SWD infestation

Asked October 15, 2018, 12:46 PM EDT

SWD infested the raspberry bushes this summer. There were many raspberries left rotting on the vines and surrounding mulch. What can be done this fall with the vines to better prepare for next year.? Should the vines get cut back and mulch be burned to keep any adults from over wintering?

Cass County Minnesota

1 Response

Sanitation is an important component of SWD control. Cleanup is a good idea. However, SWD hatch and feed on fruit, so the important part of cleanup is to make sure no fruit is allowed to remain on the canes or on the ground. While burning old canes is a good idea for other reasons, it probably won't help with the SWD.

I wouldn't cut back the primocanes. Summer bearing varieties produce on old wood, so you'd lose next years crop. You'd also lose the early crop of everbearing varieties. Furthermore, as I said, SWD's life cycle is spent mostly on the fruit.

You can also cover the plant with a row cover next spring. Since raspberries are wind pollinated, bees don't need access. Read here about SWD:
https://extension.umn.edu/yard-and-garden-insects/spotted-wing-drosophila-home-gardens