A food-grade gum as a management tool for Drosophila suzukii

Drosophila suzukii is an insect pest of worldwide distribution on soft-skinned fruit. This species is able to utilize different habitats and substrates for nutrition and reproduction, a capacity that can be attributed to olfactory cues. The first aim of the current study was to create and evaluate a novel gum matrix as a management tool for D. suzukii in a commercial cropping system. Next, we identified a biologically important volatile from an important ingredient within the matrix. The efficacy of the proof of concept matrix as a management tool was assessed in laboratory and semi-field conditions. The detection of active volatile compounds was performed using gas chromatography (GC) coupled with electroantenna detection (EAD) techniques. Volatiles significantly modified response of D. suzukii in controlled electrophysiology and orientation studies, resulting in 46.7% mean oviposition reduction in controlled laboratory trials on five susceptible fruit types. Field trials were thereafter conducted over periods of 72 +/- 2 to 96 +/- 2 hours on commercial-standard blueberry bushes. Fruit on bushes exposed to predetermined numbers of D. suzukii displayed 50 to 76% reductions of fruit infestation and total eggs laid, respectively, in gum treatments. Up to 40% of fruit on untreated plants were targeted by D. suzukii, whereas less than 20% of fruit on treated bushes were targeted. These results indicate that the insecticide-free gum matrix significantly reduces D. suzukii damage under commercial production conditions. This reduction may be due to a combination of altered behaviour and the division of reproductive resources. The current work will likely expand integrated pest management options to control D. suzukii populations in commercial field settings.