Sweet SWD control: non-target effects and field trials with erythritol

Picture of Jana Lee
Jana Lee

Man-Yeon Choi, Ramesh Sagili

Erythritol is a non-caloric sugar used in artificial sweeteners such as Truvia and is safe for human consumption. Formulations with erythritol have induced mortality among spotted-wing drosophila (SWD) adults in the lab and greenhouse, and reduced infestation rates among fruits in the field.

While promising, the erythritol formulation needs to be improved for field application and its non-target effects considered. Recently, we developed two new formulations to reduce the stickiness of sprays: 1) 1.5M erythritol:0.5M sucrose and 2) 1.5M erythritol:0.1M sucralose (patented). To facilitate registration of erythritol as an insecticide, our first objective examined non-target effects on beneficial insects. The formulations were not detrimental to honey bees when larvae were exposed to high doses in the hive. While the erythritol formulations can kill a parasitic wasp of SWD, the risk was minimized when floral nectar was available. To develop grower recommendations, our second objective examined the efficacy of the new formulations in the field, while monitoring visitation by honeybees, and impacts on the plant.  Natural infestation by SWD was often low to detect impacts in open field trials or there was no impact. Caged female SWD laid fewer eggs on sprayed blueberries. The number of foraging bees was not different towards sprayed and unsprayed bushes. Lastly, erythritol formulations did not impact the firmness, sweetness (°Brix), and mold development on fruit. While sprays were observed to cause leaf spotting, no impact on the leaf photosynthetic potential, stomatal conductance (gas exchange) and water content was observed. In summary, erythritol can reduce SWD egg laying with minimal impacts on honeybees, a parasitoid of SWD, fruit quality and short-term plant performance. 

View Project Final Report

Price, B.E., C. Breece, G. Galindo, A. Greenhalgh, R. Sagili, M-Y. Choi, J.C. Lee.  2022.  Non-nutritive sugars for spotted-wing drosophila control have minimal no-target effects on honey bee larvae, a pupal parasitoid, and yellow jackets.  J Econ Ent, in press.

Price, B., J.C. Lee, M.-Y. Choi. 2021. Erythritol combined with non-nutritive phagostimulant sucralose increases feeding by Drosophila suzukii, quickens mortality and reduces oviposition. Crop Protection 150: 105812. doi.org/10.1016/j.cropro.2021.105812

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