There are several flies that are a serious economic threat to certain fruits, especially cherries, blueberries, raspberries, and blackberries. Drosophila suzukii, commonly known as the spotted-wing drosophila, is a great threat to raspberries. Widely recognized as the vinegar fly, Raspberries are not only victim to the Drosophila suzukii, but also to beetles, wasps, and sawflies. This, having become a big concern for raspberry growers, initially it was detected in Minnesota in 2012 and was confirmed in St. Louis County in 2013.
- Suzukii acts as a saver and destroyer when it comes to raspberries; however, there is a notable alarm on other soft-fleshed fruits, such as blueberries, cherries, grapes, and strawberries.
Farmers have reported that, by the time, they try to pick the ripened fruit, the female SWD would have deposited the eggs and the larvae, and in addition, it would have hatched inside the fruit. This, in turn, results in discoloration, disfiguration, and mushiness. In view of the fact that, they are active from the start to the end of harvest season, to control this act is highly challenging and moreover, it is observed that they tend to peak during August.
How to get rid of it?
Good cultural practices, be it on the plant or on the ground, not allowing the ripened fruit to stay for a long period of time, then picking the fruit every day are some of the most important activities to tag along to stay away from devastations. Having said that, it is vital to take care of the nearby wild fruits as well, timely maintenance is important; seeing that buckthorn too can become bug-ridden, it is suggested to do away with the invasive buckthorn as well. Predominantly, processing the fruit, the day you pick it, is said to help.
Consider using row covers to defend fruits that are chiefly wind-pollinated, cider vinegar traps can also be used and will help you identify small flies and fruit flies. The spot near the tip of both wings on the males is the differentiating factor of the SWD from other flies. Upon experiencing SWD infestation, you can follow the aforesaid steps and control the adult flies by using insecticides, however, they are unproductive to the larvae inside the fruit. If using an insecticide, apply in the late evening to trim down the impact on pollinators.