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WSU Tree Fruit

Spotted Wing Drosophila Management Reminders

Dr. Elizabeth Beers, WSU Professor of Entomology; Tianna DuPont, WSU Tree Fruit Extension Specialist

Here are a few reminders for managing Spotted Wing Drosophila (SWD). Remember that cherries are susceptible to egg laying from SWD starting at straw. Dr. Beers has seen over three years that even when SWD has no choice in a laboratory situation females are not able to lay eggs in green fruit, likely due to hard skins. A small number of SWD were able to lay eggs and emerge from fruit at straw (21 days before harvest (DBH) Bing, 35 DBH Lapin, 21 DBH Ranier, 35 DBH Sweetheart). Significant incidence began at blush. See example table below.

It is important to trap to see if SWD is near your orchard. In the past traps have captured a large number of other drosophila species. AlphaScents yellow sticky traps are more selective for SWD, and when combined with either the Scentry or AlphaScents lure has a strong catch with greater selectivity.

For resistance management it is recommended to use products with three modes of action over the course of the season. Mixing is not the same as rotating. It does not manage for resistance. You will likely want to start with products with a longer PHI and end with those with a shorter PHI.

Fruit maturity, oviposition and adult emergence of D. suzukii in laboratory bioassays of fruit (cv. Lapins, CV14), 2014

swd emergence