FIELD RESEARCH on the effect of pesticides on honey bees has been conducted in California since 1952. F. E. Todd of the Bee Research Branch, USDA, ARS cooperated in these field tests through 1968. Several methods have been used to collectively measure the effects of pesticide treatments on honey bees. Of these, colony strength, forager bee visitation in the field, caged bees in the field, bioassay of foliage residues in cages using honey bees, and dead bees at the colony are the most useful, according to previous tests.