Residues on honey bees, hive products, and foliage following applications of the emulsifiable concentrate of ethyl parathion to blooming sunflowers

Two aerial applications of EC ethyl parathion onto blooming sunflower, Helianthus annuus L., in northern Texas caused a serious loss of adult honey bees, Apis mellifera L., in colonies adjacent to the sprayed field. The number of dead bees collected from the dead-bee traps was more than 50 times larger in exposed colonies than in comparable unexposed check colonies during the first 2 days following the insecticide applications. Parathion residues in dead bees the first day after each spray averaged 3.6 ppm and 1.5 ppm, respectively, but residue levels dropped rapidly. Only 0.1 ppm was found by the fifth day. Pollen collected from pollen traps contained up to 3.7 ppm of parathion, but averaged between 0.5 and 0.9 for 7 of the days that samples were taken.