Utilizing protein marker technology for studying movement of Drosophila suzukii

Spotted wing drosophila, Drosophila suzukii Matsumura, readily utilizes wild Himalayan blackberry, Rubus armeniacus, as a host and is suspected of invading berry and stone fruit crops from field margins containing this invasive weed. This study was conducted to determine the effect of field margins with R. armeniacus on D. suzukii movement into a red raspberry field in Oregon’s Willamette Valley in 2011 and 2012. One ha plots adjacent to field margins with R. armeniacus or non-hosts (wheat in 2011; grass in 2012) as control were replicated three times. Each plot contained two transects with D. suzukii traps spaced approximately 40, 70 and 100 m from field margins. Field margins were treated weekly with 10% liquid chicken egg white, an inexpensive immunomarking tool for mark-capture studies, using a cannon sprayer from pre-harvest through harvest. D. suzukii adults were collected from traps weekly and assayed using protein-specific enzyme-linked immunosorbent assays (ELISA). Three times more total adults were caught near R. armeniacus than near non-hosts. Furthermore, about 70% of all D. suzukii that were marked positive for the egg protein were caught near R. armeniacus. These findings support the hypothesis that D. suzukii trapped in the field visited or originated from R. armeniacus. Management recommendations for the pest and weed are discussed.