|Cooper, Rodney - William|
|KAO, ROBERT - Heritage University|
|NOTTINGHAM, LOUIS - Washington State University|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/14/2020
Publication Date: 6/19/2020
Citation: Wentz, K.M., Cooper, W.R., Horton, D.R., Kao, R., Nottingham, L.B. 2020. The artificial sweetener, erythritol, has insecticidal properties against pear psylla (Hemiptera: Psyllidae). Journal of Economic Entomology. 113(5):2293-2299. https://doi.org/10.1093/jee/toaa124.
Interpretive Summary: Pear psylla is a key pest of commercial pear that requires repeated applications of insecticides to manage. New management tools are needed to reduce the risk that pear psylla populations will develop resistance to current insecticides. The artificial sweetener, erythritol, is non-toxic to humans but is insecticidal when ingested by certain insects. Researchers at the USDA laboratory in Wapato WA and Heritage University in Toppenish WA examined whether erythritol is also lethal to pear psylla. In both laboratory and field experiments, they showed that treatment of pear with 20% erythritol causes 60-80% mortality of psylla nymphs and adults. Results of these experiments suggest that erythritol may provide a new safe and effective tool for the management of pear psylla.
Technical Abstract: Erythritol is an alternative dietary sweetener that is used for low-calorie or diabetic diets. Although safe for human consumption, erythritol is lethal to certain Dipteran pests, but insecticidal effects of erythritol on phloem-feeding insects have yet to be examined. Our goal was to determine whether erythritol has insecticidal activity against pear psylla, Cacopsylla pyricola (Foerster) (Hemiptera: Psyllidae), which is a key pest of pear that often requires multiple insecticide applications to manage. We first demonstrated that ingestion of erythritol solutions by pear psylla caused reduced feeding, impaired motor functions, and reduced survival time of adults. We then tested whether foliar treatment of pear leaves with erythritol was also lethal to pear psylla. Foliar treatment of erythritol led to reduced 3-day survival of pear psylla nymphs and adults, and reduced rates of oviposition by pear psylla adults. Psylla adults also preferred to settle on untreated leaves than on erythritol-treated leaves in preference assays. Finally, we conducted field experiments to test whether applications of erythritol provided pear trees with protection against pear psylla under natural field conditions. Those experiments showed a reduction in pear psylla nymphs on erythritol-treated trees compared with untreated trees, but only if the erythritol was completely dissolved into solution by heating. Results of our experiments demonstrate that erythritol is insecticidal to pear psylla nymphs and adults and provide the first report that erythritol is lethal to a phloem-feeding insect. These findings suggest that erythritol may provide a new safe and effective tool for the management of pear psylla.