Master's Student Oregon State University Corvallis, Oregon
Spotted wing drosophila (Drosophila suzukii) is a vinegar fly and an invasive pest of small and stone fruits. Due to its ability to oviposit in ripening rather than rotting fruit, D. suzukii has caused significant economic damages to growers since its arrival on the West Coast in 2008. Erythritol, an artificial sweetener, has been shown to increase mortality in D. suzukii adults and larvae when ingested. Many beneficial insect species do not appear negatively affected by erythritol exposure, and fruit quality is not impacted by erythritol treatments, making erythritol a candidate for wider testing. However, erythritol solutions have been observed to damage plants, causing desiccation and spotting on 1-17% of treated leaves inconsistent with mold, diseases, or insect damage. Leaf damage appears to differ between outdoor vs protected plants, between insect phagostimulants in the erythritol solution (sucrose vs sucralose), and between an expensive erythritol vs a cheaper source. Our objectives were to compare if spotting symptoms occurred and the impact on plant function with varying formulations using purified or bulk erythritol, combined with sucrose or sucralose, creating 4 combinations of treatments and a control. Potted blueberry plants are being treated with these formulations to monitor variation in appearance, osmotic pressure, turgor pressure, and photosynthesis, and stomatal conductance. Next, treatments with the most impact will be tested in the field by spraying blueberry bushes and monitoring these parameters, with the final objective of elucidating the mechanism of leaf damage and effects on the condition of the whole plants.