Synthetic Insecticides Research Articles

The V410L kdr allele in the VGSC confers higher levels of field resistance to permethrin in urban mosquito populations of Aedes aegypti (L.).

Females of Aedes aegypti transmit emerging arboviruses including Zika, dengue, yellow fever, and chikungunya. Control of these adult mosquitoes heavily relies on synthetic insecticides, including pyrethroids. However, insecticide resistance development in populations poses a significant challenge to vector control, particularly from knockdown resistance (kdr) mutations in the voltage-gated sodium channel (VGSC), the target of pyrethroids. This study investigated the field efficacy of Permanone, a pyrethroid-based insecticide, against Ae. aegypti by assessing the impact of three common kdr mutations (V410L, V1016I, F1534C) on mosquito survival under a real operational mosquito control scenario, by quantifying the pesticide delivered in the field. Field cage tests (FCTs) were conducted while conducting a realistic mosquito control application. Female mosquitoes from six operational areas from Harris County, TX, USA were exposed to Permanone delivered with a handheld sprayer. Permanone deposited near the cages was estimated from aluminum boats placed in the field during FCTs using gas chromatography-mass spectrometry (GC-MS). Mortality rates were recorded, and individual mosquitoes were genotyped for kdr mutations. A probit regression model was used to analyze the factors influencing mosquito survivorship. As the distance from the application source route increased, the amount of Permanone deposited decreased, resulting in higher survivorship frequency of Ae. aegypti females with the triple-resistant kdr genotype (LL/II/CC). The L allele at the 410-site significantly contributed to an increased resistance level when co-occurring with other kdr mutations. This study linked the survival probabilities of mosquitoes with different kdr genotypes, and the amount of pesticide they received in the field. Pesticide quantification, control efficacy results and genotyping allowed us to empirically determine the impact of genotypic resistance on vector control in the field. © 2024 Society of Chemical Industry.

The Susceptibility of Malaysian Rice Brands To Sitophilus oryzae and The Potential Application of Zinc Oxide Nanoparticles For Control Purposes

The rice weevil, Sitophilus oryzae, is an insect pest that can pose severe harm to stored grains. Rice weevils, both adults and larvae, cause significant economic losses because they can infest a wide range of plants and stored goods. Nanoparticle insecticides are created and studied to replace the overly-used synthetic chemical insecticides. The purpose of this study is to investigate the susceptibility of several commercialized rice brands towards S. oryzae infestation and to assess the toxicity of different types of zinc oxide (ZnO) against S. oryzae. The study involved twelve rice brands, and S. oryzae infestation rates were observed in the laboratory for 17 weeks. The infestation rates were obtained at the end of the observation period. To obtain the required dosages of 0.1, 0.2, 0.4, and 0.8% (w/w), four different concentrations of each type of ZnO nanoparticle that had undergone various reactivity modifications were mixed with rice for bioassays test. S. oryzae has been proven to be susceptible to almost all commercialized rice brands studied in this research. Based on the data, it can be concluded that the ZnO nanoparticle modified with gamma-ray is the most effective at controlling S. oryzae, as 100% mortality was seen after three days of treatment at concentrations between 0.4 to 0.08% (w/w). The slow emergence of pests in monitored rice brands is attributed to the protectants and their residue, which work by eradicating eggs and adults that have consumed the grain. Zinc oxide type 7A is the most toxic towards S. oryzae because of its exposure to gamma-ray which has the highest energy compared to neutron and beta rays. This results in the release of more active molecules to act on the pest.

Neurotoxicity, Cytotoxicity, and Genotoxicity of Phyto-radio Synthesized Selenium Nanoparticles in Culex pipiens Complex.

Effective mosquito management strategies are crucial to minimize the number of mosquito-borne diseases. Selenium nanoparticles (SeNPs) are promising in mosquito control because they are effective and eco-friendly rather than synthetic insecticides. The current study was conducted to evaluate the impact of SeNPs on the detoxification enzymes, acetylcholine esterase (AChE), glutathione S-transferase (GST), and α-carboxyl esterase (α-CarE), in larval instars of Culex pipiens complex at the LC50 concentration. In 3rd instar larvae treated with microwave-assisted selenium nanoparticles (SeNPs-MW) and gamma-assisted selenium nanoparticles (SeNPs-G), it was found that AChE activity was significantly inhibited. On the other hand, significant increases in GST and α-CarE activities were observed. Additionally, genotoxic and ultrastructure studies of midgut epithelial cells in 3rd instar larvae revealed DNA damage and cell lysis, including destruction of the cell membrane, microvilli, and nuclei. These findings suggest that SeNPs have an adverse effect on AChE gene expression, resulting in its downregulation. This downregulation can be attributed to the formation of reactive oxygen species induced by SeNPs that can modulate the host defense mechanism leading to apoptosis and subsequent larval mortality. The present study was the first to use phyto-microwave-assisted and gamma-assisted synthesis of SeNPs which provides an eco-friendly and cost-effective solution to reduce the risk of chemical insecticides. Furthermore, an integrated pest management program (IPM) using nanocides can be successfully developed for mosquito control.

Unveiling the Larvicidal Potential of Golpar (Heracleum persicum Desf. ex Fisch.) Essential Oil and Its Main Constituents on Aedes and Anopheles Mosquito Vectors

Natural products are thoroughly studied as valuable alternatives to synthetic insecticides. Heracleum persicum Desf. ex Fisch. (Apiaceae), commonly known as Golpar, is an Iranian medicinal plant largely employed as a spice, which has previously revealed insecticidal potential. The chemical composition of H. persicum essential oil (EO) was investigated by GC-MS and was mainly dominated by hexyl butyrate (36.1%) and octyl acetate (23.7%). The EO and its main esters were tested on three mosquito species. Aedes aegypti (L.) larvae were the most sensitive to all tested products. Lethal concentrations (LC50) of 59.09, 53.59, and 47.05 ppm were recorded for the EO, hexyl butyrate, and octyl acetate, respectively. Aedes albopictus (Skuse) and Anopheles gambiae Giles demonstrated comparable sensitivity to the EO, with LC50 values of 102.97 and 97.91 ppm, respectively, whereas the isolated constituents appeared more active on An. gambiae (LC50 of hexyl butyrate and octyl acetate of 70.97 and 60.71 ppm, respectively) with respect to Ae. albopictus (LC50 of hexyl butyrate and octyl acetate of 85.40 and 91.38 ppm, respectively). Low toxicity was registered for both EO and single components against human embryonic kidney (HEK293) cells. Overall, the H. persicum EO, hexyl butyrate, and octyl acetate could be further considered for larvicide development.

Molecular Docking Assessment of Limonoids from Cameroonian Entandrophragma Species as Potential Inhibitors of Anopheles gambiae Acetylcholinesterase (AChE)

Malaria remains one of the great killers in tropical regions of the world due to the transmission of the Plasmodium parasite by the bites of the female mosquito Anopheles. The resistance of this species to synthetic insecticides contributes to an increase in the incidence of malaria and therefore necessitates the development of new potent and eco-friendly insecticides. In this study, twelve previously reported limonoids from four Entandrophragma species collected in Cameroon have been computationally evaluated for their Anopheles gambiae AChE inhibitory activity. The docking procedure was carried out through Molecular Operating Environment 2019.01 (MOE), while the UCSF Chimera program was used to model the docking results based on interactions between proteins and ligands, and molecular dynamics trajectories were analyzed using the GROMACS 2021.1 tool. Entandrophragmin and encandollens B and C with docking scores ranging from −6.45 to −7.28 kcal/mol were the most promising hits compared to the reference azadirachtin (−6.22 kcal/mol) and were further evaluated for their mechanism of action. Subsequent evaluation classified encandollen C as the best candidate for the development of new potent eco-friendly insecticides based on its lower average RMSD and RMSF and its compactness over a 150 ns duration with acetylcholinesterase.

Evaluation of the insecticidal efficacy of four plants to protect stored Bambara groundnuts [Vigna subterranea (L.) Verdc. (Fabaceae)

Bambara groundnuts [Vigna subterranean] is one of the main legumes consumed in Northern Cameroon. However, stored nuts by farmers are quickly destroyed by pests leading to low yields. To overcome this constraint, the efficient control of stored grains from insect pests is dependent on synthetic insecticides. To reduce post-harvest losses of stored voandzou seeds, four botanicals insecticides have been developed and evaluated on the main pest. Plant powders prepared from Piper nigrum Linn. (Pipericaceae), Syzygium aromaticum (L.) Merr. & L.M.Perry (Myrtaceae), Xylopia aethiopica Dunal (Annonaceae) and Phaseolus vulgaris L.( Fabaceae), at different doses were tested on Callosobruchus maculatus Fabricius under laboratory conditions. The rest of the study involved combining black bean powder with the three condiment species in different proportions. The analysis shows a highly significant difference (p < 0.0001) between the mortality induced by formulations on day two of exposure with the lowest dose (0.5 g). These mortalities are 100%, 94.44 ± 3.79%, 72.5 ± 96 and 8.33 ± 4.77, respectively for S. aromaticum, P. nigrum, X. aethiopica and P. vulgaris powders. In relation to the formulation, the results show S. aromaticum powder induced 100% mortality compared with 94.44%, 72.59% and 8.33% respectively for P. nigrum, X. aethiopica and P. vulgaris plant powder at a dose of 5%. The results show that the natural substances used had a good insecticidal action against bruchid. The persistent compounds present in the studied spice plant powders are not toxic for human consumption at the concentrations used, but rather a beneficial effect. Key words: botanical insecticide, aromatic plants, powder, seeds, storage, insect pest.

Botanical extracts for insect management: lessons from participatory research in peri-urban horticultural systems of central Argentina

ABSTRACT We evaluate botanical insecticides as a technological device for synthetic input substitution in peri-urban horticultural system transitions. For that purpose, a Participatory Action Research (PAR) framework was proposed, and garlic extracts (GE) performance was evaluated for pest and natural enemy regulation in lettuce crops in conventional and agroecological contexts. Through three PAR cycles under actual production conditions, we observed GE effectiveness on aphids, thrips, and natural enemies. Additionally, context-specific adaptations were noticed: for conventional systems; the extract is useful near harvest and serves as a trust-building tool while reducing synthetic insecticide dependence. Instead, for agroecological systems, garlic extract highlighted biodiversity’s relevance for system redesign.

The Effect of Spinosad on the Oak Lace Bug Corythucha arcuata (Hemiptera: Tingidae)-A Preliminary Study Performed Under Laboratory Conditions.

The effect of biopesticide compound spinosad in different concentrations was tested for the first time under laboratory conditions against the rapidly spreading forest pest, oak lace bug (Corythucha arcuata, Say 1832), and its effects were compared with the synthetic pesticide lambda-cyhalothrin. These results revealed a significant effect of spinosad at 2 mL/4 L and 2 mL/2 L water concentrations against C. arcuata nymphs. The mortality rate after 3 days was similar to synthetic insecticide effects and reached 94% and 98%, respectively. Overall, it can be concluded that spinosad is an effective biological method to control oak lace bug; treatments under field conditions should consider the high diversity of other insects in oak forests.

Future semiochemical control of codling moth, Cydia pomonella

Codling moth (CM), Cydia pomonella, is a significant pest of apple (Malus domestica) and other orchard crops worldwide, posing challenges due to the decrease in registered insecticides, rising resistance, and a changing climate. The pest exhibits a strong resistance capacity to both synthetic and natural insecticides, while shifting seasonal temperatures disrupt the reliability of phenology-temperature models for predicting targeted control strategies. Alternative control strategies are necessary to future-proof control of this pest. Current control methods primarily rely on chemical insecticide sprays or granulosis virus applications during egg hatching. This review focuses explicitly on semiochemical-based manipulation of CM adults and larvae for control in orchards. Topics covered include the role of semiochemicals in integrated pest management, area-wide control, mating disruption, female attractants, larval kairomones, and incorporation into monitoring and control strategies. The potential of CM repellents in a push–pull strategy is also discussed. Primary sources for identifying relevant literature included GoogleScholar and ResearchGate, with a focus on papers published since 2013 but also include relevant papers from 2003. Nine review papers and 119 papers were reviewed. The review emphasizes that effective control necessitates an area-wide approach targeting all life stages (eggs, larvae, pupae, and adults). Comprehensive monitoring is crucial for identifying CM “hot-spots” and enhancing targeted interventions. Growers must consider landscape context when designing control programs. Lastly, recommendations are provided for future research and CM management strategies. There are opportunities to explore and exploit female kairomone attractants and repellents in control strategies and modify monitoring traps to be more attractive and autonomous.

Yield Yield loss and economic threshold estimates for pod borer (Helicoverpa armigera) in late maturing pigeonpea (Cajanus cajan)

Pod borer [Helicoverpa armigera (Hubner)] is a major biotic constraint to global pigeonpea production. The farmers largely apply synthetic insecticides to control this pest in pigeonpea. The study was conducted to quantify yield losses and estimate economic thresholds for H. armigera. The late maturing cultivar, IPA-203 was infested with different larval densities to determine the insect density-yield loss relationships. The yield response was variable and grain yield declined with increasing larval density from 1–5/plant. Yield loss of 4.56 kg/ha was evident for each unit increase in larval population. Economic threshold estimates indicated that the control measures for pod borer in IPA 203 cultivar should be initiated at an insect density of ≈1 larva/2 plants or at 3% pod damage to avoid the economic crop losses. The damage potential and economic threshold estimates are prerequisite for integrated pest management and reducing production costs (Alves et al. 2017). Present results indicated that relatively low infestations of H. armigera can cause significant yield reduction in pigeonpea hence intensive monitoring and timely control measures are necessary. Based on present economic threshold estimates, the farmers could decide the timing and kind of control measures to be initiated against pod borer in late pigeonpea cultivars to avert the economic losses.

Entomopathogenic nematodes as a lethal bioagent to deter <i>Pieris brassicae</i> L. (Lepidoptera: Pieridae) infesting different cole crops: A review

Cole crops are the most important and attractive vegetables, belonging to the family Cruciferae are extremely grown all over the world. In India, their annual production has been reported to be about 191.77 million metric tons so chips into the economy by a huge amount. Pieris brassicae, one of the dreaded insect pests incur damage to different vegetables to a tune of 40%. To curb this pest damage various synthetic insecticides are applied, albeit showing promising results yet posing drastic negative imprints on non-target organisms, environment and pest resistance. These drawbacks demand a perfect alternative which seals all the glitches created by the chemical insecticides. For this Infective Juveniles (IJs) of Entomopathogenic Nematodes (EPNs) act as perfect biological agents. So, work done in these lines has been reviewed to facilitate students and researchers for advanced research related to entomopathogenic nematodes and P. brassicae.

Bioassay of Plant-based and Synthetic Insecticides for the Management of Tomato Leaf Miner, Tuta absoluta (Meyrick) in Open-field Conditions in Salyan, Nepal

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most parts of Nepal and threatens tomato production. Their management primarily relies on insecticides in Nepal. Market-available and locally-madeplant-based pesticides are not equally effective in managingT. absoluta. Therefore, this study aimed to evaluate the effectiveness of such potential insecticides in managing T. absoluta in open-field conditions. This study was carried out in the Salyan district of Nepal in 2021 and treatments were designed in a randomized complete block design (RCBD)with seven treatments and three replications. All treatments were sprayed at12-dayintervalsfor two times. The treatments used were Emamect in benzoate 5% SC, Imidacloprid 17.8 SL, Jholmol (botanical mixture extract and urine mixture), Chlorantraniliprole 18.5 SC, Spinosad 45 SC, Azadirachtin 300ppm and Control. The results showed that the lowest percentage of leaves and fruit damage was recorded in Chlorantraniliprole 18.5 SC and Spinosad 45 SC sprayed plots. Insecticide efficiency was ranked as Chlorantraniliprole > Spinosad>Ema-mectin Benzoate > Azadirachtin >Imidaclroprid>Jholmol>Control. Marketable yield was obtained highest in Chlorantraniliprole (85.26 t/ha) treated plots followed by Spinosad (79.26 t/ha); both were not significantly different. This study provides an opportunity to select the most suitable and effective pesticides for the management of tomato leaf miners and can be used in integrated pest management strategies as a selective insecticides.

Comparative transcriptional analysis between susceptible and resistant populations of Aedes (Stegomyia) aegypti (Linnaeus, 1762) after malathion exposure.

Aedes aegypti is an important vector of arboviruses, including dengue, chikungunya and Zika. The application of synthetic insecticides is a frequently used strategy to control this insect. Malathion is an organophosphate insecticide that was widely used in Brazil in the 1980s and 1990s to control the adult form of A. aegypti. In situations where resistance to currently used insecticides is detected, the use of malathion may be resumed as a control measure. Many studies have confirmed resistance to malathion, however, comparative studies of differential gene expression of the entire transcriptome of resistant and susceptible insects are scarce. Therefore, understanding the molecular basis of resistance to this insecticide in this species is extremely important. In this paper, we present the first transcriptomic description of susceptible and resistant strains of A. aegypti challenged with malathion. Guided transcriptome assembly resulted in 39,904 transcripts, where 2133 differentially expressed transcripts were detected, and three were validated by RT-qPCR. Enrichment analysis for these identified transcripts resulted in 13 significant pathways (padj < 0.05), 8 associated with down-regulated and 5 with up-regulated transcripts in treated resistant insects. It was possible to divide the transcripts according to the mechanism of action into three main groups: (i) genes involved in detoxification metabolic pathways; (ii) genes of proteins located in the membrane/extracellular region; and (iii) genes related to DNA integration/function. These results are important in advancing knowledge of genes related to resistance mechanisms in this insect, enabling the development of effective technologies and strategies for managing insecticide resistance.

Investigation on the mosquitocidal property of cis-13-Octadecenoic acid isolated from Andrographis paniculata against Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae)

Mosquitoes are a critical global public health concern, causing millions of deaths each year due to the viral infections and diseases they spread. In recent decades, synthetic insecticides and repellents have been used to control mosquito populations and virus transmission, but they often harm the environment and non-target organisms, including humans. This research investigates the isolation, characterization, and structural elucidation of cis-13-Octadecenoic acid derived from Andrographis paniculata, and its effectiveness against the immature stages of Aedes aegypti and Culex quinquefasciatus. The extracts from A. paniculata underwent fractionation, with the most bioactive fractions being further purified and analyzed. Spectroscopic techniques were employed to confirm the structure of cis-13-Octadecenoic acid. Biological assays were then performed to evaluate its ovicidal, larvicidal, and pupicidal activities. cis-13-Octadecenoic acid exhibited notable ovicidal activity, causing 25 % mortality in Ae. aegypti eggs and 29 % mortality in Cx. quinquefasciatus eggs at a concentration of 2 ppm. Additionally, it showed strong larvicidal and pupicidal activities, with LC50 values of 2.67 ppm and 3.39 ppm for Ae. aegypti larvae and pupae, and 3.10 ppm and 2.93 ppm for Cx. quinquefasciatus larvae and pupae, respectively. These findings demonstrate the potential of cis-13-Octadecenoic acid as an effective natural compound for mosquito control, highlighting the broader importance of natural products as alternatives to synthetic insecticides in the management of vector-borne diseases.

Ecological Management of Stored Grain Pests: Global Insights and Future Directions

Abstract Post-harvest losses due to pests in cereals and pulse warehouses represent a major challenge to global food security. These losses have widespread negative impacts on the food supply chain, leading to the widespread use of synthetic insecticides to control the spread of pests in stored commodities. Although these chemicals are initially effective against warehouse pests, their prolonged use leads to increased resistance, resulting in increased health and environmental risks. In addition, the residues left by these synthetic insecticides can alter the quality of stored food, thereby posing a threat to human and animal health. In response to this problem, several studies have focused on ecological management aimed at combating warehouse pests without compromising the quality of stored grain. These studies include an assessment of traditional, ecological, and modern approaches as well as a summary of technological advances in cereal storage. This analysis describes new emerging ecological methods such as varietal resistance, use of semiochemicals, and physical and biological control methods. The challenges and research prospects associated with ecological practices were also discussed. It is emphasized that ecological control is not only safer and more sustainable in the long term but also contributes to the preservation of the environment and human health by reducing exposure to harmful substances.

Soft soap and linalool as potential management tools for Philaenus spumarius (Hemiptera: Aphrophoridae), vector of Xylellafastidiosa

Philaenus spumarius (Hemiptera: Aphrophoridae) is one of the most polyphagous xylem-feeding pests. It recently acquired bad fame when it was identified as the main vector of the bacterium Xylella fastidiosa, the causal agent of the Olive Quick Decline Syndrome that, within ten years, has affected and led to the death of more than 21 million olive trees in the Southern Italian region Apulia alone. Despite the agricultural practices and synthetic insecticides available, as not sufficiently effective, more strategies to target all the developmental instars of the pest and eco-friendly formulations, especially in organic orchards, are urgently needed. Therefore, the main goals of this work were to test the toxicity of a solution of potassium salts of fatty acids (soft soap) on P. spumarius juveniles and assess the attractiveness exerted by linalool on adults in a planar olfactometer. According to our results, the average neanids/nymphs’ mortality was 82.2 ± 10.4% 24h after spraying the soft soap on them at the labelled dose. Regarding the adults, linalool was significantly attractive to both sexes in a concentrations range between 0.01 and 0.12 μL linalool L−1 air. Our purpose is to potentially suggest a dual, integrated control approach against P. spumarius, with the soft soap as a biopesticide to reduce the immature stages of the pest and attractive, linalool-activated traps to numerically cull the population of the meadow spittlebug as part of a broader management system.

Inhibitory activity of some short-chain aliphatic aldehydes on pheromone and ammonium carbonate-mediated attraction in olive fruit fly, Bactrocera oleae.

The olive fruit fly (OFF), Bactrocera oleae (Rossi), is the main insect pest of olive trees worldwide. Legislation limits to the use of some synthetic larvicidal insecticides is leading to the development of new control options for preventive control of adult flies. In the present study, the biological activity of four short-chain aliphatic aldehydes, namely hexanal, (E)-2-hexenal, heptanal and (E)-2-heptenal, previously reported as repellents to the OFF adults was investigated. Electroantennography (EAG) recordings showed that antennae of OFF males and females are able to perceive the test compounds in a wide range of doses. In field trapping experiments, reservoir-type polypropylene (PP) membrane dispensers loaded with individual compounds did not elicit a significant attraction of OFF males and females. On the contrary, a significant reduction of male catches was noticed when sex pheromone dispensers and PP membrane dispensers, loaded with one of the test compounds, were applied on the same white sticky traps ≈20 cm apart. Likewise, male and female catches in yellow sticky traps baited with ammonium carbonate (AC) dispensers as food attractant were significantly reduced by the presence of PP membrane dispensers of individual aliphatic aldehydes on the same traps. In small plots control trials, solid formulations of the four aldehydes into a bentonite clay support induced a significant reduction of the OFF active infestation mainly when C6 and C7 aldehyde-activated bentonites were used. Short-chain aliphatic aldehydes showed inhibitory effects on sex pheromone and food attractant-mediated attraction of OFF. Results of field trials suggest potential of short-chain aliphatic aldehydes to develop new semiochemical-based OFF control options. © 2024 Society of Chemical Industry.

Impact of triflumezopyrim (insecticide) on blood and serum biochemistry of freshwater fish, subadult Labeo rohita (Hamilton, 1822)

The impact of insecticides on water bodies can be evaluated by studying the physiology and health of fish. These chemicals pose a significant and direct risk to aquatic ecosystems and hence aquatic animals like fish. Therefore, this study was designed to investigate the toxic effects of sub-lethal concentrations of triflumezopyrim, a novel synthetic insecticide commonly used in crop protection, on the biochemical and hematological parameters of freshwater sub-adult Labeo rohita L. Here, fish were subjected to sub-lethal doses of triflumezopyrim at various concentrations (1.41 ppm, 3.27 ppm, and 4.97 ppm) for 21 days. In addition, fish were grown in an insecticide-free control group to determine the toxic effects of the insecticides. The obtained data on various biochemical and hematological parameters of the fish were analyzed using state-of-the-art statistics. Our findings suggest that triflumezopyrim exposure has a significant effect on blood variables. However, variable response, such as mean corpuscular volume, hemoglobin concentration, neutrophils, and eosinophils were unaffected by insecticide treatment, regardless of the dose. Our interhematological parameter analysis revealed varying interrelationships at various insecticide doses. Similarly, triflumezopyrim exposure significantly affected the response of serum biomarker profiles i.e., the difference in mean treatment pairs (control and three doses of triflumezopyrim) had a significant effect on the response of most serum profile parameters.

INVESTIGATION OF COMBINED EFFECT OF THREE PLANT POWDERS WITH DIATOMACEOUS EARTH AGAINST CALLOSOBRUCHUS MACULATUS

The study was conducted to investigate the combined effects of various plant powders and Silico-sec, a diatomaceous earth, on Callosobruchus maculatus at the research laboratory of the Department of Crop Pest and Soil Management, the Federal University of Technology, Akure. The study included three replications. The treatments consisted of three (3) plant materials derived from the dry flower buds of Eugenia aromatica, seeds of Piper guineense, and leaves of Nicotiana tabacum and their combination with Silico-sec. In one experiment, 0.4g of each plant material was added to 20 C. maculatus adults (10 couples, aged 1-2 days) in 20g of Ife Brown cowpea seeds, all contained within an air-tight plastic container. Another experiment involved the addition of 0.4g mixtures of Silico-sec and each plant powder (E. aromatica, P. guineense, and N. tabacum) in various ratios (1:5, 5:1, 1:10, 10:1, and 1:1) to the same number of C. maculatus adults in 20g of cowpea seeds, also in separate air-tight plastic containers. All the treatments and their combination were laid out in a completely randomized design (CRD) repeated three times. Data were collected at 12, 24, and 48 at p,0hours post-treatment. Oviposition, adult emergence, and seed weight loss were evaluated. The results demonstrated that both the plant powders and Silico-sec were effective in controlling C. maculatus infestation on cowpea by causing significant adult mortality at p&lt; 0.05, reducing oviposition, suppressing F1 adult emergence, and minimizing seed damage. Among single applications, Silico-sec and E. aromatica powder provided the best protection for stored cowpea, yielding the highest adult mortality, lowest oviposition, most suppressed F1 adult emergence, and minimal seed damage. However, the mixture of Silico-sec and P. guineense at ratios of 5:1 and 10:1 offered the best protection, exhibiting significantly higher mortality, lower oviposition rates, suppressed F1 adult emergence, and reduced seed damage compared to other treatments. This study suggests that combination of P. guineense and Silico-sec is particularly effective in controlling cowpea storage pests and could serve as a viable alternative to synthetic insecticides for protecting stored cowpea against C. maculatus.

Characterization of ATP-binding cassette transporters associated with emamectin benzoate tolerance: from the model insect Drosophila melanogaster to the agricultural pest Spodoptera frugiperda.

Multiple families of detoxification genes, including the increasingly recognized family of ATP-binding cassette (ABC) transporters, work together to influence the toxicity of synthetic insecticides and thus their resistance. Effective management of insecticide resistance requires identification of all toxicity-affecting members from each family of toxicity-related genes. Here, we used emamectin benzoate (EB), ABC transporters and Spodoptera frugiperda as a working case to test whether the strategy of 'from the model insect Drosophila melanogaster to agricultural pests' can identify all or most ABC transporter members related to EB tolerance in S. frugiperda. After confirming the involvement of ABC transporters in the toxicity of EB against fruit fly with the ABC inhibitor verapamil, four ABC transporter genes (DmCG3327, DmCG11147, DmCG4822, and DmCG7627) were found to be involved in EB tolerance using RNA interference-based family-wide functional screening. A combination of phylogenic analysis and a reciprocal TBLASTN search identified five S. frugiperda ABC transporter members as homologs (SfABCC4, SfABCG1, and SfABCG23) or one-way best hits (SfABCG4 and SfABCG20) of the four fly ABC genes. Real-time quantitative polymerase chain reaction (qPCR) analysis found that all five S. frugiperda ABC transporter genes were inducible by EB, and expressed in all the developmental stages and larval tissues, but with significant quantitative differences among stages and tissues. A cytotoxicity assay of ABC-overexpressing Sf9 cell lines showed that all the five S. frugiperda ABC transporter genes made Sf9 cells tolerant to EB. This study not only identifies nine ABC transporter genes related to EB tolerance from D. melanogaster (four genes) and S. frugiperda (five genes), but also demonstrates the utility and effectiveness of the 'model to pests' strategy to identify most toxicity-affecting members from a given family of toxicity-related genes. © 2024 Society of Chemical Industry.