigate the pre- and post-breakpoint trends of monthly standardized rates in suicide and suicide by pesticide. The standardized pesticide suicide rate decreased by 60.5% from 6.50 in 2006 to 2.56 per 100,000 in 2018. Larger declines were evident among people in urban areas (67.3%), female individuals (63.5%), and people aged 15-44 years (68.1%). The effect of policies banning highly hazardous organophosphorus pesticides (HHOP) [rate ratio (RR) = 0.993, 95% CIs (0.991-0.994)] in December 2008 and stopping domestic sales and use of paraquat aqueous solution (RR = 0.992, 95% CIs: 0.990-0.994) in July 2016 were more pronounced than regulating the paraquat-related products (RR = 1.003, 95% CIs: 1.002-1.004) in April 2012. Declines in suicide by pesticide in China occurred contemporaneously with regulatory bans and restrictions implemented on several pesticides, particularly in urban areas, among female individuals, and the relatively low age profile. These findings indicate the potential influence of these bans on trends of suicide by pesticides.

Prediction and Early Diagnosis of Bronchial Asthma in Workers Specializing in Argon Welding Based on Fuzzy Mathematical Models

The purpose of research is to develop fuzzy mathematical models for predicting and early diagnosis of bronchial asthma developing under the influence of toxic substances released during argon welding providing an acceptable quality of decision-making for practical medicine Methods. The paper uses the method of synthesis of fuzzy mathematical models of forecasting and early diagnosis of occupational diseases provoked by the action of industrial pesticides developed in the South-Eastern Federal University on the basis of the methodology of synthesis of hybrid fuzzy decision rules allowing to take into account the multiplicative nature of the links between the risk of occurrence and development of occupational diseases with the concentration and time of exposure to harmful chemicals. Results. Using the chosen method, fuzzy hybrid models of forecasting and early diagnosis of industrial bronchial asthma in welding workers were obtained in which, in addition to the effects of ozone, dust and fibrogenic risk factors on the human body, unfavorable environmental and ergonomic factors combined with individual health characteristics are taken into account. In the course of modeling and expert evaluation, it was shown that the obtained mathematical model provides confidence in the correct prognosis of the occurrence of industrial bronchial asthma in welding workers at least 0.85, and early diagnosis at least 0.9. Conclusion. Hybrid fuzzy models of forecasting and early diagnosis of industrial bronchial asthma in welding workers caused by the presence of ozone and fibrogenic dust in combination with individual, environmental and ergonomic risk factors were obtained, the quality of which was tested on representative control samples. During the control check, it was shown that the prognostic model provides diagnostic specificity and sensitivity at the level of 0.87, and the early diagnosis model - at the level of 0.92, which is a good result for the class of tasks under consideration.

In vitro profiling of pesticides within the Tox21 10K compound library for bioactivity and potential toxicity

Pesticides include a diverse class of toxic chemicals, often having numerous modes of actions when used in agriculture against targeted organisms to control insect infestation, halt unwanted vegetation, and prevent the spread of disease. In this study, the in vitro assay activity of pesticides within the Tox21 10K compound library were examined. The assays in which pesticides showed significantly more activities than non-pesticide chemicals revealed potential targets and mechanisms of action for pesticides. Furthermore, pesticides that showed promiscuous activity against many targets and cytotoxicity were identified, which warrant further toxicological evaluation. Several pesticides were shown to require metabolic activation, demonstrating the importance of introducing metabolic capacity to in vitro assays. Overall, the activity profiles of pesticides highlighted in this study can contribute to the knowledge gaps surrounding pesticide mechanisms and to the better understanding of the on- and off-target organismal effects of pesticides.

Farmers’ Perception towards Agricultural Pesticides and Associated Human Health Impact in Misrak Badawacho Woreda, Ethiopia

Pesticides are applied to control weeds and insect infestation in agricultural fields and various pests and disease carriers. As the modes of action for pesticides are not species-specific, concerns have been raised about risks associated with their exposure through various routes. The main objective of this study was to assess farmers’ perception towards agricultural pesticides and associated human health impact in Misrak Badawacho Woreda, Ethiopia. Community-based cross-sectional study was used to assess farmers’ perception towards agricultural pesticides and associated human health impact. Systematic random sampling technique was used to select study subjects. Structured questionnaires were used to collect data. Data were entered and analyzed using SPSS 20. Descriptive statistics were used during this study. About 361 study subjects completed the questionnaires. Among the studies subjects (81%) of them were males and 19% were females. The results showed that commonly applied pesticides comprised of herbicides (55%), fungicides (28%), Veterinary control (14%) and insecticides (3%). About 54% of the farm workers were used normal clothe, 17% were used boots,11% were used eye glass, 8% were used handkerchief, 3% were used mask and 2% were used Cotton during pesticide application. From total study subjects 38% do not follow instructions during pesticide application and 55% reuse pesticide containers for storing food and water in the home. Majority (93%) reported that they had suffered from pesticide-related health signs and symptoms during or after application of pesticides. Itching and skin irritation was the common symptom (74%) followed by headache (68%) during pesticide application. Generally the Farm workers had poor handling practices during pesticide application. Therefore continuous pesticide training programs for workers could be implemented.

Comparison of transcriptome alterations induced by pendimethalin or its commercial formulation Stomp Aqua in human MCF-7, MCF-10 A and MCF-12 A mammary epithelial cells

ObjectiveThe toxicology of herbicides, which are currently in use is under-explored. One highly used but under investigated herbicide is pendimethalin. Here we mined high-throughput data from the US National Toxicology Program (NTP) to identify whether pendimethalin possesses an estrogenic capability in human cells. We also evaluated effects of pendimethalin and its reference commercial formulated herbicide Stomp Aqua on the transcriptome profile of three human mammary epithelial cell lines, cancerous MCF-7 and non-cancerous MCF-10 A and MCF-12 A to see whether this compound could have endocrine disrupting effects and if co-formulants present in the commercial formulation could amplify its toxicity.ResultsThe data mined from the US NTP database suggests that pendimethalin activates estrogen receptors at a concentration of approximately 10?M. MCF-7, MCF-10A and MCF-12A cells were exposed to 10 ?M pendimethalin and Stomp Aqua at an equivalent concentration. Transcriptome analysis showed changes in gene expression patterns implying that pendimethalin affected ubiquitin-mediated proteolysis and the function of the spliceosome. The formulated pendimethalin product Stomp Aqua gave comparable effects suggesting pendimethalin was responsible for the observed transcriptome alterations. Given the lack of information on the exposure to this pesticide, our study prompts the need for biomonitoring studies, especially under occupational use scenarios, to understand if low level exposure to pendimethalin could have endocrine disrupting effects on populations exposed to this compound. A deeper understanding of the exposure and mechanisms of action of this endocrine-disrupting pesticide is needed.

Оценка мутагенного эффекта проб воды и почвы, собранных вблизи бывших хранилищ хлорорганических пестицидов в Жамбылском районе Алматинской области с использованием различных модельных тест-систем

Устаревшие хлорорганические пестициды в настоящее время запрещены как стойкие органические загрязнители окружающей среды. Не утилизированные должным образом, они продолжают загря з-нять почву и воду, накапливаться в пищевой цепи и наносить вред растениям, животным и организму человека. Цель исследования — оценить загрязнение воды и почвы вокруг складов неутилизирован-ными запрещенными хлорорганическими пестицидами и их возможное генотоксическое действие. Были обследованы бывшие склады пестицидов в двух поселках Жамбылского района Алматинской области. Химический анализ показал загрязнение почвы вокруг складов хлорорганическими пестици-дами и тяжелыми металлами. Пробы воды и почвы, отобранные вблизи хранилищ, использовались для оценки экологического риска. Генотоксическое действие проб воды и почвы оценивали на раз-личных модельных объектах: Salmonella typhimurium, Drosophila melanogaster, Allium cepa, культурах лимфоцитов овец и человека. Было обнаружено, что образцы воды и почвы вызывали слабый мута-генный эффект во всех модельных системах, увеличивая частоту мутаций и хромосомных аберраций. Хотя генотоксический эффект был продемонстрирован для каждой из моделей, разные модели пока-зали разную чувствительность к действию пестицидов и разную степень реакции. Поэтому для адек-ватной оценки мутагенности пестицидов необходимо применять батарею тестов с разными модельными объектами. Результаты исследований показали, что остатки устаревших пестицидов по-прежнему загрязняют окружающую среду и должны быть своевременно утилизированы безопасным способом, чтобы избежать загрязнения окружающей среды.

Mechanistic action of pesticides on pests and their consequent effect on fishes and human health with remediation strategies

Abstract Population detonation and inflated demand for agricultural products have resulted in the rampant use of pesticides in recent years. These pesticides are used to reduce the number of pesticides by different mechanisms. They have been utilized in agriculture to expand agrarian profit, crop yield, quality, and storage life. The incessant and extensive use of resistant pesticides has contaminated the water bodies, fields, crops, and aquatic biota as well as poses a threat to human health. As a result, stringent regulations and limits are established to monitor the pesticide matrix. The current review focuses on pesticide contamination in the food chain, particularly from the aquatic bodies to fishes and humans. It also discusses strict regulations and limits including maximum residual limits for food items, acceptable daily intake, theoretical maximum daily intake, and estimated carcinogenicity/non-carcinogenicity for fishes and human health risks. In addition to conferring the negative effects of pesticides, this article discusses cost-effective remediation techniques such as phytoremediation, adsorption, the Fenton oxidation method, microalgal/high-rate algal ponds, and nanotechnology with the comparison of their remediation cost.

Mixture effects of thiamethoxam and seven pesticides with different modes of action on honey bees (Aplis mellifera)

Even though honey bees in the field are routinely exposed to a complex mixture of many different agrochemicals, few studies have surveyed toxic effects of pesticide mixtures on bees. To elucidate the interactive actions of pesticides on crop pollinators, we determined the individual and joint toxicities of thiamethoxam (THI) and other seven pesticides [dimethoate (DIM), methomyl (MET), zeta-cypermethrin (ZCY), cyfluthrin (CYF), permethrin (PER), esfenvalerate (ESF) and tetraconazole (TET)] to honey bees (Aplis mellifera) with feeding toxicity test. Results from the 7-days toxicity test implied that THI elicited the highest toxicity with a LC50 data of 0.25 (0.20–0.29) μg mL−1, followed by MET and DIM with LC50 data of 4.19 (3.58–4.88) and 5.30 (4.65–6.03) μg mL−1, respectively. By comparison, pyrethroids and TET possessed relatively low toxicities with their LC50 data from the range of 33.78 (29.12–38.39) to 1125 (922.4–1,442) μg mL−1. Among 98 evaluated THI-containing binary to octonary mixtures, 29.59% of combinations exhibited synergistic effects. In contrast, 18.37% of combinations exhibited antagonistic effects on A. mellifera. Moreover, 54.8% pesticide combinations incorporating THI and TET displayed synergistic toxicities to the insects. Our findings emphasized that the coexistence of several pesticides might induce enhanced toxicity to honey bees. Overall, our results afforded worthful toxicological information on the combined actions of neonicotinoids and current-use pesticides on honey bees, which could accelerate farther comprehend on the possible detriments of other pesticide mixtures in agro-environment.

In vitro antifungal evaluation of L-ascorbic acid (vitamin C) towards Monilia frucigena, Alternaria solani and Venturia inaequalis

In vitro antifungal tests with one of the most popular medical substance in the world – L – ascorbic acid, widely known as vitamin C, were conducted with three of the most spread plant pathogens in Bulgaria: Monilia frucigena, Alternaria solani and Venturia inaequalis in order to evaluate the direct antifungal action of the acid used in agriculture as ISR promoter (phytovaccine). The expression of pesticide action of ISR promoters is not unusual unlike the vaccines for the animals and humans. Conducted tests shows the strong antifungal activity of L – ascorbic acid towards mycelium and conidiospores of Alternaria solani and Venturia inaequalis and a very weak antifungal action towards Monilia frucigena which means that vitamin C can be used as a direct fungicide agent and phytovaccine in the pest management simultaneously. The substance has excellent water solubility which make is very appropriate for formulation as a plant protection product.

Prediction of acute poisoning in agricultural workers during using pesticides on berry and melon crops

acute pesticide poisoning is a global health problem. According to the WHO, poisoningby chemicals, including chemical plant protection products, is a leading non-communicable disease.Violation of the rules for working with pesticides leads to the occurrence of occupational diseasesamong workers. Therefore, compliance with pesticide regulations and the use of personal protective
 equipment is a very important preventive measure. The purpose of our work: to predict the occur-rence of acute toxic effects in workers who treat berry and melon crops with pesticides. Research
 materials and methods: to assess the probability of acute toxic effects among workers who deal withactive substances and preparations based on them. We calculated three indicators: the coefficient of
 possible inhalation poisoning (DSanPiN 8.8.1.002-98), the selectivity of pesticides by inhalation pes-ticides and the selectivity of pesticides under dermal exposure according to the method of Sergeeva
 S.G. Results: according to the “Hygienic classification of pesticides by degree of danger” DSanPiN8.8.1.002-98 all tested active substances belong to the 4th class of danger according to the coefficientof possible inhalation poisoning, which was less than 0,5. The coefficient of selectivity of the actionof pesticides during inhalation exposure to active substances was in the range of 7,41 – 1000,0.
 For cyprodinil, phenhexamid, azoxystrobin, pyraclostrobin, copper chloride, pendimethalin, S-me-tolachlor, glyphosate, and abamectin, it was less than 100, indicating their relatively low selectivity
 of action. Other studied active substances had a high selectivity of action, since this coefficient was
 more than 100. It was established that all studied drugs have sufficient selectivity of action when in-haled. The coefficient of selectivity for dermal exposure was more than 100 for all the studied active
 substances, except for S-metolachlor and glyphosate. Preparations Trinol, VG, Signum, VG, RidomilGold R 161 WG, VG, Stomp Aqua, SK, Dual Gold 960 EC, KE, Herbolex v.r. have low selectivityof action when entering through the skin, all other pesticides have sufficient selectivity of action. Theobtained data indicate that all the active substances under study are not dangerous (hazard class 4),according to DSanPiN 8.8.1.002-98. Therefore, when working with these substances you need tofollow hygienic regulations.

Pest control switching models with instantaneous and non-instantaneous impulsive effects

In this paper, it is considered that the predation rate and transformation rate of natural enemies on pests in different time periods of pesticide action and non-action are different, and after spraying pesticides, the pesticides kill the pests and natural enemies instantaneously, and at the same time bring non-instantaneous residual effects on them. Firstly, an integrated pest control switching model with instantaneous and non-instantaneous impulsive effects at the fixed time is proposed. It assumes that spraying pesticides is more frequently used than releasing natural enemies. The sufficient condition for the global asymptotic stability of the pest-eradication periodic solution is obtained. By numerical simulations, we find that the system we study has many complex dynamics including period-doubling bifurcation, period-halving bifurcation, chaos and multiple attractors. Further, the effects of some key parameters on the threshold for pest eradication are analyzed. The results imply that it is not that the more frequent, the more conductive to pest control, and within each releasing period, applying pesticides too early or too late is not good for pest control. Finally, with the purpose of preventing pests below the economic injury level, a state-dependence pest control switching model with instantaneous and non-instantaneous impulsive effects is investigated numerically. Our results show that the frequency of applying pesticides depends on the key parameters of the established system, such as initial population density, the releasing amount of natural enemies and the period of releasing natural enemies, etc.