PLANT EXTRACTS ALONG WITH SELECTIVE CHEMICALS AND Bacillus thuringiensis israelensis: A NOVEL APPROACH TO TACKLE THE PROBLEM OF INSECTICIDAL RESISTANCE IN MOSQUITOES

Abstract

Mosquitoes act as vectors for many life-threatening diseases such as malaria, dengue fever, West Nile virus, zika virus etc. Continuous use of pesticides caused insecticidal resistance in mosquitoes along with many other detrimental effects on the environment. Therefore, this study was designed to manage the mosquito population under laboratory conditions with synthetic insecticides, plant extracts, and Bacillus thuringiensis israelensis(Bti). Mosquito larvae (Aedesaegypti) were collected, identified and reared in cages for bioassay. Along with synthetic chemicals and Bti, fifteen plants were selected for this study and their extracts were obtained through ether as a solvent. Two concentrations (0.001 and 10%) of each treatment were applied against 2ndand 3rdinstar larvae for screening trails. Data were collected to check knockdown effect after 4 and 64 h and analysed through two-level factorial design. Datura (Datura wrightii)leaf, kortumma (Citrullus colocynthis), chirata (Swertiachirayaita), Bti, deltamethrin and mortein liquid was screened out as significant factors. After screening experiments, significant factors were tested in combination with five concentrations (0.001, 0.01, 0.1, 1.0 and 10%) of each treatment totest their efficacy after 2, 4, 8, 16, 32, 64 and 128 h. In the mixing trials, the highest mortality was observed with those solution having kortumma, insecticides and Bti whereas the least value of LC50(45.2%) with 100% mortality was found in combination of Kortumma, Datura leaf, Bti, deltamethrin and mortein liquid. Plant extracts along with chemicals and Bti can be considered as an alternative strategy for the control of mosquitoes.