Acute contact toxicity study on bees (Apis mellifera) of DI-31, a semi-synthetic brassinosteroid analogue

DI-31 is a semi-synthetic brassinosteroid analogue obtained in the Faculty of Chemistry of the Havana University. This product improves crops yield and quality, as well as enhances plants tolerance to water and salt stresses. The goal of the present work was the evaluation of the contact toxicity of DI-31 on bees. The substance assayed was topically applied in one dose of 100 μg per bee. Two hundred bees of the Apis mellifera species were used. The appearance of signs of toxicity and the mortality at 4, 24 and 48 hours after administration were scored (OECD, 1998). The results showed that bees treated did not present any sign of toxicity derived from the product assayed. Taking into account the results from this assay, it can be concluded that toxic effects of DI-31 on Apis mellifera are unlikely.