Constant Challenge Of SWD

There was both good news and bad news in the fight against the spotted wing drosophila (SWD) this year. The bad news was, SWD continues to be detected in new areas, including Pennsylvania, New England, and the Southeast. The good news was with another year to learn more about the pest, researchers have been able to help growers stay on top of monitoring and controlling SWD, which has helped mitigate its damage.

SWD (Drosophila suzukii) targets primarily berry crops such as raspberries, blackberries, and strawberries, but because it can easily penetrate thin-skinned fruit, it may also be found in grapes and cherries. What makes SWD such a challenge is that it targets fruit throughout the season, including during harvest. Because of this, unmarketable fruit needs to be removed and destroyed immediately. 

Control Options

Monitoring remains the most important tool in controlling SWD. Identification of adults can be difficult because of their similarity to other fruit fly species. When it comes to trapping, California researchers are looking at bait combinations ranging from yeast/sugar/water to apple cider vinegar.

Many crop protection materials have proven to have fairly good efficacy against SWD including some organic options. Effective insecticides for which 2(ee) labels for spotted wing drosophila have been issued for berry crops are — in alphabetical order:
– Danitol (fenpropathrin, Valent USA), labeled for strawberries, caneberries (raspberries, blackberries, etc.), and bushberries (blueberries, currants, etc.);
– Delegate (spinetoram, Dow AgroSciences), labeled for caneberries and bushberries;
– Entrust, Spintor, and Success (spinosad, Dow AgroSciences), labeled for strawberries, caneberries, and bushberries (Entrust can be used in organic production);
– Mustang Max (zeta-cypermethrin (FMC Corp.), labeled for caneberries and bushberries;
– Pyganic (pyrethrins), which can be used on all berry crops and in organic production, but has very short residual activity.

Grower Resources

As growers finish up the 2011 season and prepare for what’s ahead, there are several resources they can use to keep up with the latest SWD news.
– Michigan State University has set up an SWD website that includes fact sheets, as well as reports from around the country. In addition, the upcoming Great Lakes Fruit, Vegetable, and Farm Market Expo will include sessions devoted to SWD.
– Peerbolt Crop Management, based in Oregon, publishes a “Small Fruit Update” during the growing season that is heavily focused on SWD, including regional meetings, where it’s been found, and what growers are doing to control it.
– The Fruit Insect Control channel on GrowingProduceTV includes videos devoted to SWD, including identification, monitoring, and more.