Safe Organic Control of Peach Leaf Curl and other Fungal Diseases

Safe Organic Control Of Peach Leaf Curl and other Fungal Diseases

It also controls brown rot and other insects. I came up with this recipe based on the knowledge of the excellent anti-fungal properties of Melaleuca (Tea Tree) oil and vinegar. Neem oil has also some anti-fungal and insecticidal properties. The soap acts as an emulsifier and sticker. My peaches and Nectarines have been disease free. No peach leaf curl, no mildew, no brown rot on the fruits, and no aphids.

This recipe is so safe that I don’t need a mask to apply it, and I can lick it off my hands without a problem, and yet it has been very effective for my peaches and nectarines. Beware though the aroma is so addictive, like aroma therapy, from the Meleuca oil. Diluted further (see instructions below), it also controls rust on my roses and citrus leaves.

The Italian Dressing Recipe for Peach Leaf Curl by Joe Real

  1. Add 2 oz of 5% vinegar to 1 gallon of water. Always add acid to water and not the other way around.
  2. In a small cup, mix well together 2 TBSP of Melaleuca Oil, 1 TBSP of Neem Oil, 2 TBSP of Dawn Liquid dishwashing soap.
  3. Add to the 1 gallon diluted vinegar solution, and stir well, hence oil and vinegar and it makes for Italian Dressing.
  4. Mix and Shake very well like you would an Italian dressing before spraying.
  5. Spray during bud swell, but not during the full bloom, and when air temperature is above 40 deg F but below 75 deg F, preferably in the late afternoon.

During the growing season, you can use the same spray but use a diluted version, use 2-3 gallons of water instead of one to control mildew and other fungal diseases but apply towards the evening. Make sure to try out small portion of your trees or plants first to determine the dilution that they can take. It varies with cultivars or species.

You can buy Tea Tree or Melaleuca oil from Amazon or eBay, the cheaper ones work, it doesn’t need to be food grade quality. Neem oil can be bought from Home Depot. Vinegar, just raid your kitchen or buy the cheapest one you can get from CostCo or WalMart.

The above recipe is often enough and would want you to try that one first. And if you have stubborn diseases, such as when they built resistance through the years of using the Italian Dressing Recipe, here’s the ultimate upgrade that as a winemaker I came up with.

In the lowlight evening or morning hours, spray your plants with 0.5% hydrogen peroxide (prepared by mixing 5 volumes of water to one volume of the store bought 3% hydrogen peroxide). Light, especially sunlight quickly degrades hydrogen peroxide so apply during lowlight. Hydrogen peroxide is by itself a very good antimicrobial but the dilution we apply is not that strong.

While the plant is still wet from the hydrogen peroxide spray, follow it up quickly with a spray of my Italian Dressing Recipe mentioned above. This causes a reaction to produce peracetic acid, a mild acid but very effective against numerous kinds of plant and human pathogens. This an additional recipe requested by Daniel Chappell that I mentioned to him when he visited.

Peracetic acid is one of the antiseptics used to clean up wineries and it is easy to produce by combining hydrogen peroxide and acetic acid. So why not simply combine vinegar and hydrogen peroxide in the first place to produce peracetic acid, and then spray? Well, peracetic acid is a very bad irritant, and you don’t want spraying it around without the proper gear.

With my technique, there is no danger of inhaling any peracetic acid as they aren’t being sprayed but formed at the reaction site. By spraying the plants first with hydrogen peroxide and then the vinegar and oil mix, the reaction to produce peracetic acid occurs at the surface where it is also coated by oil, preventing any peracetic acid to form air droplets. The Meleuca and Neem oil, aside from being antifungal, and with the liquid soap, will also minimize the evaporation of the peracetic acid formed, having a more prolonged effect. After a couple days of sunshine, the peracetic acid degrades to water and carbon dioxide and no trace of it but has efficiently killed vast majority of the microbes on the surface from a more prolonged contact. The oils will have also prevented microbial spore formation and dispersal. So if applied at the proper time, Peach Leaf Curl disease would be effectively controlled. Too late though if applied after the leaves pushes out.

Caution: Never apply any fertilizer or micronutrients along with these formulations. It could have unwanted reactions or it could damage the plants!!!


What is your climate and disease pressure like? I live in GA and often organic/milder options that work other places will not work here.

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Nectarines and peaches quickly die out as they suffer from Peach Leaf Curl diseases every year.
Usually rains come in late winter during the bud swell of peaches and nectarines.

Kocide doesn’t work well and lime sulfur is very smelly and can burn the tree limbs.

Good information. Thanks for posting this for us.

Did you once mention immediately following up with a spray of diluted hydrogen peroxide to form peracetic acid on the dormant plant?


When the disease is stubborn, you spray first with a 0.5% H2O2 and then spray with the Italian Dressing right after. To get the 0.5% H2O2, dilute the 3% solution from the store by adding 5 volumes of water.

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Hi Joe,
Thanks for sharing your secret recipe. I wonder have you gotten feedback from East Coast growers who tried your recipe? Are they as successful using it in the humid East Coast?

Usually organic methods are more successful in arid climate like where you are in CA. Not so much in the humid east.

I would like to know if @scottfsmith has tried your recipe. He is our organic guru in the east.


This is actually my first time of sharing this. Been keeping it with me but figured if I’ll be gone too soon, no one will know.


It’s harmless to try. It sounds tasty, too. Thank you for sharing.

Saw your name way back. Read some of your posts. Glad you are here.


I confess I am skeptical of west coast remedies in the east. I think the hot humid nights are a whole different game in terms of diseases spreading. But, we are never going to learn if we don’t try stuff! Hopefully some experimentally-minded easterners will give it a go.


I intend to give it a try. I’ve already sprayed copper for leaf curl so I can’t test for that but I’ll try it on fruit trees and vegetables for other problems.

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Try the ultimate one with H2O2. Best time is few days before bud break. Repeat if rains come again.

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I would disagree with that, not if you use Nufilm sticker with it. or an oil. I have zero peach leaf curl and it’s bad here. I would agree with you if you use the copper liquids. Kocide is much stronger. Plus Copper Hydroxide remains effective longer than the copper sulfates in the liquid, which they have a decreased percentage of sulfate in recent years, too bad!

That could be every other day here in the spring.

Still the method looks super safe, and may work in the Mid-West. It can rain every other day and does at times, although here in the Midwest it’s better than the Northeast for total amount of rain.
Thanks for sharing.


That is so true about respraying so much because of the frequent rains we get around our areas. Almost a daily event.


In the last year I have been reading a lot here about people using copper with oil in the dormant sprays, I myself would not for this very reason you mention, the frequent rains. Nu Film sticker will keep the copper on at least 2 weeks, if not months even if it rains a lot.Great stuff! and it’s made from the pine tree, so a natural chemical. Pinene is the active ingredient. We have bacteria now that can produce this compound. No need to extract it from trees. Cannibis contains pinene too,

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I need to find some of that to use. I got tired of spraying every other day last year to try and keep the sprays on the trees. I had peach leaf curl on the same tree because of the frequent rains would wash it off. I have a pond below my trees and I worry about spraying the copper so often.

I often use copper plus oil plus nufilm in my dormant sprays. I never use copper without nufilm. I also use about 4x the usual dose of nufilm, I want that copper glued on. Do watch out you are not clogging your sprayer, lots of nufilm plus copper can really stick things up and a soap and rinse may be required after. In order to minimize copper I only use it when I really need it, which is currently on the stone fruits in the spring. The apples get lime-sulphur in place of copper, and no nufilm is needed for that.


Agree that copper works. A peach tree dropped half it’s leaves from leaf curl. The next year I used Southern Ag copper with Bonide Turbo sticker and only found two leaves with leaf curl. Timing is very important, with spray in fall and late winter before any sign of bud green.


I am beginning to think that it may not be the copper that effectively works in cases where you have lots of rains. It may have got to do with your sealer, the Nufilm. Through time, these fungi would have developed resistance already, like in our case here, copper don’t work as effectively like before. The most important factor, thinking out loud here, maybe is that when you have a coating of Nufilm that is rainproof or have some waterproof properties, it actually has prevented the spores from spreading by trapping them in. If copper has indeed killed them, even if the spores has spread, there would have been no need for Nufilm because the dead spores shouldn’t germinate on the leaves when they break out. The fact that you needed Nufilm to be effective may not be due to copper but due to the Nufilm itself. Just my thoughts on this. One way to test this is to apply Nufilm without copper. Or you can mix Nufilm with my Italian salad dressing recipe sprayed right after hydrogen peroxide to trap the peracetic acid that was formed for a much longer time.

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An Organic version of Kocide 3000 is scheduled to be released in February.

Its called Kocide 3000 O

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