Mortality of the House Fly (Diptera: Muscidae) after exposure to combinations of Beauveria bassiana (Hypocreales: Clavicipitaceae) with the polyol sweeteners Erythritol and Xylitol

Authors: BURGESS, EDWIN - NORTHERN ILLINOIS UNIVERSITY; JOHNSON, DANA; Geden, Christopher - Chris

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2018
Publication Date: 6/1/2018
Citation: Burgess, E.R., Johnson, D.M., Geden, C.J. 2018. Mortality of the House Fly (Diptera: Muscidae) after exposure to combinations of Beauveria bassiana (Hypocreales: Clavicipitaceae) with the polyol sweeteners Erythritol and Xylitol. Journal of Medical Entomology. 55(5):1237-1244.

Interpretive Summary: The common house fly, Musca domestica, is a ubiquitous pest around livestock and poultry farms. It is a nuisance pest of people who live near the farms and a known carrier of a myriad of human and animal diseases. Fly resistance to traditional insecticides is long-standing problem and has brought about a need for new methods of control. One such method is the use of biological control organisms such as the entomopathogenic fungus, Beauveria bassiana. This fungus is effective when mixed with sugar and placed in the field as an infective bait, but there is a troublesome catch. Because the fungus takes several days to kill the fly, and because flies in the field often have a hard time finding high-quality food, there is a concern that sugar-baited B. bassiana could have the unintended effect of giving the flies a “free meal” that makes them live longer. In this study, researchers at Northern Illinois University and USDA’s Center for Medical, Agricultural, and Veterinary Entomology (Gainesville, FL) looked at using artificial sweeteners instead of “real” sugar to make a fungal bait. The two sweeteners, xylitol and erythritol, are commonly used to replace sugar in beverages and snacks for human consumers and have almost no nutritional value for the fly. The scientists found that the flies fed avidly on these sweeteners and that they were as effective as sugar for delivering B. bassiana to kill the fly. The results open new possibilities for using this promising biocontrol agent.

Technical Abstract: Documented resistance to traditional insecticides in the house fly, Musca domestica L. (Diptera: Muscidae) has brought about a need for new forms of control. One such method is the use of biological control organisms such as the entomopathogenic fungus, Beauveria bassiana. Administering B. bassiana with a nutritive phagostimulant such as sucrose may have the unintended effect of increasing fly vitality and thus reproduction before mortality sets in. Here B. bassiana was combined with the non-nutritive sweeteners erythritol and xylitol as potential substitutes for sucrose. Female flies consumed as much xylitol alone as they did sucrose alone, but less erythritol than both. After 24 h of exposure, B. bassiana administered at 1 mg in erythritol and in sucrose were equally effective at reducing survival and better than xylitol. B. bassiana administered at 10 mg worked equally well at reducing survival in all three sweeteners. When exposed to 10 mg of B. bassiana in sweetener for 1 h, sucrose reduced survival more than in either erythritol or xylitol, but mortality was still in excess of 97% after 8 d in all three sweeteners. Each sweetener mixed with B. bassiana worked as well in an environment with additional food sources and stimuli as they did in an environment lacking these additions. Erythritol and xylitol appear to be strong candidates to replace sucrose in baits formulated around B. bassiana.