Location: Southern Horticultural ResearchTitle: Erythritol and Lufenuron detrimentally alter age structure of Wild Spotted Wing Drosophila (SWD) Drosophila suzukii (Diptera: Drosophilidae) populations in blueberry and blackberry
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2016
Publication Date: 4/1/2017
Citation: Sampson, B.J., Marshall-Shaw, D.A., Smith, B.J., Stringer, S.J., Werle, C.T., Magee, D., Adamczyk Jr, J.J. 2017. Erythritol and Lufenuron detrimentally alter age structure of Wild Spotted Wing Drosophila (SWD) Drosophila suzukii (Diptera: Drosophilidae) populations in blueberry and blackberry. Journal of Economic Entomology. 110(2):530-534.
Interpretive Summary: The nutritive sweetener, Truvia, and the insect growth regulator, Lufenuron, were highly toxic to each life stage of spotted wing Drosophila flies inside blackberry and blueberry fruits (eggs, and larvae) in the field. Truvia and Lufenuron were equally effective at reducing larval loads in both fruit species by 75%; although, these compounds were not synergistic. Lufenuron was more toxic to the second larval stage, whereas, Erythritol was particular toxic to eggs and the first larval stage. In untreated berries (control), the mortality of eggs and young larvae were 80-90% with only ~1 - 4% of offspring surviving to the mature larval stage, which suggest facultative parasitism (cannibalism) among larvae may regulate the size of wild populations of spotted wing Drosophila.
Technical Abstract: We report on the efficacy of 0.5 M (61,000 ppm) Erythritol (E) in Truvia Baking Blend®, 10 ppm Lufenuron (L), and their combination (LE) to reduce egg and larval densities of wild populations of spotted wing Drosophila, Drosophila suzukii (Matsumura) (SWD) infesting fields of rabbiteye blueberries (Vaccinium virgatum) and blackberries (Rubus sp.). Formulations included the active ingredients (Lufenuron, Erythritol, or both), sugar (in control and Erythritol treatments), and Dawn® hand-soap applied to plants with pressurized 3-gallon garden spray tanks. The three chemical treatments (E, L, LE) had no effect on SWD ovipositing in blackberry and blueberry fruit, but they did reduce larval loads by 75%, particularly densities of first and second instars. Erythritol and Lufenuron were equally efficacious compounds as an SWD ovicide/larvicide, but they did not display additive or synergistic activity. Extremely high larval mortality in control fruits show an age structure heavily skewed toward egg output, and infer facultative predation among larvae (cannibalism) may regulate the size of natural SWD populations.