How to Defend Against the Cherry Maggot

Cherry Maggot

By DEBORAH GIRAUD, University of California Cooperative Extension

If you have found white worms in your cherries and other fruits in the last few years you know how disappointing it is. The Spotted wing drosophila fruit fly is the culprit. It was first seen in California in 2008 and quickly spread across the state. It attacks many fruits and the fly can poke eggs into intact skin, it doesn’t need soft or rotten spots as the other fruit flies do. There is a lot of information on its biology that is fascinating to read, and here is a web site with a lot of details. I would like to just point out a few management practices you can try.

Make some traps to monitor when the flies are flying. Traps alone don’t really control it, but let you know the timing to spray
Refresh the traps weekly and identify the flies

Spinosad, available at all the garden centers, is an organic spray. It has the best chance to kill the flies – before they lay the egg in the fruit
Spray cherries as you see the slightest sign of color.

Check blueberries and cherries for very small pinprick holes. Cut open to see if there are small maggots, harvest as fast as you can. Keep harvesting as fruit show color. Sort out any fruits with holes, or bake with them; very small maggots won’t hurt anyone.

Cherry Maggot damage

Netting for small bushes can help, you have to get it on before any ripening, and it has to be the smallest mesh, .98 to work.

Clean up all fallen fruit, for instance your early raspberries can harbor insects that can attack your later ripening fruits

A hose end sprayer can be used, but a pump up one is better.

Here are a few resourceful websites:

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