This test guideline is a laboratory test method, designed to assess the acute contact toxicity of pesticides and other chemicals to adult worker bumblebees. Adult worker bumblebees are exposed to the test chemical dissolved in an appropriate carrier, by direct application to the dorsal thorax (droplet). The test duration is at least 48 h. Mortality is recorded daily and compared with control values. Results are analysed in order to calculate the LD50 and NOED, if possible, at 24 h & 48 h and furthermore at 72 h & 96 h in case the study is prolonged.