Deep sequencing SWD gut contents to reveal non-crop alternative host plants

Spotted wing drosophila (SWD) is a devastating pest of Washington soft fruits including cherries, blueberries, and red raspberries. Since its arrival in 2009, the cost and intensity of insecticide programs for these crops has dramatically increased. SWD adults generally develop and invade crops from unknown alternative host plants, complicating management. Despite great efforts to identify the non-crop hosts of SWD, no reliable method has been devised. In this project, we will address this issue with a novel molecular approach. We hypothesize that previous plant hosts of SWD can be accurately identified via next-generation sequencing (i.e. deep sequencing) of plant DNA remaining the guts of field collected adults. We will test this hypothesis by first attempting to identify known plant species fed to SWD adults and larvae in the lab via deep sequencing. Next, we will determine if the same technique can identify unknown prior host plants from field-collected SWD adults. This project fits the BIOAg mission because it will examine a novel tool that could answer one of the most difficult questions related to a major agricultural pest. If successful, the ability to identify SWD’s non-crop hosts will allow growers to implement ecologically based management strategies, such as non-crop host treatment or removal. Furthermore, this work will provide a pivotal new approach for studying insect behavior and ecology at a landscape level.