Effects of non-nutritive sugar inclusion in laboratory diets and attracticidal spheres on survivorship and mobility of two Dipteran species, Rhagoletis pomonella and Drosophila suzukii

Authors: NIXON, LAURA - Orise Fellow; DOUGLAS, MORGAN - Former ARS Employee; IBRAHIM, AYA - Fondazione Edmund Mach; JONES, SHARON - Retired ARS Employee; PINERO, JAIME - University Of Massachusetts, Amherst; Leskey, Tracy

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2024
Publication Date: 1/24/2024
Citation: Nixon, L.J., Douglas, M., Ibrahim, A., Jones, S., Pinero, J.C., Leskey, T.C. 2024. Effects of non-nutritive sugar inclusion in laboratory diets and attracticidal spheres on survivorship and mobility of 2 Dipteran species, Rhagoletis pomonella (Diptera: Tephritidae) and Drosophila suzukii (Diptera: Drosophilidae). Journal of Economic Entomology. https://doi.org/10.1093/jee/toae003.
DOI: https://doi.org/10.1093/jee/toae003

Interpretive Summary: Native apple maggot fly (AMF) and invasive spotted-wing drosophila (SWD) are key pests of apple and small fruit, respectively, in the US. Visually attractive red spheres fitted with caps containing insecticide and sucrose (attracticidal spheres) have been shown as effective management tools for AMF and SWD; however, regulatory hurdles prevent the use of this tool commercially. Here, we evaluated the potential of using non-nutritive sugars as replacement toxicants. We established that, although certain sugar alcohols such as erythritol and mannitol have some toxic effects on AMF and SWD in high amounts, this may not be applicable for fruit fly management in the field. These findings add to the wealth of current and emerging literature on the use of sugar alcohols against fruit flies.

Technical Abstract: Native apple maggot fly, Rhagoletis pomonella, and invasive spotted-wing drosophila, Drosophila suzukii, are key pests of apple and small fruit, respectively, in the US. Both species are typically managed with standard insecticide applications. However, interest in alternative strategies that result in insecticide reductions have led to evaluations of non-nutritive sugars as toxicants for Drosophila species and development of attracticidal spheres for both species. Here, we evaluated survivorship of R. pomonella and D. suzukii when provided with standard diets that substituted saccharin, sucralose, aspartame, erythritol, dextrose, or mannitol for the sucrose component and compared them with standard diets and a water-only controls for up to 15 days. Presence of erythritol and mannitol significantly decreased survivorship of R. pomonella, and erythritol significantly decreased the survivorship of D. suzukii. However, mobility trials following a 2-hour exposure to aqueous solutions of each sugar treatment resulted in no strong impact on either species. Survivorship after 30 minutes of exposure to erythritol or mannitol alone, or in combination with varying concentrations of sucrose (serving as a phagostimulant) at 30 minutes and 24 hours were evaluated for both species. Only D. suzukii survivorship was affected with decreased survivorship on erythritol: sucrose solutions of 20:0% and 15:5% for 24 hours. Based on all results, erythritol appeared most promising and was integrated into attracticidal spheres as a toxicant; but even at the highest concentration, survivorship remained unaffected for either species, thus, making this non-nutritive sugar impractical and ineffective as a toxicant substitute in attracticidal spheres.