Effects of drift sprays of endosulfan, applied for Tsetse fly control, on honeybees (Apis mellifera L.) in Somalia

Activity at the hive entrance, hive occupancy and worker survival were monitored in two spraying operations involving 10 spray cycles and application rates of 10-41 g active ingredient ha^-1. Applications of 15-41 g ha^-1 caused hyperactivity and some colonies probably deserted their hives. Sprays of 10-24 g ha^-1 had no immediate effect on survival, but mortality increased after sprays of 28-41 g ha^-1. Foraging by workers before sunrise, when spraying ended, and the greater toxicity of endosulfan at high temperatures, may have increased the hazard of endosulfan drift sprays to honeybees in Somalia.