Mosquito-borne diseases with an economic impact create loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates. Mosquito control is facing a threat because of the emergence of resistance to synthetic insecticides. Extracts from plants may be alternative sources of mosquito control agents because they constitute a rich source of bioactive compounds that are biodegradable into nontoxic products and potentially suitable for use to control mosquitoes. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, this study was undertaken to assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate, and methanol solvent extracts from the medicinal plant Delonix elata against the medically important mosquito vectors, Anopheles stephensi and Aedes aegypti (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in methanol extract of leaf of D. elata against the larvae of A. stephensi and A. aegypti with the LC(50) and LC(90) values being 93.59 and 111.83, and 163.69 and 202.77 ppm, respectively. Compared to leaf extracts, seeds have low potency against two mosquitoes with the LC(50) and LC(90) values being 115.28 and 139.04, and 225.07 and 273.03 ppm, respectively. The mean percent hatchability of the eggs was observed after 48 h post-treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the methanol extract showed the highest ovicidal activity. One hundred percent mortality was observed at 300 ppm for leaf methanol extract and 500 ppm for seed methanol extract of D. elata against A. stephensi and A. aegypti, respectively. These results suggest that the leaf and seed extracts have the potential to be used as an ideal ecofriendly approach for the control of mosquitoes. This is the first report on the mosquito larvicidal and ovicidal activities of the reported D. elata plant.

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Thirty isolates of Bacillus were collected from chickpea rhizosphere and screened for their in vitro inhibition against root rot (Rhizoctonia bataticola) and wilt (Fusarium oxysporum f.sp. ciceri) pathogens and growth promotion of chickpea. Based on the in vitro inhibition and growth promotion tests, the best eight isolates were selected and PCR-based detection of antibiotics genes viz., surfactin, iturin, fengycin and bacillomycin D was carried out. The isolate which produced all these antibiotics and showed maximum in vitro inhibition (CaB 5) was further used for crude antibiotics extraction and inhibition assays. The presence of antibiotics in crude extract was detected through TLC. The inhibitory effect of the crude extract was proved through agar-well diffusion assay and spore germination inhibition test. From this study, it was inferred that the Bacillus subtilis strain CaB5 was promising in inhibiting the root rot and wilt pathogens of chickpea and enhance seedling vigour.