Pesticide Susceptibility Research Articles

Purification, characterization of a plant esterase from red kidney bean and its feasibility for pesticide residue analysis in foods

Plant-derived esterase is a promising alternative enzyme source for pesticide residue analysis. The present study aimed to obtain purified red kidney bean esterase (RKBE), investigate its biochemical properties and application potential in pesticide residue assay. RKBE was extracted and purified by simple aqueous two-phase extraction combined with dextran gel filtration chromatography, with specific activity of 11.845 U/mg and purification fold of 18.952. SDS-PAGE revealed that RKBE has a molecular weight of 33 kDa. Preliminary structural characterization showed the amino acid sequence of RKBE was similar to that of α/β-hydrolase (ESW18998) derived from Phaseolus vulgaris with 19.5% sequence coverage, and the relative contents of β-sheet, β-turn, α-helix, and random coil were 22.69%, 24.19%, 30.12%, and 23.00%, respectively. The optimal pH and temperature of RKBE were 6.5 and 40 °C. Ca2+, Mg2+, Zn2+, and low concentrations of methanol and ethanol stimulated the enzyme activity. The half-life was 138.6 days at −20 °C. Kinetic studies showed that RKBE exhibited a high affinity and catalytic activity towards 1-naphthyl acetate, with a Km of 0.277 mM and a Kcat/Km of 0.455 s−1 mM−1. Enzyme-specific inhibition assay indicated RKBE to be a carboxylesterase. Finally, pesticide susceptibility experiments confirmed that organophosphorus and carbamate pesticides exerted inhibitory effects on RKBE catalytic activity. For methamidophos, methomyl, dichlorvos, and carbaryl, the limit of detection (IC10) values in cabbage were 0.0031, 0.0045, 0.001, and 0.0065 mg/kg, respectively, suggesting that RKBE can serve as a new, widely available and cost-effective enzyme source for pesticide residual assay in foods.

Developing practical measures of the price of pesticide resistance: A flexible computational framework with global sensitivity analysis

AbstractPesticide resistance poses an increasing challenge for agricultural sustainability. Pesticide susceptibility is a depletable biological resource, but resistance management rarely quantifies marginal, forward‐looking economic costs to users of depletion. To facilitate the development of such costs, we use a generic stochastic bioeconomic model of resistance evolution in a crop pest population, stochastic dynamic programming, and global sensitivity analysis to analyze the “marginal user costs” of resistance. The most impactful parameters are population density dependence and pesticide prices. The least impactful is the fitness cost of resistance, which is noteworthy because of prior emphasis on this parameter in the resistance management literature.

The symbiont Wolbachia alleviates pesticide susceptibility in the two-spotted spider mite Tetranychus urticae through enhanced host detoxification pathways.

The two-spotted spider mite (Tetranychus urticae) is one of the most well-known pesticide-resistant agricultural pests, with resistance often attributed to changes such as target-site mutations and detoxification activation. Recent studies show that pesticide resistance can also be influenced by symbionts, but their involvement in this process in spider mites remains uncertain. Here, we found that infection with Wolbachia, a well-known bacterial reproductive manipulator, significantly increased mite survival after exposure to the insecticides abamectin, cyflumetofen, and pyridaben. Wolbachia-infected (WI) mites showed higher expression of detoxification genes such as P450, glutathione-S-transferase (GST), ABC transporters, and carboxyl/cholinesterases. RNA interference experiments confirmed the role of the two above-mentioned detoxification genes, TuCYP392D2 and TuGSTd05, in pesticide resistance. Increased GST activities were also observed in abamectin-treated WI mites. In addition, when wild populations were treated with abamectin, WI mites generally showed better survival than uninfected mites. However, genetically homogeneous mites with different Wolbachia strains showed similar survival. Finally, abamectin treatment increased Wolbachia abundance without altering the mite's bacterial community. This finding highlights the role of Wolbachia in orchestrating pesticide resistance by modulating host detoxification. By unraveling the intricate interplay between symbionts and pesticide resistance, our study lays the groundwork for pioneering strategies to combat agricultural pests.

Pesticide susceptibility monitoring of fall armyworms (Spodoptera frugiperda (J.E. Smith)): a simple methodology for information-sharing among Southeast Asian countries

BackgroundThe fall armyworm, Spodoptera frugiperda, is a destructive moth pest. It is highly migratory and was first detected in Southeast Asia in 2018, rapidly becoming a major pest of corn production in this region. Monitoring the susceptibility of S. frugiperda populations is important for efficient insecticide resistance management. Because of the high mobility of this pest, information-sharing of susceptibility levels among neighboring countries is required for insecticide resistance management. To this end, we developed simple standard methods for pesticide susceptibility monitoring of S. frugiperda to contribute to information-sharing among Southeast Asian countries.MethodsThe developed methods included mass rearing of larvae using an artificial diet and bioassay by diet overlay. The lethal concentrations for 50% and 95% mortality (LC50 and LC95) and resistance coefficient values were calculated. We tested the susceptibilities of samples of S. frugiperda collected from the six major corn planting areas in Thailand to emamectin benzoate, spinetoram, chlorantraniliprole, indoxacarb, chlorfenapyr, and lufenuron using the developed methods.ResultsThe mortality of artificial diet-fed larvae was higher than those fed corn leaves, especially in the early instars. However, more than half of the specimens reared on the artificial diet became pupae. In the case of three of the six pesticides, emamectin benzoate, indoxacarb, and chlorfenapyr, the LC50 values of the samples collected in 2021 and 2022 were significantly higher than those collected in 2019, indicating increasing resistance to those three pesticides. According to the resistance coefficient values, only samples from one area exhibited low resistance to lufenuron.ConclusionsWe developed a simple standardized methodology for Southeast Asian countries to compare insecticide susceptibility. The calculated LC50 and resistance coefficient values can be used as a baseline for monitoring the development of pesticide resistance in the region. The LC50 values of several pesticides have increased significantly over the years. However, the resistance coefficient values indicated that S. frugiperda developed low resistance to only one pesticide (lufenuron). This study offers helpful information for insecticide selection and improved resistance management of fall armyworms in Thailand.

Updating integrated mite management fifty years later: comparing laboratory pesticide susceptibility of a "new" generalist predatory mite to a cornerstone specialist predator.

Historically, integrated mite management in Washington apple orchards has focused on the conservation of the predatory mite Galendromus occidentalis (Nesbitt) to reduce secondary pest mite pressure. However, pesticide use has changed to include more selective products, coinciding with a shift in the predatory mite community composition to include a new major predator, Amblydromella caudiglans (Schuster). There is evidence that A. caudiglans is more pesticide sensitive than G. occidentalis. Therefore, updates on pesticide selectivity recommendations are needed to conserve this "new" key predator. Using bioassays, we examined lethal (female mortality) and sublethal effects (fecundity, egg hatch, larval survival) of four fungicides and 11 insecticides on A. caudiglans, to determine if existing conservation recommendations can be applied to this predatory mite. Susceptibility was compared to prior research on G. occidentalis. Mancozeb was the least selective fungicide tested on A. caudiglans; it caused high acute toxicity and sublethal effects. Carbaryl was the least selective insecticide and caused 100% mortality. Captan was the most selective fungicide. Chlorantraniliprole and cyantraniliprole were the most selective insecticides and therefore least likely to disrupt biological control by A. caudiglans. Non-target effects on A. caudiglans and G. occidentalis were similar, but A. caudiglans experienced higher mortality to some broad-spectrum insecticides. All products tested had some non-target effects on A. caudiglans. However, A. caudiglans sensitivity to most tested pesticides was similar to G. occidentalis. In general, existing spray recommendations for conserving G. occidentalis can be adjusted slightly and applied to A. caudiglans conservation. This article is protected by copyright. All rights reserved.

The peritrophic matrix delays Nosema ceranae infection in the honey bee Apis mellifera midgut

AbstractThe midgut of bees plays a significant role in digestion and absorption and is a gateway for pathogens. As a protection for the organism, the midgut lumen is lined by a peritrophic matrix rich in chitin fibrils, associated with proteins that form multiple resistant layers with gelatinous consistency, with several functions, including the mechanical barrier against infection by pathogens. The obligate intracellular microsporid Nosema ceranae is an important pathogen that decreases honey production, increases pesticide susceptibility, and may cause mortality in the honey bee Apis mellifera. This study evaluated whether the peritrophic matrix has a protective function against infection by N. ceranae in A. mellifera adult workers. The peritrophic matrix integrity was changed by feeding the bees with calcofluor white (CFW), followed by an artificial infection with N. ceranae spores. Results shown that 0.5% CFW affect the integrity of the peritrophic matrix with areas of interruption of this envelope. This disorganization of the peritrophic matrix reduces the life cycle period of N. ceranae from eight to four days, after inoculation, and increases the concentration of new spores released in the midgut lumen. This is the first report on the importance of the peritrophic matrix as a protective barrier against N. ceranae infection in A. mellifera.

Intra-specific variation in sensitivity of Bombus terrestris and Osmia bicornis to three pesticides

There is growing evidence that pesticides may be among the causes of worldwide bee declines, which has resulted in repeated calls for their increased scrutiny in regulatory assessments. One recurring concern is that the current frameworks may be biased towards assessing risks to the honey bee. This paradigm requires extrapolating toxicity information across bee species. Most research effort has therefore focused on quantifying differences in sensitivity across species. However, our understanding of how responses to pesticides may vary within a species is still very poor. Here we take the first steps towards filling this knowledge gap by comparing acute, lethal hazards in sexes and castes of the eusocial bee Bombus terrestris and in sexes of the solitary bee Osmia bicornis after oral and contact exposure to the pesticides sulfoxaflor, Amistar (azoxystrobin) and glyphosate. We show that sensitivity towards pesticides varies significantly both within and across species. Bee weight was a meaningful predictor of pesticide susceptibility. However, weight could not fully explain the observed differences, which suggests the existence of unexplored mechanisms regulating pesticide sensitivity across bee sexes and castes. Our data show that intra-specific responses are an overlooked yet important aspect of the risk assessment of pesticides in bees.

Seasonal Occurrence and Pesticide Susceptibility of the Phytoseiid Mite, Typhlodromus vulgaris, in Commercial Apple Orchards in Aomori Prefecture

Seasonal Occurrence and Pesticide Susceptibility of the Phytoseiid Mite, <i>Typhlodromus vulgaris</i>, in Commercial Apple Orchards in Aomori Prefecture

Effects of acute arsenic exposure in two different populations of Hyalella curvispina amphipods from North Patagonia Argentina

ABSTRACT Arsenic (As) is a toxic metalloid present in high levels in diverse regions of Argentina. The aim of this study was to determine acute As-mediated toxicity in two different populations of autochthonous Hyalella curvispina amphipods from a reference site (LB) and an agricultural one (FO) within North Patagonia Argentina. Previously, both populations exhibited significant differences in pesticide susceptibility. Lab assays were performed to determine acute lethal concentrations, as well as some biochemical parameters. Lethal concentration (LC50) values obtained after 48 and 96 hr As exposure were not significantly different between these populations, although FO amphipods appeared slightly less susceptible. LC50-48 hr values were 3.33 and 3.92 mg/L As, while LC50-96 hr values were 1.76 and 2.14 mg/L As for LB and FO amphipods. The no observed effect concentration (NOEC) values were 0.5 mg/L As. Cholinesterase (ChE) activity was significantly diminished by As acute exposure (0.5–1.5 mg/L As), indicative of a significant neurotoxic action for this metalloid in both amphipod populations. Activities of catalase (CAT) and glutathione S-transferase (GST) and levels of reduced glutathione (GSH) were differentially altered following As exposure. CAT activity was increased after 96 hr As exposure. GST activity and GSH levels were significantly elevated followed by either a decrease or a return to control values after 96 hr treatment. However, additional studies are necessary to understand the mechanisms underlying the As-mediated oxidative effects in H. curvispina. Our findings suggest that measurement of ChE activity in H. curvispina amphipods might serve as a useful biomarker of As exposure and effect.

Polyphenols as Food Supplement Improved Food Consumption and Longevity of Honey Bees (Apis mellifera) Intoxicated by Pesticide Thiacloprid.

Simple SummaryWorldwide, mass losses of honey bee colonies are being observed more frequently. Poor nutrition may cause honey bees to be more susceptible to pesticides and more vulnerable to diseases, and as a direct result of this, honey bee colonies can collapse. Another cause of mass bee colony collapse that is no less important is the use of pesticides. The level of toxicity of most pesticides is greatly affected by nutrient uptake. In addition, the honey bee genome is known to be specific for a significantly lower number of genes associated with detoxification compared with other insect species. Intake of phenolic and flavonoid substances in food can lead to increased expression of genes encoding detoxification enzymes in bees. Therefore, in this study, we evaluated in vitro the effect of phenolic and flavonoid substances on bee mortality and food consumption in the case of intoxication by pesticide thiacloprid. The results of this study showed a significant positive effect on honey bee survival rate as well as increased food intake. In addition, the expression level of genes encoding detoxification enzymes was determined.Malnutrition is one of the main problems related to the global mass collapse of honey bee colonies, because in honey bees, malnutrition is associated with deterioration of the immune system and increased pesticide susceptibility. Another important cause of mass bee colonies losses is the use of pesticides. Therefore, the goal of this study was to verify the influence of polyphenols on longevity, food consumption, and cytochrome P450 gene expression in worker bees intoxicated by thiacloprid. The tests were carried out in vitro under artificial conditions (caged bees). A conclusively lower mortality rate and, in parallel, a higher average food intake, were observed in intoxicated bees treated using a mixture of phenolic acids and flavonoids compared to untreated intoxicated bees. This was probably caused by increased detoxification capacity caused by increased expression level of genes encoding the cytochrome P450 enzyme in the bees. Therefore, the addition of polyphenols into bee nutrition is probably able to positively affect the detoxification capacity of bees, which is often reduced by the impact of malnutrition resulting from degradation of the environment and common beekeeping management.

Effect of age on insecticide susceptibility and enzymatic activities of three detoxification enzymes and one invertase in honey bee workers (Apis mellifera)

Honey bee is an economically important insect for honey production and pollination. Frequent exposure to toxic pesticides is one of the major risk factors causing the pollinator population decline. However, age effects of honey bees on pesticide susceptibility have been largely ignored and many researchers use bees of unknown age for assessing the risk of pesticides. Honey bee workers are known to go through physiological and behavioral changes in order to differentiate different phenotypes to perform specific duties over their natural lifetime of 6 weeks or longer. In this study, we provide multi-parameter evidences of unignorable age effects of honey bee workers and suggest using a standard bee age to produce reliable and comparable data when assessing variable and realistic situations of in-hive and field exposures to pesticides. Using honey bee workers aged 4- to 42-days old, we examined susceptibility of the bees to five different insecticides from five different classes and measured enzymatic activities of three major detoxification enzymes and an invertase involved in honey production. Results showed gradual increase of natural mortality and decrease of soluble protein content in bees over the age span from 4 days to 42 days. Significant increases of mortality after separate treatments of five different insecticides confirmed drastic age effects of bees over the assessed age span. As they aged, honey bees also showed a gradual increase of cytochrome P450 oxidase activity while still maintaining constant levels of two other detoxification enzymes (esterase and glutathione S-transferase) and an invertase responsible for honey production.

Antibiotic and pesticide susceptibility and the Anthropocene operating space

Rising levels of antimicrobial and pesticide resistance increasingly undermine human health and systems for biomass production, and emphasize the sustainability challenge of preserving organisms su ...

Pyrethroid and organophosphate pesticide resistance in field populations of horn fly in Brazil.

Pesticides are used worldwide to control arthropod parasites in cattle herds. The indiscriminate and/or inappropriate use of pesticides without veterinary guidance is a reality in several countries of South America. Improper pesticide use increases the chances of contamination of food and the environment with chemical pesticides and their metabolites. Reduction of these contamination events is an increasing challenge for those involved in livestock production. The horn fly, Haematobia irritans (Linnaeus) (Diptera: Muscidae), is one of the most economically important parasites affecting cattle herds around the world. As such, horn fly control efforts are often required to promote the best productive performance of herds. Pesticide susceptibility bioassays revealed that pyrethroid resistance was widespread and reached high levels in horn fly populations in the Brazilian state of Rondônia. The knockdown resistance (kdr) sodium channel gene mutation was detected in all horn fly populations studied (n = 48), and the super kdr sodium channel gene mutation was found in all homozygous resistant kdr individuals (n = 204). Organophosphate resistance was not identified in any of the fly populations evaluated.

Molecular detection of M. tuberculosis and M. bovis and hematological and biochemical analyses in agricultural sprayers exposed to pesticides: A cross-sectional study in Punjab, Pakistan during 2014-2016.

We determined the correlation between a pesticide exposure, physical health and susceptibility toward tuberculosis along with hematological indices and liver enzymes' alterations in sprayers exposed to pesticides. Molecular detection of Mycobacterium tuberculosis and Mycobacterium bovis was detected by targeting histone-like protein (hupB) gene. The WBC (white blood cells) and RBC (red blood cells) levels of male sprayers and non-sprayers were significantly different (P<0.05). In female spray workers, the WBC and neutrophils levels were significantly different as compared with non-sprayers. Overall, in both male and female pesticide-exposed sprayers, mean values of alanine amino transferase and aspartate amino transferase were higher as compared with unexposed workers. M. Tuberculosis were detected in 15% male sprayers and 36% female sprayers while, M. bovis was detected in 5% male sprayers and 10% female sprayers. A χ2-test indicated that there existed a significant different (P<0.05) between positive and negative M. tuberculosis and M. bovis in both male/female spray workers out of total. The susceptibility of pesticide-exposed sprayers to tuberculosis and alterations in hematology and liver enzymes is crucial for health. Toxic effects of pesticides may lead to a weak immune system and increased tuberculosis susceptibility.

Pesticide-mediated displacement of a phytoseiid predator, Neoseiulus womersleyi, by another phytoseiid predator, N. californicus (Acari: Phytoseiidae).

Neoseiulus womersleyi and N. californicus are two predators that are frequently used to control spider mites in fruit-tree orchards. Neoseiulus womersleyi used to be the dominant predator species in Japan, but since the 1990s in central and southwestern Japan, N. californicus populations have been increasing and have displaced populations of N. womersleyi. We previously observed the same phenomenon under laboratory conditions when these species were released at a 1:1 ratio, and attributed the displacement to asymmetrical intraguild predation. However, the ratio in fruit-tree orchards could be different from 1:1. Therefore, we hypothesized that differential susceptibilities to pesticides might accelerate species displacement of N. womersleyi by N. californicus, even if the ratio between these two species was extremely skewed in favor of N. womersleyi and no species displacement occurred otherwise. We examined the effects of 21 pesticides on egg-to-adult and adult survivorship in N. womersleyi and N. californicus. Among these pesticides, two neonicotinoids (acetamiprid and imidacloprid) had much severer effects on N. womersleyi than on N. californicus and thus could possibly account for the species displacement. When the two species were released onto leaf arenas at an N. californicus: N. womersleyi ratio of 1:9 in the absence of insecticide, no displacement was observed. However, just after acetamiprid or imidacloprid application, the proportion of N. californicus increased, causing N. californicus to displace N. womersleyi. Our results indicate that displacement in predator complexes of fruit-tree orchards could be due to different degrees of pesticide susceptibility.

Early-life experience affects honey bee aggression and resilience to immune challenge.

Early-life social experiences cause lasting changes in behavior and health for a variety of animals including humans, but it is not well understood how social information ‘‘gets under the skin’’ resulting in these effects. Adult honey bees (Apis mellifera) exhibit socially coordinated collective nest defense, providing a model for social modulation of aggressive behavior. Here we report for the first time that a honey bee’s early-life social environment has lasting effects on individual aggression: bees that experienced high-aggression environments during pre-adult stages showed increased aggression when they reached adulthood relative to siblings that experienced low-aggression environments, even though all bees were kept in a common environment during adulthood. Unlike other animals including humans however, high-aggression honey bees were more, rather than less, resilient to immune challenge, assessed as neonicotinoid pesticide susceptibility. Moreover, aggression was negatively correlated with ectoparasitic mite presence. In honey bees, early-life social experience has broad effects, but increased aggression is decoupled from negative health outcomes. Because honey bees and humans share aspects of their physiological response to aggressive social encounters, our findings represent a step towards identifying ways to improve individual resiliency. Pre-adult social experience may be crucial to the health of the ecologically threatened honey bee.

Assessment of groundwater contamination risk in an agricultural area in north Italy

In the present study a specific approach is followed, considering the Pesticide DRASTIC and Susceptibility index (SI) methods and a GIS framework, to assess groundwater vulnerability in the agricultural area of Albenga, in north Italy. The results indicate “high” to “very high” vulnerability to groundwater contamination along the coastline and the middle part of the Albenga plain, for almost 49% and 56% of the total study area for Pesticide DRASTIC and SI methods, respectively. These sensitive regions depict characteristics such as shallow depth to groundwater, extensive deposits of alluvial silty clays, flat topography and intensive agricultural activities. The distribution of nitrates concentration in groundwater in the study area is slightly better correlated with the SI (0.728) compared to Pesticide DRASTIC (0.693), thus indicating that both methods are characterized by quite good accuracy. Sensitivity analysis was also performed to acknowledge statistical uncertainty in the estimation of each parameter used, assess its impact and thus identify the most critical parameters that require further investigation in the future. Depth to water is the parameter that exhibited the largest impact on the Pesticide DRASTIC vulnerability index followed by the impact of the vadose zone and topography. On the other hand, the SI method is more sensitive to the removal of the topography parameter followed by the aquifer media and the depth to water parameters.

Comparative biology and pesticide susceptibility of Amblydromella caudiglans and Galendromus occidentalis as spider mite predators in apple orchards.

The successful integrated mite management program for Washington apples was based on conservation of the mite predator Galendromus occidentalis (Nesbitt). In the 1960s, this mite was assumed to be the only phytoseiid in Washington commercial apple orchards, due to its preference for the most common mite pest of that period, Tetranychus mcdanieli McGregor, as well as its resistance to organophosphate pesticides. A recent survey of phytoseiids in Washington apple found that another phytoseiid, Amblydromella caudiglans (Schuster) has become common. It is a more generalized predator than G. occidentalis (it is not a Tetranychus spp. specialist) and is not known to be organophosphate-resistant. A series of experiments was conducted to compare the life history, prey consumption, and pesticide tolerance of these two species. Galendromus occidentalis developed more quickly than A. caudiglans, but had slightly lower egg survival. Although A. caudiglans attacked more Tetranychus urticae Koch eggs than G. occidentalis, it could not reproduce on this diet. Both predators performed equally well on a diet of T. urticae protonymphs. Unlike G. occidentalis, A. caudiglans experienced significant mortality when exposed to carbaryl, azinphosmethyl, and bifenazate. Both predators experienced significant mortality due to imidacloprid and spinetoram. These results highlight the key differences between these two predators; the shift away from organophosphate use as well as the change in dominant mite pest to Panonychus ulmi (Koch) may be driving factors for the observed increased abundance of A. caudiglans in Washington apple.

Cross comparison of five popular groundwater pollution vulnerability index approaches

Summary Identification of a suitable overlay and index method to map vulnerable zones for pollution in weathered rock aquifers was carried out in this study. DRASTIC and four models derived from it, namely Pesticide DRASTIC, modified DRASTIC, modified Pesticide DRASTIC and Susceptibility Index (SI) were compared by applying them to a weathered rock aquifer in southern India. The results were validated with the measured geochemical data. This study also introduces the use of temporal variation in the groundwater level and nitrate concentration in groundwater as input and for validation respectively to obtain more reliable and meaningful results. Sensitivity analysis of the vulnerability index maps highlight the importance of one parameter over another for a given hydrogeological setting, which will help to plan the field investigations based on the most or the least influential parameter. It is recommended to use modified Pesticide DRASTIC for weathered rock regions with irrigation practises and shallow aquifers (

Diet-dependent gene expression in honey bees: honey vs. sucrose or high fructose corn syrup

Severe declines in honey bee populations have made it imperative to understand key factors impacting honey bee health. Of major concern is nutrition, as malnutrition in honey bees is associated with immune system impairment and increased pesticide susceptibility. Beekeepers often feed high fructose corn syrup (HFCS) or sucrose after harvesting honey or during periods of nectar dearth. We report that, relative to honey, chronic feeding of either of these two alternative carbohydrate sources elicited hundreds of differences in gene expression in the fat body, a peripheral nutrient-sensing tissue analogous to vertebrate liver and adipose tissues. These expression differences included genes involved in protein metabolism and oxidation-reduction, including some involved in tyrosine and phenylalanine metabolism. Differences between HFCS and sucrose diets were much more subtle and included a few genes involved in carbohydrate and lipid metabolism. Our results suggest that bees receive nutritional components from honey that are not provided by alternative food sources widely used in apiculture.