The residual contact toxicity to honey bees of insecticides sprayed on to white clover (trifolium repens l.) in the laboratory

摘要

Abstract A spray tower was adapted to enable insecticide sprays to be applied to the flowers of white clover (Trifolium repens L.) held in jars of water. Honey bees were enclosed with the flowers for an hour (3. 18. or 42 hours after application) to determine the residual contact toxicities of the sprays. Comparative tests on artificial flowers made of foil indicated that they cannot be used as a substitute for clover flowers. Direct contact toxicity tests appear of little value as guides to residual toxicity.