A nano-delivery system expands the insecticidal target of thiamethoxam to include a devastating pest,the fall armyworm

Nano-delivery systems have been applied to deliver various synthetic/botanical pesticides to increase the efficiency of pesticide use and reduce the volumes of pesticides applied. Previous studies have supported the hypothesis that the nanocarriers can help expand the insecticidal target of pesticides to include non-target pests. However, the potential mechanism underlying this interesting phenomenon remains unclear. Herein, a widely applied star polycation (SPc) nanocarrier was synthesized to construct a thiamethoxam (TMX) nano-delivery system. The SPc-based delivery system could promote the translocation of exogenous substances across the membrane of Sf9 cells, increase the cytotoxicity of TMX against Sf9 cells by nearly 20%, and expand the insecticidal target of TMX to include Spodoptera frugiperda (the fall armyworm), with a 27.5% mortality increase at a concentration of 0.25 mg/mL. Moreover, the RNA-seq analysis demonstrated that the SPc could upregulate various transport-related genes, such as Rab, SORT1, CYTH, and PIKfyve, for the enhanced cellular uptake of TMX. Furthermore, enhanced cell death in larvae treated with the TMX–SPc complex was observed through changes in the expression levels of death-related genes, such as Casp7, BIRC5, MSK1, and PGAM5. The SPc-based nano-delivery system improved the cellular uptake of TMX and expanded its insecticidal target by adjusting the expression levels of death-related genes. The current study mainly identified the transport and cell death genes related to nanocarrier-based insecticidal target expansion, which is beneficial for understanding the bioactivity enhancement of the nano-delivery system.     

从植物中寻找农药活性物质

从植物中寻找农药活性物质,判明结构,使之成为创新类型农药有效母体,是创制新农药品种的重要途径之一,受到当今全世界农药界的广泛重视。本文综合性介绍植物与农药的关系,该交叉学科研究的一般程序和方法以及通过对有效母体的结构改造,构一效关系的研究,创制新农药的研究过程。     

Perspectives for nano-biotechnology enabled protection and nutrition of plants

Indiscriminate use of pesticides and fertilizers causes environmental pollution, emergence of agricultural pests and pathogens, and loss of biodiversity. Nanotechnology, by virtue of nanomaterial related properties, has potential agro-biotechnological applications for alleviation of these problems. The literature pertaining to the role of nanotechnology in plant and soil systems demonstrates that nanomaterials may assist in a) the controlled release of agrochemicals for nutrition and protection against pests and pathogens, b) delivery of genetic material, c) sensitive detection of plant disease and pollutants and d) protection and formation of soil structure. For instance, porous silica (15 nm) and biodegradable, polymeric chitosan (78 nm) nanoparticles displayed slow release of encapsulated pesticide and fertilizer, respectively. Further, nanosized gold (5–25 nm) delivered DNA to plant cells while iron oxide (30 nm) based nanosensors detected pesticides at minute levels. These functions assist the development of precision farming by minimizing pollution and maximizing the value of farming practice.     

低剂量农药作用下拟环纹豹蛛对褐飞虱的功能反应及搜寻行为

在室内研究了低剂量农药作用下拟环纹豹蛛对褐飞虱的功能反应及搜寻行为。结果表明,拟环纹豹蛛对褐飞虱的功能反应均符合Holling Ⅱ模型,且在最适的低剂量农药(V_药∶V_水为2∶5 000甲胺磷,12∶5 000杀虫双和1∶20烯丙菊酯)刺激下,蜘蛛捕食褐飞虱的数量是最多的,蜘蛛用于对1头褐飞虱进行制服和取食等活动所需的时间（处理猎物时间,Th）短,仅分别为未经农药处理的蜘蛛所需时间的0.45、0.32和0.35倍;而施用较高剂量8∶5 000的甲胺磷、28∶5 000的杀虫双和6∶20的烯丙菊酯的蜘蛛,处理猎物时间长得多,依次是经最适低剂量3种农药作用的蜘蛛所用时间的9.70、13.60和13.62倍。拟环纹豹蛛在稻株上的搜寻行为属非随机搜索型,在相同的低剂量农药作用下,蜘蛛的搜寻效应随飞虱密度的增加而下降;但在相同的猎物密度下,蜘蛛的搜寻效应与使用的农药浓度有密切的关系,在上述最适低剂量农药作用下,豹蛛对猎物的寻找效应最佳,其在稻株上的总滞留时间依次是未施药情形的1.56、1.49、1.48倍,总搜寻距离依次是未施药情形的1.36、1.42、1.39倍。据此,进一步证实了低剂量农药增强了稻田蜘蛛的控虫效能和对害虫的相对活力。     

Pesticide desorption from soils facilitated by dissolved organic matter coming from composts: experimental data and modelling approach

Dissolved organic matter (DOM) interaction with pesticides was examined studying the ability of DOM to desorb 8 pesticides previously sorbed to soil. DOM was originating from municipal waste composts at two maturity degrees, recovered at 20°C and by hot-pressurised subcritical water. Pesticide desorption depended on their previous sorption on soil. When sorption was low (K_OC ≤ 50, sulcotrione, metalaxyl), water was more efficient than DOM for desorption. On the contrary, when sorption was high (K_OC ≥ 2000, trifluraline), little effect of DOM was observed. For the moderately sorbed pesticides, DOM favoured pesticide desorption compared to water. For the lowest sorbed pesticides (K_OC ≤ 100), hysteresis was increased with larger proportions of DOM extracted with subcritical-water. Dissolved organic matter extracted from fresh-immature compost had larger capacity to mobilize the sorbed pesticides than the DOM from the mature compost. The pesticide desorption resulted from the positive and competitive interactions between pesticide, DOM and soil surfaces. These interactions were modelled considering separate partitioning coefficients. A general equation allowed the deduction of specific coefficients describing interactions in solution between pesticides and the non-sorbed fraction of DOM remaining in solution. This fraction was supposed to contain the most hydrophilic fraction of DOM and was able to interact with the most polar pesticide (amitrol). When pesticide hydrophobicity increased, the partitioning between pesticide and DOM decreased. Modelling the three-phase system (liquid, DOM and solid phases) pointed out that the solid phase played the most important role on pesticide behaviour through the sorption process of DOM and pesticides.     

A method to assess the effects of pesticides on the predatory mite Phytoseiulus persimilis (Acari Phytoseiidae) in the laboratory

Phytoseiulus persimilis Athias-Henriot (Acari Phytoseiidae) is a major predator of Tetranychus urticae (Acari Tetranychidae). The performance of P. persimilis in controlling T. urticae may be altered by pesticides used to manage other pests. Therefore, knowledge of the side-effects of pesticides is essential for IPM. A number of laboratory methods were suggested to evaluate pesticide side-effects on predatory mites. Most methods assess residual effects only, and a number of them are characterised by high predator escape rates from experimental units. A method aimed at evaluating the topical and residual effects of pesticides on P. persimilis is herein described. Mites were treated by microimmersion and then reared in holding cells, on bean leaves previously dipped in a pesticide solution. Three insecticides (pyrethrins, spinosad and thiamethoxam), an insecticide-acaricide (abamectin), and two fungicides (azoxystrobin and tolylfluanide) were evaluated. The strain of P. persimilis used for evaluation was collected from unsprayed vegetable plants. All the pesticides affected the survival and fecundity of P. persimilis. Pesticides did not affect the egg-hatching of P. persimilis females exposed to pesticides. Pyrethrins and abamectin proved to be more toxic than other pesticides, and thiamethoxam was more toxic than spinosad, azoxystrobin and tolylfluanide. The escape rate from experimental units was lower than 5% in all trials. Additional experiments were performed on P. persimilis eggs by dipping leaves with eggs in the pesticide solution. None of the pesticides affected egg survival. Semi-field trials conducted on potted bean plants obtained results similar to those reported in laboratory trials.     

Gold nanoparticles based dipstick immunoassay for the rapid detection of dichlorodiphenyltrichloroethane: An organochlorine pesticide

Gold nanoparticles (GNPs) based dipstick competitive immunoassay was developed to detect organochlorine pesticide such as DDT at nanogram level (ppb). GNPs of definite size were synthesized and conjugated to anti-DDT antibodies (IgY), which served as the detecting reagent. DDA-BSA conjugate (antigen) was immobilized on to nitro cellulose (NC) membrane containing strip. GNPs conjugated anti-DDT antibodies were treated with different concentrations of free DDT ranging from 0.7 ng mL⁻¹ to 1000 ng mL⁻¹ to form an immunocomplex. This immunocomplex solution was further reacted with DDA-BSA conjugate immobilized NC membrane containing strips by dipping the strip in the immunocomplex solution. The free GNPs conjugated anti-DDT antibodies present in the immunocomplex solution were targeted for competitive binding with immobilized DDA-BSA on NC membrane containing strip. Depending on the concentration of free DDT in the sample the binding of GNPs conjugated anti-DDT antibodies to the immobilized DDA-BSA varied and was detected by the development of red color (due to gold nanoparticles) in the detection zone of NC membrane containing strips. The intensity of color development was inversely proportional to the DDT concentration with maximum intensity at zero DDT concentration. The lowest detection limit of DDT was determined to be 27 ng mL⁻¹ with the optimized conditions. The dipstick technique based on GNPs is suitable for the detection of several toxins in food and environmental samples and can be applied for rapid on-site testing of pesticides.     

Determination of thiacloprid,thiamethoxam and imidacloprid in tea samples by quenching terbium luminescence

Consumption of herbal teas, infusions and other plant‐related products has always been popular due to the related health benefits. However, the safety of these products needs to be assessed, for example monitoring the potential presence of contaminants such as pesticides. In this paper, we report an analytical method for determining three neonicotinoid insecticides ? thiacloprid, thiamethoxam, and imidacloprid ? that are widely used worldwide. This method is based on quenching by analytes of the luminescence signal of terbium ions. Terbium presents a time‐resolved luminescence signal at 256/545 nm/nm, which is quenched by the presence of low concentrations of the selected analytes. Detection limits of 0.1, 0.2 or 0.75 μg ml^?1 were obtained for thiamethoxam, thiacloprid and imidacloprid, respectively. Recovery experiments in different teas (green tea, black tea, chamomile, peppermint) were performed at concentrations lower than the maximum residue limits established by the European Union and the Codex Alimentarius for tea samples. In all cases, satisfactory recovery yields were observed, and the results were compared with a chromatographic reference method. The proposed method therefore proved suitable for quantifying these insecticides, fulfilling the current legislation.     

Pesticide-induced susceptibility of rice to brown planthopper Nilaparvata lugens

The effects of rice plants treated with various pesticides (jingganmycin, bisultap and methamidophos) on feeding, survival rates and population growth of Nilaparvata lugens Stål (Homoptera: Delphacidae), susceptibility of the treated rice plants and amounts of free amino acids and sucrose were studied. Experiments indicated that the effects of the tested pesticides were dependent on nymphal age, pesticide and their dose and time after application. Jingganmycin at 75 g a.i. ha^–1 significantly increased the N. lugens population. Both jingganmycin and bisultap increased the survival rate of N. lugens nymphs. The feeding rate of the insects was also affected by the pesticide application, but the effect varied between nymphal age and time after application and lasted no longer than 15 d. Results clearly indicated that pesticide application increased the susceptibility of rice plants to N. lugens. Although the free amino acids in rice plants did not change with the pesticide treatments, the concentration of sucrose significantly decreased 5 d after application and the C/N ratio significantly decreased in jingganmycin treated plants 5 d and 10 d after application.     

Scale dependent drivers of wild bee diversity in tropical heterogeneous agricultural landscapes

Factors associated with agricultural intensification, for example, loss of seminatural vegetation and pesticide use has been shown to adversely affect the bee community. These factors may impact the bee community differently at different landscape scales. The scale dependency is expected to be more pronounced in heterogeneous landscapes. However, the scale‐dependent response of the bee community to drivers of its decline is relatively understudied, especially in the tropics where the agricultural landscape is often heterogeneous. This study looked at effects of agricultural intensification on bee diversity at patch and landscape scales in a tropical agricultural landscape. Wild bees were sampled using 12 permanent pan trap stations. Patch and landscape characteristics were measured within a 100 m (patch scale) and a 500 m (landscape scale) radius of pan trap stations. Information on pesticide input was obtained from farmer surveys. Data on vegetation cover, productivity, and percentage of agricultural and fallow land (FL) were collected using satellite imagery. Intensive areas in a bee‐site network were less specialized in terms of resources to attract rare bee species while the less intensive areas, which supported more rare species, were more vulnerable to disturbance. A combination of patch quality and diversity as well as pesticide use regulates species diversity at the landscape scale (500 m), whereas pesticide quantity drove diversity at the patch scale (100 m). At the landscape scale, specialization of each site in terms of resources for bees increased with increasing patch diversity and FL while at the patch scale specialization declined with increased pesticide use. Bee functional groups responded differentially to landscape characteristics as well as pesticide use. Wood nesting bees were negatively affected by the number of pesticides used but other bee functional groups were not sensitive to pesticides. Synthesis and Applications: Different factors affect wild bee diversity at the scale of landscape and patch in heterogeneous tropical agricultural systems. The differential response of bee functional groups to agricultural intensification underpins the need for guild‐specific management strategies for wild bee conservation. Less intensively farmed areas support more rare species and are vulnerable to disturbance; consequently, these areas should be prioritized for conservation to maintain heterogeneity in the landscape. It is important to conserve and restore seminatural habitats to maintain complexity in the landscapes through participatory processes and to regulate synthetic chemical pesticides in farm operations to conserve the species and functional diversity of wild bees.     

Establishment of an EC50 database of pesticides using a Vibrio fischeri bioluminescence method

An EC₅₀ database was established to assess the acute toxicity of 16 PESTANAL pesticide standards and of seven pesticide commercial formulations using a Vibrio fischeri bioluminescence method. Half maximal effective concentration ( EC₅₀) is defined as the concentration of pollutant (in this case, pesticide) destroying 50% of the bacteria population and causing 50% bioluminescence inhibition, after a specified exposure time. Linear curves of bioluminescence inhibition versus pesticide concentration and EC₅₀ values were obtained for exposure times (t) of 5 or 15 min for these pesticides. The EC₅₀ values ranged from 6.90 × 10^?4 to 0.83 mg/ml (t = 5 min), and from 9.00 × 10^?4 to 0.37 mg/ml (t = 15 min) for pesticide standards, plus from 0.0077 to 0.74 mg/ml (t = 5 min), and from 0.0076 and 0.57 mg/ml (t = 15 min) for pesticide commercial formulations. The EC₅₀ database allowed classification of the pesticides under study into three categories according to their toxicity: very toxic, toxic and moderately toxic. These results demonstrated that the establishment of an EC₅₀ database and of linear curves of bioluminescence inhibition versus the pesticide concentration resulted in very important and irreplaceable tools to estimate the global and individual toxicity of pesticides present in environmental samples.     

Identification of markers of depression and neurotoxicity in pesticide exposed agriculture workers

Earlier, we reported that chronic exposure to pesticides causes a reduction in the acetylcholinesterase activity and hematological and biochemical alterations in agriculture workers. In continuation with that, the present study aimed to investigate the pesticide‐induced neurochemical imbalance and its association with behavior alterations in agricultural workers. A significant increase in depressive symptoms, assessed by the Beck Depression Inventory‐II was observed in pesticide exposed workers as compared to the unexposed. A decrease in the level of dopamine in plasma and levels of dopamine, 3,4‐dihydroxyphenylacetic acid, homovanillic acids, norepinephrine, serotonin, and hydroxyindoleacetic acid in urine was also observed. An increase in the levels of MAO‐A and MAO‐B has also been observed in these individuals. The decreased levels of neurotransmitters in the blood and urine have been linked with increased levels of MAO and pesticide residues in plasma and urine. Furthermore, these changes were associated with a higher incidence of depression in agricultural workers.     

Occurrence and distribution of pesticides in soil at agrichemical facilities in Illinois

Detectable concentrations of pesticides were found in soil samples collected from 49 agrichemical facilities located throughout Illinois. Analysis of 822 soil samples resulted in the detection of 53 pesticides and nitrate; 20 pesticides were found in fewer than 1% of the samples. Most frequently detected were alachlor, atrazine, metolachlor, trifluralin, pendimethalin, cyanazine, metribuzin, metribuzin DA, butylate, and α‐BHC. Chlordane, dieldrin, and DDT, although not distributed at the facilities in recent years, were found in soil samples from more than one third of the sites. Approximately 24% of the pesticide detections occurred in a concentration range between the detection limit and 50 μg/kg, and 79% of all detections were less than 1000 μg/kg.

Pesticides were detected at sampling depths to 4.5 m. However, approximately 50% of all pesticide detections were found in the gravel fill that serves as the parking lot/road base for each facility. No predictable pattern in pesticide occurrence in relation to sampling depth could be determined on the basis of the mobility or persistence of the pesticide.     

Yield Reduction in ‘Tahiti‘ Lime from Panonychus Citri Feeding Injury Following Different Pesticide Treatment Regimes and Impact on the Associated Predacious Mites

A series of experiments was initiated on Tahiti lime trees to assess possible involvement in yield reduction by one or more species of thrips, especially Frankliniella bispinosa (Morgan) and F. kelliae Sakimura (Thysanoptera: Thripidae). Different pesticides were applied to ensure adequate coverage on flowers and to maintain effective thrips control. Outbreaks of spider mites were anticipated because of the pesticides used and frequency of application. Therefore, population dynamics of the citrus red mite, Panonychus citri (McGregor) (Acari: Tetranychidae) and the predacious mites Typhlodromalus peregrinus (Muma) (Acari: Phytoseiidae) and Agistemus floridanus Gonzalez (Acari: Stigmaeidae) were monitored in four pesticide treatment regimes during flowering on Tahiti lime, Citrus latifolia Tanaka in south Florida. Yield was significantly reduced in four pesticide treatment regimes by 41, 31, 28 and 17% relative to the untreated control. Elimination of predacious mites by the selected pesticides resulted in higher sustained populations of P. citri on treated trees compared to those untreated. The pesticide regimes resulted in differences in population densities of both citrus red mite and its key predators. Depending upon the treatment regime and application date(s), the duration and magnitude of disruption resulted in significant differences in yield. P. citri densities that averaged 5.2 or more per leaf during January–February, or 4.3 or more per leaf during January–March, or 3.9 or more per leaf during January– April contributed substantially to the feeding injury and resulted in reduced yield. Typhlodromalus peregrinus was the most common predacious mite collected during this study (80.4%) followed by A. floridanus with 15.7%.This study demonstrated that the use of one or more pesticides on Tahiti lime trees can negatively impact populations of citrus red mites and their associated predators to the detriment of yield. The magnitude of impact was dependent upon the treatment regime and application date(s). Spider mites increased because of reduced predator populations and use of these pesticides, especially in combination, is to be discouraged.     

Hepatoprotective effect of Aloe vera against cartap- and malathion-induced toxicity in Wistar rats

Exposure to mixture of pesticides in agricultural practices pose a serious threat to the nontarget animals. In present work, we have evaluated the synergistic effect of cartap and malathion on rat liver followed by impact of Aloe vera leaves aqueous extract, which is not known. The animals in eight groups were used; each containing six rats: Group 1 acted as a control, Group 2—control with A. vera leaves aqueous extract, Group 3—with cartap, Group 4—with malathion, Group 5—with mixture of cartap and malathion, Group 6—cartap with the pretreatment of A. vera leaf extract, Group 7—malathion with the pretreatment of A. vera leaf extract, Group 8—mixture of cartap and malathion with the pretreatment of A. vera leaf extract . The animals treated for 15 days were killed after 24hr of last treatment. The biochemical studies in the rat liver demonstrated significant perturbations in the levels of nonenzymatic (glutathione and malondialdehyde) and enzymatic (superoxide dismutase, catalase, and glutathione- S-transferase) antioxidative indices. The histopathological examination of liver revealed serious congestion in central vein and the disorganization of hepatic cords due to pesticide treatment. The administration of A. vera leaves aqueous extract was able to markedly protect rat liver from the pesticides-induced toxicity. The data indicated that pesticides were able to significantly induce oxidative stress which was substantially reduced by the application of plant extract .     

Pesticide or wastewater: Which one is a bigger culprit for acute health symptoms among vegetable growers in Pakistan's Punjab?

Literature highlights harmful effects of pesticides and untreated wastewater use on farmers' health but none of the studies explore the magnitude of deleterious health effects simultaneously. The objective of the study is to quantify pesticide and untreated wastewater induced health symptoms among vegetable growers and to investigate which one is a bigger culprit. A sample of 830 vegetable growers was selected by stratified random sampling from three major vegetable growing districts of Pakistan's Punjab. A two stage estimation technique is employed to estimate unbiased health effects of vegetable growers after controlling for pesticide endogeneity. The results demonstrate that both untreated wastewater and pesticide quantities are responsible for acute symptoms, but comparison of their scaled coefficients indicates that wastewater is twofold responsible for acute symptoms than pesticide. To minimize these negative effects, a policy of untreated disposal of wastewater in peri-urban areas for crop production needs to be re-designed. The installation of a treatment plant by collecting pollution premium from untreated wastewater emitters seems to be the most sustainable and practically viable option. It is also observed that pesticide is contributing to farmers' acute symptoms; hence, awareness campaigns about judicious and safe use of pesticides may help to mitigate acute symptoms.     

Unraveling uncultivable pesticide degraders via stable isotope probing (SIP)

Uncultivable microorganisms account for over 99% of all species on earth, playing essential roles in ecological processes such as carbon/nitrogen cycle and chemical mineralization. Their functions remain unclear in ecosystems and natural habitats, requiring cutting-edge biotechnologies for a deeper understanding. Stable isotope probing (SIP) incorporates isotope-labeled elements, e.g. ^13?C, ^18?O or ^15?N, into the cellular components of active microorganisms, serving as a powerful tool to link phylogenetic identities to their ecological functions in situ. Pesticides raise increasing attention for their persistence in the environment, leading to severe damage and risks to the ecosystem and human health. Cultivation and metagenomics help to identify either cultivable pesticide degraders or potential pesticide metabolisms within microbial communities, from various environmental media including the soil, groundwater, activated sludge, plant rhizosphere, etc. However, the application of SIP in characterizing pesticide degraders is limited, leaving considerable space in understanding the natural pesticide mineralization process. In this review, we try to comprehensively summarize the fundamental principles, successful cases and technical protocols of SIP in unraveling functional-yet-uncultivable pesticide degraders, by raising its shining lights and shadows. Particularly, this study provides deeper insights into various feasible isotope-labeled substrates in SIP studies, including pesticides, pesticide metabolites, and similar compounds. Coupled with other techniques, such as next-generation sequencing, nanoscale secondary ion mass spectrometry (NanoSIMS), single cell genomics, magnetic-nanoparticle-mediated isolation (MMI) and compound-specific isotope analysis (CSIA), SIP will significantly broaden our understanding of pesticide biodegradation process in situ.     

Reduced Pesticide Use in Scandinavian Agriculture

In all industrialized countries, the use of individual pesticides has been regulated on the basis of the presumed hazard that each poses to health and the environment. In Sweden, Norway, and Denmark, programs aimed at reducing total pesticide use have been initiated as well.

In Swedish and Danish agriculture, the amount of active ingredients used has decreased steadily since around 1980; however, the area treated has increased during the same period. The reduction during the 1980s can be ascribed to several factors affecting pesticide use in agriculture. First, old pesticides have been replaced by new ones that are active at lower doses. A general decrease in herbicide doses applied has been possible because of decreased weed pressure. Improved spraying technique also is important.

Environmental concern and political ambitions to reduce pesticide use in Scandinavian agriculture must be understood primarily within the historical framework of societal values and political and social experiences. The success in the reduction of pesticide use, however, cannot be measured and evaluated without taking into account the specific technical and agroecological prerequisites existing in Scandinavian agriculture. As in many other areas of complex changes in modern society: Opinion proposes, Technology disposes.     

Sublethal effects of Bt toxin and chlorpyrifos on various Spodoptera exigua populations

Bt cotton (Cry1Ac) has been commercially grown in China since 1997, saving China's cotton production from attack by Bt‐target pests and also tremendously reducing pesticide usage. In recent years, however, Bt cotton, with 4.2 million ha of cultivation, has suffered from a secondary target pest, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). In China, growers have even had to re‐adopt conventional pesticides to control the pest, and this practice has already caused serious pesticide residue. In order to clarify the sublethal effects of chemical pesticide, the responses of a Bt‐susceptible and a Bt‐tolerant (Bt10) S. exigua strain to three treatment combinations were examined, including Bt toxin, sublethal chlorpyrifos, and Bt + sublethal chlorpyrifos. The susceptible and the Bt10 strain responded differently to dual pressure. Bt toxin + sublethal chlorpyrifos treatment lowered larval mortality and stimulated population increase of the susceptible S. exigua, whereas it delayed growth and development of the Bt10 strain. Under dual pressure, although larvae of the Bt10 strain developed faster than larvae of the susceptible strain, the Bt10 population experienced higher larval mortality, prolonged pupal duration, decreased pupal weight, decreased emergence rate, and shortened adult longevity. Compared with the susceptible strain, the Bt10 strain was deleteriously affected by sublethal chlorpyrifos. The Bt‐tolerant/resistant S. exigua population was more vulnerable to chemical pesticides like chlorpyrifos regardless of whether it was exposed to Bt toxin or not. Our study provides a reference for increasing the efficacy of control of S. exigua in Bt‐cotton planting areas.     

Pesticide‐mediated disruption of spotted wing Drosophila flight response to raspberries

The disruption of chemical communication between insects and host plants may take place due to an interference with the signal‐emitting host plant, or the signal‐receiving insect, compromising the signal production and emission, or its reception and processing. Anthropogenic compounds, in general, and pesticides, in particular, may impair the chemical communication that mediates host location by insects. Five different pesticides (the insecticides malathion, pyrethrins and spinetoram, and the fungicides fenhexamid and pyrimethanil) were applied at their field rates to raspberry fruits, or Petri dishes enclosing adult spotted wing Drosophila (SWD; Drosophila suzukii), and the attraction to fruit volatiles was evaluated in a series of two‐choice flight bioassays. The application of raspberry fruit with pesticides did not statistically affect attraction of unexposed adults, with exceptions being the spinetoram treatment, which led to mild insect avoidance, and the pyrethrin treatment, which resulted in slightly preferential attraction. In contrast, adults sublethally exposed to the pesticides had their flight take‐off impaired by the insecticides, but not by the fungicides. Furthermore, all pesticides, and particularly the insecticides, compromised the upwind capture of adults. Thus, the treatment with pesticides may indeed interfere with the flight response of SWD to host volatiles, particularly when the insects were previously exposed to pesticides. These findings are suggestive of the potential for sublethal insecticidal exposures to aid pest control and also provide evidence that pesticide use may compromise sampling/trapping strategies for this pest species that are based on attraction to host volatiles.