The honey bee brood test under semi-field conditions for the assessment of positive reference chemicals in Korea

Abstract

Honey bee brood tests under semi-field conditions are higher-tier studies for investigating the potential impact of pesticides on brood development in honey bee colonies. Semi-field studies on the effects of pesticides on honey bees have been mainly carried out in the EU and USA, with only a relatively small number conducted in Korea and other Asian countries. Here, we report the first semi-field test in Korea, which was carried out from April to May 2016. The experiment included three treatment groups (control and two toxic reference chemicals), each with three replicate tunnels. The honey bee colonies were placed in tunnels covering 70 m2 and containing Brassica napus. Flight activity, mortality, the condition of the colonies, and brood development were assessed during the 28 days of testing period. The toxic reference treatments were 400 g dimethoate a.i./ha and 600 g diflubenzuron a.i./ha. Brood termination rates for marked eggs were 31.3% in the control group, 83.5 and 68.0% for dimethoate and diflubenzuron, respectively. These results confirm the sensitivity of the test method and indicate that these two chemicals could be used as appropriate toxic reference compounds in future semi-field tests in Korea.