Bleach as a Brown Rot Fungicide?

As my later peaches are starting to get close to ripe, I’m seeing MAJOR brown rot problems- I mean major- on both the fruit and branch tips near infected fruit.

I have sprayed Myclobutanil every 4 weeks and captan every 4 weeks staggered 2 weeks. So every 2 weeks my peaches have been sprayed with either Myclo or Captan. My fruit also has more peach scab spots than ever.

I’m sure this is a crazy idea, but knowing how effective bleach is on mildrew and other fungi that can appear in a house or basement, I can’t help but wonder if might help to spray my peaches right before they ripen? I am sure there woud be no long term residual or effectiveness- it would be a one shot thing- but I wonder if it might help. I’ve tried hitting peaches with more traditional fungucides right before they ripen but it has little effect. If you haven’t stopped it by the time fruit is almost ripe, my standard fungucides don’t do much of anything. But I wonder if bleach might? I might kill all the bacteria or fungi on the fruit good enough to keep it from regrowing in the 3-5 days between spraying it and harvest.

I guess bleach might sound scary to a lot of you, but of course it breaks down pretty good, pretty fast. I co0uld use a diluted mix, too. And some extra precautions while spraying.

anyway, just a crazy idea. A little googling led me to some discussions on other sites so I’m not the only one to think of it, but I found no clear answer to whether it might work. Crazy or not, you guys got any thoughts. I guess I’ll try Indar next year but this year I’d like to save my peaches

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we were raised on well water but even wells get mold/ bactiria build up so my father used to open the well in june and dump 3 gal. of bleach in it. for 2 weeks we couldnt drink the water but still washed with it. you could smell it but by week 3 it was gone and we just drank the water like normal. he did this every year. diluted properly id think it would be ok.

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Sadly my story matches yours to the T. I think my brown rot is immune to everything. Time for more stone fruit trees to leave. All that intense spraying is getting to be to much and I am still losing the fight.

As a side note. I sprayed the exact same thing you did using almost the same timing. Others were saying that the myclo is worthless. I think our matching stories confirms that.

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It’s my understanding that myclubutanil has vey little effect on BR and captan once a month may not be enough in our humidity without rotating something else in there. I’d replace the myclo with something else before I’d try bleach. Propiocanazole has worked well for me and others. That said, I’m generally a big fan of trying new things.

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Robert, @barry said what a lot of us have experienced. Myclobutanil cannot handle brown rot. If you can get a hand on propriconazole, Indar or Luna Sensation, you probably will get a good result.

I use Indar, 3 -4 spray a year appear to have worked well.


I would use caution. Some plants are sensitive to chlorine
Peach is listed as sensitive in this article.

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Are you using Captan with a sticker and vinegar to get a PH of 5? So far it is working for me. I also used chlorothalonil at petal fall. Actually I’m surprised it is working since we are getting too many days of rain. My fruit is not as mature as yours so I still my have a problem as they sweeten.

I absolutely am! I use pinene II (ie pine sap) as a sticker, and vinegar to lower the ph every single time. So I just don’t know. We had a very wet spring this year so it may have gotten a better foothold back then and is just showing itself now at near-ripening. Brown Rot is always like that for me…and I suppose its that way for everyone but I’m not sure. My trees and fruit look fabulous all spring and summer- even the few fruit that get some kind of rot durring that time don’t shown BR- and then right about the time my stone fruit ripens, BR shows up like crazy. Of course I try to pick off and remove any fruit or branch tips with the brown mold-looking fungus, but with all my trees its hard to keep up.

@Robert I really, really appreciated you telling me that. I kept thinking maybe I’d screwed up a tank, forgot my vinegar once or more (very possible) or otherwise had somehow just screwed up. Hearing that you used almost the same things and same timing does, as you say, tend to confirm that our chemicals and/or timing just aren’t enough. I absolutely do intend to take the advice of @mamuang and others here who are saying use Indar. . But this is frustrating. Before I started using what I do use, brown rot would wipe me out almost completely. So when I started my current routine I was really thrilled with the results. Even last year I didn’t see much BR. But its back with a vengeance!

@barry I think you REALLY hit the nail on the head. You see, last year everytime I sprayed- every 2 weeks, I would use BOTH Myclobut AND Captan. And it REALLY controlled brown rot. But of course it seemed so wasteful and redundant (and expensive) to use both of those every time. So this year I just alternated them. So it one of them isn’t effective on BR (Myclo sounds like its not) then last year they were still getting CAPTAN every 2 weeks but this year they only get it ever 4- and like you said that just may not be enough.

@Hillbillyhort Yea, your probably right about the sensitivity. It was a crazy idea anyway. I just remember once I had a damp basement and mold would grow on one wall that looked a lot like BR fugus. I’d clean it off and it would return. Finally I bleached it and it didn’t come back for a very long time, so my mind keeps making me wonder if I couldn’t do the same thing with BR “mold”. Probably not. thanks.

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I sprayed captan and myclo alternating. Neither were really effective. I have a lot of stone fruit trees and I have been scared of the brands you listed because of their giant prices. Guess it’s time to break out the wallet.

@Kenny_Zone7B_NYC may still have some in small containers for sale. You can reach out to him if you want to try.

If you notice varieties you have that are very prone to rot, you could take them out and keep only the less susceptible ones.

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I wondering, how do you know how much to use in the sprayer? Are you converting oz per acre to amount per sprayer?

There is some member who is good at math and calculate it for me. @BobVance is one of them. I use Indar. Scott has it at 1/4 tsp per gallon of water.


I am OK with math, I just don’t know what amount of water is needed per acre of fruit trees

I sucks at math so I am married to a math teacher :grin:

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For a short term solution I would mix Captan with Myclobutanil and spray both together. Captan is pretty effective against brown rot but it’s easily washed off if you get a lot of rain. Myclobutanil is absorbed into the leaf tissue and much more rain fast. It’s much less effective against brown rot but if you get a lot of rain and high winds it will provide some protection until you can get out and spray again. You might also shorten your spray interval to 10 days or less.

Bleach would kill fungus but as soon as it dries it provides no protection. Plus it may damage leaf tissue and its not legal to use as a fungicide any way.

Long term your best bet is Captan mixed with Indar. Using the Captan at either the full or half rate. You could also substitute Propiocanazole for Indar but I don’t think Propiocanazole is labelled for apples so you would need a separate spray mix for apples.

For you guys that have lots of trees Olpea calculated costs on a per acre basis.

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I think I’m pretty decent at math (98th percentile on sat, engineering degree, etc), but according to my wife, I’m bad at math. Evidently, the math classes in China are much more rigorous. And it probably doesn’t hurt that her father was a math professor (now retired).

She introduced me and our youngest daughter to 24 the other day, a game where you lay out four cards and the first person to figure out how to get them to equal 24 (using any combination of basic operations and parenthesis) wins. I was only able to win 2 of ~10 rounds and our daughter didn’t get any. And my wins were the type where you just add them all up (I was quick enough at that :slight_smile: )

Gardening does give you a chance to actually use math. Not just in calculating concentrations- I’ve even used trigonometry to calculate ground elevation, shade angles from trees, etc. How many people can say they’ve used trig outside the classroom…


I am waiting to know how math could be applied to eliminate pests like squirrels, groundhog, raccoons, opossums and the like?


Range , windage, elevation ,and for those long shots , earths rotation must be factored in, so math .and a bit of luck … Too

Math doesn’t eliminate them, but it shows you what will happen if you don’t (figure how many offspring per generation when ample food is available (your trees…), how long the generations are, etc). Don’t forget rabbits- they breed like…rabbits. So, if you eliminate earlier generations, then they won’t be around to have kids and grandkids.

I saw a youtube video recently which relates in a grim way. During WW 2, Russia lost so many people that every 20-25 years, their birthrate drops when the kids, grandkids, great-grandkids, etc of those people would have been having kids of their own. Only 20% of the Russian boys born in 1923 lived to see their 23rd birthday in 1946. The end result is that while Russia was 3rd in world pop in 1900, they have barely grown at all while most of the others on the list have grown 3X or more (US from 76M to >300M).

Now, while it is a bad for people, it is generally a good thing to have all the squirrels, raccoons, etc die. The trick is finding a way to do it.

And while Russia doesn’t have enough immigration to boost their population after 80 years, it is a lot quicker for new squirrels to move into the area. :frowning:


Glad you started this post. A few days ago I didn’t have a problem with brown rot and was happy my previous sprays where successful. I checked this morning and I have it now. 4.6 inches of rain in the last two weeks. Only a few sunny days in two weeks. Woke up to 95% humidity the last few days. I was waiting for a few dry days before spraying but that was a mistake. I removed as much of it that I could find and sprayed with Captan and Propiconazole, the only safe fungicides I had available.