Analysis of side effects of diflubenzuron and tebufenozide in pollinating bumblebees bombus terrestris

Abstract EN

This research project examined the potential hazards of two important insecticides on survival, reproduction and larval growth of bumblebees Bombus terrestris.

We tested two insect growth regulators (IGRs), the chitin synthesis inhibitor diflubenzuron and the ecdysone agonist tebufenozide ; both important in the control of insect pests in greenhouses.

The two IGRs were applied via three different routes of exposure (contact via topical application, and orally via the drinking sugar water and via pollen) under laboratory conditions and tested at their respective maximum field recommended concentrations (MFRC).

In a second test, a dose-response assay was performed to calculate LC50 values.

Generally, the two IGRs did not show acute toxicity on worker bumblebees.

However, there was a dramatic reduction on brood production especially after diflubenzuron oral treatment with pollen and sugar water.

In contrast tebufenozide did not exert a significant effect on brood production.

Overall our laboratory results suggest that diflubenzuron should be applied with caution in combination with bumblebees, while tebufenozide is compatible with the pollinator.