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GF-120 (spinosad) and fruit flies

Posted by David Maxwell 
GF-120 (spinosad) and fruit flies
August 20, 2012 09:50PM
I have been using GF-120, which I think is spinosad dissolved in mollasses, as a spray against apple maggot. My wife was complaining bitterly about the fruit flies in the kitchen, and I put out a small dish of the mix in the kitchen also. The counter is littered with Drosophila corpses. Out of curiosity, has anybody any experience with efficacy against Spotted Wing Drosophila? [which has not yet reached us in NS].

Broomholm Orchard
Zone 5b in Nova Scotia

Edited 1 time(s). Last edit at 08/21/2012 05:49PM by Michael Phillips.
Re: GF-120 (spinosad) and fruit flies
August 23, 2012 08:35PM
Good application, David! I like this very much . . . though of course folks have to figure the best way to apply GF-120 to berry plantings and softer tree fruits in order to knock back the SWD scourge. California research has shown that spinosad is the more effective material in our organic tool box . . . but the rub is resistance issues . . . if applied again and again and again and again on a 10 day spray interval. The nice thing about placing GF-120 "hither and thither" on the undersides of leaves is the lure aspect of the sweetner. Now we need people actually dealing with Spotted Wing Drosophila to weigh in with actual observations. You and I may be far enough north to not yet be facing this but in truth, our day will come.
Re: GF-120 (spinosad) and fruit flies
July 19, 2013 06:04PM
Here is sunny central California, Spotted Wing Drosophila arrived with a vengeance a few years back. We were lucky, as the cherries 15 miles north of us mature 2 to 3 weeks earlier than ours. We heard they had a problem, and started monitoring. Our local U.C. Cooperative Extension Agent (Bill Coates, now retired) recommended trying GF120. Our monitoring program worked, and we started treating with GF120!
We spray GF120 2 times per week, starting when we find the first fly or larva. Using a Gator, one worker drives, and the other sprays. A quick spurt on the side of the tree is all that is required, just a small spot. More spots are better than big spots! We only spray one side of the row per treatment.
We monitor using apple cider vinegar traps hung in the shade on the north side of the tree. We also monitor by picking large numbers (100 per acre) of fruit, starting at first pink on the fruit, and opening them looking for the larva. Almost always, it is obvious once you open the fruit, as the larva likes to burrow right around the pit, so the pit is loose and slides out. The larva is small, but easy to find once you know what you are looking for. Generally, we find zero to a few adult flies in our apple cider traps during the whole season, but that is useful information. It tells us our spray program is working.
Some berry farmers in the area have failed badly utilizing GF120 to control SWD, and I've seen literature that says cherry growers in Washington have also failed. For us, in two orchards located 15 and 30 miles respectively from the Monterey Bay, it's worked.
The resistance issue is an interesting one. We only spray for 4-5 weeks, from Black Tartarians to Lapins. We will have to research this more.
An odd fact: the orchard located 30 miles inland was infested for the first time with SWD in 2012. In 2013, it did not show up, and we don't know why not. Saved some spraying!
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