Laboratory evaluation of the entomopathogenic fungus Beauveria bassiana, bacterium Bacillus thuringiensis, and insecticide emamectin benzoate treatments, alone and in dual combinations against Spodoptera frugiperda

A precise and low-toxicity pesticide delivery system is essential to enhancing pesticide efficacy and sustainability. Herein, a facile strategy is developed to construct leaf-adhesive and pH-responsive emamectin benzoate nanopesticides (EB NPs), in which Ca2+ cross-links copolymer surfactant/nonionic surfactant/sodium alginate in coacervates. The uniform nanosize of EB NPs enables them to penetrate the microstructure of plant leaves, thereby improving their deposition and antiwashing ability. Moreover, the pH-responsive EB NPs facilitate precise release of encapsulated emamectin benzoate (EB) in the alkaline midgut (pH 9-10) of Plutella xylostella larvae by displacing Ca2+ in the alginate nanoskeleton, along with the nanostructure disintegration. Notably, the acute toxicity of EB NPs to zebrafish is reduced to less than one-seventh that of commercial EB microemulsion formulation. This nanopesticide approach shows excellent potential to improve the pesticide efficacy and safety.

ABSTRACT Flow injection (FI) with chemiluminescence (CL) detection system applying tris-2,2/-bipyridylruthenium(II) – potassium permanganate ([Ru(bpy)3]2+–KMnO4) CL reaction was established to determine spinosad and emamectin benzoate Microbail-origin insecticides in freshwater samples. Experimental parameters were optimised, and solid phase extraction (SPE) was employed as phase separation techniques. Linearity of calibration plots for the standard solutions ranges of spinosad and emamectin benzoate were of 0.005–2.0 mg/L (R 2 = 0.9997 (n = 8)) and 0.01–2.0 mg/L (R 2 = 0.9994 (n = 7)), respectively. The respective Limit of Detections (LODs) and Limit of Quantifications (LOQs) for spinosad and emamectin benzoate were found as 1.3 × 10−3 and 3 × 10−3 mg/L [3σ blank, and 3.5 × 10−3 and 8.9 × 10−3 mg/L [10σ blank]. The injection throughput was 105 h−1. Because of applying tests of significance, the acquired results by the proposed method were not significantly different from those of reported methods at a 95% confidence level. Recoveries for spinosad and emamectin benzoate were achieved over the ranges of 94–107% (RSD = 1.8–3.6%) and 92–110% (RSD = 2.1–3.6%), respectively. The most possible CL reaction mechanism was investigated and formulated.

Insecticide resistance monitoring and identification of ryanodine receptor mutations driving diamide resistance in Cnaphalocrocis medinalis.

Comparative study on the ecotoxicity of nanoformulated and conventional emamectin benzoate to Raphidocelis subcapitata: A mechanistic disparity analysis.

Pseudocapillaria tomentosa infections in laboratory larval and Adult Zebrafish (Danio rerio): Development and advances in an in vivo anthelmintic drug discovery model.

The voltage-gated sodium channel mutation and detoxification enzymes associated with the resistance of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) to lambda-cyhalothrin.

The purpose of the study is to characterize the cumulative exposure and quantify the risk of specific effects of insecticidal pesticides of different chemical classes on the nervous system when they enter the body simultaneously with apples at the level of approved maximum permissible levels. By literature data, inactive and minimal dose levels of abamectin, emamectin benzoate, milbemectin, alpha-cypermethrin and acetamiprid for their specific effects on the nervous system were established. Domestic reference values – acceptable daily doses, maximum permissible levels of insecticides in apples were studied and their comparative characteristics were carried out with those established in the European Union. A comparative characteristic for the daily exposure of the studied insecticides in apples when they enter the children and adults’ bodies according to the scenario of maximum permissible levels is carried out. It was found that acetamiprid (0.00026/0.0001 mg/kg bw (body weight) for children 2-6 years/adults, respectively) is characterized by the highest level of exposure for which the maximum permissible level is approved – 0.05 mg/kg. The greatest contribution to the risk of cumulative alimentary effects is made by abamectin (65.8-66.4%), for which the lowest permissible daily dose (0.0002 mg/kg) is justified. The determined risk parameters from cumulative alimentary exposure are within accep­ table values (hazard index <1, total exposure margin >100). It was found that the cumulative effect per unit of body weight for children is higher compared to adults. It is shown that the effect of a mixture of the studied substances when they are taken with apples in the maximum permissible quantities will not lead to adverse health consequences for different age groups of the population (adults and children 2-6 years), in particular, the effect on nervous system. The results obtained indicate that the reference values of the studied insecticides approved in Ukraine will ensure safety for the health of consumers when they enter the body with apples. Recommendations are given on the need to take into account processing factors in food production technology and baby food hygiene.

Coordinated regulation of glutathione S-transferases confers metabolic flexibility in multi-insecticide-resistant Frankliniella occidentalis (Pergande).

Whitefly (Bemisia tabaci Genn.) is a serious sucking pest which causes significant damage of brinjal in Bangladesh. An experiment was conducted at the Entomology Field Laboratory, Bangladesh Agricultural University, Mymensingh during October to March to evaluate the efficacy of selected biorational insecticides viz. Award 40 SC (Buprofezin); Neem oil extract (Azadiractin); Bioneem plus 1% (Azadiractin); Suspend 5 SG (Emamectin benzoate); Tracer 45 SC (Spinosad) and Imidagold 20 SL (Imidacloprid) against whitefly in brinjal. the research was done in RCBD design with three replications of each treatment. Three sprays were applied on the pest infested plants and data were collected on 3, 5 and 7 days after each spray. Data were collected on no. of nymph & adult leaf-1, total no. of infested leaf & twig plant-1. Among the tested biorational insecticides, Buprofezin showed the best efficacy in reducing pest population after all sprays. In case of percent reduction of nymph on leaf over control, a remarkable decrease of 77.81%, 67.53% and 79.13% was observed from 1st, 2nd and 3rd sprays, respectively. In case of percent reduction of adult whitefly on leaf over control, 71.33%, 67.76% and 57.72% was recorded after 1st, 2nd and 3rd sprays, respectively. The highest reduction of leaf and twig infestation was also noticed in Buprofezin treated plots. Mean percent reduction of infested leaf over control was 48.81%, 53.19% and 49.46% from 1st, 2nd and 3rd sprays, respectively. The mean percent reduction of twig infestation over control was 41.21%, 36.42% and 31.76% after 1st, 2nd and 3rd sprays, respectively in Buprofezin treated plants and 48.21%, 34.38% and 17.62% after 1st, 2nd and 3rd sprays, respectively in Bio-neem plus treated plants. Therefore, Buprofezin could be used as the best management practice for whitefly in brinjal ecosystem. J Bangladesh Agril Univ 23(4): 491–497, 2025

Intensification of fish aquaculture worldwide has led to severe problems of diseases caused by parasitic dactylogyrideans. In this study, the anti-dactylogyridean efficacy of treating Colossoma macropomum with baths of emamectin benzoate (EMB) was investigated for the first time, along with the effects of this treatment on the haematology and histology of its gills. Thirty-nine fish (three replicates of 13 each) received four consecutive daily baths with EMB at a concentration of 0.5 g L-1 and one control group of 39 fish (three replicates of 13 each) only received water from the cultivation tank. The EMB treatments showed effectiveness of 50.2% against Anacanthorus spathulatus, Notozothecium janauachensis and Mymarothecium boegeri infecting the gills of C. macropomum. Fish treated with EMB only caused decreases in the total red blood cell, total thrombocytes, leukocytes, monocytes and neutrophils numbers, while the mean corpuscular haemoglobin concentration (MCHC) increased. Aneurysm was the gill structural alteration caused by EMB treatment, and mean assessment values (MAV) indicated moderate to severe damage due to this irreversible gill alteration. Our results lay a safe foundation for the application of EMB as a potential chemotherapeutic agent for dactylogyridean control in C. macropomum aquaculture, because this drug should be used cautiously for anthelminthic treatment in fish.

Pesticides are well-known harmful substances that cause oxidative stress and testicular dysfunction in both humans and animals, whereas omega-3 fatty acids (ω3FAs) have been demonstrated to possess antioxidant and anti-inflammatory properties. Thus, the primary focus of this investigation was the protective role of (ω3FAs) and their related molecular mechanism in testicular dysfunction induced by acetamiprid plus emamectin benzoate in rats. Rats were divided into four groups: control, omega-3 fatty acids (ω3FA; 300 mg/kg BW), insecticide mixture (Insec Mix; Acetamiprid (30 mg/kg BW) and emamectin benzoate (9 mg/kg BW)), and ω3FA + Insec Mix, respectively. ω3FA was taken orally an hour before insecticide treatment for three weeks daily. The results demonstrated that lipid peroxidation markers and lactate dehydrogenase activity were significantly elevated in rats intoxicated with pesticides; however, enzymatic antioxidants, aminotransferases, phosphatases, and reduced glutathione decreased. Furthermore, notable changes in testicular Bax, Cas-3, Bcl-2, P53, IL-1β, TNF-α, NFkB, Nrf2, hormones, sperm quality, testis structure, and Ki-67 protein expression were detected. Otherwise, ω3FA pre-treatment before insecticide intoxication substantially recovered most of the molecular and biochemical indicators and improved testicular cellular structure. Conclusively, ω3FA was highly effective in mitigating testicular toxicity conferred by acetamiprid and emamectin benzoate insecticides.

Chemical control remains a preferred choice among the farmers for pest management, with tolfenpyrad and emamectin benzoate popularly used in vegetable crops. To ensure consumer safety and assess the potential risks of these pesticides to human health, a field experiment was conducted for the estimation of residues of the combination product of tolfenpyrad and emamectin benzoate (Tolfenpyrad 18.75% + Emamectin Benzoate 0.94% W/W SC) in cauliflower and brinjal following SANTE (2021) guidelines. The extraction of residues was done using modified QuEChERS, and residues were estimated using Liquid chromatography coupled with a triple quadrupole processor. The average recovery of tolfenpyrad in cauliflower and brinjal was 86.17%-106.19% and 85.53%-106.16%, respectively, whereas the average recovery of emamectin benzoate in cauliflower was 92.33%-102.00% and in brinjal it was 93.36%-99.44%. The dissipation studies for tolfenpyrad revealed that the half-life at X and 1.25X was 0.94 and 1.25 days, and 1.96 and 1.92 days in cauliflower and brinjal, respectively. The half-life of emamectin benzoate in cauliflower and brinjal at X and 1.25X was 1.25 and 1.48 days, and 1.08 and 1.17, respectively. The pre-harvest interval (PHI) of emamectin benzoate in cauliflower and brinjal was 4.66-5.51 days and 8.68-10.64 days, respectively, which was less than the PHI of tolfenpyrad with values of 8.03-11.13 days and 12.85-13.07 days in cauliflower and brinjal, respectively. Dietary risk assessment revealed a Hazard quotient of less than 1, indicating negligible risk to human health when used according to the recommended dose and PHI.

The diamondback moth, Plutella xylostella (L.), is a major pest of cruciferous crops with a remarkable capacity to develop insecticide resistance. The present study evaluated the susceptibility, resistance ratios, and detoxification mechanisms of field populations collected from Andhra Pradesh, India, against tolfenpyrad 15 EC and emamectin benzoate 5 SG. Laboratory selection studies revealed declining LC50 values over successive generations reared without insecticide pressure, indicating partial recovery of susceptibility. Field bioassays showed resistance ratios ranging from 9.8 to 13.1 for tolfenpyrad and 5.3 to 10.2 for emamectin benzoate, with the Ponnur population exhibiting the highest resistance levels. Biochemical assays demonstrated that tolfenpyrad resistance was primarily associated with increased glutathione-S-transferase (GST) activity, while emamectin benzoate resistance was largely mediated by elevated carboxylesterase (CarE) activity, supported by moderate induction of mixed-function oxidases (MFOs). Specifically, GST activity increased by 2.06-fold and CarE activity by 1.90-fold in resistant populations compared with the susceptible strain, confirming the role of detoxification enzymes in resistance development. These findings highlight distinct enzymatic pathways involved in insecticide resistance and emphasize the importance of regular resistance monitoring. Adoption of insecticide rotation with different modes of action, combined with non-chemical pest management strategies, is recommended to prolong the efficacy of these insecticides in crucifer pest management programs.

Fall armyworm (FAW) [Spodoptera frugiperda (J.E. Smith)] is a destructive pest threatening global maize production. Conventional chemical control is effective but raises sustainability concerns. Drone-assisted ultra-low volume (ULV) spraying enables precision-targeted application, reducing pesticide input, energy consumption, and associated environmental footprints. This study reports the development of a drone-compatible oil dispersion (OD) formulation combining chlorantraniliprole and emamectin benzoate for FAW control. The formulation was optimized using emulsifiers (E1 + E2, 8-10% + 5-5.9%), dispersant D1 (2-5%), and thickener R1 (1-3%), achieving desirable emulsion stability, viscosity, and pourability. The OD met FAO/WHO standards and remained stable under accelerated (54 ± 2 °C, 14 days) and cold storage (0 °C, 7 days) conditions. Surface tension and contact angle analyses confirmed effective spreading on maize foliage. Biochemical assays indicated significant inhibition of glutathione S-transferase and acetylcholinesterase in FAW, suggesting synergistic molecular action. Field trials with Unmanned Aerial Vehicle (UAV) application demonstrated superior efficacy over commercial formulation (knapsack-sprayed), with reduced leaf damage (up to 47.4%, score: 2.56-4.1), lower cob infestation (13%) compared to untreated (40%) and commercial treatment (20%), and increased grain yield (13.43 t ha-1 in Delhi, 11 t ha-1 in Pune). This study demonstrates the potential of precision-engineered OD formulation, optimized for UAV-based ULV delivery, to enhance FAW management in maize while aligning with sustainable agriculture practices. © 2025 Society of Chemical Industry.

A toxicant may induce several types of injuries, and the severity of its effects is usually related to the dose and duration of exposure to the chemical under a specified exposure. Therefore, this study aimed to assess the impact of 1/10 LD50 of lambda-cyhalothrin, imidacloprid, and emamectin-benzoate insecticides on hematological and biochemical parameters in albino rats. No significant changes were observed in the treated rat’s body weight compared with control, except for emamectin, which caused a significant decrease after the recovery period. Emamectin-benzoate induced a significant increase in WBCs after the 5th and 10th doses, and imidacloprid caused a significant increase after the 10th dose (+ 89.5%); at the same time, lambda-cyhalothrin caused a slight increase. After the recovery period, white blood cell counts decreased in all treated rats compared to the treatment period but did not return to the control level. Imidacloprid caused a significant decrease in red blood cells (RBC) after the 5th dose (-6.6% below the control level). In contrast, after the recovery period, a significant decrease in RBCs was observed in rats treated with lambda-cyhalothrin and emamectin benzoate. The data also revealed a significant increase in GOT and GPT activities after the 5th and 10th doses in treated rats, while no significant differences in GPT activity were found in emamectin-benzoate-treated rats compared with control rats at the same time points. After the recovery period, the activity of both enzymes in all treated rats decreased but did not return to the control level. Similarly, lambda-cyhalothrin and emamectin benzoate had the greatest effect on kidney function compared to imidacloprid. Generally, there is no fixed pattern of the ill effects of different classes of pesticides on hematological and vital parameters. Therefore, it is of utmost importance to check and reduce the indiscriminate use of pesticides and to look into other environmentally friendly agrochemical approaches to increase crop productivity.

Synergistic enhancement of emamectin benzoate and Metarhizium anisopliae against late-instar Spodoptera frugiperda by promoting fungal pathogenicity.

Emamectin benzoate inhibits growth and development of Hyphantria cunea, accompanied by disruptions in lipid metabolism and hormonal balance.

Expanded UDP-glycosyltransferase gene clusters underlie insecticide detoxification in Spodoptera frugiperda.

Identification and validation of ABCB transporter genes involved in chlorantraniliprole and emamectin benzoate tolerance in Spodoptera exigua.