Impact of Spherix (Bacillus sphaericus B-101, serotype H5a, 5b) spraying on the control of mosquito breeding in rural areas of Farrukhabad District, Uttar Pradesh

Spray impact of Spherix (Bacillus sphaericus B-101, Serotype H5a, 5b) was assessed against larval and adult populations of mosquito species in rural areas of Farrukhabad district, Uttar Pradesh. High mortality (> 95%) was observed against anopheline and culicine larvae within 48 h of spray @ 1 g/sq m. But the biolarvicidal effect declined within a week which indicated nonrecycling capacity and weekly reapplications were required. The encouraging results obtained through weekly sprays were short-lived because of decline in efficacy in some perennial intradomestic Culex breedings after 15 rounds of spray. The two year intensive field trials, however, had no appreciable impact on adult densities of both malaria vector An. culicifacies and bancroftian filariasis vector Culex quinquefasciatus. Environmental disturbances and manmade problems also affected the efficacy of the biolarvicide.