Evaluation of certain insecticides on nettings for their efficacy and wash resistance against mosquito species.

Five insecticides (Bifenthrin, Deltamethrin, Etofenprox, Permethrin and Lamda cyhalothrin) recommended by WHO, at their recommended dose were compared for their efficacy and wash resistance through bioassay against mosquito vectors, Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi. Etofenprox treated nettings exhibited better knockdown and mortality than the other insecticides. The order of efficacy of the insecticides treated nettings was Etofenprox > or = Deltamethrin > Lambda cyhalothrin > Permethrin > Bifenthrin.

Larvicidal activity of neem and karanja oil cakes against mosquito vectors, Culex quinquefasciatus (say), Aedes aegypti (L.) and Anopheles stephensi (L.).

Larvicidal effect of neem (Azadirachta indica) and karanja (Pongamia glabra) oil cakes (individuals and combination) was studied against mosquito species. Both the oil cakes showed larvicidal activity against the mosquito species tested. The combination of neem and karanja oil cakes in equal proportion proved to have better effect than the individual treatments. The combination of the two oil cakes recorded an LC95 of 0.93, 0.54 and 0.77% against the mosquitoes, Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi respectively The increase in efficacy of the combination treatment over individuals in all the mosquito larvae tested was found to range about 4 to 10 fold in terms of LC50 and 2 to 6 fold in terms of LC95.

Comparative efficacy and persistency of permethrin in Olyset net and conventionally treated net against Aedes aegypti and Anopheles stephensi.

The efficacy of the Olyset net was compared to a net treated conventionally with permethrin 10% emulsifiable concentrate at the World Health Organization recommended dose. The nets were assessed under laboratory conditions against the mosquito vectors Aedes aegypti and Anopheles stephensi. Knockdown efficacy for the Olyset net was assessed after the first 10 washings and then after the 15th and 20th washings. Data were not collected for the conventionally treated netting after 5 washings because the conventional treatment was no longer effective. The results of the study indicate permethrin effectively persisted on Olyset net for at least 20 washings, confirming the regeneration of pesticide after each wash.

Rotational application of bioinsecticide with deltamethrin-An antilarval measure for the control of filarial vector, Culex quinquefasciatus (Culicidae: Diptera).

A laboratory investigation was undertaken to study the cyclic usage of field recommended doses of Bacillus thuringiensis israelensis (Bti), Bacillus sphaericus (Bsp) and combination of Bti and Bsp (half the recommended dose of each) with deltamethrin 2.8 EC to attain better control of mosquito larvae. To understand the susceptibility status of the Culex quinquefasciatus larvae in the field, early fourth instar field collected larvae were exposed to the above treatments of biopesticides and were monitored for their persistency till 50% mortality was obtained. The larvae those survived in each treatment were transferred to the concentration of deltamethrin that gave 50% mortality. Observations on larval mortality after the treatment with deltamethrin were recorded after 24 h. The results revealed that Bti excels Bsp, as it recorded 54% mortality only on 17th day after application. The other salient finding of this study is LC50 of deltamethrin is sufficient to follow the biopesticides application for an effective control of Culex larvae.