Evaluating potential phytotoxicity of erythritol, a novel control method for Drosophila suzukii, in blueberry, cherry, and wild Himalayan blackberry

Authors: SRIRAM, ABIGAIL - Oregon State University; Scagel, Carolyn; Choi, Man-Yeon; Bryla, David; Lee, Jana

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2024
Publication Date: 10/4/2024
Citation: Sriram, A., Scagel, C.F., Choi, M.Y., Bryla, D.R., Lee, J.C. 2024. Evaluating potential phytotoxicity of erythritol, a novel control method for Drosophila suzukii, in blueberry, cherry, and wild Himalayan blackberry. Crop Protection. 187:106961. https://doi.org/10.1016/j.cropro.2024.106961.
DOI: https://doi.org/10.1016/j.cropro.2024.106961

Interpretive Summary: Spotted-wing drosophila is serious pest of small and stone fruits across the world. The consumption of the non-caloric sugar erythritol, kills the fly while the sugar is approved for human consumption. Past research indicated that sprayed erythritol formulations protected the fruit from insect infestation, but some leaf spotting was observed. This research explored whether erythritol sprays on blueberry, cherry and wild Himalaya blackberry caused phytotoxicty. There was no consistent negative impact on plants in terms of gas exchange, water content, sugar content and photosynthetic potential of leaves indicating that erythritol may be a viable pest control option.

Technical Abstract: Drosophila suzukii is a recent but prolific pest of small and stone fruits across the United States. While control is commonly achieved through broad-spectrum pesticides, these chemicals are often harmful to beneficial insects. A new candidate for spotted-wing drosophila control is erythritol, a non-nutritive sugar alcohol with insecticidal properties. Erythritol solutions with a sucrose (E:S) or sucralose (E:Sul) phagostimulant demonstrate efficacy at reducing larval infestation and deterring oviposition when applied to fruits pre-harvest, but also reportedly lead to spotting damage on plant leaves. Our objectives were to determine the extent and physiological impacts of the damage in several plant systems and assess the role of individual components in potential phytotoxicity. In the first year, bulk or lab-grade erythritol were combined with a sucrose or sucralose phagostimulant to evaluate the effects of the 4 solutions and a water control on visible leaf damage, stomatal conductance, chlorophyll fluorescence, leaf relative water content, and osmolality in blueberry, cherry, and blackberry leaves. When bulk erythritol did not have discernible impacts, second year trials focused on evaluating solutions of lab-grade erythritol with a phagostimulant and solutions of individual chemicals on leaf damage and physiological factors. Solutions of E:S and E:Sul caused the greatest visible damage, but damage was highly variable between years, treatments, and plant systems. There were no consistent physiological effects associated with any formulation. These results suggest that while visible leaf damage may be a dose-dependent effect of erythritol application, the lack of associated physiological impacts make it a viable candidate for further testing.