Search Results (23)

Pleurotus ostreatus cultivation is often affected by pest infestations, which contaminate the bag by eating nutrients and mycelium. This contamination eventually leads to a decline in the quality and yield of edible mushrooms and affects farmers’ income. Therefore, pesticides are commonly used for pest control. To examine the impact of insecticides on the growth of P. ostreatus, this study quantified the activities of antioxidant enzymes, including catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and phenylalanine deaminase (PAL), in the mushroom under different insecticide treatments. Additionally, transcriptome sequencing was performed to investigate the underlying regulatory mechanisms. The findings indicated that dinotefuran, diflubenzuron, chlorantraniliprole, and beta-cypermethrin treatments resulted in a significant reduction in catalase and peroxidase activities in P. ostreatus. Conversely, the application of beta-cypermethrin and chlorantraniliprole significantly enhanced PAL and SOD activities in the mycelium. PAL activity was significantly increased in all the mixed substrates, whereas only spray treatments with diflubenzuron resulted in a significant increase in PAL activity. SOD activity in the substrates was reduced by diflubenzuron in the mixed treatment and chlorantraniliprole in the spray treatment. In contrast, all other treatments resulted in a significant increase in SOD activity in the substrates. Transcriptome sequencing revealed that differential genes were predominantly enriched in valine, leucine, and isoleucine degradation, fatty acid degradation, tyrosine metabolism, ascorbate and aldarate metabolism, and histidine metabolism, among others. These biological processes are hypothesized to be involved in the growth regulatory effects of insecticides on the mycelium and ascospores of P. ostreatus. The reliability of the transcriptomic data was also validated through quantitative real-time polymerase chain reaction. Full article

Control interventions against mosquito larvae are the primary measure to reduce the adult abundance and risk of arbovirus outbreaks in Europe. One of the most commonly used larvicides in Italy is diflubenzuron (DFB), which targets chitin synthase 1 (chs-1), interrupting the normal development of larvae into adults. Recent studies identified high levels of DFB resistance in Culex pipiens populations from Emilia-Romagna (Italy) associated with I1043L/M/F mutations at position 1043 of the chs-1 gene. The aim of the present study was to assess the circulation of 1043 resistance alleles in Cx. pipiens populations across Italy, outside Emilia-Romagna, with a focus on the Veneto region. Overall, 1032 specimens were genotyped. The 1043L allele was found in all examined Italian regions (Trentino-Alto Adige 19–36%; Veneto 0–91%; Piemonte 11%; Liguria 28%; Lazio 0–8%; Puglia 5%). The highest frequencies (up to >90%) were observed in the Venetian lagoon, where 1043M was also detected (6–11%). Overall, the relatively low frequencies of 1043 mutations despite extensive and longstanding use of DFB in Italy suggest a high fitness cost worthy of further investigations, while their extremely high frequencies in coastal touristic sites point to these sites as the most relevant for resistance monitoring and larvicide rotation. Full article

Sixty commercial honey bee colonies were monitored over the course of one year with the goal of assessing potential correlations between measured colony strength and environmental stressors, including exposures to pesticides and pathogens. We developed a new method for assessing colony health by determining the fractional change in population of the four colonies on each pallet between peak population on 1 June and the last population assessment prior to winter on 1 October. This fractional change in population was evaluated as a function of pesticide load per pallet for each of the 37 pesticide chemicals detected, grouping pallets by beekeeper. The analysis of individual chemicals showed that both imidacloprid and cyprodinil were negatively correlated with colony health, while tau-fluvalinate and dinotefuran (at very low concentrations) were positively correlated, possibly because of effects on Varroa control. Exposure to groups of chemicals was also evaluated. Normalization of each chemical concentration to the maximum observed for that chemical provided an equal weighting for each chemical, even though their relative occurrence in the environment and their effective toxicities might differ. A total of 24 chemical groups whose members share a structural commonality, a functional commonality, or suspected synergistic actions were considered, demonstrating negative correlations between colony health and exposures to neonicotinoids as a group and neonicotinoids in combination with (1) methoxyfenozide (2) organophosphates, and (3) diflubenzuron. Analysis of several groups of fungicides applied to almonds during pollination also showed negative correlations with colony health. Full article

Pesticide residues in human diets pose significant health hazards, particularly for vulnerable populations such as infants and children. This study aimed to determine pesticide residues in apples and to assess the cumulatively chronic risk posed to adult and child consumers from simultaneous exposure to multiple residues. During the 2022–2023 harvest seasons, 100 apple samples from Turkey were analyzed for the presence of 225 different pesticide residues. Pesticide extraction was performed using the QuEChERS method, followed by detection through liquid chromatography coupled with tandem mass spectrometry. Fifteen distinct pesticides (ten insecticides and five fungicides) were detected in 64 out of the 100 apple samples analyzed. Eleven samples contained pesticide residues that exceeded the maximum residue limit (MRL) set by the Turkish Food Codex and the European Union. Thiophanate-methyl was the most frequently detected pesticide (34%) in apples, with concentrations ranging from 0.012 to 0.108 mg kg⁻¹, all of which were well below the MRL of 0.5 mg kg⁻¹. Other commonly detected residues included chlorantraniliprole (28%), acetamiprid (24%), sulfoxaflor (22%), bifenazate (18%), indoxacarb (13%), diflubenzuron (12%), and carbendazim (10%). Under a worst-case scenario, the hazard index (HI) values for adults and children were 0.85% and 2.60%, respectively, indicating that these values remain significantly below the risk threshold of 100%, suggesting no associated health risks from apple consumption. However, regular monitoring of pesticide residues in fresh fruits and vegetables remains critically important. Full article

Spodoptera frugiperda (J.E. Smith) (Noctuidae: Lepidoptera) is a notable insect pest that invades major cereal crops, causing significant damage and loss. Resistances of 2nd instar larvae of two Egyptian field populations of S. frugiperda, collected from the Fayoum and Giza governments, were measured against eight insecticides, including traditional insecticides (profenofos and cypermethrin), bio-insecticides (emamectin benzoate, spinosad, and Bacillus thuringiensis), and insect growth regulators (IGRs) (lufenuron, diflubenzuron, and methoxyfenozide). In addition, the synergistic effects of three synergists (Piperonyl butoxide (PBO), diethyl maleate (DEM), and triphenyl phosphate (TPP) were assessed, and the activities of detoxification enzymes (acetylcholine esterase (AChE), cytochrome P-450 (CYP-450), carboxylesterase (CarE), and glutathione-s-transferase (GST) were also determined. Resistance surveillance revealed that the Fayoum field population showed moderate resistance to cypermethrin (RR = 5.75-fold), followed by spinosad (RR = 2.62-fold), and lufenuron (2.01-fold). On the other hand, the Giza population exhibited significant resistance to cypermethrin only (RR = 3.65-fold). Our results revealed that emamectin benzoate was the most effective insecticide, with an LC₅₀ value of 0.003 mg/L for the Fayoum population and 0.001 mg/L for the Giza population, compared to the susceptible strain (0.005 mg/L). Among the biological insecticides, Bacillus thuringiensis was the least toxic insecticide of all the tested strains. Synergism assays indicated that DEM and TPP had the most synergistic effect on spinosad (SR = 8.00-fold for both), followed by PBO (SR = 5.71-fold) for the Fayoum population, compared with spinosad alone. The assay of detoxification enzymes showed that GST activity significantly (p < 0.05) increased in the two field strains compared to the susceptible strain. However, no significant changes were observed among the tested strains in CYP-450, CarE, or AChE. The findings of this study provide substantial insights into tracking and managing the development of insecticide resistance in S. frugiperda in Egypt. Full article

Residual pesticides in Agrocybe aegerita mushroom have emerged as a significant concern and bring much uncertainty due to processing procedures. In this study, a modified QuEChERS sample preparation procedure and UPLC-MS/MS were used to analyze the residual levels of four commonly used pesticides in A. aegerita from field to product processing. The field results showed that dissipation of these targeted chemicals was consistent with the first-order kinetics, and the half-life time ranged from 20.4 h to 47.6 h. The terminal residues of the four pesticides at harvest time ranged from 9.81 to 4412.56 μg/kg in raw mushroom. The processing factors (PFs) of clothianidin, diflubenzuron, chlorbenzuron, and pyridaben ranged from 0.119 to 0.808 for the drying process and from 0.191 to 1 for the washing process. By integrating the data from the field trials, the PFs, and the consumption survey, the chronic dietary risks of the target chemicals via A. aegerita intake ranged from 2.41 × 10⁻⁵ to 5.69 × 10⁻² for children and from 6.34 × 10⁻⁶ to 1.88 × 10⁻² for adults, which are considerably below the threshold of 1, indicating no unacceptable risk to consumers in the Fujian province of China. This research offers foundational data for appropriate use and the maximum residue limit (MRL) establishment for these four insecticides in A. aegerita. Full article

Diflubenzuron (DFB) and pyriproxyfen (PPF) are larvicides used in crops to control insect plagues. However, these pesticides are known to impact non-target organisms like fish and mammals. Here, we aimed at assessing the embryotoxicity of purified DFB, PPF, and their mixtures in a non-target organism—zebrafish. Zebrafish embryos were exposed to different concentrations for 120 h: 0.025, 0.125, 0.25, 1.25, 2.5, and 10 mg/L of purified PPF and purified DFB, while we used 0.025 mg/L PPF + 10 mg/L DFB (Mix A), 0.125 mg/L PPF + 10 mg/L DFB (Mix B), and 0.25 mg/L PPF + 10 mg/L DFB (Mix C) for the mixtures of PPF + DFB. We observed mortality, teratogenicity, and cardiotoxicity. For the neurotoxicity tests and evaluation of reactive oxygen species (ROS) levels in the brain, embryos were exposed for 120 h to 0.379 and 0.754 mg/L of PPF and 0.025 and 0.125 mg/L of DFB. We established the LC₅₀ for PPF as 3.79 mg/L, while the LC₅₀ for DFB was not determinable. Survival and hatching were affected by PPF concentrations above 0.125 mg/L, DFB concentrations above 1.25 mg/L, and the lower pesticide mixtures. PPF exposure and mixtures induced different types of malformations, while a higher number of malformations were observed for the mixtures, suggesting a potentiating effect. Pesticides diminished avoidance responses and increased the levels of ROS across all concentrations, indicating neurotoxicity. Our findings underscore the detrimental impact of PPF and DFB exposure, spanning from biochemistry to morphology. There is a critical need to reconsider the global use of these pesticides and transition to more ecologically friendly forms of pest control, raising an alarm regarding repercussions on human and animal health and well-being. Full article

In 2017, the hibiscus bud weevil (HBW), Anthonomus testaceosquamosus Linell (Coleoptera: Curculionidae), was found outside of its native range of Mexico and Texas, infesting hibiscus plants in Florida. Therefore, we selected 21 different insecticide and horticultural oil products to evaluate their effects on the reproductive rate, feeding, and oviposition behavior of the HBW. In laboratory experiments, significant mortality was observed in adult weevils exposed to diflubenzuron-treated hibiscus leaves and buds, and hibiscus buds treated with diflubenzuron contained the fewest number of eggs and feeding/oviposition holes. Among horticultural oil products, significant mortality was only observed in experiments in which adult weevils were directly sprayed (direct experiments). Pyrethrins and spinetoram plus sulfoxaflor reduced the oviposition rate and caused significant mortality in direct experiments. Diflubenzuron, pyrethrins, spinetoram plus sulfoxaflor, and spirotetramat were further tested via contact toxicity experiments and greenhouse experiments. Contact toxicity experiments demonstrated that the tested insecticides (except diflubenzuron) were highly toxic to HBW adults. In greenhouse experiments, only those hibiscus plants treated with pyrethrins had significantly fewer feeding/oviposition holes and larvae within their flower buds when compared to control (water-treated) plants. These results constitute an important first step in the identification of effective chemical control options for the HBW. Full article

Insecticide resistance is a major threat challenging the control of harmful insect species. The study of resistant phenotypes is, therefore, pivotal to understand molecular mechanisms underpinning insecticide resistance and plan effective control and resistance management strategies. Here, we further analysed the diflubenzuron (DFB)-resistant phenotype due to the point-mutation I1043M in the chitin-synthase 1 gene (chs1) in the mosquito Culex pipiens. By comparing susceptible and resistant strains of Cx. pipiens through DFB bioassays, molecular analyses and scanning electron microscopy, we showed that the I1043M-resistant mosquitoes have: (i) a striking level of DFB resistance (i.e., resistance ratio: 9006); (ii) a constitutive 11-fold over-expression of the chs1 gene; (iii) enhanced cuticle thickness and cuticular chitin content. Culex pipiens is one of the most important vector species in Europe and the rapid spread of DFB resistance can threaten its control. Our results, by adding new data about the DFB-resistant phenotype, provide important information for the control and management of insecticide resistance. Full article

Mosquito management programs in the urban environment of Italian cities mainly rely on larval control with conventional insecticides, primarily targeting the road drains that constitute the principal mosquito breeding sites encountered in public. The repeated utilization of synthetic insecticides may have adverse effects on non-targets and lead to resistance development issues, while the performance of biopesticides encounters limitations in field use. Botanical insecticides as single larval control agents or in binary mixtures with conventional insecticides have been extensively studied in the laboratory as an effective and eco-friendly alternative mosquito control method with promising results. The study herein concerns the investigation, for the first time under realistic conditions in the field, of the joint action of a carvacrol-rich oregano Essential Oil (EO) with two conventional insecticides, namely, the insect growth regulator diflubenzuron and the bio-insecticide Bacillus thuringiensis israelensis (B.t.i.), in road drains in Crevalcore city, Italy, against Culex pipiens and Aedes albopictus. According to the obtained results, the application of both plain EO and its mixtures with diflubenzuron and B.t.i. exerted very high efficacy in terms of immature mosquito population reduction over a two-week period. Three weeks after treatment, the performance of the oil and its mixtures diminished but remained high, while the addition of diflubenzuron potentiated the persistent action of the oil against Cx. pipiens. These findings are indicative of the potential of mixing carvacrol-rich EO with diflubenzuron and B.t.i. as an efficient eco-friendly alternative to mono-insecticide applications in road drains against Cx. pipiens and Ae. albopictus larvae. Full article

Diflubenzuron is an insecticide that serves as a chitin inhibitor to restrict the growth of many harmful larvae, including mosquito larvae, cotton bollworm and flies. The residue of diflubenzuron is often detected in aquaculture, but its potential toxicity to aquatic organisms is still obscure. In this study, zebrafish embryos (from 6 h to 96 h post-fertilization, hpf) were exposed to different concentrations of diflubenzuron (0, 0.5, 1.5, 2.5, 3.5 and 4.5 mg/L), and the morphologic changes, mortality rate, hatchability rate and average heart rate were calculated. Diflubenzuron exposure increased the distance between the venous sinus and bulbar artery (SV-BA), inhibited proliferation of myocardial cells and damaged vascular development. In addition, diflubenzuron exposure also induced contents of reactive oxygen species (ROS) and malondialdehyde (MDA) and inhibited the activity of antioxidants, including SOD (superoxide dismutase) and CAT (catalase). Moreover, acridine orange (AO) staining showed that diflubenzuron exposure increased the apoptotic cells in the heart. Q-PCR also indicated that diflubenzuron exposure promoted the expression of apoptosis-related genes (bax, bcl2, p53, caspase3 and caspase9). However, the expression of some heart-related genes were inhibited. The oxidative stress-induced apoptosis damaged the cardiac development of zebrafish embryos. Therefore, diflubenzuron exposure induced severe cardiotoxicity in zebrafish embryos. The results contribute to a more comprehensive understanding of the safety use of diflubenzuron. Full article

Grasshoppers are integral parts of rangeland ecosystems but also have the potential to reach population densities high enough (outbreaks) to cause serious economic damage from forage loss and affect adjacent crops. The objective of this study was to investigate the efficacy of treating grasshopper population hotspots with a liquid insecticide using a remotely piloted aerial application system (RPAAS), as opposed to fixed-wing aircraft, which is the most common method currently in use. A liquid insecticide, Sevin XLR PLUS (containing carbaryl), was applied on replicated 4.05-hectare (10-acre) plots with an RPAAS on a ranch in New Mexico. Our results demonstrated that Sevin XLR PLUS significantly suppressed grasshopper populations over a 14-day period (normalized population reduction was 79.11 ± 8.35% SEM) and quite rapidly (mostly by day 3) compared to untreated controls. These results are comparable to those achieved with fixed-wing aircraft. The RPAAS covered the whole test area in a single flight in approximately 5 min, making these population hotspot treatment applications relatively rapid, potentially more cost-effective, and more targeted in comparison to fixed-wing aircraft. Before adoption as an application method option, further research is recommended on using an RPAAS to cover larger areas in combination with using diflubenzuron-based insecticides, which are often preferred. Full article

Diaphorina citri Kuwayama is the vector of HLB and one of the most common pests in citrus orchards in southern China. One of the most significant genes in D. citri’s growth and development is the chitin synthase gene. In this study, the CHS gene (DcCHSA) of D. citri was cloned and analyzed by bioinformatics. According to RT-qPCR findings, DcCHSA was expressed at many growth processes of D. citri, with the greatest influence in the fifth-instar nymph. The molting failure rate and mortality of D. citri rose as DFB concentration increased in this research, as did the expression level of DcCHSA. Feeding on DcCHSA caused a large drop in target gene expression, affected nymph molting, caused failure or even death in freshly eclosion adults, increased mortality, and reduced the molting success rate over time. These findings showed that DcCHSA was involved in nymph to adult development and may aid in the identification of molecular targets for D. citri regulation. It provided new ideas for further control of D. citri. Full article

Aedes albopictus is an invasive mosquito species responsible for local transmission of chikungunya and dengue viruses in Europe. In the absence of available treatments, insecticides-based control remains one of the most important viable strategies to prevent emerging problems. Diflubenzuron (DFB) and Bacillus thuringiensis var. israelensis (Bti) are among the most commonly used larvicides for Ae. albopictus control with consequent concerns for the potential development of resistance. Studies on the resistance emergence in Ae. albopictus and its persistence in the wild to both DFB and Bti are essential for the efficient and sustainable planning of the control programmes. In this context, larvae from a recently laboratory established population were subjected to increasing selective pressure for nine successive generations using both DFB and Bti. The resistance levels and the overwintering success of the selected populations relative to control (colonies that received no selection) were determined. Results revealed an 8.5- and 1.6-fold increase on the resistance levels following selection with DFB and Bti, respectively. The selection process to both larvicides had no apparent impacts on the overwintering capability relative to control, suggesting the successful persistence of the selected individuals in the wild on an annual base. Full article