"New" pest: Spotted-Wing Drosophila

Amanda Witman
By Amanda Witman on Thu, Aug 29, 2013 - 12:08pm

I just had my first hands-on experience with the spotted-wing drosophila yesterday.  That would be the "new" fruit-fly that can lay its eggs in perfect, ripe fruit...doesn't need to wait until the fruit rots to make use of it.

Have others encountered this?  It's a big deal here where I live in Vermont, because I believe this is the first season it's making itself at home in this region in a wide-scale way. 

Makes me want to curse evolution.  Berries are such a wonderful resource for home gardeners and people who like to feed themselves from their yards.

We picked in a friend's raspberry patch yesterday.  (This year was the first summer after transplanting my blueberries from our old house, so I didn't let them set fruit, so haven't had my own experience with this yet.)  Pick-your-own places are closing up shop early in the season once the fruit flies get too much of a foothold.  My friend (an experienced farmer) said you have to pick every day to stay ahead of the fruit fly or lose your crop.  I felt like we were doing her a favor by doing the daily pick for her.  I understand traditional fruit-fly traps can also be used, but I have no idea if the flies are any more attracted to rotten fruit than fresh, and if not, they wouldn't have any reason to find the traps attractive.

The berries we picked that had been affected came off the stem very mushy on the inside, almost like they were bleeding from the inside.  If you looked closely in the "soup" inside, there were little white wiggly maggots, teeny-tiny ones.

We were advised to drop the infected ones on the ground and grind them underfoot as we picked.  I am sure no harm would come to humans for eating them, but they are unappetizing and the "mush" berries aren't firm enough to transport and freeze.

We just froze them all immediately to prevent any newly-laid eggs from hatching and turning seemingly-fine berries into mush a day or two later.

So frustrating!

Does anyone have more information on what home gardeners and homesteaders can do to manage this?

1 Comment

Wendy S. Delmater's picture
Wendy S. Delmater
Status: Diamond Member (Offline)
Joined: Dec 13 2009
Posts: 1982
Amanda, Bt might work

Bacillus thuringiensis (called "Bt") has been used for decades by organic farmers to control crop-eating insects; it gets into larval guts and kills them. Not sure how much this would help with things like raspberries but it protects our peaches, cabbages, cow peas and other things. In my experience you have to spray when things flower, and then once more at 3 to 5 days from then. At-risk crops seem to need a new spray after rain or watering, as it seems to wash the Bt off.

(here is an artile on same.)

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