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Crude mature leaves extract of Day Jasmine, Cestrum diurnum (Solanaceae: Solanales), was investigated for larvicidal activities against Culex quinquefasciatus, the vector of human filariasis. All the graded concentrations (0.1%, 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, and 3% v/v) showed significant (P

The present study was carried out to investigate the biocontrol potentiality of active ingredient isolated from ethyl acetate extract of mature leaves of Solanum nigrum L. (Solanaceae) against the larval form of Culex quinquefasciatus Say. Mortality rate at a concentration of 25 mg/L of the active compound was highest (P < 0.05) amongst all tested concentrations. Result of log-probit analysis (at 95 % confidence level) revealed that LC50 and LC90 values are inversely proportional to exposure period of bioassay. A clear dose-dependent mortality was observed, as the rate of mortality (Y) was positively correlated with the concentrations of the compound (X); having regression coefficient value close to 1. The compound was found to be ecofriendly as it did not show any adverse effect to the studied nontarget organisms. Chemical characterization of the active ingredient was also carried out by infrared spectroscopic analysis (IR), mass analyses (GC-MS) and carbon-hydrogen-nitrogen-sulphur analyses (CHNS), that revealed the presence of a glucosinolate compound [1-thio-s-d-glucopyranose-1-[(R)-3-hydroxy-2-ethyl-N-hydroxysulfonyloxy propanimidate] having the molecular formula of C11H21NO10S2.

The present study was carried out to establish the larvicidal properties of crude extracts of three plants, viz. Carica papaya, Murraya paniculata and Cleistanthus collinus against Culex quinquefasciatus as target species. The relative efficacy of the plant extracts in vector control was as follows: C. papaya seed extract > M. paniculata fruit extract > M. paniculata leaf extract > C. collinus leaf extract. Result of log-probit analysis (at 95% confidence level) revealed that LC(50) and LC(95) values gradually decreased with the exposure periods similar to the result in bioassay experiment for each of the plant extract. The results of preliminary qualitative phytochemical analysis of all the plants revealed the presence of many bioactive principles such as steroids, alkaloids, terpenes, saponins, etc. that may be responsible for their biocontrol potentiality. The appropriate lethal concentrations at 24 h for each of the extracts were also studied on non-target organisms such as Diplonychus annulatum and Chironomus circumdatus, and no change in the swimming behaviour and survivality was noticed, which indicates that all the extracts are safe for the aquatic ecosystem.