Search Results (146)

Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is a major insect pest that severely affects various crops. Our study provides new insights by combining field efficacy trials with enzymatic analysis to evaluate the effects of emamectin benzoate mixtures with other insecticides (lufenuron, cypermethrin, chlorpyrifos, and spinosad) against S. littoralis. The aim of our work was to investigate the effectiveness of five insecticides, i.e., emamectin benzoate, lufenuron, cypermethrin, chlorpyrifos, and spinosad, for controlling this pest under field conditions during two consecutive seasons (2023–2024). Each insecticide was applied individually at the recommended rate, while some were mixed with emamectin benzoate at half its recommended rate. The results indicated that emamectin benzoate was the most effective insecticide, followed by lufenuron. The joint action of emamectin benzoate (LC₂₅) and its mixtures with other insecticides (chlorpyrifos, spinosad, cypermethrin, and lufenuron) at various concentrations (LC₅₀) against second- and fourth-instar S. littoralis larvae was evaluated. Results showed additive effects with chlorpyrifos, lufenuron, and cypermethrin, while potentiation occurred with cypermethrin (LC₅₀) and chlorpyrifos (LC₅₀). Antagonistic effects were observed in the combination of emamectin benzoate with spinosad (LC₂₅ and LC₅₀). This study concluded that applying insecticides individually is more cost-effective for managing cotton leafworm infestations in cotton crops. Additionally, enzyme activity analysis showed significant changes in alpha-esterase, beta-esterase, carboxylesterase, acetylcholinesterase, and glutathione S-transferase levels in larvae treated with different insecticide combinations. Full article

Overusing chemicals to manage Diaphorina citri has created insecticide resistance and negative impacts on the natural ecosystem. This has prompted the need to develop new methods of control. In the present study, we evaluated the toxicity of plant spray oil, Metarhizium anisopliae, and their combined formulations against D. citri adults through laboratory bioassays. We tested varying concentrations and application doses of the individual agents and their mixtures to determine synergistic effects. The optimal mixing ratio of M. anisopliae and plant spray oil for enhanced pest control efficacy was also identified. The results showed that the control effect of plant spray oil and M. anisopliae on D. citri became more pronounced as the concentration increased. When the two were mixed in different proportions, the synergistic effect of plant spray oil was the strongest when the mixing ratio was 5:5. Field trials demonstrated that a combined treatment of plant spray oil emulsion (9.10 g/L) and M. anisopliae (1 × 10⁸ spores/mL) achieved over 80% relative control efficacy against adult D. citri by the 6th day post-treatment. Its efficacy further increased to 96.28% by the 8th day, demonstrating its potential to replace chemical control methods. This study provides a practical example for exploring biopesticides and leveraging the synergistic effects of biogenic pesticides in preventing and controlling pests. Full article

Ecuador, located in South America, ranks among the countries with the highest rates of pesticide use per unit of cropland. Pesticide exposure is linked to genotoxic effects and carcinogenicity. While most studies evaluating the effects of pesticides focus on the active ingredient, commercial formulations are complex mixtures of several components that may alter their toxicological profile. In this study, we analyzed four pesticides commonly used in corn cultivation, and their typical field mixtures, including the herbicides atrazine and pendimethalin, the insecticides chlorpyrifos and cypermethrin, and a fertilizer, to evaluate their genotoxic effects, oxidative status, and potential to induce cellular transformation. CHO-K1 cells were treated with subtoxic doses of these formulations. MTS, comet, micronucleus, H2AX expression, SOD and GPx activity, and wound healing assays were performed. The results showed these formulations induced genotoxicity, evidenced by the comet assay. Additionally, exposure activated cellular DNA repair mechanisms, evidenced by a 1.89- to 2.63-fold increase in H2AX expression across all treatments and mixtures after 10 h. Notably, pendimethalin was associated with signs of cellular transformation, as evidenced by a 1.4-times greater cell migration observed in the wound healing assay. These findings suggest that even at subtoxic concentrations, these pesticide formulations can cause genetic damage and potentially alter cellular control mechanisms. Full article

Sitophilus zeamais, a major pest of stored grains, causes significant post-harvest losses and challenges effective control. While synthetic insecticides pose risks of resistance and toxicity, essential oils (EOs) offer a safer alternative. However, the insecticidal potential of their individual volatile constituents (VCs) remains largely unexplored. This study evaluated the insecticidal activity of 51 EO-derived volatile compounds (VCs) against S. zeamais, identifying the most toxic ones, optimizing 15 synergistic mixtures, and assessing their effects on key insect enzymes. A structure–activity relationship (SAR) analysis determined functional groups associated with insecticidal activity, while a cluster analysis pre-selected 29 ternary mixtures, later refined using response surface methodology (RSM). Additionally, enzymatic assays explored their impact on detoxification and nervous system enzymes, providing insights into potential mechanisms of action. Among the 51 VCs tested, 37 exhibited significant toxicity, with 11 acting as fumigants and 13 displaying contact toxicity. Monocyclic monoterpenoids with ketone or alcohol functional groups and exocyclic unsaturation demonstrated the highest insecticidal activity via both exposure routes. Notably, pulegone enantiomers were particularly effective (LC₅₀ < 0.1 mg/L, LD₅₀ < 7.5 µg/adult). Among the optimized mixtures, 10 displayed strong insecticidal effects, 8 were active through both routes, and 5 exhibited synergistic fumigant interactions. The most effective formulations were M2 (R-pulegone + S-pulegone + S-carvone, LC₅₀ 0.48 mg/L) and M20 (isopulegone + δ-3-carene, LC₅₀ 2.06 mg/L), showing the strongest fumigant and synergistic effects, respectively. Enzymatic assays revealed that while some compounds mildly inhibited GST and CAT, others, such as δ-3-carene (IC₅₀ 0.19 mg/L), significantly inhibited AChE. Five mixtures exhibited synergistic neurotoxicity, with M20 (IC₅₀ 0.61 mg/L) and M12 (IC₅₀ 0.81 mg/L) emerging as the most potent AChE inhibitors. These findings highlight the potential of plant-derived volatile compounds as bioinsecticides, leveraging synergistic interactions to enhance efficacy, disrupt enzymatic pathways, and mitigate resistance. Full article

This study examines the phytochemical composition, antioxidant, antifungal, and insecticidal properties of Origanum syriacum (Syrian oregano plant) and Cymbopogon wimterianus (Java citronella plant) extracts. Their potential applications in food preservation and pest control are explored based on their bioactive properties. The phytochemical screening indicated a rich presence of secondary metabolites in the extract. The hydrodistillation of plant leaves resulted in an extraction yield of 4.3% Syrian oregano essential oil. The major component of the essential oil was carvacrol (79.30%). The Syrian oregano ethanolic extract contained 110.674 ± 1.842 mg GAE/g total phenols and 52.57 ± 0.086 mg RE/g total flavonoids, and exhibited a high antioxidant activity with a half-maximal inhibitory concentration (IC₅₀) equal to 168.28 μg/mL. Flatbread was prepared with additions of Syrian oregano and Java citronella powders, followed by analysis of moisture content, visual appearance, and sensory characteristics. The results showed that the powders of Syrian oregano and Java citronella have promising food preservative effects. These findings were supported by a significant decrease in fungal growth in several samples and a shelf life extension of one day. The inclusion of a 2% mixture of Syrian oregano and Java citronella powder in the flatbread resulted in the sample receiving the highest overall acceptability mark from consumers, while also extending its shelf life. To assess the insecticidal activity, weevils (Sitophilus granarius L.) were exposed to Syrian oregano and Java citronella essential oils. The insecticidal activity was at its peak when Syrian oregano and Java citronella essential oils were combined resulting in 7% lethal dose (LD₅₀) towards grain weevils. Future research should focus on optimizing extraction methods, evaluating long-term storage effects, and assessing the broader applicability of these extracts in various food products and agricultural settings. Full article

A two-year field study was conducted using canola to check the efficacy of different soil amendment treatments (SAT), i.e., with elemental sulfur (ES), bio-sulfur (BS), and compost (Cp) mixtures against insecticide-treated (Carbosulfan) and untreated controls regarding aphid populations. The results of the experiment revealed that ES treatments significantly reduced aphid abundance, followed by Cp and ES+Cp. However, BS improved aphid herbivory. The number of siliques, seeds, thousand-seed weight, and yield were improved with a trend of ES+Cp > Cp > BS+Cp. Similarly, physiological mechanisms revealed the regulation of nutrient and phenolic contents in canola with ES improving sulfur, BS nitrogen, Cp, and ES+Cp calcium, and BS+Cp enhancing phosphorus, potassium, iron, and zinc. Furthermore, RP-HPCL indicated that ferulic acid was highest in insecticide-treated plot. Similarly, Cp improved quercetin and gallic acid; ES+Cp caffeic, chlorogenic, m-coumaric, and sinapic acid; and BS+Cp enhances syringic, vanillic, ferulic, p-coumaric, and cinnamic acid. The analysis regarding health risk assessment revealed among different SAT, ES+Cp significantly reduced the Hazardous Quotient (HQ) of Cu and Zn. However, further research is still needed to explore SAT’s potential to remediate other heavy metal stresses with possible implications for pest management in different field crops. Full article

The emergence of insecticide resistance among malaria vector populations poses a significant threat to existing malaria vector control tools. This phenomenon necessitates an increased pace of developing and deploying new effective compounds in insecticides for vector control. Therefore, this study investigated the comparative performance of newly formulated indoor residual spray compounds, Klypson 500WG (Clothianidin alone) and 2GARD-WP (a mixture of Clothianidin 50% and Deltamethrin 6.25%) against An. gambiae in the lower Moshi area of the rural Moshi district, Tanzania. Before the wall cone bioassay tests, the susceptibility of field-collected adult An. gambiae s.l. to 0.75% Permethrin, 2% Klypson 500WG, 0.05% Deltamethrin, and 0.25% Pirimiphos-methyl was assessed following WHO procedures. For the cone-bioassay testing, 160 houses were randomly selected and sprayed with Klypson 500WG and 2GARD-WP. For the walls sprayed with Klypson 500WG and 2GARD-WP, the knockdown rate of Anopheles gambiae after 60 min of exposure over six months ranged from 70% to 98%, with mortality rates after 24 to 168 h consistently exceeding 90% across all villages and wall types throughout the six months. The susceptibility of wild-collected mosquitoes to Pirimiphos-Methyl, Permethrin, Deltamethrin, and Klypson 500WG was 61, 81, 86, and 93%, respectively. These findings suggest that Klypson 500WG and 2GARD-WP are suitable alternative insecticides that can be incorporated in the vector control toolbox used for malaria control. Full article

Urban areas are expanding rapidly and experience diverse and complex contamination of their surface waters. Addressing these issues requires different tools to describe exposures and predict toxicological risk to exposed biota. We surveyed 21 stormwater management ponds in Brampton, Ontario using three types of sampling methods deployed concurrently: time-integrated water sampling, biofilms cultured on artificial substrates, and organic-diffusive gradients in thin films (o-DGT) passive samplers. Our objective was to compare pesticide occurrences and concentrations to inform monitoring in stormwater ponds, which reflect pesticide pollution in urban areas. We detected 82 pesticides across the three sampling matrices, with most detections occurring in o-DGT samplers. The in situ accumulation of pesticides in o-DGTs during deployment and the high analytical sensitivity achieved establishes o-DGTs as excellent tools for capturing the mixtures of pesticides present. Water and biofilm sampling demonstrated that pesticide concentrations available for uptake are relatively low, with most below toxicological thresholds. Yet our results demonstrate that urban areas are subject to a wide range of pesticides, including herbicides, insecticides, and fungicides, and underscores the urgency of research to quantify the risks of chronic exposure to this chemical mixture. Full article

Stored grain pests like Sitophilus oryzae pose significant challenges to food security and quality, necessitating eco-friendly pest management strategies. This study investigates the combined efficacy of reduced doses of diatomaceous earth (DE) and basil (Ocimum basilicum L.) essential oil (EO) as an alternative to conventional pesticides. Laboratory trials evaluated the effectiveness of the treatments—DE, EO, and a mixture of both (at halved doses)—against S. oryzae in wheat, alongside their impact on bread quality and sensory attributes. Results showed that DE and the DE + EO at halved doses combination achieved over 82% pest mortality, comparable to standard DE doses but with reduced mechanical and environmental drawbacks. EO alone demonstrated limited insecticidal activity. Bread made from treated wheat retained high sensory acceptability, with DE enhancing elasticity and crumb aroma. EO-enriched bread exhibited a complex aromatic profile due to methyl chavicol, though with reduced crumb elasticity and a slightly bitter aftertaste. Shelf-life assessments indicated that DE and DE + EO at halved doses extended mold-free storage by one day compared to untreated bread. These findings highlight the potential of combining DE and EO at reduced doses to manage stored grain pests sustainably, aligning with integrated pest management (IPM) and organic farming principles, while preserving the technological and sensory qualities of derived food products. Full article

The impact of agrochemicals on pollinators, especially honey bees, has drawn significant attention due to its critical implications for worldwide food stability and ecosystems. Given the potential threat of insecticides to honey bees, bees may encounter multiple insecticides simultaneously during foraging. This study investigated the toxic effect of an insecticide mixture (IM) containing acetamiprid (neonicotinoid) and deltamethrin (pyrethroid) on the survival and cognitive appetitive performance of Apis mellifera jemenitica, a vital native pollinator in arid regions of Saudi Arabia. The lethal concentration (LC₅₀) was determined by assessing bees’ mortality rates following exposure to IM through topical and oral routes. Significant bee mortality occurred at 4–48 h post treatment with IM through both exposure routes, showing a trend of increased mortality with higher IM concentrations compared to the control bees. Throughout all tested times, topical exposure proved relatively more effective, resulting in significantly greater bee mortality compared to oral exposure to IM. Food intake declined progressively with rising IM concentrations during oral exposure. The LC₅₀ values of IM at 24 h after treatment were 12.24 ppm for topical and 10.45 ppm for oral exposure. The corresponding LC₁₀, LC₂₀, and LC₃₀ values were 3.75 ppm, 5.63 ppm, and 7.54 ppm for topical exposure and 2.45 ppm, 4.04 ppm, and 5.78 ppm for oral exposure, respectively. The combination index (CI) revealed a synergistic effect (0.43) for topical exposure and antagonistic effects (1.43) for oral exposure, highlighting differential toxicity dynamics. IM exposure significantly impaired cognitive acquisition and memory reinforcement in honey bees, as demonstrated through behavioral assays, indicating potential neurotoxic effects. Learning and memory formation significantly declined at 2, 12, and 24 h after exposure to sublethal concentrations of IM through both topical and oral routes. Thus, evaluating the interactive impact of multiple pesticides on bees’ health and cognitive function is essential, particularly in regions where diverse agrochemicals are routinely utilized. Full article

Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Liviidae), is one of the most devastating pests in citrus orchards due to its role in transmitting Huanglongbing (HLB). Currently, chemical control remains the most effective strategy for ACP management. Mineral oils are commonly used as insecticides or adjuvants in integrated pest management (IPM) practices. To extend the product life of synthetic pesticides, we evaluated the toxicity of chlorpyrifos (CPF), thiamethoxam (THX), or pyriproxyfen (PPF) mixed with mineral oil Lvying (LY) against ACP nymphs under different weather conditions. Individual application of CPF, THX, and PPF effectively controlled against ACP nymphs under no rain conditions, with mortality rates varying from 20 to 100% during 1–5 d after treatment. The addition of LY at 1.0% or 0.5% rates to CPF, THX, and PPF significantly enhanced their control efficacy, achieving sustained mortality rates from 60 to 100% during the same period. Light rain had less impact on the control efficacy of these insecticide mixtures compared to individual insecticides. However, cumulative rainfall above 20 mm significantly reduced the control efficacy of individual insecticides and their mixtures. The addition of LY decreased both surface tension and contact angle of THX solution on citrus leaves, thereby enhancing the solution’s wetting and increasing THX deposition. Moreover, the rainfastness of THX was improved after adding LY, leading to a greater retention on the leaves. LY at a rate of 1.0% exhibited excellent efficacy against ACP nymphs, and observations using scanning electron microscopy (SEM) showed that LY altered ACP mouthpart morphology and blocked spiracles, likely contributing to its insecticidal effects. This study revealed that mineral oils can serve as both insecticides to combine with synthetic pesticides for enhancing toxicity against ACP and as adjuvants to facilitate the deposition and rainfastness of synthetic pesticides on leaves, which could be recommended for sustainable ACP management in citrus orchards. Full article

Although pesticides have been a constant concern for decades, in the last ten years, public discussions and scientific research have emphasized their impact on human health and the environment, drawing increased attention to the problems associated with their use. The association of environmental stressors such as pesticides with a sugar-rich diet can contribute to the growing global metabolic disease epidemic through overlapping mechanisms of insulin resistance, inflammation, and metabolic dysregulation. The main aim of this study was to evaluate the behavioral effects of the exposure of Silver crucian carp (Carassius auratus gibelio) to a commercial insecticide formulation containing fipronil, pyriproxyfen, and other additives, as well as sucrose and their mixtures. The behavioral responses in the T-test showed significant abnormalities in the exploratory activity evocative of memory deficits and an increased degree of anxiety in the groups of fish treated with the insecticide formulation and the mixture of the insecticide with sucrose. Aggression, quantified in the mirror-biting test, as biting and the frequency of approaches to the mirror contact zone, was significantly decreased only in the insecticide and sucrose group. All three groups showed behavioral changes reflective of toxicity, but only the combination of the two stress factors, environmental (insecticide) and metabolic (sucrose intake), resulted in pronounced memory alterations. Full article

Flavonoids have multiple functions, including host-plant defense against attacks from herbivorous insects. This manuscript reviewed and analyzed the scientific literature to test the hypothesis that flavonoids can be utilized to manage pests without causing significant harm to beneficials. The methodology involved using recognized literature databases, e.g., Web of Science, Scopus, and CAB Abstracts, via the USDA-ARS, National Agricultural Library, DigiTop literature retrieval system. Data were compiled in tables and subjected to statistical analysis, when appropriate. Flavonoids were generally harmful to true bugs and true flies but harmless to honey bees. Flavonoid glycosides showed a tendency to harm true bugs (Heteroptera) and true flies (Diptera). Flavonoid glycosides were harmless to sawflies. Flavonoids and flavonoid glycosides produced a mixture of harmful and harmless outcomes to herbivorous beetles, depending on the species. Flavonoid glycosides were harmless to butterflies. In conclusion, specific flavonoids could function as feeding stimulants or deterrents, oviposition stimulants or deterrents, chemical protectants from pesticides, mating attractants, less-toxic insecticides, and other functions. Flavonoids could manage some insect pests without causing significant harm to beneficials (e.g., honey bees). Flavonoid-based insecticides could serve as environmentally benign alternatives to broad-spectrum insecticides against some pests, but field testing is necessary. Full article

Environmental contamination from mixtures of chemical substances and materials resulting from anthropogenic activities has adverse effects on aquatic biota. Fipronil (FP) is an insecticide widely used in agriculture and public health and is frequently detected in environmental compartments. Microplastics (MPs) represent another class of contaminants that have raised concerns due to their ability to adsorb pollutants, potentially acting as a vector. This study evaluated the influence of polyethylene microplastics on the toxicity of FP in zebrafish (Danio rerio) embryos/larvae. Zebrafish embryos were exposed to aqueous suspension containing purified FP and the FP + MP mixtures for 120 h. Mortality, teratogenicity and cardiotoxicity were observed during the zebrafish development. Larvae were more sensitive to FP than the embryo. The presence of MPs reduced lethality; however, no significant changes were observed for sublethal endpoints. Our findings demonstrate the acute impact of FP on zebrafish embryos/larvae, demonstrating that MPs interfere with toxicity. Therefore, understanding the mechanisms of interaction between contaminants of different classes is essential for predicting the associated risks to biota. Full article

Cry2Ab is a significant alternative Bacillus thuringiensis (Bt) protein utilized for managing insect resistance to Cry1 toxins and broadening the insecticidal spectrum of crops containing two or more Bt genes. Unfortunately, the identified receptors fail to fully elucidate the mechanism of action underlying Cry2Ab. Previous studies have demonstrated the involvement of vacuolar H⁺-ATPase subunits A, B, and E (V-ATPase A, B, and E) in Bt insecticidal activities. The present study aims to investigate the contribution of V-ATPase C to the toxicities of Cry2Ab against Helicoverpa armigera. The feeding of Cry2Ab in H. armigera larvae resulted in a significant decrease in the expression of V-ATPase C. Further investigations confirmed the interaction between V-ATPase C and activated Cry2Ab protein according to Ligand blot and homologous and heterologous competition assays. Expressing endogenous HaV-ATPase C in Sf9 cells resulted in an increase in Cry2Ab cytotoxicity, while the knockdown of V-ATPase C by double-stranded RNAs (dsRNA) in midgut cells decreased Cry2Ab cytotoxicity. Importantly, a higher toxicity of the mixture containing Cry2Ab and V-ATPase C against insects was also observed. These findings demonstrate that V-ATPase C acts as a binding receptor for Cry2Ab and is involved in its toxicity to H. armigera. Furthermore, the synergy between V-ATPase C protein and Cry2Ab protoxins provides a potential strategy for enhancing Cry2Ab toxicity or managing insect resistance. Full article