Wild berries are more attractive to an invasive vinegar fly, spotted-wing drosophila (Diptera: drosophilidae), than cultivated berries

Authors: URBANEJA-BERNAT, PABLO - Rutgers University; CLOONAN, KEVIN - Trece, Inc; Zhang, Aijun; SALAZAR-MENDOZA, PAOLO - Universidade De Sao Paulo; RODRIGUEZ-SAONA, CESAR - Rutgers University

Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/24/2020
Publication Date: 1/7/2021
Citation: Urbaneja-Bernat, P., Cloonan, K., Zhang, A., Salazar-Mendoza, P., Rodriguez-Saona, C. 2021. Wild berries are more attractive to an invasive vinegar fly, spotted-wing drosophila (Diptera: drosophilidae), than cultivated berries. Journal of Pest Science. https://doi.org/10.1007/s10340-021-01332-z.
DOI: https://doi.org/10.1007/s10340-021-01332-z

Interpretive Summary: The spotted wing drosophila (SWD), is an exotic fruit fly and attacks a wide variety of fruits. Since it invaded California in 2018, it has rapidly spread across the United States and Europe. A specific and efficient SWD detection tool is urgently needed for growers/farmers, so that they can deliver timely management interventions. In our previous study, we have identified a quinary blend from apple juice that can effectively attract SWD. In this study, we identified 9 different volatile compounds from wild blueberries which were more attractive to D. suzukii flies and present in higher concentrations than cultivated blueberries. Our results show that domestication/cultivation of blueberries is associated with lower quantities of fruit volatile emissions, whichhas resulted in decreased attraction of SWD. These results open the door for developing more a efficient and specific SWD attractant for management of this pest.

Technical Abstract: Highbush blueberry (Vaccinium corymbosum) is a crop native to the northeast USA that has been domesticated for about 100 years. During the domestication process, blueberries were selected primarily for bigger fruit and higher yields. Our hypothesis is that, due to domestication and associated agronomic selection (i.e., cultivation practices), cultivated blueberries would differ from their wild ancestors in fruit volatile emissions, affecting the response of a frugivorous insect pest. For this, we compared the attraction of adult spotted-wing drosophila (Drosophila suzukii) to wild and cultivated blueberry fruit volatiles in choice assays. We also conducted headspace volatile analysis and electrophysiological analysis (gas chromatography-electro-antennographic detection, GC-EAD) of the D. suzukii antennae to identify and quantify the antennally-active compounds. Fruit from wild and cultivated blueberries, growing in close proximity, were sampled from 5-6 farms located in the Pinelands National Reserve (New Jersey, USA), a blueberry-producing region with a forest understory consisting largely of wild blueberries. Compared to cultivated blueberries, wild blueberries were more attractive to D. suzukii flies and volatiles were emitted at higher concentrations. Nine EAD-active compounds from wild blueberries (isobutyl acetate, ethyl butyrate, ethyl 2-methylbutyrate, ethyl-3-methyl butyrate, hexanal, isoamyl acetate, 3-hydroxybutanone (acetoin), 6-methyl-5-hepten-2-one, and 1-hexanol) were attractive individually, and as a blend, to D. suzukii flies. However, a 4-component blend composed of isoamyl acetate, acetoin, 6-methyl-5-hepten-2-one, and 1-hexanol was more attractive to D. suzukii than the 9-component blend. Altogether, our results show that domestication/cultivation of blueberries has lowered fruit volatile emissions, which resulted in decreased attraction of a frugivorous pest, D. suzukii.