Spotted Wing Drosophila (SWD)
SWD (Drosophila suzukii) is native to Southeast Asia, preferring warm temperatures and therefore going through many more life cycles per year than the fruit fly we are all familiar with.
First found in BC in 2009, SWD is now distributed over all fruit production areas of the Fraser Valley and the BC Interior. Unlike our regular fruit fly which only infests fallen, over-ripe or decaying fruit, SWD lays eggs in harvestable fruit while still on the bush. While the regular fruit fly is only annoying, SWD will cause crop loss. No one wants to bite into a blueberry and find a maggot in it. All types of fruit crops, and many wild fruit plants, are subject to infestation. SWD is hard to tell apart from regular species of fruit fly. For those with good eyes and in possession of a magnifying glass, the photographs below show the distinguishing features of SWD adults. If you cannot spend the time and effort to monitor for SWD on your own, and/or find it difficult to identify them, you can hire monitoring firms to routinely check your farm.
Although producers depend on consistent chemical applications to achieve control, cultural methods that should be adhered to include good sanitation, removal of alternate wild hosts where possible, and good fruit handling (ie: use shorter picking intervals, frequent harvesting, moving harvested fruit into cold storage quickly). Above all, it is very important to learn all you can, and to participate in population monitoring.
Chemical Control
Control with insecticides will be necessary if trapping shows that adult SWD flies are present in the area when berries begin to ripen. Adult flies are the target and are killed by direct spray contact or when they are exposed to residues of insecticide on the treated fruit and leaves.
There are a variety of pest control products currently registered for use on SWD. Here are some of them (as of 2021):
Keep SWD at bay. We can help you choose the right product for your crops.
Reference: BC Ministry of Agriculture