While the recent hot weather may limit damage to our plums if it keeps up, we’ve spotted the Spotted Wing Drosophila in our berries now that the cherry crop is history. The Sonoma County Ag Extension IPM rep pointed me toward the UC IPM How to Manage Exotic and Invasive Pests page, which includes the following useful links:

Spotted wing Drosophila

In addition, there are a bunch of other resources out there, including Oregon State’s Spotted Wing Drosophila page and this story on OregonLive.com.

Though the berries and stonefruits are an important part of the California ag economy, the fly has the potential for much bigger impact — Oregon researchers identified the larvae in samples of Willamette Valley wine grapes in 2009. A posting on Reign of Terroir summarizes developments to date, with the discouraging list of possible host plants:

“D. suzukii has a wide host range and can attack many fruit crops, including small fruit crops, fruit trees and grapevine. Its host range includes: Actinidia spp. (kiwis), Diospyros kaki (persimmons), Ficus carica (figs), Fragaria ananassa (strawberries), Malus domestica (apples), Prunus avium (sweet cherries), P. domestica (plums), P. persica (peaches), Pyrus pyrifolia (Asian pears), Rubus armeniacus (Himalayan blackberries), R. loganobaccus (loganberries), R. idaeus (raspberries), R. laciniatus (evergreen blackberries), R. ursinus (marionberries), and other blackberries (Rubus spp.), Vaccinium spp. (blueberries), Vitis vinifera (table and wine grapes).”

U.S. fruits have already been quarantined for Australia, which fears infestation of their wine grapes, and will likely be quarantined for Europe as well.

The hardy flies, which can produce as many as 13 generations a year and can overwinter through fairly harsh conditions, will likely become established throughout the U.S. Unless effective management techniques can be developed soon, we may see very widespread infestations until predators are introduced or natural selection takes its course.

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