Erythritol sprays reduce D. suzukii infestation without impacting honey bee visitation nor fruit quality.

Abstract

Spotted-wing drosophila, Drosophila suzukii, is an economic pest of small fruits and cherries. Insecticides primarily control this pest while alternative controls are in development. Laboratory studies show that erythritol is insecticidal to D. suzukii and other pests while safe for human consumption. Moreover, erythritol combined with sucrose or non-caloric sucralose can stimulate feeding and quicken mortality. Before growers can use erythritol, the impact on crop protection, non-target insects, and fruit quality need evaluation. 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 unsprayed controls. Fly infestation (larval or adult counts from fruit) was 90% lower in a greenhouse blueberry trial, and 49% lower in an open field blueberry trial with 2M erythritol: 0.5M sucrose. Infestation was also 57% lower in an open field cherry trial with 1.5M erythritol: 0.5M sucrose. Other field trials with very low pest pressure or frequent rains revealed no differences from controls. Field trials consistently revealed that honey bees did not preferentially visit plants sprayed with either erythritol formulation, although yellow jackets visited erythritol:sucrose-sprayed plants more frequently. Erythritol formulations consistently led to more leaf spotting, but there was no reduction in quality of treated blueberries or cherries in terms of mold development, firmness, diameter, epidermal penetration force, and Brix° (total soluble solids; TSS) at harvest. Eleven trials conducted over four years show that erythritol formulations can reduce D. suzukii pressure without attracting foraging honey bees nor negatively impacting fruit quality. This article is protected by copyright. All rights reserved.