A fixed-spray system for spotted wing Drosophila management in high tunnel raspberries

Abstract: Spotted wing Drosophila (SWD) is widely distributed in New York State, with raspberries being especially vulnerable. Raspberries grow well in high tunnels and produce exceptionally high quality fruit over an extended growing season. The invasion of SWD has forced berry growers to dramatically increase insecticide applications to produce marketable fruit, a significant logistical challenge for high tunnel production. A spray system fixed into the tunnel structure was used to apply pesticide sprays to control SWD in research and commercial bramble plantings from July-Sept, 2013. All sprays were applied through a system of microsprinkler nozzles attached to polyethylene tubing running along the top of the tunnel and supplied by a central tank/pumping station. Identical applications were made in check tunnels using backpack sprayers. SWD traps were deployed in both treatments to check for adult presence, and weekly fruit samples were collected and held to rear out any larvae infesting the berries. Results were variable depending on site, ranging from equal low levels of infestation for fixed vs. control at the commercial raspberry site (mean: 10 SWD/50 raspberries over the season) to 4X higher infestations in the fixed sprayer blackberry planting vs. the control (78 SWD/sample vs. 20, respectively). Fixed sprayer systems may be particularly cost-effective in high tunnels since the scaffolding for the fixed lines is already present.