VIII SIMPOSIO INTERNAZIONALE ICPBR

HAZARDS OF PESTICIDES TO BEES

Bologna, 4-6 Settembre 2002

Controllo dei parassiti delle api

The effect of antagonistic micro-organisms on the brood of honeybees (Apis mellifera L.) and bumblebees (Bombus terrestris L.)

Jozef J.M. van der Steen (1) and Aleid J. Dik (2).

(1) Applied Plant Research, Bee Research Unit, Ambrosiusweg 1, 5081 NV Hilvarenbeek, The Netherlands. E-mail: J.J.M.van.der.Steen@ppo.dlo
(2)Applied Plant Research, Applied Research Unit Glasshouse and Horticulture, P.O. Box 8, 2670 AA Naaldwijk, The Netherlands

Several plant pathogenic fungi enter the plant trough open flowers. Spores of antagonistic micro-organisms present on the flowers can successfully compete with the possible pathogens. Honeybees and bumblebees can be used for transporting these antagonistic micro-organisms from the hive into flowers in order to prevent infections of the flowers. It is unavoidable that this antagonistic material also enters the brood nest of the bees. Since a healthy brood nest is an essential stimulant for the foraging activities of the bees and knowing that fungi and yeast may be able to cause infections of the brood, the effect of two antagonistic micro-organisms is tested on the honey bee and bumble bee brood.

Eggs and larvae were contaminated and during the larval and pupal phase, samples were taken and checked for the presence these antagonistic micro-organisms.

The antagonistic micro-organisms were not found in the samples and no significant changes in the broodnest were observed. These results show that antagonistic micro-organisms that were used do not develop in the brood nest of honeybees and bumblebees and that these antagonistic micro-organisms can safely be spread by honey bees and bumble bees to flowers to prevent infections.