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Mosquitoes are the most common disease vectors for several prevalent diseases, such as Dengue, Zika, Malaria, Encephalitis, Chikungunya, and yellow fever. Since the last few years, the world has recorded an unprecedented rise in Aedes-borne dengue incidences. Frequent use of chemicals has resulted in hazardous effects on the environment, non-targets and humans, necessitating the need to develop a safer and more efficient control strategy using plant-based products. The present study investigated the effects of Cassia occidentalis on various biological parameters of the Aedes aegypti larvae. The hexane extracts obtained from the leaf and stem of the plant were utilized to treat the larvae for 24 hours. The LC50 values for the leaf and stem extracts of C. occidentalis were determined as 0.103 mg/mL and 0.088 mg/mL, respectively. The corresponding lethal values of leaf and stem extracts obtained against pupae were 0.111 and 0.138 mg/mL. The extracts also imparted latent toxic effects and reduced the % adults developed from the survived larvae in the 60.00-61.67% range at the median lethal dose. The extract-treated larvae were restless and showed abnormal behaviour, like aggressive movements and self-biting of anal papillae. The inner membrane cuticle of anal papillae was shrunken and the gut region was damaged and disintegrated. The adults who emerged from the larvae, treated with 1.0 mg/mL of C. occidentalis hexane stem and leaf extracts, showed 1.8-fold and 2.29-fold decreased oviposition, respectively. Further study with identified bioactive constituents in the extracts can help to formulate green insecticides for Ae. aegypti management.

Helicoverpa armigera, a global polyphagous pest, attacks a wide variety of crops causing huge agricultural loss. Overuse of conventional insecticides for Helicoverpa control has made Helicoverpa resistant to insecticides leading to more severe attacks on crops diverting interest of researchers to explore alternate control agents. Present study investigates the cidal and antifeedant potential of Emamectin benzoate; a semi-synthetic avermectin derived from the soil actinomycetes, Streptomyces avermitilis; against early IV instars of H. armigera. Larvae were fed on the castor leaf discs (3.5 cm diameter) dipped in different concentrations of Emamectin benzoate; ranging from 0.05 µg/mL-1.5 µg/mL. The leaf disc areas were measured pre-and post-larval feeding to estimate the antifeedant potential of compound. The effect of feeding was also assessed on the survival of larvae by scoring the larval mortality till 96 h. Our investigations showed significant larvicidal potential of Emamectin benzoate against H. armigera revealing respective LC50 values of 0.26 µg/mL, 0.095 µg/mL, 0.043 µg/mL and 0.027 µg/mL after 24, 48, 72 and 96 h feeding. Furthermore, a remarkable decrease of 93.59% was observed in larval feeding potential indicating significant antifeedant efficacy of Emamectin benzoate. A strong correlation between antifeedant index and the Emamectin benzoate concentration resulted in 1.48-fold index reduction with a decrease in concentration. Our results demonstrated efficacy of Emamectin benzoate as an effectual larvicidal and antifeedant agent against H. armigera. Employing selective insecticide can tackle issues of pest resistance and pest resurgence after ascertaining in the fields as Helicoverpa control agent and negating impact on non-target organisms.&nbsp