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Spotted Wing Drosophila

Written for the Davis Enterprise, February 25, 2010

A new pest in fruit trees

2012 update:
Based on customer feedback and conversations with other local experts, we consider the Spotted wing Drosophila to be an unmanageable pest for home gardeners. We no longer recommend or sell any varieties of sweet or pie cherries in the Sacramento Valley.

Homeowner information for monitoring and control of Spotted Wing Drosophila (aka Cherry Vinegar Fly).

Damage in cherries. Photo courtesy of Larry Strand, UC Statewide IPM Program.

Drosophila suzukii, the Spotted Wing Drosophila, showing the wing spots on the male.
Photo courtesy of John Davis, from http://bugguide.net, reprinted with permission.

Spotted Wing Drosophila are typical fruit fly size: 2 - 3 mm, as illustrated by this specimen on a raspberry. You may need a hand lens! Female SWD look just like other fruit flies.
A native of Asia, it was first reported in Hawai'i in 1980, identified in California in raspberries and strawberries near Watsonville in 2008, and in cherries elsewhere in the state in 2009.
Photo courtesy of Ed Show, c/o UC Cooperative Extension, Santa Cruz County

The lifecycle of this pest

What are we going to do about this?

If you didn't have a problem last year, you can monitor

Traps can be made readily from materials at home; it's pretty easy to attract and catch fruit flies! Mason jars or Rescue Fly Traps can be filled with any number of vinegar or sugar solutions. Options include a mix of yeast and sugar, or yeast with banana slices, or just an inch or so of apple cider vinegar. In field tests, the yeast/sugar mix caught the most flies. Trapping can be part of an overall management strategy.
Photo courtesy of Ken Payton, winemaker, and administrator of the informative blog Reign of Terroir

What control measures are available?

What is spinosad?

ethylene

Sweeten the pot?

2012 update: Our customers who tried spraying, and even those who went out and bought GF-120, simply didn't get good results. Commercial growers spray multiple times as the fruit is ripening, using orchard sprayers that get good coverage. Most homeowners who tried to spray still had nearly complete fruit infestation in 2012.

UC Davis IPM web site article

Reign of Terroir blog notes

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© 2010 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca 95616
www.redwoodbarn.com
Feel free to copy and distribute this article with attribution to this author.
Click here for Don's other Davis Enterprise articles