Search Results (307)

Triatoma infestans is one of the primary vectors of Chagas disease. This vector has developed increasing resistance to pyrethroids, the main insecticides used for its control. Recent studies have highlighted the repellent and lethal effects of Cannabis sativa on insects, suggesting its potential use in pest management. Based on this, we hypothesize that C. sativa could be a viable bioactive for controlling T. infestans. To test this hypothesis, acetone and ethanol extracts were obtained from the inflorescences of C. sativa L. (Deep Mandarine variety) using sonication. These extracts were analyzed through gas chromatography and high-performance liquid chromatography. The repellent and lethal effects of the extracts were evaluated on fifth-instar nymphs of T. infestans from a laboratory colony, as well as on the beneficial non-target species, Apis mellifera. The most abundant terpenes identified were β-caryophyllene and β-pinene, with concentrations exceeding 100 ppm in both extracts. Cannabidiol and Δ⁹-tetrahydrocannabinol were the predominant cannabinoids. Both extracts exhibited maximum lethal activity 48 h after insect contact, with the acetone extract demonstrating a potency five times greater than the ethanolic extract. Binary combinations of C. sativa extracts with major terpenes showed dose-dependent interactions against T. infestans, ranging from strong synergy (e.g., AE + β-caryophyllene, CI = 0.06–0.17) to marked antagonism (e.g., AE + E-ocimene, CI = 1.60–4.80). Furthermore, the acetone extract showed a more effective repellent action compared to the ethanol extract, even outperforming N,N-Diethyl-meta-toluamide (DEET, positive control). At a concentration of 25 µg/cm² for 60 min, the acetone extract achieved a 100% repellent effect, whereas DEET required a concentration of 50 µg/cm² to achieve the same effect. Unlike imidacloprid (positive control), neither extract showed toxicity to adult A. mellifera at the evaluated doses. Full article

Cabbage (Brassica oleracea Linnaeus) is an important vegetable crop for food security and income generation for farmers in the Democratic Republic of Congo (DRC). However, production is severely undermined by a complex of insect pests. This study investigates farmers’ knowledge, perception, and pest management practices in key cabbage-growing areas surrounding Goma city in Eastern DRC. A total of 430 farmers were interviewed using a structured survey administered via the KoboToolbox platform. The diamondback moth (Plutella xylostella Linnaeus, 1758) and the cabbage aphid (Brevicoryne brassicae Linnaeus, 1758) were identified as the main pests, with peak incidences reported during the dry mid-season. Pest damages are most frequently observed at the post-transplanting and heading stages of cabbage. Although chemical control was the dominant strategy (69.4%), concerns arise due to the widespread use of moderately to highly hazardous insecticides, including pyrethroid, organophosphorus, and avermectin-based formulations. The insufficient use of personal protective equipment (PPE) and limited training on safe pesticide handling remain further challenges. While indigenous practices, such as crop rotation, handpicking of insects, and the use of botanical extracts, are employed to a lesser extent, awareness and implementation of biological control are almost nonexistent. The findings underscore the need to promote integrated pest management (IPM) approaches based on agroecological principles, including the safe use of (bio-)pesticides, training programs, and stakeholder engagement to enhance sustainable cabbage production. Full article

Dichlorodiphenyltrichloroethane (DDT), used in the 20th century to combat malaria, is considered harmful to health and the environment. As an alternative, insecticides such as pyrethroids have been used, especially alphacypermethrin, which is applied in mosquito nets impregnated with long-lasting insecticide (LLIN). This study analyzed the concentrations of DDT and alphacypermethrin in soils from three municipalities in the Legal Amazon (Mazagão, Porto Velho, and Cantá) using gas chromatography. The results showed the presence of DDT and metabolites, indicating slow degradation in the region, especially in Cantá, with an average of 2.694 mg/kg of total DDT. Alphacypermethrin stands out in Porto Velho, with an average of 0.364 mg/kg, possibly due to the use of LLINs. DDT did not represent a significant ecological risk in this study, but it did present risks to human health, mainly through food intake. The incremental lifetime cancer risk (ILCR) indicated potential danger, with values of up to 2.93 × 10⁻³ for DDT and 1.17 × 10⁻¹ for alphacypermethrin. The total non-carcinogenic risk index (HI) was extreme, with a maximum value of 336.61. The pesticides evaluated did not present an ecological risk, but they do pose risks to human health, indicating irregular use of LLINs and the need for continuous monitoring. Full article

Organochlorine insecticides (DDTs), organophosphate insecticides (malathion), carbamate insecticides (carbaryl and thiram), pyrethroid (cypermethrin and fenvalarate) insecticides, and herbicides (glyphosate and atrazine) were selected for this study because they disrupt cervical and myometrial function in the bovine oestrous cycle. However, their potential to affect reproductive success in cattle during pregnancy has not been directly confirmed. The aim of this study was to determine the effects of the investigated pesticides on cervical contractions in pregnant cows. Cervical strips from cows at 4–6 months of gestation were treated with the eight singular pesticides (used at non-toxic, environmental dose) or oestradiol (E2) under two different conditions (37.5 °C for 24 h and 4 °C for 48 h), which were applied to assess pesticide effects under both physiological and prolonged-exposure settings. The strength of the contractions was then measured. The findings of the study demonstrated that both the carbamates and glyphosate increased the force of cervical strip contractions to a greater extent than cypermethrin. In contrast, fenvalerate was observed to induce a state of cervical relaxation, analogous to the effects of E2, while DDT, malathion and atrazine exerted no effect on cervical motor function during the period of pregnancy under investigation. These preliminary findings indicate a potential impact of pesticides on cervical function during pregnancy, but should be interpreted with caution as they are based on isolated tissue at a single concentration. Further in vivo and dose–response studies are needed to confirm their biological and clinical relevance. Full article

For pest control to be sustainable, the methods applied must be efficient and have a low environmental impact. Pest control failures bring economic and environmental problems. Phthorimaea absoluta is the main pest in tomato crops worldwide. Benzoylureas, diamides, and pyrethroids are among the insecticides with the highest reports of pest control failures, and Brazil is the country where this has been most observed. Machine learning models are suitable for predicting biological events. Thus, this study aimed to determine the risks of failures in the control of P. absoluta by insecticides in Brazilian biomes using the MaxEnt machine learning algorithm. The risks of pest control failures by benzoylureas and pyrethroids were higher in tomato crops located in the Cerrado and Atlantic Forest biomes, and annual precipitation was the critical variable associated with these failures. The risks of control failures by diamides were higher in crops located in the Caatinga, Cerrado, and Atlantic Forest, and temperature seasonality was the critical variable associated with these failures. In conclusion, the models determined in the study are robust to predict the regions with higher risks of P. absoluta control failures by insecticides, and they indicated the environmental variables associated with these risks. Full article

Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) is one of the most destructive pests of stored grains worldwide. Sublethal concentrations of insecticides are known to influence insect behavior, potentially disrupting critical processes such as mating. This study investigated the effects of λ-cyhalothrin at the lethal concentration (LC) values LC₁₀ and LC₃₀ and lateralization on the mating behavior patterns of S. zeamais males. Results showed that the exposure to sublethal concentrations of λ-cyhalothrin significantly altered the copulation success rate and key time-related parameters, including mate recognition and copulation duration, while the lateralization caused significant differences in mating time-related parameters within each tested group (control, LC_10, and LC₃₀). Additionally, the λ-cyhalothrin-treated groups showed prolonged mate recognition times and required more mounting attempts to achieve mating. These findings highlight the potential of sublethal insecticide applications to control S. zeamais populations by impairing reproduction. Full article

Background: Experimental studies suggest that some insecticides, fungicides, and herbicides can result in liver cell death, but population-based evidence is lacking. We investigated associations between urinary pesticide metabolites and liver biomarkers among adolescents and adults in an Ecuadorian agricultural area. Methods: We examined participants in 2016 (N = 528, 11–17 years) and 2022 (N = 505, 17–24 years). Plasma alanine aminotransferase (ALT), aspartate aminotransferase, soluble cytokeratin-18, and erythrocytic acetylcholinesterase were measured. Urinary biomarkers included four organophosphates, six neonicotinoids, three pyrethroids, two herbicides, and two fungicides. Generalized estimating equation (GEE) models examined associations and introduced sex and age interaction terms and quadratic terms. Quantile g-computation evaluated the effects of pesticide mixtures. Results: No significant associations were observed between pesticide biomarkers and liver biomarkers in longitudinal or cross-sectional analyses. A curvilinear association was found between 3-phenoxybenzoic acid (3-PBA; pyrethroid) and ALT (β_quadratic = −0.35, 95% CI: [−0.67, −0.04]) in 2016, but not in 2022. Sex modified the associations of 3-PBA with AST, ALT, and CK18-M65 in adolescents (2016), with non-significant positive associations observed in males and non-significant negative associations observed in females. No pesticide mixture effects were observed. Conclusions: Urinary biomarkers of various insecticides, herbicides, fungicides, and their mixtures were not associated with liver biomarkers among adolescents and young adults in agricultural settings. These largely null findings, consistent across time points, suggest background-level exposures in these settings possibly do not harm liver health in this population, though effects at higher exposures cannot be ruled out. Full article

In this study, we investigated the insecticidal potential of Eucalyptus globulus Labill. and Cymbopogon citratus Stapf essential oils (EOs), both alone and in synergistic blends with their primary active compounds, against adult houseflies (Musca domestica L.). Toxicity assessments were also conducted on non-target organisms—dwarf honeybees (Apis florea Fabricius) and guppies (Poecilia reticulata Peters)—to evaluate environmental safety. All binary EO mixtures demonstrated superior efficacy compared to individual EOs and the synthetic pyrethroid α-cypermethrin (1% positive control). The most potent formulation, combining 2.5% (v/v) geranial with 2.5% (v/v) E. globulus EO, exhibited a synergistic effect, achieving complete fly mortality (LT₅₀: 0.06 h). This mixture’s mortality index significantly exceeded those of single-component formulations, with a mortality index of 0.22, confirming greater toxicity to flies than α-cypermethrin. Importantly, all the tested EOs and their blends were non-toxic to honeybees and guppies; in comparison, α-cypermethrin caused significant harm. These findings highlight the 2.5% (v/v) geranial + 2.5% (v/v) E. globulus EO blend as a highly effective and environmentally friendly alternative to conventional insecticides. Further research is recommended to optimize its formulation for practical use in sustainable fly management. Full article

The escalating challenge of resistance to insecticides among agricultural and public health pests poses a significant threat to global food security and vector-borne disease control. This review synthesizes current understanding of the molecular mechanisms underpinning resistance, including well-characterized pathways such as target-site mutations affecting nicotinic acetylcholine receptors (nAChRs), acetylcholinesterase (AChE), voltage-gated sodium channels (VGSCs), and γ-aminobutyric acid (GABA) receptors, and metabolic detoxification mediated by cytochrome P450 monooxygenases (CYPs), esterases, and glutathione S-transferases (GSTs). Emerging resistance mechanisms are also explored, including protein sequestration by odorant-binding proteins and post-transcriptional regulation via non-coding RNAs, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). Focused case studies on Aedes aegypti and Spodoptera frugiperda illustrate the complex interplay of genetic and biochemical adaptations driving resistance. In Ae. aegypti, voltage-gated sodium channel (VGSCs) mutations (V410L, V1016I, F1534C) combined with metabolic enzyme amplification confer resistance to pyrethroids, accompanied by notable fitness costs and ecological impacts on vector populations. In S. frugiperda, multiple resistance mechanisms, including overexpression of cytochrome P450 genes (e.g., CYP6AE43, CYP321A8), target-site mutations in ryanodine receptors (e.g., I4790K), and behavioral avoidance, have rapidly evolved across global populations, undermining the efficacy of diamide, organophosphate, and pyrethroid insecticides. The review further evaluates integrated pest management (IPM) strategies, emphasizing the role of biopesticides, biological control agents, including entomopathogenic fungi and parasitoids, and molecular diagnostics for resistance management. Taken together, this analysis underscores the urgent need for continuous molecular surveillance, the development of resistance-breaking technologies, and the implementation of sustainable, multifaceted interventions to safeguard the long-term efficacy of insecticides in both agricultural and public health contexts. Full article

Lambda-cyhalothrin (LCY), a widely used pyrethroid insecticide, is toxic to bees—vital pollinators experiencing global declines; however, its molecular effects during early development remain poorly understood. We investigated the molecular mechanisms underlying chronic sublethal exposure to LCY in the larval and adult stages. Larvae were exposed to LCY (0.004 µg active ingredient/larva), with four groups examined: solvent-treated larvae group (SLG), solvent-treated adult group (SAG), LCY-treated larvae group (LLG), and LCY-treated adult group (LAG). We identified 1128 and 168 significantly altered genes in LLG vs. SLG and LAG vs. SAG, respectively, with 125 larval- and 25 adult-specific DEGs, indicating stage-dependent toxicity. LCY dysregulated processes such as cuticle formation, sulfur metabolism, oxidoreductase activity, and neuropeptide signaling in larvae, while adults exhibited altered redox balance, peptide receptor signaling, and monoamine transport. Neuroactive signaling disruptions were observed in both stages, with additional effects on motor function, amino acid metabolism, and glycolysis in larvae; whereas adults exhibited altered lipid biosynthesis and energy metabolism. Downregulated genes involved in chitin metabolism and antioxidant defenses in larvae suggested compromised exoskeletal integrity and increased vulnerability. Overall, our findings highlight the long-term molecular consequences of early-life exposure and emphasize the need for safer pesticide practices to protect pollinator health. Full article

Bemisia tabaci (Aleyrodidae family) is one of the most damaging pests of numerous crops worldwide. Insecticides, namely pyrethroids and organophosphates, have long been the primary control tools against this pest, resulting in several resistance cases. In Tunisia, the two most damaging biotypes of B. tabaci, MEAM1-B and MED-Q, are sympatric, and more concerns about developing resistance keep rising due to the extensive use of insecticides. Here, we aimed to elucidate the molecular mechanism of resistance to pyrethroids and organophosphorus insecticides in two Tunisian populations of B. tabaci, collected respectively on Capsicum annuum and Lantana camara, and then determine the bacterial community associated with insecticide resistance and susceptible biotypes based on 16S rRNA Illumina sequencing. The results showed that the population collected on Capsicum annuum belonged to the MEAM1-B biotype with an insecticide resistance profile. In contrast, the population collected on the Lantana camara belonged to the MED-Q biotype with a sensitive profile. The bacterial communities of the two biotypes were predominantly structured by the Proteobacteria phylum and three genera, including Candidatus Portiera, the secondary facultative symbiont, and Hamiltonella, which were unevenly distributed between the two biotopes. Our results provide the first evidence for insecticide resistance alleles in Tunisian MEAM1-B populations and suggest an association between bacterial community composition within susceptible biotypes and insecticide resistance. Full article

Cockroaches, particularly the German cockroach (Blattella germanica Linnaeus, Blattodea: Ectobiidae) and the American cockroach (Periplaneta americana (Linnaeus), Blattodea: Blattidae), are major public health pests due to their ability to transmit pathogens and develop resistance to chemical insecticides, including synthetic pyrethroids, which are widely used worldwide. Given the increasing resistance, entomopathogenic nematodes (EPNs) have emerged as a potential biological control alternative. This study evaluates the efficacy of three EPN species, Steinernema carpocapsae (Weiser), S. feltiae (Filipjev), and Heterorhabditis bacteriophora Poinar, against B. germanica and P. americana collected from different regions of Antalya, Türkiye. Laboratory bioassays were conducted under controlled conditions, testing five EPN concentrations (100, 250, 500, 750, and 1000 IJs/mL). The results showed that S. carpocapsae was the most effective, causing mortality rates of 46.7% to 100% in adult German cockroaches and 20% to 66.7% in nymphs, while S. feltiae and H. bacteriophora exhibited lower efficacy. American cockroaches showed higher resistance, with S. carpocapsae achieving a maximum mortality of 33.3% at the highest concentration, whereas S. feltiae and H. bacteriophora had no significant lethal effect. These findings suggest that S. carpocapsae could be a promising biological control agent for B. germanica, particularly in pyrethroid-resistant populations. Full article

Background: Long-lasting insecticidal nets (LLINs) have significantly reduced the malaria burden in recent decades, and this malaria prevalence reduction has been achieved through the upgrading of pyrethroid long-lasting insecticidal nets. However, this reduction has stalled due to many factors, including rapidly developing pyrethroid resistance. Method: The protocol was registered in PROSPERO, and we used Cochrane methodology to assess bias and evidence quality. Three reviewers extracted data from individual studies, and a meta-analysis was performed using Excel and STATA version 17, expressing the data as a risk ratio. Result: A study involving 21,916 households from 11 randomized controlled trials showed that the chlorfenapyr treatment group had a 10% reduction in malaria infection risk, with a pooled overall prevalence of 25.96 per 100 children in the chlorfenapyr group and 32.38 per 100 children in the piperonyl butoxide group, compared to 41.60 per 100 children in the control (pyrethroid-only) group. This meta-analysis determined that the entomological outcomes of effectiveness and efficacy showed that these treatments effectively reduced vector density per household per night and mean inoculation rates, with a 23% reduction in chlorfenapyr, a 7% reduction in pyrethroid-only treatments, and a 12% reduction in piperonyl-butoxide-treated groups. This study shows that chlorfenapyr (CFP) and pyriproxyfen (PPF) LLINs are highly effective and more efficacious in reducing malaria infection, case incidence, and anemia among children, as well as in reducing mean indoor vector density, mean entomological inoculation rate, and sporozoite rate, compared to pyriproxyfen (PPF) LLINs in Africa. Conclusions: This study found that chlorfenapyr (CFP) LLINs are highly effective and more efficacious in reducing malaria infection, case incidence, and anemia among children in Africa. Therefore, policymakers and health planners should place strong emphasis on addressing the effectiveness, efficacy, and resistance management of LLINs as part of their current public health agenda to eliminate malaria. Full article

Microsporidia MB (MB), a promising biological control agent, suppresses Plasmodium falciparum transmission in Anopheles mosquitoes. This study examined the spatial distribution of MB infection in natural populations of An. gambiae s.l. mosquitoes collected in Nigeria and Niger Republic, and its association with insecticide susceptibility in the mosquitoes. Microsporidia MB has wide geographic distribution across Nigeria and Niger Republic. The overall prevalence of MB in F₀ mosquitoes was 12.25% (95% CI: 7.76–16.75%); 25 mosquitoes out of 204 were positive. Geographic variation was observed, with a higher prevalence (5/15 mosquitoes) in Ebonyi State (33.33%, CI: 9.48–57.19%, Fisher’s exact test, p = 0.008). Infection rates were higher in An. coluzzii mosquitoes (21/133 mosquitoes), estimated at 15.79% (CI: 9.59–21.99%) compared to An. gambiae s.s. mosquitoes (4/71), with approximately 5.63% (CI: 0.27–11.00%, χ² = 4.44; df = 1, p = 0.035). Resistant mosquitoes had a significantly higher prevalence of MB infection than susceptible mosquitos at 28.57% (CI: 16.74–40.40%) with an odds ratio of 3.33 (CI: 1.23–9.03, p = 0.017). These findings suggests that MB can be exploited as an alternative for vector control in Nigeria and Niger, but its possible association with pyrethroid resistance suggests that it should be taken into account as a potential confounder when designing insecticide resistance management strategies. Full article

Democratic Republic of the Congo (DRC) is among the countries that have a high malaria incidence. In an effort to combat this public health challenge, innovative tools and strategies are being developed and evaluated. Among the new generation of nets with improved effectiveness of insecticides, those treated with a combination of piperonyl butoxide (PBO) and pyrethroids appear to be a promising malaria control tool. This study evaluated the effectiveness of this combination under community conditions of use in the DRC. A quasi-experimental study was carried out from January to December 2018, in Kisantu Health Zone. Thirty villages were randomly allocated as clusters (1:1) to receive one of two types of long-lasting insecticidal nets (LLIN) treated with deltamethrin alone, or PBO with deltamethrin. After the intervention, the assessments were conducted monthly, quarterly, and every six months for malaria infection, mosquito density, and LLIN durability, respectively. Comparison of changes in different indices between the two groups was made using generalized linear models to correct for non-linear effects. A total of 1790 children were included. There was a significant non-linear effect of time (months) on the malaria infection incidence. The malaria infection incidence was higher in January–March, May–June, and November. It remained higher in the control group compared to the intervention group over time. Similarly, there was a significant non-linear effect of time on the density of both Anopheles funestus s.l. and Anopheles gambiae s.l. These densities decreased after the first month following the intervention and increased after 6 months. Twelve months later, a cohort follow-up showed that the bio-efficacy of LLINs was better in the intervention group. The nets treated with the combination of PBO and deltamethrin appear to be more effective for malaria control under community conditions in the DRC, but a loss of chemical durability is noted after the first year of use. Full article