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Overlap Timing of Granulosis Virus and Sulfur

Posted by Susan Fancy 
Overlap Timing of Granulosis Virus and Sulfur
April 09, 2014 12:18PM
I am wondering if anyone has needed to work with granulosis virus, either Cyd-X (CM) or Madex (CM + OFM) at petal fall and the immediate weeks beyond, while at the same time needing to apply micronized sulfur for disease?

How should I get Madex down around sulfur? We are working through a case of
brown rot with plums that requires a stiffer whack to get back to lower inoculum levels.

The virus label is clear that one should not use it with sulfur....but I am not finding guidance on what to do. Use Dipel instead for the moth situation? Wait a few days and then apply Madex? We'll be monitoring the GDD and maybe that will help us out but usally the moths are smart and ready to go at petal fall to do their thing ... any input would be welcomed. Thanks!

Susan Fancy
Sassafras Oaks Farm Zone 5 in SE Michigan

Edited 2 time(s). Last edit at 04/10/2014 09:41AM by Michael Phillips.
Re: Overlap Timing of Granulosis Virus and Sulfur
April 10, 2014 06:03AM
I suspect this label instruction is more about not tank mixing granulosis with sulfur. Most living organisms (including a virus) don't do well in an acidic bath, period. That said, overlapping applications made separately in the same week may not be an issue.

First egg hatch for Codling Moth typically falls between 10 and 14 days after apple petal fall, based on accumulating warmth. Oriental Fruit Moth is related as these are internal feeding moths -- and thus why "regular granulosis" for CM picks up approximately 60% of OFM. I can't speak specifically to how OFM egg hatch ties to the timing of CM, especially in a mixed fruit setting, but do know that Lesser Appleworm (yet another cousin) is just a couple days following CM. One to two weeks after petal fall is basically the right timing for the first application of granulosis virus on apple, followed by a second application 10 days later.

Sulfur applied for brown rot on prunus species at this point is a tad late for the blossom / shoot canker phase of this disease and possibly a bit early for the next phase where spores infect the fruit. (Keep in mind that stone fruit bud phases are a beat ahead of apple.) Sulfur is possibly helpful during plum bloom in this regard ... but once we're into the fruit sizing and fruit ripening windows ... brown rot defense is more about boosting silica and calcium levels. Low-dose copper soap might be the better choice if going the allopathic route.

Lost Nation Orchard
Zone 4b in New Hampshire

Edited 2 time(s). Last edit at 04/12/2014 05:13AM by Michael Phillips.
Re: Overlap Timing of Granulosis Virus and Sulfur
April 10, 2014 10:45AM
You confirmed a suspician about something alive added with a strong chemical as not faring that happily in the tank for the alive creatures. The labels were not helping me figure that out. Intuitively it's what I kept thinking but the compatbility lists don't make that clear. Anyway, OFM is usually 10 days (1-2 weeks) earlier than CM in our setting so it usually backs up to petal fall. The advice to make these sprays in the same week, but separately, is incredibly helpful. I think this will work for us, we'll do that.

Sounds like you've had brown rot and the schedule you proposed worked for you? I noticed the difference between what you shared and the Michigan State University commercial fruit applicator guide - it has some organic options and call for sprays at bloom, petal fall and shuck split, then first and second cover with sulfur, then wait until about 3 weeks before harvest when fruit starts to color for secondary. I wasn't happy with the idea of spraying anything caustic during bloom.

Edited 1 time(s). Last edit at 04/11/2014 06:10PM by Michael Phillips.
Re: Overlap Timing of Granulosis Virus and Sulfur
April 11, 2014 09:33AM
This thread speaks to those immediate weeks after petal fall when numerous concerns come together at the same time. As growers, we choose the solutions that make the most sense for the economy of our operation and the severity of the challenge. Disease inoculum builds up just as do pest numbers. There are years when something more impactful needs to be done, and years when subtler methods will bring success. I happen to believe that health works and tend towards holistic approaches ... recognizing there are situations that warrant an application or two of organic mineral fungicides. I learned long ago that extension agent recommendations for "organic disease control" do little more than mimic the season-long fungicide bath recommended to our IPM friends. That requires very unhealthy orchard practices to justify.

The point being we make choices. And these choices may come with restraints, like granulosis not to be tank mixed with sulfur. Or Entrust (spinosad) not to be used with nutrients that acidify the spray mix. Or Sea Crop not to be mixed with foliar phosphorous as everything will gel. Things are more complicated in the fruit-sizing window than at any other point in the season.

[Editor's Note: Another thread on early season copper speaks to preventing the blossom phase of brown rot. Limiting round one goes far in preventing round two, being the fruit phase of brown rot. Which would be a good topic in its own right.]

Lost Nation Orchard
Zone 4b in New Hampshire
Re: Overlap Timing of Granulosis Virus and Sulfur
April 11, 2014 01:46PM
Looked at that copper thread Michael, will give it a whirl. We are not copper excess in the soil, which is also part of our problem......hopefully it will knock it out. Last year we tried softer stuff (kaligreen, serenade, compost teas) after the rot appeared, new last year, but it won.
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