Safety of Four Entomopathogens for Caged Adult Honey Bees (Hymenoptera: Apidae)

Abstract

Four entomopathogens were tested to determine their safety to caged adult honey bees, Apis mellifera L. The bacterium Bacillus sphaerlcus Neide and the fungus Entomophaga maimaiga Humber, Shimazu and Soper did not affect bee longevity and did not cause disease among treated bees. Both of these microorganisms are considered safe for honey bees. A technical powder and a formulated product of the bacterium Bacillus thurlngiensis var. tenebrionis Krieg, Huger, Langenbruch and Schnetter reduced bee longevity at the higher concentration tested 108 spores/ml sucrose syrup), but did not cause disease. This bacterium will probably not cause undesirable effects on honey bee colonies under field application conditions. The fungus Beauveria bassiana (Balsamo) reduced bee longevity at the two highest concentrations tested and caused mycosis among treated bees at all three concentrations tested (approximately 106 – 108 spores per bee). Although the concentrations tested were artificially high, further tests of the safety of this fungus for nontarget invertebrates may be warranted.