Search Results (533)

Callosobruchus maculatus (Fabricius, 1775) is a major postharvest pest of stored legumes, causing significant quantitative and qualitative losses. This study evaluated host preference, biochemical determinants of susceptibility, and the insecticidal efficacy of plant powders and aqueous and ethanolic extracts against C. maculatus among selected pulse species. In free-choice assays, oviposition preference did not correspond with developmental success, as Phaseolus vulgaris Linnaeus, 1753, received the highest number of eggs but supported minimal adult emergence, whereas Vigna radiata (Linnaeus) A. Jussieu, 1954, exhibited the highest level of infestation and seed damage. Biochemical analysis revealed correlational patterns: higher carbohydrate and lipid contents were positively associated with infestation and seed weight loss, whereas fiber content showed a negative association with pest performance. Protein content was correlated with oviposition, while moisture and fiber were associated with reduced developmental success. Plant-derived treatments significantly affected all biological parameters of C. maculatus in a concentration- and time-dependent manner, with the exception of sex ratio. Among the tested botanicals, Azadirachta indica A. Jussieu (1830) consistently showed the highest toxicity, with the lowest LC₅₀ values across exposure periods. Ethanolic extracts showed greater insecticidal activity than aqueous extracts, indicating solvent-dependent extraction of bioactive compounds. Mortality increased progressively with exposure duration, accompanied by decreasing LC₅₀ values, suggesting cumulative toxic and developmental effects. Overall, the results demonstrate that host suitability is governed by the interaction between nutritional composition and structural seed traits, while botanical extracts, particularly those from A. indica, offer effective, eco-friendly alternatives for managing C. maculatus in stored legumes. Full article

Juvenile hormone (JH) analog insecticides are widely used in pest management because of their ability to disrupt insect growth and metamorphosis; however, the molecular mechanisms linking endocrine disruption to metabolic dysregulation remain incompletely understood. In addition to their established roles in diapause and developmental regulation, JH signaling pathways have also been implicated in carbohydrate and lipid metabolism. In the present study, we investigated the effects of two JH analogs, pyriproxyfen and hydroprene, on the migratory locust, Locusta migratoria, with particular emphasis on lipid metabolic regulation and the function of midgut-enriched fatty acid-binding protein gene (Mg-FABP). Bioassays were performed to evaluate insecticidal activity, and transcriptomic analyses were conducted to identify differentially expressed genes associated with endocrine signaling and lipid metabolism. Functional characterization of Mg-FABP was further performed using RNA interference (RNAi) and Oil Red O staining assays. In addition, the tertiary structure of LmMg-FABP was predicted using AlphaFold 3, and molecular docking analyses were carried out to investigate its interactions with fatty acid ligands. Both pyriproxyfen and hydroprene caused approximately 70% mortality in locust nymphs and induced significant transcriptional changes in pathways related to hormone signaling and lipid metabolism. Transcriptomic analysis revealed pronounced downregulation of Mg-FABP following JH analog exposure. RNAi-mediated silencing of Mg-FABP significantly reduced lipid droplet accumulation in the fat body, indicating that Mg-FABP plays an essential role in lipid transport and metabolic homeostasis in L. migratoria. Structural analyses further demonstrated that LmMg-FABP possesses a conserved tertiary structure highly similar to FABP homologs from other insect species. Molecular docking identified key amino acid residues involved in fatty acid binding and suggested that hydrophobic interactions are critical for ligand stabilization within the binding cavity. Collectively, our findings demonstrate that pyriproxyfen and hydroprene disrupt insect development not only through endocrine imbalance but also through perturbation of Mg-FABP-associated lipid metabolic pathways. This study provides new mechanistic insight into the coordinated interaction between hormonal signaling and lipid metabolism during JH analog exposure and identifies FABP-mediated lipid transport as a potential molecular target for the development of more selective insect growth regulators. Full article

Botanical insecticides have re-emerged as promising tools within Integrated Pest Management (IPM) due to their biodegradability, chemical diversity, and potential compatibility with resistance management strategies. Although frequently considered safer alternatives to synthetic pesticides, growing evidence indicates that these compounds may also affect non-target organisms, particularly bees. This review discusses the selectivity of botanical insecticides toward pollinators by integrating historical perspectives, mechanisms of action, ecotoxicological effects, and current limitations in risk assessment approaches. Botanical insecticides may induce both lethal and sublethal effects, including alterations in behavior, locomotion, feeding, development, reproduction, and physiology across different bee groups. We also demonstrate that most available studies remain concentrated on Apis mellifera, adult workers, and acute laboratory assays, while important pollinator groups and chronic exposure scenarios remain poorly explored. Furthermore, current regulatory protocols are still largely based on models developed for synthetic pesticides. Expanding ecotoxicological approaches is therefore essential to improve pollinator safety assessments and support more sustainable pest management strategies. Full article

Essential oils obtained from Siparuna plants, e.g., S. guianensis and S. gesnerioides, have potential for use as biorational insecticides. However, the activities of S. gesnerioides oils remain largely unexplored compared to S. guianensis oils. Using an integrative approach combining toxicological bioassays, geometric morphometrics, and in silico modeling, we assessed the adulticidal potential, selectivity, and the effects of early-life exposure to these oils on the larval susceptibility and adult wing morphometry of Aedes aegypti. Adulticidal assays revealed high toxicity, with S. guianensis (LC₅₀ = 15.0 nL/mL) being 15-fold more potent than S. gesnerioides (LC₅₀ = 233.0 nL/mL). Beyond acute lethality, early-life (i.e., eggs to L2 larvae) exposure to sublethal concentrations (S. guianensis = 7.4 nL/mL and S. gesnerioides = 118.0 nL/mL) was associated with wing morphometric disruptions and increased fluctuating asymmetry in Ae. aegypti adults, especially in those exposed to S. gesnerioides essential oil. Furthermore, early-life exposure to S. gesnerioides modulated L4 larvae susceptibility, which was associated with lower mortality in subsequent exposures. Selectivity assays demonstrated low acute oral toxicity in initial laboratory screenings with Apis mellifera, while molecular docking approaches predicted higher affinity of bicyclogermacrene and α-copaene for Ae. aegypti TRPV channels. Collectively, while S. gesnerioides oil was less acutely toxic, early-life sublethal exposures reduced fourth instar larvae (L4) susceptibility, which may have contributed to developmental instability and morphological alterations in adults. Our findings highlight the potential of Siparuna essential oils in mosquito management by impacting mosquito fitness beyond acute mortality. Full article

This study aimed to isolate, characterize, and evaluate bacterial consortia capable of degrading the diamide insecticide cyantraniliprole in aqueous systems and to assess their bioremediation potential under environmentally relevant conditions. Four bacterial consortia, each comprising six isolates, demonstrated significant growth in mineral media containing cyantraniliprole as the sole carbon source, and the isolates were identified using conventional microbiological techniques in combination with MALDI-TOF-MS analysis. The bacterial consortia were enriched from pesticide-contaminated environments and systematically evaluated using microbiological, physiological, and analytical approaches to determine their degradation potential and environmental adaptability. The degradation performance of the consortia was systematically assessed under varying environmental parameters, including temperature, pH, salinity, and incubation time, with optimal degradation observed at 30–35 °C, pH 7.0–8.0, 0.5–5.0% NaCl, and 11 days of incubation at 150 rpm using an initial cyantraniliprole concentration of 50 mg/L. Biodegradation efficiency was further evaluated using DCPIP reduction assays, alongside measurements of biofilm formation and biomass production, indicating enhanced metabolic activity and adaptive responses under pesticide-induced stress. The consortia also exhibited the capacity to degrade structurally related diamide pesticides, including flubendiamide, chlorantraniliprole, cyclaniliprole, and fluchlordiniliprole, suggesting broad-spectrum biodegradation potential. Their performance was further validated in a simulated water microcosm system designed to mimic environmentally relevant contamination scenarios. In simulated contaminated water (60 mg/L cyantraniliprole), bacterial inoculants standardized to 10⁷ CFU/mL achieved substantial degradation after 20 days of incubation at 30 °C, as confirmed by HPLC analysis, with the six-strain consortium (T4), comprising Bacillus subtilis subsp. subtilis AZFS3, Bacillus pumilus AZFS5, Bacillus mojavensis AZFS15, Bacillus paramycoides AZFS18, Pseudomonas aeruginosa KZFS4, and Alcaligenes aquatilis KZFS11, demonstrating the highest removal efficiency (98.27%) and reducing the pesticide concentration to 1.00 mg/L, followed by consortium T3 (96.72%), which consisted of Bacillus subtilis Ht1, Bacillus subtilis Ht2, Bacillus mojavensis Ht3, Pseudomonas aeruginosa Ht4, Pseudomonas aeruginosa Ht5, and Pseudomonas aeruginosa Ht6. Residue analysis and predictive bioinformatic assessment further supported the biodegradation capacity of the selected bacterial communities and suggested the formation of simpler transformation products. Overall, the investigated bacterial consortia exhibited high degradation efficiency and environmental adaptability, highlighting their potential as effective and eco-friendly agents for the bioremediation of cyantraniliprole-contaminated water systems. Full article

Although information on insecticide toxicity on pests abounds, this is limited on non-target organisms like ants in cocoa production systems. This study determined the toxicity of insecticides (containing acetamiprid 40 g L⁻¹ EW, acetamiprid 64 g L⁻¹ + emamectin benzoate 48 g L⁻¹ EC, acetamiprid 20 g L⁻¹ + lambda-cyhalothrin 15 g L⁻¹ SC, emamectin benzoate 5% WDG and pyrethrins 50 g L⁻¹ EW) used against cocoa pests on non-target predatory ants (Crematogaster africana, Oecophylla longinoda and Pheidole megacephala) under laboratory (using filter-paper method) and field conditions to identify less harmful products for use in the cropping system. Ant knockdown and mortality varied significantly among insecticides at their recommended rates, with emamectin benzoate being the least toxic and acetamiprid + lambda-cyhalothrin the most toxic. LC₉₅s varied significantly, with emamectin benzoate having the highest predator safety index, while pyrethrins had the lowest. Generally, selectivity towards O. longinoda was higher than that towards the other ants. In the field, emamectin benzoate had the least acute adverse effect on ant abundance. Ant population generally rebounded to pre-treatment levels at 1 month after the last insecticide application. The study indicates differential toxicity and identifies ant-compatible insecticide options contingent on the autochthonous ant composition. Full article

The growing demand for natural, safe, and sustainable bioactive compounds has sparked interest in indigenous essential oils (EOs) for their antimicrobial, antioxidant, and therapeutic properties. Their practical applications are often limited by poor solubility, volatility, and susceptibility to degradation when exposed to light, heat, and or oxygen. The literature lacks exploration of the indigenous EOs in nanoencapsulation studies. Using nanosystems and carriers, the oil can be delivered to targeted areas over a longer period. This is useful for various applications, including biopesticides, regenerative medicine, gene therapy, textiles, and antimicrobial coatings. Studies reveal that nanoencapsulated EOs exhibit higher insecticidal and antimicrobial activity than free oil. In this review, we observed that Lippia javanica is the most used EO in nanoencapsulation processes. This may be attributed to its broad spectrum of biological activities and its wide distribution in South Africa. This review examines the applications of selected nanoencapsulated indigenous EOs of the Eastern Cape province in medicine, food, and agriculture. The findings underscore the potential of nanoencapsulation to transform indigenous EOs into multifunctional agents that can support health, food security, and sustainable agricultural practices, while calling for further research on safety, regulatory frameworks, and commercialization pathways. Full article

Botanical insecticides represent a promising alternative to synthetic chemicals for controlling stored-grain pests. However, their use is limited by formulation-related challenges that affect grain quality. This study conducted a comparative evaluation of the insecticidal effectiveness of Artemisia herba-alba crude extract and a solidified matrix formulation (Tablet-like formulation), against Sitophilus oryzae. The formulation involved embedding the extract in a cellulose–starch base. The evaluation included insect mortality, repellency behavior, oxygen consumption, and selected biochemical parameters. Chemical profiles were analyzed using gas chromatography–mass spectrometry (GC–MS). The crude extract demonstrated strong insecticidal activity, achieving 100% mortality at 10,000 ppm after 72 h. In contrast, the tablet-like formulation showed reduced mortality (33%) under the same conditions. Similar trends were observed in repellency tests, with the crude extract showing higher immediate activity (100%) compared to the tablet formulation (67.44%). Both treatments significantly decreased oxygen consumption and levels of lipase, α-amylase, and neuropeptide F. Only the crude extract affected protease and monoamine oxidase activities. GC–MS analysis revealed that, despite variations in the number and relative abundances of compounds detected, both formulations shared several major constituents. In sum, the crude extract showed superior performance in several parameters, particularly in rapid activity, while both forms exhibited comparable effects in other responses. These findings indicate that the intended application should guide formulation selection, with the crude extract is more suitable for rapid pest control, while the tablet-like formulation may be better for long-term protection and preservation of grain quality during storage. Full article

The fall armyworm (Spodoptera frugiperda), a highly destructive invasive Lepidopteran pest, poses a serious threat to global agriculture, particularly maize production. Plant essential oils (EOs) represent a promising class of botanical pesticides owing to their diverse bioactivities and low environmental persistence. In this study, we evaluated the insecticidal and antifeedant activities of 40 commercially available EOs against third-instar S. frugiperda larvae. After an initial screening at 4 μL/mL, 10 EOs that caused ≥70% mortality at 72 h were selected for bioassays to estimate LC₅₀ value and chemical analysis by GC-MS. Contact toxicity assays showed that geranium EO had the highest activity (LC₅₀ = 2.105 μL/mL at 72 h), followed by cypress (2.123 μL/mL) and niaouli (2.391 μL/mL), whereas tea tree EO exhibited the lowest activity (3.592 μL/mL). Antifeedant tests revealed that clove EO caused the strongest feeding deterrence at both 24 h (antifeedant indices AFI = 72.8%) and 48 h (AFI = 63.4%), while most other EOs lost their deterrent effect within 48 h. GC-MS analysis of the 10 active EOs identified a complex mixture of monoterpenes, sesquiterpenes, and oxygenated derivatives; major constituents included D-limonene, 4-terpineol, carvacrol, caryophyllene, and longifolene. These results provide laboratory evidence that several plant EOs, particularly geranium, cypress, niaouli, and clove, possess strong insecticidal and antifeedant activities against S. frugiperda larvae, supporting their potential as eco-friendly botanical insecticides. Full article

Megalurothrips usitatus (Bagnall) is a major pest of cowpeas that severely affects their yield and quality. Spinetoram (a semi-synthetic derivative of natural spinosyns, modified to improve potency, residual activity, and stability) is currently one of the primary insecticides used for its control; however, prolonged or repeated exposure to this insecticide may lead to sublethal effects and the development of resistance. This study aimed to clarify the transgenerational effects of sublethal spinetoram stress on the development, reproduction, and population parameters of M. usitatus, with F₄ offspring reared on untreated pods to assess maternal effects. The LC₂₅ of spinetoram against M. usitatus was determined using an improved leaf-tube residual film method, and the thrips were successively selected for three generations (F₁–F₃) at this concentration. An age-stage, two-sex life table was constructed to systematically analyze the developmental duration, adult longevity, fecundity, and population life table parameters of the F₄ generation. The results showed that after three consecutive generations of LC₂₅ stress, the resistance ratio of M. usitatus to spinetoram reached 2.7. Compared with the water control, the F₄ generation from the treated group exhibited significantly shortened 1st and 2nd instar nymphal durations, as well as the total egg-to-adult period, while the prepupal duration was significantly prolonged. Adult longevity in females decreased from 23.65 ± 1.05 days to 16.07 ± 1.40 days (32.1% reduction), and male longevity decreased from 18.78 ± 0.96 days to 15.40 ± 0.82 days (18.0% reduction). Mean fecundity per female decreased from 247.15 ± 30.47 to 34.53 ± 6.02 eggs (86.0% decrease). Regarding population parameters, the net reproductive rate (R₀) decreased from 98.80 ± 0.07 to 10.36 ± 0.01 (89.5% decrease), the intrinsic rate of increase (r) decreased from 0.2506 ± 0.0001 to 0.1452 ± 0.0001 (40.0% decrease), the finite rate of increase (λ) decreased from 1.2849 ± 0.0001 to 1.1564 ± 0.0001 (10.1% decrease), and the mean generation time (T) was shortened from 18.24 ± 0.001 days to 15.84 ± 0.001 days (13.2% reduction). Age-stage-specific life expectancy (e_xj) was significantly reduced across all developmental stages, indicating a shorter survival time. The peak age stage-specific reproductive value (v_xj) was significantly lower and occurred earlier. The peak values of the age-specific survival rate (l_x) and fecundity (f_x, m_x) curves were significantly lower in the treated group. These findings indicate that multigenerational sublethal exposure to spinetoram can induce low-level resistance in M. usitatus and suppress the population growth potential by shortening developmental duration, reducing life expectancy, and reproductive contribution, and significantly inhibiting fecundity and survival. These results reveal the transgenerational sublethal effects of spinetoram and provide a theoretical basis for the integrated pest management (IPM) and resistance control of M. usitatus. Full article

The Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) is an important pathogen of the fall armyworm and is used as the basis for biological insecticides. In this study, we examined the relationship between the size–frequency distribution of SfMNPV occlusion bodies (OBs) and their insecticidal characteristics when collected at the end of the replication cycle. Exposure of OBs to 40%, 70%, and 90% (wt/wt) glycerol had no effect on OB pathogenicity. Glycerol density gradient (50–100%) centrifugation was used to separate OBs into two fractions. OBs recovered from the upper fraction of the gradient had a significantly smaller median cross-sectional area than those harvested from the lower fraction. These fractions also differed significantly in their size–frequency distributions. The OB concentration–mortality response of S. frugiperda second instars did not differ significantly between the two fractions or with non-centrifuged OBs. The median survival time was similar for insects inoculated with OBs from the upper and lower fractions but was significantly shorter in insects inoculated with non-centrifuged OBs. The proportion of mature OBs (67–71%) and the number of viral genome copies (1.33–1.40 × 10⁸ copies/µL) did not differ significantly between the upper and lower OB fractions. These findings suggest that altering the size–frequency distribution by density gradient centrifugation is not a useful technique for selecting large OBs with high insecticidal activity as part of the baculovirus insecticide production process. Future studies should evaluate a range of OB size separation techniques to determine their effects on OB insecticidal characteristics. Full article

Control of resistant mosquito populations may be approached by the development of novel synergists to improve the performance of already commercialized compounds. Extracts of black pepper (Piper nigrum), Cha Plu (Piper sarmentosum), and Sichuan pepper (Zanthoxylum spp.) synergized natural pyrethrins applied topically to Aedes aegypti females. Both black pepper and Sichuan pepper extracts synergized natural pyrethrins over 13-fold. Synergism was also observed directly on the mosquito larval central nervous system (CNS), suggesting this effect is an important contributing factor distinct from that of reduced metabolism. Piperine, from black pepper, and α-hydroxysanshool (α-HS) from Sichuan pepper, synergized natural pyrethrins on susceptible CNS, but only piperine was capable of synergizing natural pyrethrins on the CNS of a pyrethroid-resistant strain of Ae. aegypti, indicating that these molecules may possess slightly different mechanisms of action or binding sensitivities. These results demonstrate that pepper alkamides are capable of enhancing select insecticidal chemistries via target-site synergism, a novel mechanism of synergism that might be important for enhancing future insecticidal formulations. Full article

The tomato borer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a highly destructive invasive pest of tomato, and its ability to develop resistance to insecticides is well known. The susceptibility of three field populations from Egypt (Luxor, Assuit, and Giza) to the insecticides chlorantraniliprole, chlorfenapyr, indoxacarb, emamectin benzoate, and spinetoram was evaluated by leaf-dip bioassays. The second-instar larvae were exposed, and mortality was noted 24, 48, and 72 h later. Probit analysis was used to calculate lethal concentrations (LC₅₀ and LC₉₀) and resistance ratios (RR₅₀). Furthermore, key detoxification enzymes (α-esterases, cytochrome P450 monooxygenases, and glutathione S-transferases) were also measured to identify possible metabolic resistance mechanisms. Considerable inter-population differences were observed. Detoxification enzymes (α-esterases, cytochrome P450 monooxygenases, and glutathione S-transferases) were measured. The Luxor population showed the highest LC₅₀ values and resistance ratios, especially to chlorfenapyr and indoxacarb, suggesting low-to-moderate resistance, while the Giza population was the most susceptible. Emamectin benzoate and spinetoram provided excellent control of all laboratory and field strains. Full article

Understanding how sublethal insecticide exposure affects natural enemies is crucial for sustainable pest management, yet such effects remain largely unexplored in some scelionid parasitoids, including Telenomus busseolae Gahan (Hymenoptera: Scelionidae). This study evaluated the compatibility of widely used insecticides with different modes of action—imidacloprid, indoxacarb, teflubenzuron, and chlorantraniliprole—with the biological control of the Mediterranean corn borer, Sesamia nonagrioides (Lefèbvre) (Lepidoptera: Noctuidae), by the egg parasitoid T. busseolae, a key natural enemy. Risk quotients (RQ), calculated as the ratio of field concentrations to LC₅₀ (median lethal concentration) values, indicated low acute risk for all insecticides. Sublethal effects on adult parasitoids were assessed at LC₂₅ concentrations using the age–stage, two-sex life table approach revealing significant impacts on longevity, fecundity, oviposition duration, and population growth parameters, including intrinsic rate of increase (r) and finite rate of increase (λ), with the most pronounced effects observed under imidacloprid exposure. Host exploitation remained mostly unaffected except under imidacloprid, which reduced net parasitism rate (P₀), while the transformation rate (Q_p = P₀/R₀), representing the relationship between net parasitism (P₀) and net reproductive rate (R₀) at the population level, the stable parasitism rate (ψ), representing parasitism capacity under a stable age–stage structure, and the finite parasitism rate (ω), integrating parasitism capacity with population growth to describe overall parasitism potential, were unchanged. Population projections over 60 days (three generations) suggested the greatest decline under imidacloprid exposure. These findings demonstrate that even sublethal exposure can affect parasitoid fitness, host utilization, and population trajectories, emphasizing the importance of choosing insecticides that are selective for T. busseolae to maintain effective biological control. Full article

Alkaloids are structurally diverse, nitrogen-containing plant secondary metabolites with well-documented insecticidal activity. This review examines alkaloid-based insecticides, focusing on their chemical diversity, biosynthetic origins, plant distribution, and physicochemical properties relevant to pest control on farms. The principal molecular targets and modes of action are discussed, including interactions with nicotinic acetylcholine receptors, acetylcholinesterase, ryanodine receptors, and GABAergic signaling. Another focus is key metabolic enzymes, together with their activity spectra against major agricultural pests. Recent advances in rational structural modification, supported by crystallographic data, computational modeling, and structure–activity relationship studies, are highlighted as strategies to enhance the potency, selectivity, and stability of these compounds. Toxicological profiles, food residue behavior, analytical challenges, and regulatory considerations are critically assessed, emphasizing that natural origin does not equate to inherent safety. The review further evaluates the role of alkaloid-based insecticides within integrated pest management systems and identifies key research gaps related to environmental safety, non-target effects, and regulatory development and harmonization. It concludes that alkaloids are positioned as potentially valuable tools for sustainable agriculture when deployed within science-based regulatory frameworks and integrated control strategies. Full article