Fungal and Disease control at high temps?

[HanksHill]

I have 150 vines in the ever-so-humid and wet state of Maryland. I learned the hard way last year you can't really spray wettable sulfur mixed with mancozeb anytime when the temp will get above 90 in the next 3 days without burning your foliage. Luckily everything made it, but the problem is in MD it's pretty much assured you will have temps above 90 sometime in the next 3 days. I've gotten pretty lucky this year but have some powdery mildew starting and am looking for another alternative. Any help would be appreciated! PS I'm using a backpack sprayer/mister if that matters.

 

[VinesnBines]

You are going to have to pull sulfur from the rotation until the temps drop. Are your grapes bearing? If so you need to switch off Mancozeb as well. Mancozeb has a PHI of 66 days and depending on variety, you are probably past that pre harvest interval or mighty close.

This season is high fungal pressure year. I've had black rot, downy mildew and I'm seeing powdery on my baby table grapes.

So, if not bearing, hang with the Mancozeb and add Rally or Immunox (both are myclobutanil) or something else that is PM specific. Prolivo or Gatten are non sytemic. Rally is systemic.

I splurged on Pristine last year and one spray this year seems to have halted the DM. I didn't use it on the table grapes, hence the PM. I'm alternating Pristine with Captan and Rally.

Check out the Vinesmith Spray guides. The entire set is pricy but one set will last for several years. I've been reading the charts every couple days to keep on top of these sprays.

 

[HanksHill]

Thanks - yeah they're not bearing yet. I talked to a commercial vineyard owner yesterday who uses sulfur at all temps below 90 but I'm still wary. I sprayed a very low sulfur mix yesterday since it was only 80 and not supposed to get above 85 today but I will check out Rally. Systemic is always good. Do you mix it in a small tank? If so would you mind sharing the ratio? Most stuff is measured in lbs/acre or something like that which doesn't really translate into a small vineyard/backpack sprayer.

 

[VinesnBines]

I use Immunox (same as Rally) in the hand sprayer. The instructions are on the bottle. I think 1.5 ounces per gallon but check the label to be sure. I get it at Lowe's or this is the Amazon link.
https://www.amazon.com/Spectracide-...&qid=1658148044&sprefix=Immunno,aps,67&sr=8-2
I had foliage burn by using Fruit Tree Spray. It has captan, carbyl and malathion. I think the malathion was the culprit. I also have some FR/AM red hybrids that are sensitive to sulfur so I am careful.

 

[wood1954]

Sulfur is really only good for powdery mildew, so if you don’t use it, you can use Heritage, myclobutanil or tebuconazole thru in Captan and you’re covered for all the major mildew, Heritage is azoxystobulin

 

[balatonwine]

am looking for another alternative.

Above comments gave good non-organic alternatives.

If you are looking for organic alternatives let me know.

 

[VinesnBines]

Above comments gave good non-organic alternatives.

If you are looking for organic alternatives let me know.

Vine smith has organic charts. The problem is finding the organic products.

I have sulfur and copper sensitive vines so those products are in rotation only for part of the vineyard.

I’m looking for alternatives as well.

 

[balatonwine]

I have sulfur and copper sensitive vines so those products are in rotation only for part of the vineyard.

I’m looking for alternatives as well.

Have you considered Potassium Bicarbonate (commercial product Armicarb®, et al), Serenade®, or Neem Oil? Only to name a few options.

Non petroleum based horticulture oils* also work well against powdery mildew, but not the other diseases so much. When things get wet, see above, et al.

* or if not organic, petroleum oils also work well. But these are oils designed for spaying plants. Do not spray your 10W-40 auto oil on your plants.....