Laboratory assessment of pesticide toxicity to bumblebees

The toxicity towards Bombus terrestris (L.) of the insecticides acephate, buprofezin, carbaryl, cartap hydrochloride, chlorpyrifos-methyl, cyfluthrin, cyromazine, dimethoate, heptenophos, imidacloprid, lamda-cyhalothrin, methomyl, phosalone, pirimicarb, quinalphos, rotenone, and teflubenzuron, of the acaricides fenazaquin, fenpyroximate, hexythiazox, propargite, and tebufenpyrad and of the insecticide-acaricides abamectin and amitraz was tested in the laboratory. Oral, topic contact, and indirect contact trials were carried out for each pesticide, employing formulated compounds dispersed in water at the highest field dose marked on the label. The pesticides that caused a mortality higher than the untreated controls were tested also at decreasing concentrations until the mortality was statistically insignificant in comparison with that of the control; also the acute oral and topic contact LD50, the indirect contact LC50 and the related hazard ratios were calculated for these pesticides.