Effects of biocontrol agent Gliocladium catenulatum on the behaviour of honeybee, Apis mellifera

BICOPOLL is a European study on protecting organic strawberries from the most important disease, the grey mould (Botrytis cinerea), using biological control. Honeybees are used to deliver biological fungicide Prestop® Mix (PM) containing biological control agent fungi Gliocladium catenulatum to the flowers to provide control of diseases. Bees gathered PM in a dispenser exit placed at the hive entrance and delivered it to the flowers. The effect of PM on the behaviour of the honeybee was studied. The behaviour of foragers in dispenser was observed by two video cameras. PM reduced the number of direct crossings of the dispenser and bees were trying to avoid it. Changes were the most obvious in the first hour, and then subsided. In homing ability experiment the treated and untreated bees were released from a distance of 40 m from the hive. Results showed prolonged flights in bees that were exposed to PM but did not affect returning rate until evening. The effect of exposure to PM on learning and memory was tested using olfactory conditioning of proboscis extension reflex (PER). Bees were conditioned to the olfactory stimulus once and tested for PER response by presenting odour alone 1 or 12 min after conditioning. Before learning experiment responsiveness to ascending sucrose solution was tested to see whether bees differ in sucrose responsiveness which affects learning abilities. The results did not confirm any effect. We suggest some improvements of the dispenser to decrease affects of PM on behavior of honeybees.