Vol. 10, Issue 10 (2021)

Author(s):
M Gokulakrishnan, C Gailce Leo Justin and S Sheeba Joyce Roseleen

Abstract:
Honey bees are essential for pollinating wide variety of plants and biodiversity conservation. In this study, we examined the toxicity of pesticides to Apis cerana indica by three tier assessment system (laboratory, confinement, field studies). Topical and oral bioassay method revealed similar mortality percentage for all pesticides. Average honey bee mortality was reported to be substantially higher in topical and oral bioassays than in indirect filter paper bioassay. Insecticides viz., profenofos, thiodicarb, imidacloprid, fipronil, emamectin benzoate causing 100 per cent mortality in all the methods at 48 HAT. Chlorantraniliprole was found moderately toxic and acetamiprid was found least toxic to bees. In fungicide treatments, none of the fungicides caused 100 per cent mortality to bees in all the experiment. Azoxystrobin and copper oxy chloride were found least toxic to bees. Difenoconazole, hexaconazole, tebuconazole, probiconazole were found slight to moderately toxic to bees. Carbendazim+mancozeb was found toxic to bees. In terms of biorationals, except 3G extract all are safe to bees. Particularly NPV and NSKE caused least mortality in all experiment. There is no significant difference between the confinement and laboratory studies experiment results both were having similar values. In field studies NPV treated plot having maximum number of bee count in all the days followed by NSKE, azoxystrobin, copper oxy chloride, acetamiprid. Upto 3DAS chlorantarniliprole treated plots had minimum bee visitation. Hence, all biorationals can use in the field without any restriction. The results of the field studies support the use of acetamiprid against sucking pests in blooming plants.