Erythritol sprays can reduce Drosophila suzukii oviposition with minimal impact on short-term fruit quality or pollinator visitation

Authors: Lee, Jana; Price, Briana; ADAMS, CHRIS - Oregon State University; FREEMAN, MAGGIE - Oregon State University; Rutkowski, Emily; Choi, Man-Yeon

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2023
Publication Date: 8/4/2023
Citation: Lee, J.C., Price, B.E., Adams, C., Freeman, M., Rutkowski, E.M., Choi, M.Y. 2023. Erythritol sprays can reduce Drosophila suzukii oviposition with minimal impact on short-term fruit quality or pollinator visitation. Pest Management Science. http://doi.org/10.1002/ps.7701.
DOI: https://doi.org/10.1002/ps.7701

Interpretive Summary: The invasive spotted-wing drosophila (SWD) is an economic pest of small fruits and cherries. Insecticides typically control this pest while alternative controls are still in development. Laboratory studies show that erythritol is toxic to SWD and other pests but safe for human consumption. Moreover, erythritol combined with sucrose or non-caloric sucralose can stimulate feeding and quicken mortality. Before growers can use erythritol, field efficacy, attraction to non-target insects and impacts on fruit quality need evaluation. A greenhouse trial and eleven field trials were conducted over four years. In three blueberry and cherry field cage trials, egg laying on fruit sprayed with erythritol:sucrose or erythritol:sucralose formulations in 24 h was lowered by 59-81% compared to controls. Infestation among weekly harvested fruit was lowered by 90% in a greenhouse blueberry trial, and by 49-57% in an open field blueberry and cherry trial. In six field trials that monitored insect visitation, honey bees did not preferentially visit plants sprayed with either erythritol formulation. In five out of five field trials that examined plant effects, erythritol formulations led to more leaf spotting. Yet, there were no clear differences in quality between erythritol and control blueberries or cherries in terms of mold development, firmness, diameter, epidermal penetration force and Brix° at harvest. Erythritol formulations can reduce SWD pressure with minimal non-target attraction by honey bees foraging and detriment to fruit quality parameters.

Technical Abstract: Background: The invasive spotted-wing drosophila, Drosophila suzukii, is an economic pest of small fruits and cherries. Insecticides typically control this pest while alternative controls are still in development. Laboratory studies show that erythritol is toxic to D. suzukii and other pests but safe for human consumption. Moreover, erythritol combined with sucrose or non-caloric sucralose can stimulate feeding and quicken mortality. Before growers can use erythritol, field efficacy, attraction to non-target insects and impacts on fruit quality need evaluation. Results: In three blueberry and cherry field cage trials, oviposition on fruit sprayed with erythritol:sucrose or erythritol:sucralose formulations was lowered by 59-81% compared to controls. Infestation was lowered by 90% in a greenhouse blueberry trial, by 49% in an open field blueberry trial with 2M erythritol: 0.5M sucrose, and by 57% in an open field cherry trial with 1.5M erythritol: 0.5M sucrose. In six field trials that monitored visitation, honey bees did not preferentially visit blueberry bushes or cherry trees sprayed with either erythritol formulation, although yellow jackets visited erythritol:sucrose-sprayed plants more frequently. In five out of five field trials that examined plant effects, erythritol formulations led to more leaf spotting, but no clear differences in quality between erythritol and control blueberries or cherries in terms of mold development, firmness, diameter, epidermal penetration force and Brix° at harvest. Conclusion: Trials conducted over four years show that erythritol formulations can reduce D. suzukii pressure with minimal non-target attraction by honey bees foraging and detriment to fruit quality parameters.