Effects of chemical and biological plant protection products on R&D colonies of the buff-tailed bumblebee Bombus terrestris : (2.5 Part 1)

Bumblebees (Bombus terrestris) are exposed daily to Plant Protection Products through their foraging and feeding activities. Through all possible means of contact with pesticides, consumption through sugarwater is the most severe. In the present study, lethal and sublethal effects of the consumption of sugarwater solutions with the pesticides Sivanto WG (flupyradifuron), Exalt SC (spinetoram) and Oikos EC (azadirachtin) were studied using a sequential dilution testing scheme of 1/1 and 1/10 of the maximum field recommended concentration (MFRC). For the weekly assessment, parameters such as the survival of the mother queen, of workers and drones, the formation of gynes, and the weight and volume of the colonies were recorded. Moreover, by the end of the colony’s life, the total number of formed workers/drones, the number of newborn gynes and queen brood were also recorded. The IOBC side-effect classes for laboratory trials were applied in order for the results to be categorized and conclusions made. Both tested concentrations of Sivanto WG (flupyradifuron) were slightly harmful for queen, worker and drone populations, Exalt SC (spinetoram) was harmful at 1/1 dilution but only slightly harmful at the 1/10 dilution, and both concentrations of Oikos EC (azadirachtin) were slightly harmful for workers and drones but toxic for queens at both dilutions