Toxicity of Pesticides to Honey Bees in Laboratory and Field Tests in Southern California, 1955-19561

Abstract

In laboratory tests 33 compounds were compared for relative toxicity to honey bees. Ten of these materials (mostly phosphates) were found to be more toxic than the DDT standard treatment, four were about as toxic as DDT, and all the rest (mostly phosphates) were practically nontoxic to honey bees. Sabadilla at dosages comparable to those used in citrus groves was nontoxic to bees, while dosages comparable to those used on vegetable crops were highly toxic. Studies of DDT, toxaphene, and sulfur, alone and in various combinations, showed that DDT was moderately toxic to bees, and that sulfur and toxaphene were only slightly toxic. No synergistic effects were noted in the combinations. In field tests parathion was found to be highly toxic to honey bees, and its use is not recommended on alfalfa in bloom. Although malathion is moderately toxic to bees, it appears to be less toxic than parathion, and with proper timing of applications it has been used on blooming alfalfa without serious loss of bees. In these tests Trithion and Dipterex had no serious effects on honey bees in blooming alfalfa fields.