Field and laboratory tests of the effects of fipronil on adult female bees of Apis mellifera, Megachile rotundata and Nomia melanderi

摘要

The toxicity of fipronil to adult female bees was least to the alkali bee, Nomia melanderi, (LD50=1.130μg/bee), intermediate to the honey bee, Apis mellifera, (0.013μg/bee) and greatest to the alfalfa leafcutter bee, Megachile rotundata, (0.004μg/bee), both in topical tests and tests involving fipronil residues on alfalfa [lucerne] (Medicago sativa) foliage. Adding an adjuvant to fipronil sprays changed the toxicity of fipronil to bees in residue bioassay studies, with varying results with adjuvant and species of bee. Fipronil at 100 ppm and 500 ppm in feeders containing a sucrose/honey syrup caused a significant reduction in honey bee visitation. Spraying fipronil at 0.014 or 0.028 kg a.i./ha on flowering canola [rape] cv. Legend did not causesignificant mortality of adult honey bees or reduce bee visitation.