Protecting Against Spotted Wing Drosophila

Spotted Wing Drosophila

Well, you may have heard that the Spotted Wing Drosophila (SWD) fruit fly has arrived in Powell River. It can cause a lot of damage to all soft ripe fruit and there are a few things we can do to protect our crops from it.  Below are details that we found online, with links to good quality images and information that can help identify the bug and help to deal with these unfortunately very hearty and prolific fruit flies.

(from: — click on that link for many images and lots of information, albeit from an Ontario perspective; local bulletins appear at the end of this post)

Why worry?

Growers are accustomed to the vinegar flies that are commonly associated with overripe, damaged and dropped fruit. What makes the SWD different is that the female has a heavily serrated ovipositor that allows her to saw through intact fruit and lay her eggs under the skin. Larvae hatch and feed on the fruit, rendering it unmarketable. Disease pathogens and other insect pests can also enter through the egg-laying holes, causing further deterioration of the fruit.

Which crops are at risk?

According to the BC Ministry of Agriculture: In British Columbia, spotted wing drosophila has been confirmed infesting:
– strawberry (Fragaria)
– crabapple (Mallus)
– plum (Prunus) – including Italian prune plum
– cherry (Prunus)
– Raspberry (Rubus) — the first choice, and most susceptible to attack
– Himalayan blackberry (Rubus)
– loganberry, tayberry, boysenberry
– blueberry (Vaccinium)
– peach, nectarine, apricot (Prunus) — though not a first choice
SWD is suspected in:
– hardy kiwifruit (Actinidia)
– grapes (Vitis) — especially soft-skinned varieties or if skin is broken
– fig (Ficus) — can be infested when conditions are right, or like grapes, if the skin is broken.
Berries in the Ribes genus are also susceptible:
– currant
– gooseberry
– jostaberry

Please refer to these two locally produced documents by Margaret Cooper and Jo-Ann Canning, on how to deal with this! We will add new bulletins to this list as they occur.

  • Bulletin 1 
  • Bulletin 2

There is also this brochure by the BC Ministry of Agriculture, that is very useful.