I’ve had almost 100% success using copper in late winter for leaf curl. Most articles say to use it in late winter when tree is dormant. For Bacteria Spot they recommend use from late winter to shuck split. I do remember reading a research article that recommended using copper from pink to first blossoms open for Leaf Curl also.
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Good isn’t bad. Right now its all I have to work with but you do have a way to purchase Indar. Or something better, Check on a group buy as all of these products are expensive.
Copper is fungicide and bactericide but it is not a cure all for several diseases peaches has for growers in the east coast.
Copper helps with peach leaf curl and bacterial spot but is not helpful with brown rot. Sooner or later, you will encounter brown rot in peaches (cherries and plums, too).
If you cannot find a group purchase of Indar, Bonide Infuse (propicanozole) is a good alternative and affordable. For a few trees, I am less worried about a fungicide resistance problem.
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Of course, for apples Cornell considers it very effective for scab and CAR as well. This is why I can use Indar in my second post petal fall spray in an attempt to reduce brown rot inoculum. After that a subsequent summer spray of Indar or Pristine is often all I need to counter brown rot in the orchards I manage.
Fungicides that don’t wash off in the rain are extremely helpful in the east where we tend to get rain throughout the growing season.
Indar basically eliminated my brown rot problem. Propiconazole was good, Indar is great.
Are any of the more highly-rated things not too expensive (and not in group 3)? I am using Elevate as my alternating chemical with Indar to keep resistance down, I bought it due to price. I think I have another year or two supply of it before I will be looking for something to replace it.
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On a cost per acre basis, I don’t know of anything cheaper than Indar and Propiconazole.
Captan is the next cheapest. It runs something like $20/acre. I think Indar is closer to $15/acre. As you know, propiconazole is even cheaper.
I tank mix propiconazole with a 1/2 rate of captan for very good control, at a very reasonable cost.
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Mark,
Your combo of propiconazole and Captan is reasonable-priced so we don’t need to mortgage our houses to afford pesticides 
.
If I use food grade vinegar, is it a tbsp of white vinegar per a gallon of water for Captan?
Hi Tippy. Sorry for answering so late.
It depends on the concentration of acetic acid in the vinegar. It also depends on the pH of the water and the alkalinity (ability to resist acidification).
For my water, one teaspoon of citric acid per 16 gallons of water, will bring my pH down to 5.9, which is about where I like it for Captan, or any other pesticide subject to alkaline hydrolysis.
Vinegar of course can be used as an acidifier, but it takes about 24 times the amount of vinegar (by volume) as it does citric acid. So one teaspoon of vinegar will acidify about 2/3 of a gallon of water at the 5.9 pH level. Vinegar is convenient and cheap enough for small batches of spray, but it gets a bit pricey for large volumes of spray.
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What is your pH to begin with?
Mine is very high. It starts out at about 9.4 pH.
Wow, so my 7.2 pH water should probably only need about half a teaspoon for my 25 G tank. I’m thinking of using it instead of the chemical penetrant and acidifier I’ve been using. I’m not sure I really need the penetrant, although I tend to go for overkill. The crap can be dangerous if you splash it into your eyes.
Thanks, Mark. My hubby said we have food grade citric acid.
My town water is not that as high in ph as yours but I will check to be sure.
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Mark,
Why half rate of Captan instead of full rate of both Captan and propiconazole? How often you you spray this mix? From petal fall and a few times afterward?
Every different water supply has a different ORP which means one persons water at 9.4ph with a low orp could be swung to 6.0 by a few points with a tablespoon per gallon where as another person could have a ph of 7.4 and very high ORP a tablespoon of vinegar may not get it under 7.0.
This is why Its best to use a meter or drops to measure ph
It’s also why I question some people’s usage of pesticides I’m not sure they understand all the downhill affects and wish people would do things to slowly improve the issue rather than make it worse
Different people have different views on how to accomplish this, and different levels of experience and knowledge in which to draw their conclusions.
It isn’t always the best informed who feel most compelled to preach their perspectives- but this forum isn’t about preaching perspectives.
The way to do this indirectly is to share good advice about specific methods that lead to the results we all want.
Hi Tippy,
There are several reasons. One is cost. Propiconazole is less than a couple bucks per acre to spray (Rate is only 4 Oz/acre). Captan is about $12/acre at the half rate. So that’s about $14/acre total.
Second, Captan, at the full rate, leaves an unsightly film on the fruit. So I don’t like to use it at the full rate close to harvest.
Lastly, I’ve found it only takes Captan at the half rate (if mixed with propiconazole) to get pretty good brown rot control.
Captan has multiple modes of action against fungi. So adding it to the propiconazole not only gives better control, it also reduces risk of fungi resistance vs. just propiconazole.
Under high pressure, with frequent rain, I use the full rate of captan in the tank mix.
Like other DMIs, propiconazole is labeled for a couple applications early on (for blossom blight) and a couple pre-harvest applications for brown rot on fruit. I only use it pre-harvest for brown rot.
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Some formulations more than others, in my experience. Captan Gold 80 doesn’t leave much, even at full strength for me.
Hmm, I’m not used the specific Adama forumulation. I do use an 80% active ingredient vs. a 50% formulation more commonly sold.
Maybe I’ll give Captan Gold 80 a try.
You can try it out with a small bag- not too much investment.
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I guess its just crazy to me that people do not know what ph they are spraying these chemicals at and i also assumed in whatever pesticide registration class or whatever you took they would have taught you about ORP and potential hydrogen.
Maybe pesticides that require specific ph should come pre mixed or you should go to your chemical supplier for refills. Its hard for me to find a chemical they dont want you spraying with reverse osmosis water or distilled also and i feel very few people do that on here. Maybe you should have to pass a questionaire before you go spray these things into peoples backyards OR maybe we are doing things the smartest and best way possible currently.