Bioactivity and Molecular Responses of Bitter Gourd Leaf Extracts Against the Invasive Leafminer, Liriomyza trifolii (Diptera: Agromyzidae)

Unveiling the toxicological and biochemical evaluation of selected botanical extracts against adult Aphis gossypii (Aphididae: Hemiptera)

The present study evaluated the toxicity and biochemical effects of selected botanical extracts against the adult stage of Aphis gossypii. Two fixed oils, namely Croton tiglium seed oil and Simmondsia chinensis seed oil, in addition to ethanolic extracts of Urtica dioica and Hyoscyamus muticus, were assessed for their insecticidal activity under laboratory conditions. Toxicity was determined based on LC50 values after 48 h of exposure. The results revealed that C. tiglium seed oil exhibited the highest toxicity against adult aphids, with an LC50 value of 1224.03 ppm, followed by U. dioica extract (1239.0 ppm), H. muticus extract (2297.24 ppm), and S. chinensis oil (3602.58 ppm). Sub-lethal effects of the tested botanical materials at LC50 concentrations were further investigated through biochemical analyses of total soluble proteins, total carbohydrates, and total lipids. Exposure to C. tiglium oil caused the greatest reduction in total protein and carbohydrate contents by 42.44% and 40.00%, respectively, whereas U. dioica extract reduced protein and carbohydrate levels by 36.95% and 26.66%, respectively, compared with the untreated control. In contrast, total lipid content significantly increased following treatment, reaching 47.61% and 33.33% above the control after exposure to C. tiglium oil and U. dioica extract, respectively. These findings demonstrate that the tested botanical extracts induce both toxic and metabolic disturbances in A. gossypii adults, suggesting their potential as eco-friendly alternatives for aphid management within integrated pest management programs.

Valorization of Ficus carica Pruning Residues as Selective Botanical Insecticides: Optimized Furanocoumarin Extraction, Efficacy Against Neotropical Stink Bugs, and Mechanistic Insights via Molecular Docking

ABSTRACT The Neotropical stink bugs Euschistus heros and Diceraeus melacanthus are major pests of soybean and maize in South America, yet current chemical control strategies face widespread resistance, highlighting the urgent need for sustainable alternatives. This study investigates Ficus carica pruning residues as a source of selective botanical insecticides, integrating optimized extraction, phytochemical profiling, bioassays, and molecular modeling. Eight extracts were prepared under varying solvent, temperature, and acidity conditions, and analyzed for total phenolic content (TPC) and the key furanocoumarins psoralen and bergapten. Acidification enhanced overall mass yields, while mild ethanol extraction at room temperature selectively maximized furanocoumarin recovery, yielding psoralen concentrations up to 14.83 mg g−1, which is substantially higher than previously reported in leaves or fruit. Biological evaluation of the optimized ethanolic extract (ERA) revealed strong insecticidal activity, with 86% mortality of E. heros and 40% of D. melacanthus nymphs at 48 h, and a calculated LC50 of 1232 mg L−1 for E. heros. The differential susceptibility between species suggests both metabolic and cuticular factors influence efficacy. Computational docking and phylogenetic analyses suggested a potential mechanistic basis for the observed selectivity: furanocoumarins are predicted to bind hemipteran AChE via a compensatory polar scaffold, whereas binding to Apis mellifera AChE is predicted to be weaker due to lineage‐specific differences in aromatic density within the catalytic gorge, potentially explaining the minimal off‐target susceptibility. The molecular modeling results characterize these compounds as low‐affinity, reversible inhibitors, combining effective pest control with a favorable safety profile for pollinators. The present work demonstrates that valorizing agro‐industrial waste from F. carica can yield potent, selective, and environmentally safer insecticidal agents. The integration of extraction optimization, biological evaluation, and molecular modeling provides a robust framework for developing sustainable botanical insecticides, advancing circular economy principles in pest management and offering promising alternatives to synthetic neurotoxins.

Insecticidal activity, chemical characterization, and biochemical responses induced by selected essential oils against Tuta absoluta (Lepidoptera: Gelechiidae)

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major pest causing severe damage to tomato crops worldwide. The present study evaluated the insecticidal efficacy of Cymbopogon nardus (citronella) and Pelargonium graveolens (geranium) essential oils against T. absoluta larvae and their impact on selected biochemical and oxidative stress parameters under laboratory conditions. GC-MS analysis identified citral and related monoterpenes as the major components of citronella oil, while geranium oil was rich in citronellol. Toxicity assays demonstrated dose-dependent larval mortality for both oils, with citronella oil exhibiting slightly higher potency (LC50 = 3.12%; LC90 = 6.37%) than geranium oil (LC50 = 3.88%; LC90 = 7.65%). Biochemical analyses revealed significant reductions in GABA-transaminase activity, total protein, and total lipid contents in treated larvae, indicating disruption of neurotransmission, metabolism, and energy reserves. Furthermore, oxidative stress markers showed decreased total antioxidant capacity and superoxide dismutase activity, together with increased lipid peroxidation, indicating the induction of oxidative stress in treated larvae. These findings demonstrate that both essential oils possess significant insecticidal activity and induce marked biochemical and oxidative stress responses in T. absoluta larvae. Therefore, citronella and geranium essential oils may represent promising eco-friendly botanical insecticides for incorporation into integrated pest management programs for tomato crops.

Matrine-Tea Saponin Synergism Involves Suppressed Detoxification and Digestion in a Leaf Beetle.

Botanical pesticide mixtures offer a sustainable strategy to enhance insecticidal activity and mitigate resistance. The leaf beetle Plagiodera versicolora, a destructive defoliator in forests and urban ecosystems, poses a growing management challenge. This study investigates the individual toxicity, synergistic effects, and underlying molecular mechanisms of two representative botanical agents, matrine and tea saponin, against P. versicolora. Bioassays revealed strong individual toxicity, with 6-day LC50 values of 1.948 µg/L for matrine and 5.589 mg/L for tea saponin. Notably, their binary mixture exhibited synergism (AI = 0.27), reducing the lethal concentrations required compared to individual treatments. Transcriptomic analysis revealed that this synergy was associated with coordinated suppression of key metabolic processes. Genes downregulated under combined exposure were enriched in detoxification-related genes (GSTs and CYP450s) and genes encoding digestive enzymes, including trypsins, chitinases, and lipases, suggesting impaired detoxification and digestive capacity. RNA interference further showed that silencing the trypsin-encoding gene Pver105950 or the chitinase-encoding gene Pver001190 significantly increased susceptibility to tea saponin or matrine, respectively, with Pver001190 knockdown producing survival comparable to that under the combined treatment. In conclusion, the synergistic toxicity of matrine and tea saponin is associated with impaired larval digestion and putative gut barrier dysfunction, together with transcriptional suppression of detoxification pathways in P. versicolora. The identification of Pver105950 and Pver001190 as critical molecular targets provides a theoretical foundation for developing high-efficiency botanical formulations for the environmentally friendly control of this pest.

Entomology Insecticidal, repellent and histopathological effects of selected botanical extracts on the rice leaf folder ( Cnaphalocrocis medinalis )

Insecticidal, repellent, and histopathological effects of selected botanical extracts on the rice leaf folder (Cnaphalocrocis medinalis)

The rice leaf folder (Cnaphalocrocis medinalis) is a key pest in Asian rice fields that causes significant yield loss. This study evaluated the insecticidal potential of 10 methanolic botanical extracts from Azadirachta indica, Calotropis sp., Ricinus communis, Justicia adhatoda, Aristolochia bracteolate, Cassia auriculata, Acorus calamus, Nicotiana tabacum, Pongamia pinnata, and Lawsonia inermis. The extracts were tested at concentrations of 1 %, 3 %, 5 %, 10 %, 15 % under laboratory conditions. Larval mortality was recorded at 24, 48, and 72 h and repellency was assessed using the filter paper disc method. Histopathological changes were examined in thoracic muscles, gastrointestinal tracts, and Malpighian tubules. The overall findings demonstrated that A. indica and J. adhatoda consistently caused the most larval mortality across all concentrations and time intervals, with one-way ANOVA indicating highly significant effects at 24, 48, and 72 h (p < 0.001). Probit analysis established lethal concentration values with an LC50 value of 28.5 ppm for A. indica, which is consistent with the previously reported efficacy of neem-based botanicals against rice leaf folder larvae. A. indica and P. pinnata showed 100 % repellent activity while C. auriculata and L. inermis were the least effective (<30%). A. indica extracts caused intense histopathological effects resulting in significant tissue alterations with an H-score ranging from 255 to 285 while a lower H-score was recorded for the control. Overall, the selected botanical extracts caused significant larval mortality and pronounced histopathological alterations in C. medinalis larvae.