Cherry Worms

Asked June 22, 2014, 1:42 PM EDT

This past Saturday (6/21)we discovered little white worms in our cherries. We had the cherries in a container in the cooler. The cold drove the worms from the cherries. This is the first year we have had worms in our cherries. We have three trees and only one has the worms at the moment. How do I prevent the worms for next season?

Marion County Oregon

1 Response

They are probably the larvae of cherry fruit fly. This is an insect that typically emerges from its overwintering site in the soil under the tree in late May as an adult. About 7 days after emergence it becomes sexually mature, mates and lays eggs in the fruit. Larvae feed inside the cherries for a short period before exiting, dropping to the ground and pupating until the following spring when it emerges and starts the process all over again. Control measures must start from the time of emergence until the fruit is harvested. You can spray the tree with a product containing Spinosad every 7 days from late May until harvest. Better yet, you can put out yellow sticky board traps to trap the insect then you know for sure when control should begin (within seven days of catching the first western cherry fruit fly). The PNW Insect Management Handbook gives this advice to homeowners: Home orchardists: Grow early-maturing varieties such as 'Chelan'. Pick fruit within 8 to 9 days of catching the first flies, which will happen before egg hatch. Remove all fruit from the trees to eliminate sites for the fly to reproduce. Cultivation of the soil has not been effective, as the pupae are very hard-shelled. - See more at: