Doses Of Pesticides Research Articles

Reduction of pesticide dosage and off‐target drift with enhanced control efficacy in unmanned aerial vehicle‐based application using lecithin adjuvants

AbstractBACKGROUNDUnmanned aerial vehicles (UAVs) are increasingly used in precision agriculture, particularly for pesticide application in rice cultivation. One challenge is off‐target pesticide drift, which raises environmental concerns and reduces pesticide efficiency. Lecithin adjuvants have been suggested to enhance droplet stability, reduce drift, and improve control efficacy. This study aims to evaluate the efficiency of lecithin adjuvants in reducing pesticide drift and improving deposition during UAV‐based pesticide application under various paddy field conditions.RESULTSThe addition of 1% lecithin adjuvants in 75% dosage of tricyclazole and ferimzone dual active ingredient formulations reduced off‐target drift by 2.62 to 3.16 times compared to the 100% and 75% dosage of standard formulations, with deposition efficiency along the spray path increasing by up to 155%. Wind direction and speed were found to be the primary environmental factor affecting deposition efficiency and drift rate. The control efficacy against leaf blast disease was significantly improved, with a maximum efficacy of 73.7% observed in the adjuvant‐treated group. Initial pesticide residues on rice plants were the highest in treatments with adjuvants, but their harvest products, brown rice and dried straw, were still within safe limits for human consumption.CONCLUSIONLecithin adjuvants significantly reduce off‐target drift and enhance pesticide deposition during UAV‐based application. This method allowed for lower pesticide dosages without compromising control efficacy, contributing to more sustainable agricultural practices. These findings highlight the potential of adjuvants to improve UAV pesticide application and reduce the environmental impact of pesticide use. © 2024 Society of Chemical Industry.

Farmers’ Compliance with the Recommended Doses of Pesticides on Watermelon in Yobe State, Nigeria

The study investigated farmers’ compliance with the recommended doses of pesticides on watermelon in Yobe State, Nigeria. A multi-stage sampling procedure was adopted to select one hundred and seventy-three (173) respondents for the study. Primary data were collected using a structured questionnaire. Data were collected on socio-economic characteristics, training in pesticide application, awareness of hazards associated with pesticides, access to information on hazards associated with pesticides and compliance with recommended doses of pesticides. The results revealed that the mean age of the respondents was 43.19, 97.7% were married 73.4% did not have English language reading ability. Training in application of pesticides (0.18), awareness of hazards associated with pesticides (0.28) and access to information (0.43) were low. Most (91.9%) respondents did not comply with the recommended doses of pesticides. Awareness of hazards (B= 2.74, p = 0.01) and access to information (B= 1.45, p = 0.08) significantly influenced compliance with the recommended doses of pesticides. Stakeholders in the agriculture and food sectors should plan and implement schemes to train, inform and boost awareness of the farmers on hazards associated with pesticides to motivate compliance with recommended doses of pesticides, produce safe watermelon and sustain a healthy environment.

Pervasive sublethal effects of agrochemicals on insects at environmentally relevant concentrations.

Insect biomass is declining globally, likely driven by climate change and pesticide use, yet systematic studies on the effects of various chemicals remain limited. In this work, we used a chemical library of 1024 molecules-covering insecticides, herbicides, fungicides, and plant growth inhibitors-to assess the impact of sublethal pesticide doses on insects. In Drosophila melanogaster, 57% of chemicals affected larval behavior, and a higher proportion compromised long-term survivability. Exposure to sublethal doses also induced widespread changes in the phosphoproteome and changes in development and reproduction. The negative effects of agrochemicals were amplified when the temperature was increased. We observed similar behavioral changes across multiple insect species, including mosquitoes and butterflies. These findings suggest that widespread sublethal pesticide exposure can alter insect behavior and physiology, threatening long-term population survival.

Exploring possibilities of broccoli (Brassica oleracea L. var. italica) production under organic management

Broccoli (Brassica oleracea L. var. italica) was introduced as part of the Indian government's efforts to diversify and modernize agriculture in the region. Its introduction has helped J&K farmers to increase their income through higher market prices and to gain access to new markets and trade opportunities. It being a nutrient-demanding crop, farmers use high doses of chemical fertilizers, pesticides and herbicides and if consumed as salad or half-boiled in many culinary dishes, these chemicals are likely to impact the health of consumers and affect the environment. Therefore, alternative usage to these chemicals using combinations of organic inputs was aimed at producing a healthy crop of broccoli. It was concluded that the application of FYM@ 25 t/ha as a basal dose in the presence of seedling dip treatment of biofertilizers (Azotobacter @ 0.5 kg/ha + Phosphate-Solubilizing Bacteria @l kg/ha + Potassium-Mobilizing Bacteria @ 750 ml/ha) along with the scheduled application of Neem oil +Baeuveria bassiana at 1, 3, 7 and 15 days of interval after disease symptoms was found superior in obtaining higher curd yield (109.57 q/ha) and seed yield (604.96 kg/ha).

Evaluation of Efficacy of Certain Pesticides and Black Plastic Mulch as an Approach of Developing Integrated Pest Management for Melon Fruit Fly (Bactrocera cucurbitae)

A field experiment was conducted at Pyuthan Municipality, Pyuthan district of the Federal Democratic Republic of Nepal to develop an integrated pest management strategy against melon fruit fly (Bactrocera cucurbitae). The experiment was laid out in two factorial Randomized Complete Block Design (RCBD). The first factor was different doses of pesticides; Spinosad (45% SC) @ 1ml/3l water, Cypermethrin (10% EC) @5ml/20l water and, botanical Jholmol @ 1:3 ratio (1 part Jholmol and 3 part water). The second factor was Black plastic mulch and no mulch. The pesticides were applied at 9 day intervals and data on fruit infestation, ovary damage, yield and, post-set damage were collected at 3 day intervals and the data analysed using R Studio. The result revealed highly significant differences among mulching and non-mulching plots. Mulching plots had the lowest fruit infestation (3.95%), lowest ovary damage (0.88%), lowest post-set damage (2.38%) and, higher yield per plot (21.25 kg) than non-mulched plots. Highest protection against melon fruit fly was observed by Spinosad at the third spray; percentage of fruit infestation (3.71%), ovary damage (0.76%) and yield (20.20 kg/plot) followed by Cypermethrin and Jholmol. The highest protection was obtained by the application of Cypermethrin (1.78%) at the post-set stage followed by Spinosad and Jholmol. The application of Spinosad, Cypermethrin alone with black plastic mulch provided superior protection than Jholmol and control. However, the pest reduction and yield observed on the treatments with the combination of Jholmol and black plastic mulch was satisfactory (21.87 kg/ha) than control (14.58 kg/ha). Int. J. Appl. Sci. Biotechnol. Vol 12(3): 126-136.

Pesticides and pollinator brain: How do neonicotinoids affect the central nervous system of bees?

Neonicotinoids represent over a quarter of the global pesticide market. Research on their environmental impact has revealed their adverse effect on the cognitive functions of pollinators, in particular of bees. Cognitive impairments, mostly revealed by behavioural studies, are the phenotypic expression of an alteration in the underlying neural circuits, a matter deserving greater attention. Here, we reviewed studies on the impact of field-relevant doses of neonicotinoids on the neurophysiology and neurodevelopment of bees. In particular, we focus on their olfactory system as much knowledge has been gained on the different brain areas that participate in odour processing. Recent studies have revealed the detrimental effects of neonicotinoids at multiple levels of the olfactory system, including modulation of odorant-induced activity in olfactory sensory neurons, diminished neural responses in the antennal lobe (the first olfactory processing centre) and abnormal development of the neural connectivity within the mushroom bodies (central neuropils involved in multisensory integration, learning and memory storage, among others). Given the importance of olfactory perception for multiple aspects of bee biology, the reported disruption of the olfactory circuit, which can occur even upon exposure to sublethal doses of neonicotinoids, has severe consequences at both individual and colony levels. Moreover, the effects reported for a multimodal structure such as the mushroom bodies indicate that neonicotinoids' impact translates to other sensory domains. Assessing the impact of field-relevant doses of pesticides on bee neurophysiology is crucial for understanding how neonicotinoids influence their behaviour in ecological contexts and for defining effective and sustainable agricultural practices.

Selected farm-level crop protection practices in Europe and Argentina: Opportunities for moving toward sustainable use of pesticides

Extensive use of plant protection products (PPP) in the last decades contributes to negative impacts on ecosystems, animals and humans. For the strategies of PPP reduction and replacement of hazardous pesticides, farm-level data on agronomic management practices and crop protection applications are crucial. In this study, we strategically collected data for the 2021 season at the SPRINT project case study sites (CSS) in 10 European countries and Argentina, on perennial, arable and vegetable crops. Data collection included strategically selected farm and field data, pesticide records and farming practices. Results involved more than 1700 recorded PPP applications across various crops with more than 170 different active substances from PPP in organic, integrated pest management and conventional farming practices. We explored differences in application patterns (fungicides, insecticides, herbicides and non-PPP, e.g. adjuvants, growth regulators, and fertilizers) between and within crops, countries and farming systems and calculated the costs of PPP use. The pesticide dosages applied during the crop season varied up to a factor of 20 around recommended doses. Regarding the costs of PPPs use perennial crops had the highest costs per ha crop production area. Finally, we analysed the active substances applied in different farming systems in terms of their hazard statements. Our results shed light on how PPPs are used across different crop and farming types and will help elucidate how pesticide application patterns can be changed in the future. Finally, we highlighted non-PPP use practices which help to reduce dependency on PPP use. This might be used to support decision-making and policies within agricultural advisory/support systems.

Adoption of Sustainable Cotton Farming Practices: A Pathway to Eco-Friendly Agriculture

Cotton is one of the key cash crops in Pakistan, significantly contributing to the economy and supporting the livelihoods of the farming community. However, this promising sector faces major threats from global warming and climate change. A study was conducted in District Muzaffargarh to assess the adoption of sustainable cotton farming practices. This area was chosen as it is a major cotton-producing region in Pakistan. A total of 270 cotton growers were randomly selected for data collection. The data were analyzed using the Statistical Package for Social Sciences (SPSS). Additionally, five focus group discussions were conducted to gather qualitative insights. The results revealed that a limited number of cotton varieties were cultivated in the region, with SS, CKC, IUB, BS, and NIAB being the most common. An overwhelming majority of the farmers had cotton fields of up to 5 acres. Hand sowing was the most common planting method. Among water stewardship practices, irrigation after weather forecasts, cleaning of watersheds, and reduced use of flood irrigation were prevalent. In terms of soil improvement practices, foliar spraying, soil analysis, reduced pesticide usage, and reliance on farmyard manure were widely adopted. Regarding Integrated Pest Management (IPM) practices, rotavating crop residue, proper disposal of cotton sticks, the use of recommended pesticide doses, and the application of appropriate active ingredients were the most common practices.

Biology, Distribution and Management of Fall Army Worm <i>Spodoptera frugiperda</i> (J E Smith) in Ethiopia

Fall army worm Spodoptera frugiperda (J E Smith) is a destructive insect pest that is native to tropical and subtropical regions of the Americas and later reported in Africa in 2016. The pest was first detected in Ethiopia in March 2017 and is likely to spread in the country. It is one of the most devastating pests in terms of crop loss and economic impact in developing countries like Ethiopia. It is a voracious pest that can cause significant yield loss. The most preferable host of S. frugiperda is maize and it causes serious damage by feeding on the ears of maize. Prevention of introduction, control, or eradication of S. frugiperda with appropriate measures is important. The IPM is one of the most preferred as complete elimination is not possible. There is a need to develop flexible, coordinated, and effective IPM approach combining various control measures including host plant resistance, mechanical, botanical, biological methods, cultural methods, and suitable doses of pesticides. This study generates information towards these ends.

Feature-agnostic metabolomics for determining effective subcytotoxic doses of common pesticides in human cells.

Although classical molecular biology assays can provide a measure of cellular response to chemical challenges, they rely on a single biological phenomenon to infer a broader measure of cellular metabolic response. These methods do not always afford the necessary sensitivity to answer questions of subcytotoxic effects, nor do they work for all cell types. Likewise, boutique assays such as cardiomyocyte beat rate may indirectly measure cellular metabolic response, but they too, are limited to measuring a specific biological phenomenon and are often limited to a single cell type. For these reasons, toxicological researchers need new approaches to determine metabolic changes across various doses in differing cell types, especially within the low-dose regime. The data collected herein demonstrate that LC-MS/MS-based untargeted metabolomics with a feature-agnostic view of the data, combined with a suite of statistical methods including an adapted environmental threshold analysis, provides a versatile, robust, and holistic approach to directly monitoring the overall cellular metabolomic response to pesticides. When employing this method in investigating two different cell types, human cardiomyocytes and neurons, this approach revealed separate subcytotoxic metabolomic responses at doses of 0.1 and 1 µM of chlorpyrifos and carbaryl. These findings suggest that this agnostic approach to untargeted metabolomics can provide a new tool for determining effective dose by metabolomics of chemical challenges, such as pesticides, in a direct measurement of metabolomic response that is not cell type-specific or observable using traditional assays.

A comparative analysis of beta-cypermethrin nanoemulsion and traditional emulsion dosages on enzyme activities in Blattella germanica

ObjectiveTo compare the impact of two pesticide dose forms on Blattella germanica (B. germanica)resistance enzymes.The micro-drop technique was utilized on subcultured B. germanica, and the metabolic enzyme activity was assessed.Using spectrophotometry, the relative enzyme activities of B.germanica were determined.Profile analysis was used to compare the enzyme activities of beta-cypermethrin in both nanoemulsion and traditional emulsion forms.Findings: The suppression percentages of the acetylcholinesterase enzyme (AchE), GST, and P450–O demethylases across different pesticide formulations were analyzed using regression equations, yielding F = 31.18, P < 0.001; F = 9.18, P < 0.001; and F = 4.58, P < 0.02.Conclusion: The suppression of AchE, GST, and P450–O demethylase by beta-cypermethrin nanoemulsion was more significant compared to the beta-cypermethrin emulsifiable concentrate.The study concluded that beta-cypermethrin nanoemulsion had a significant impact on insect detoxifying enzymes compared to beta-cypermethrin emulsifiable concentrate due to their numerous advantages.

Effect of chlorpyrifos on cypermethrin-induced dopaminergic neurotoxicity in rats.

The study aimed to investigate the combined effects of chlorpyrifos and cypermethrin combined on dopaminergic neurotoxicity, motor behaviours and level of selected inflammatory proteins in rats compared to either alone for delineating an interaction between these two pesticides. The rotarod and grip strength tests were employed to assess neurobehavioural changes. The striatal dopamine content and expression of tyrosine hydroxylase (TH), α-synuclein, cyclooxygenase-2 (COX-2), and tumour necrosis factor-α (TNF-α) proteins in the nigrostriatal tissue were measured. Chlorpyrifos impaired the neurobehavioural indexes, reduced the striatal dopamine level, augmented the level of α-synuclein, COX-2, and TNF-α and attenuated the expression of TH similar to but a little less than cypermethrin. Half the dose of both pesticides together produced additional neurotoxicity compared with the usual (highest employed) dose of either alone. The results showed that chlorpyrifos induced moderately less dopaminergic neurotoxicity than cypermethrin. In the combination, they produced a little higher toxicity than either pesticide alone.

The Influence of Low Pesticide Doses on Fusarium Molds

The agricultural sector is a large consumer of synthetic chemical products, especially fertilizers and plant protection products. Therefore, an emerging concern nowadays is to reduce chemicals’ use in agriculture. One of the approaches is to reduce the doses of plant protection products, as much as possible, while keeping the treatments’ efficacy. The present work presents the antifungal action of three commercial plant protection products, tested at recommended as well as reduced doses, against important phytopathogenic molds of the Fusarium genus. In vitro, results have shown that two of the tested products could be used at reduced doses while keeping their antifungal activity. The commercial pesticide containing prothioconazole 53 g/L, spiroxamine 224 g/L, and tebuconazole 148 g/L mixture was able to inhibit completely the growth of three virulent F. culmorum strains, even when fungicide treatment was applied in 25% reduced dose. Lower efficacy was seen on F. graminearum strains, however, there were no significant differences (p &lt; 0.05) between the commercially recommended dose and the 25% reduced dose. Another efficient pesticide in Fusarium control contains triadimenol 43 g/L, spiroxamine 250 g/L, and tebuconazole 167 g/L. Tested in a reduced dose (28.6% less than the commercial recommended dose) it completely inhibited the F. graminearum Fg183 (DSM 4527) strain and inhibited the growth of various F. culmorum strains with at least 97.50% efficacy. However, there are some fungal strains, such as the aggressive F. graminearum Fg96 strains that were less susceptible to pesticide treatments even at commercially recommended doses of fungicides.

Assessment of Dichlorvos, Cypermethrin, Synthetic Camphor, Pinenes, and Kerosene: Impact on Testosterone Levels, Glutathione Concentration, and Testicular Histology in Male Wistar Rats

Pesticides are integral to modern agriculture and public health but pose significant risks to human and environmental health. This study investigates the impact of selected pesticides on male reproductive health via inhalation in an improvised chamber. Male Wistar rats were assigned to groups and exposed to individual pesticides and a combined mixture to determine lethal doses. Tissue samples from 54 rats were analyzed histologically and biochemically for effects on testes and epididymides, with measured serum testosterone and GSH levels. Sniper consistently showed the highest significant decrease in GSH levels across all exposure levels (p &lt; 0.05). A significant dose-dependent relationship was observed in the recovery groups from 25% to 75% exposure (p &lt; 0.05). Pesticide exposure led to a substantial decrease in serum testosterone levels in male Wistar rats at 25% (all pesticides, p &lt; 0.05), 50% (DD Force, Sniper, Kerosene, Combined, p &lt; 0.05), and 75% (DD Force, Industrial Camphor, Edible Camphor, Kerosene, p &lt; 0.01) concentrations. Escalating damage in testicular and epididymal structures, with a more pronounced severity at higher exposure levels, including epithelial degeneration, Sertoli cell vacuolation, seminiferous tubule derangement, and ductal atrophy. Increased exposure to high doses of pesticides induces oxidative stress in male Wistar rats which could potentiate decreased testosterone levels and adversely impact the histological architecture of the testes and epididymides. Pesticide detoxifications are somewhat evident following withdrawal from the environmental insults. Significant and persistent damage occurred at higher levels, suggestive of substantial reproductive toxicity following exposure.

Induction of oxidative stress in a variety of durum wheat (Triticum durum Desf) exposed to recommended doses of pesticides

The objective of this study was to assess the toxicity of two pesticides (Prosaro® XRT and Decis® EC 25) widely used in the agricultural region of El-Tarf located in northeastern Algeria, as well as their combinations on a variety of durum wheat “Triticum durum Desf”. The toxicity of these products was evaluated using physiological (chlorophyll) and biochemical parameters (proteins, glutathione, catalase activity and glutathione S-transferase, acetylcholine esterase, lipoxygenase). The recommended dose and its double were tested individually and in combination for this. It should be noted that the protocol used and the initial concentrations selected are the same as those used in the field. After D7 and D14 of exposure, all dosages were administered. The results obtained revealed a decrease in chlorophyll contents and Glutathione levels as well as an induction of total proteins and the different enzymatic activity (catalase, glutathione S-transferase, lipooxygenase) and this for the two root and leaf compartments. Thus, it turns out that the concentrations used in open fields are not harmful to the plant but generate free radicals which are taken care of by the latter’s defense system, thus allowing it to tolerate these stress conditions. Keywords: toxicity, pesticides, Triticum durum, oxidative stress, stress biomarkers

Immobilization of Bacillus thuringiensis Cry1Ac in metal-organic frameworks through biomimetic mineralization for sustainable pest management

Traditional chemical pesticide dosage forms and crude application methods have resulted in low pesticide utilization, increased environmental pollution, and the development of resistance. Compared to traditional pesticides, nanopesticides enhance the efficiency of pesticide utilization and reduce the quantity required, thereby decreasing environmental pollution. Herein, Cry1Ac insecticidal crystal protein from Bacillus thuringiensis Subsp. Kurstaki HD-73 was encapsulated in a metal-organic framework (zeolite imidazolate framework-8, ZIF-8) through biomimetic mineralization to obtain Cry1Ac@ZIF-8 nanopesticides. The Cry1Ac@ZIF-8 nanopesticides exhibited a dodecahedral porous structure, and the introduction of Cry1Ac did not affect the intrinsic crystal structure of ZIF-8. The indoor toxicity analysis revealed that the toxicity of Cry1Ac towards Ostrinia furnacalis (Guenée), Helicoverpa armigera Hubner, and Spodoptera litura Fabricius was not affected by ZIF-8 encapsulation. Surprisingly, Cry1Ac@ZIF-8 still exhibited excellent pest management efficacy even after exposure to heat, UV irradiation, and long-term storage. More importantly, the encapsulation of ZIF-8 significantly enhanced the internal absorption performance of Cry1Ac in maize leaves and extended its persistence period. Thus, ZIF-8 could potentially serve as a promising carrier for the preparation of nanopesticides with enhanced applicability, stability, and persistence period, providing a powerful strategy to improve the application of Cry1Ac in future agricultural pest management.

Analysis of Chlorpyrifos Pesticide Residue in Locally Grown Cauliflower, Cabbage, and Eggplant Using Gas Chromatography-Mass Spectrometry (GC-MS) Technique: A Bangladesh Perspective.

Pesticides are chemical substances used to kill or control various types of pests, which are hazardous for crops and animals. Pesticides may remain on or in foods after these are applied to crops. Pesticide residue in food has been a major global concern since there are direct and indirect health hazards associated with the regular consumption of foods with pesticide residues. Chlorpyrifos is one of the most used pesticides that has received much attention worldwide due to its detrimental health impact. The presence of chlorpyrifos residue in food crops can have both long-term and short-term effects on consumer health. Bangladesh is an agricultural country that uses a high volume of pesticides every year including chlorpyrifos. This experimental study aimed to analyze chlorpyrifos pesticide residue in locally grown cauliflower, cabbage, and eggplant samples by gas chromatography-mass spectrometry (GC-MS) technique followed by a suitable extraction process. Commercially available cauliflower, cabbage, and eggplant samples along with samples cultivated with the recommended pesticide dose were collected for qualitative and quantitative analysis. Samples cultivated without chlorpyrifos were collected as control samples for the validation study. The method was validated with respect to accuracy, recovery, reproducibility, linearity, limit of detection, and limit of quantification. The method has a limit of detection (LOD) of 0.011 mg/kg and a limit of quantification (LOQ) of 0.034 mg/kg. The experimental results were compared to the maximum residue level (MRL) to assess the human health impact. Chlorpyrifos residue was found in 44% of cauliflower samples with 91% of samples higher than MRL. The residue was found in 68% of cabbage samples with 53% of samples higher than MRL. For eggplant, the residue was found in 80% of the samples with 65% of samples higher than MRL. The risk assessment based on the residue level found in this study shows a potential health hazard of having a high concentration of chlorpyrifos residue in locally grown vegetables.

A framework for evaluating the value of agricultural pest management decision support systems

Disease management decision support systems (DSS) are typically prediction algorithms that help farmers assess the risk of an epidemic, to guide whether, and to what extent, fungicide treatment is needed. However, there is frequently little information presented to quantify the value of using the DSS, i.e. the likely increased profit or reduced impact to the environment, and the risks of failing to control the pest. Validation of DSS is often limited to a small number of sites and seasons, as extensive field testing is prohibitively expensive. It would therefore be beneficial to have a method to estimate the value of a DSS using existing data sets gathered for other purposes.We present a theoretical framework for evaluating the value of DSS, and then describe how this can be applied in practice using four case studies of contrasting DSS under different data constraints. The four case studies include DSS that guide (i) the total dose of pesticide applied; (ii) the number of sprays required; (iii) the timing of the first fungicide application in a spray programme; and (iv) infection risk alerts. We demonstrate how our theoretical framework can be used to evaluate DSS, using existing field and literature data to infer the benefits and risks associated with their use. The limitations of using existing data are explored.

Synergestic and antagonistic effect of three pesticides and their combination on whole body chemistry of Channa marulius (ham)

In the present work an attempt has been made to study the effect of three pesticides namely Metacid-50 (M), Kelthane (K), Dithane (D) and their combination on water, lipid, protein, calorific values and non-lipid content in a fresh water fish, Channa marulius (Ham.). Precent water, lipid, non-lipid, protein and calorific values (K.Cal/g) in control groups were respectively 71.76, 3.84, 24.39, 19.69 and 3.32 (K.Cal./g). Exposure of fishes for 24 and 48hrs. and in different doses of individual pesticide and their combination brought changes in different biochemical constituents and energy values in this animals. Statistical relationship have also been established between concentration of pesticides Vs body water and body lipid. The details have been discussed in this paper.. KEYWORDS :Proximate composition, Energy values, Pesticides, Fish.

Fabrication of zein-coated brush-like silica nanocarriers for high foliage deposition and responsive release of pesticide

Responsive release systems have received extensive attention to enhance pesticide utilization efficiency and reduce environmental pollution. In this study, pH/GSH dual responsive release system based on brush-like silica (bSiO2) carriers was constructed to enhance the utilization of pesticides. The bSiO2 carriers present core-shell structure, length of 550 nm, diameter of 350 nm and shell thickness of 100 nm. The carrier had a high pesticide loading (20.0 %, w/w) for dinotefuran (Din). After loading Din, zein was covalently linked with cysteine-bridge to seal the loaded pesticides (namely Din@bSiO2@Zein). The Din@bSiO2@Zein exhibited superior foliar affinity, retention and photostability, and retention rate still remain above 95 % with 220 min UV irradiation. Din@bSiO2@Zein displayed pH/GSH responsive release and the cumulative release within 92 h was up to 81 % under pH=9/CGSH=6 mM, mimicking the microenvironment of lepidopteran. The Din@bSiO2@Zein possessed good control efficacy against Plutella xylostella. Appreciably, Din@bSiO2@Zein could be transported bi-directionally to various regions of tobacco plants within 24 h, which had potential to promote pesticide efficacy. This work offers a strategy to minimize the pesticide dosage and encourage sustainable agricultural development.