Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 14, 2011
Publication Date: April 1, 2011
Citation: James, R.R. 2011. Potential of ozone as a fumigant to control pests in honey bee (Hymenoptera: Apidae) hives. Journal of Economic Entomology. 104(2)353-359. Interpretive Summary: Ozone is a powerful oxidant capable of killing insects and microorganisms, and eliminating odors, taste, and color. It has been used for sanitizing drinking water and waste water, and for increasing storage life for food crops such as potatoes and grapes. ARS scientists tested the potential of ozone for sanitizing used honey comb. Honey is removed from honey bee hives in the form of wax comb. After the honey is extracted, the wax comb is stored before being used again the following season. Typically, no one keeps track of which combs came from which honey bee colonies, and beekeepers may inadvertently spread honey bee diseases from one hive to another through used comb. A safe fumigant would be useful to decontaminate honey comb between uses. The experiments here were intended to determine the exposure levels required to kill a storage pest of comb (the greater wax moth), as well as select bee pathogens (chalkbrood and American foulbrood). Ozone was effective against wax moths. Very young larvae and adults required the lowest doses and shortest exposure periods, requiring only a few hours of exposure at 460 mg O3/m3, whereas, eggs required 48 h exposures (at 460-920 mg O3/m3). Chalkbrood and American foulbrood spores could also be killed with ozone. These pathogens required much higher concentrations (3200 and 8560 mg O3/m3, respectively) and longer exposure periods (3 d) than needed to control wax moths. More rigorous treatments conditions were required to completely kill American foulbrood spores. Ozone shows potential as a fumigant for bee nesting materials, but further research is needed to evaluate its acceptability and efficacy in the field. A reliable method for sanitizing honey bee nesting materials needed for the development of an effective bee health management system.
Technical Abstract: Ozone is a powerful oxidant that can be used as a sanitizer, capable of killing insects and germs, and eliminating odors, taste, and color. For these reasons, it could be useful as a fumigant to sanitize honey comb between uses. The ozone exposure levels required to kill an insect pest and spore forming bee pathogens were determined. Ozone was effective against wax moths (G. mellonella), even on naturally infested comb. Neonates and adults were killed after only a few hours of exposure at 460-920 mg O3/m3, whereas, eggs required 48 h exposure at these concentrations. Spores of the honey bee pathogens Ascosphaera apis (a fungus that causes chalkbrood) and Paenibacillus larvae (a bacterium that causes American foulbrood), can also be killed with ozone. These pathogens required much higher concentrations (3200 and 8560 mg O3/m3, respectively) and longer exposure periods (3 d) than needed to control the insects. P. larvae was effectively sterilized only when these conditions were combined with high temperature (50 °C) and humidity (>75%RH). Thus, ozone shows potential as a fumigant for bee nesting materials, but further research is needed to evaluate its acceptability and efficacy in the field. The need for a reliable method to decontaminate honey bee nesting materials as part of an overall bee health management system is discussed.