Smoke toxicity effect of bio-fabricated mosquito coil for the sustainable management of mosquito vectors

Abstract

Mosquitoes are major disease-causing vectors. Control of adult mosquito vectors by synthetic chemical applications leads to chemical resistance and causes environmental pollution. Commercially available mosquito chemical-coils also provide health hazards like respiratory diseases probably to a larger extend than plant-based bio-coils. In our study laid smoke-exposed gravid females of C. quinquefasciatus a lower number of eggs, egg hatchability were also comparatively lower and the progeny production during the F1 generation was significantly lower. In the present study there was an 84.39% reduction of the population of bio-coil exposed mosquitoes compared to 90.13%, after the use of a chemical-coil. LC₅₀ of bio-coil extract ranged from 201.595 ppm to 374.395 ppm. LC₅₀ of achemical-coil extract ranged from 209.747 ppm to 296.307 ppm. Predation efficiency was lower in with chemical-coil treated aquatic environments than at bio-coil extract exposed breeding sites of C. quinquefasciatus. The predation efficiency against C. quinquefasciatus was 22.1% (I) with chemical-coil and 11.4% (II) with bio-coil in a natural setting, whereas it was 42.7% (I) and 22% (II) in the laboratory, respectively. Very low concentrations of bio-coil increased the predation on young mosquito instars where predators and prey co-exist. The feeding efficiency of Poecilia reticulata in the control environment was 62.3% and 53.9% for the 1st and 2nd instar larval population.There was an increase in fish predatory responses with bio-coil extract against mosquito 1st and 2nd larval instars and its predatory efficiency was 74.1% and 68.4%, respectively, whereas it was much lower with the chemical-coil with 56.5% and 46.9%, respectively. Marker antioxidant enzymes lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT) from the gill region of P. reticulata were not affected by bio-coil extract but increased substantially with chemical-coil. Bio-coil extract also inhibited the growth of several bacterial pathogens.