Larvicidal and smoke repellency effect of Toddalia asiatica and Aegle marmelos against the dengue vector, Aedes aegypti (Insecta: Diptera: Culicidae)

Investigations were made to evaluate the larvicidal activity and smoke repellent potential of Toddalia asiatica (L.) and Aegle marmelos at different concentrations (20, 40, 60, 80 and 100 p.p.m.) against first to fourth instar larvae and pupae of Aedes aegypti (L.). The LC₅₀ of A. marmelos and T. asiatica against first instars was 50.960 and 47.893 p.p.m., respectively; against second instars, 52.979 and 50.922; third instars, 56.653 and 54.461; and fourth instars, 60.778 and 61.278. The LC₅₀ and LC₉₀ for A. marmelos and T. asiatica against pupae were 56.634 and 112.992, and 53.64 and 116.22 p.p.m., respectively. The smoke toxicity of T. asiatica against Ae. aegypti was greater than that of A. marmelos . Smoke-exposed gravid females oviposited fewer eggs when compared to those that were not exposed to smoke. Smoke-exposed females hatched a lower percentage of eggs compared to unexposed females.     

Design,Synthesis, and Insecticidal Activities of Novel N-Pyridylpyrazole Amide Derivatives Containing a Maleimide

To discover ‘me-better’ insecticidal active molecules targeting ryanodine receptors (RyRs), a series of novel N-pyridylpyrazole amide derivatives containing a maleimide were designed and synthesized in accordance with the prior investigations of our group. Preliminary bioassay findings indicated some compounds containing a maleimide exhibited good larvicidal activities against lepidopteran pests at a concentration of 500 mg L⁻¹. Compound 9 j showed 60 % larvicidal activities against M. Separata at 50 mg L⁻¹. Compound 9 b exhibited 40 % larvicidal activities against P. xylostella at 50 mg L⁻¹. Molecular docking study indicated that H-bonds, π–π interaction and cation-π interaction made for the binding of compounds 9 b , 9 j with P. Xylostella RyR. These results indicated that compounds 9 b and 9 j could be developed as novel and promising insecticidal leads.