Safety and Acquisition Potential of Metarhizium anisopliae in Entomovectoring With Bumble Bees, Bombus terrestris

ABSTRACT In the context of integrated pest management with biological control and reduced pesticide use, dissemination of entomopathogenic fungi with insects has the potency to protect crops and specifically their flowers against pests and diseases. But before implementation of such entomovectoring system, a measurement of risks of the microbial biocontrol agent toward the vectoring insect is crucial. The essential contributions of this project are that 1) exposure of bumble bees, Bombus terrestris (L.) to powder containing 107 spores of the commercial biocontrol agent Metarhizium anisopliae strain F52 (Bio1020) per gram, was safe; and 2) that when bumble bees had walked through this spore concentration (107 spores per gram) in a dispenser, their body carried 9.3 ±1 × 106 spores/bumble bee, and this was still 2.6 106 spores after a flight of 60 s, representing the average time to fly from the dispenser to the crop flowers. 3) In contrast, a 100-fold higher spore concentration (109 spores per gram powder) ...