The spotted wing drosophila (SWD), Drosophila suzukii, is found in most areas of Iowa and is a pest of fruit, especially, raspberry, blackberry, blueberry, grape, aronia, strawberry and possibly tomato and apple.
Late summer is the time populations are most noticeable and when damage occurs to one of their favored crops, fall-bearing raspberries. Growers and gardeners should be monitoring for SWD and be prepared to manage this pest through harvest.
The following resources are recommended.
Commercial Growers: See Managing Spotted Winged Drosophila in Commercial Fruit Production. Commercial growers should watch for population and control updates through www.IowaProduce.org.
Home Gardeners: See Spotted Wing Drosophila in Home Gardens for details about life cycle and management options.
Traps placed in the raspberry and other at-risk crops will determine if SWD is in your garden and when your fruit crop is at risk. Place monitoring traps when the susceptible crop first starts to turn color. Check, maintain and replenish the traps through harvest.
For instructions on how to make your own SWD trap, see this Ohio State University video.
Very few insecticides are available for home gardeners that are effective and have a short harvest interval. See the home gardener link above for details on using insecticides in the home garden for SWD. The best insecticide choices for most home gardeners will be spinosad or malathion. Read and carefully follow label directions, especially the pre-harvest interval (time you wait between treatment and harvest).