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Spinosad preparation for apple maggot

Posted by David Maxwell 
Spinosad preparation for apple maggot
July 11, 2021 07:25PM
A couple of years ago I took part in a research study using GF-120 to eliminate apple maggot flies. (And it indeed seemed to work quite well.) What we were in fact testing was the effectiveness when applied as large droplets directly to alternate tree rows vs. little bait stations fabricated out of plastic containers with the cup of GF-120 changed out weekly. (This worked very well, and collected heaps of dead flies, but was hopelessly demanding of manual maintenance. But we did use it indoors in the kitchen to eliminate fruit flies.)

Michael P. made an oblique reference to making his own version of GF-120, presumably by mixing spinosad with molasses, (or ??), but I was unable to find anything more than this one tantalising reference. Can we prevail upon Michael to elaborate, and/or get the experience of others making their own GF-120? (And, is it cheaper that way?)

Broomholm Orchard
Zone 5b in Nova Scotia
Re: Spinosad preparation for apple maggot
July 12, 2021 12:22AM
The fruit fly bait recipe will be found as part of the most recent overview of apple maggot fly strategies in the Spring 2019 edition of the Community Orchardist. Very easy to do. I use approximately a half-ounce of Entrust for the spinosad component (about $8 worth at the current quart price) which I reckon to be about a 0.06% concentration. Keep in mind other spinosad formulations have less active ingredient so recipe rate needs to be upped accordingly.

Fruit Fly Bait Recipe
    0.02% spinosad (active ingredient)
    1 ounce live baker's yeast
    0.5 pound sugar
    0.5 pound dried brewer's yeast
    1 gallon water
Now have several yellow sticky cards up to monitor when AMF appears at which point I will apply the fruit fly bait. This should be spot sprayed on undersides of leaves near developing fruitlets. This location helps lessen rain loss as well as limits UV degradation of the spinosad. Capturing immature flies before egg-laying begins is a huge leg up. I follow this with Ike's version of the red ball trap – red plastic half spheres stapled to yellow-painted plywood, hung with a fruit essence lure – on early ripening varieties about 10 days later. That's generally in the third week of July here.

Lost Nation Orchard
Zone 4b in New Hampshire



Edited 2 time(s). Last edit at 07/12/2021 02:13PM by Michael Phillips.
Re: Spinosad preparation for apple maggot
July 23, 2021 01:52PM
Fly emergence seems slow. There's two possible explanations. One, the fruit fly bait is working really well and thus trap count numbers are not rising as dead flies never report in. Or two, the hoard is waiting for whatever reason after a dry start to summer and this past week of good rain. The nice thing about your GF-120 baiting stations, David, was being able to see dead flies accumulate in the bait cup.

I've decided to mix up a second batch of fruit fly bait. One small tweak is the addition of two ounces of Therm-X, the yucca surfactant, simply to help distribute the mix on the underside of the leaves. You can see the tannish sticky here and there days later so that's satisfying. This weekend I will also start putting up red ball traps with fruit essence lures.

Lost Nation Orchard
Zone 4b in New Hampshire



Edited 1 time(s). Last edit at 07/23/2021 03:06PM by Michael Phillips.
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