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Peach leaf curl questions.

Posted by beeman_gardener 5 (My Page) on
Fri, Sep 14, 12 at 18:51

My fruit trees have had a horrible year. First off a ridiculous early start, then a cold spell which set everything back. Lots of insects wiped out completely and blossoms irreparably damaged. So no fruit this year. Then a major drought over 3 months, just an odd sprinkle, hardly enough to keep anything growing. Long term damage?
Which leads to a question. My peach tree got Peach leaf curl and by the time I got it under control a lot of the small branches are leafless. Is it going to come back, or are those small branches wasted and will need removing?
Is Serenade a preventative use for Peach leaf curl?


Follow-Up Postings:

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RE: Peach leaf curl questions.

If the branches still have green wood they will probably come back, but usually PLC does its damage in spring and all infected leaves drop and new growth during summer is unaffected. I expect branches that didn't grow new leaves beyond infected area will be done.

PLC isn't much a problem for me as I grow varieties known to perform in the East and trees are planted on sites with good morning sun and pruned open. Where it tends to appear is in crowded parts of my nursery with some eastern shade.


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RE: Peach leaf curl questions.

H-man, what spray and when do you suggest is the best for PLC. Many thanks. I had one tree affected this past spring. It grew out of it. But I need to be prepared for this Feb. with spray? Mrs. G


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RE: Peach leaf curl questions.

Chlorathalinil is what I've used in the past. Spray must go down shortly before first growth. Olpea is more up to date on this I think as I've not sprayed for PLC in over a decade.


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RE: Peach leaf curl questions.

  • Posted by olpea zone 6 KS (My Page) on
    Sun, Sep 16, 12 at 9:29

Yeah chlorothalonil is the most effective product for PLC. If we don't spray for it here it shows up pretty bad, this year being the exception because of the dry spring.

For an organic option, I'd recommend copper instead of Serenade. Copper is almost as effective for leaf curl as chlorothalonil and does a good job. I don't believe Serenade is labeled for PLC. As such, it's probably not the most effective product, although it might have some effect. As I understand, part of the problem with Serenade is it's short lived, whereas copper and chlorothalonil retain efficacy pretty much until they are washed off.


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RE: Peach leaf curl questions.

Can a home orchardist buy this product, or do you need a license? Mrs. G


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RE: Peach leaf curl questions.

  • Posted by olpea zone 6 KS (My Page) on
    Sun, Sep 16, 12 at 9:43

Chlorothalonil is available in several homeowner formulations. Daconil and Fungonil are a couple homeowner formulations that should be available at big box stores. Just check the label before you buy it to make sure it's labeled for your peach trees.


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RE: Peach leaf curl questions.

H-man and Olpea, thanks so much. After searching the web, I can find it, but the amount I have to buy is rather large, but I'm sure I'll use five pounds of it over the years. There is a generic brand "Docket DF Fungicide is a low-cost generic form of the name-brand Daconil Ultrex (Chlorothalonil). It is made by Syngenta, the same company that makes the Daconil". This is what I am looking to purchase, I hope this is the right product. Many thanks guys! Mrs. G


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RE: Peach leaf curl questions.

You need License sold under these names AGRONIL, BRAVO, DACONIL, EXOTHERM TERMIL, TERRANIL.


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RE: Peach leaf curl questions.

Here a pint bottle free shipping.

Here is a link that might be useful: Fungicide


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RE: Peach leaf curl questions.

Chlorothalonil 29.6% Gator, thanks! The fungicide you recommend only has a small, percentage of chorothalonil. Is that enough to kill the PLC spores? thanks so much, Mrs. G


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RE: Peach leaf curl questions.

29.6% that for homeowners 40% for commercial application take a license to purchase.

29.6% has 7-10 spray interval 40% has 7-14 day interval.

Rain wash it all off so spray after rain dries in other words if rains 3 times in week spray 3 times.

The buds what want to spray this select last pruning time.

Remember Chlorothalonil preventive fungicide so spreader sticker helps hold Chlorothalonil on buds.

This link Tiram below my favorite. Takes care all my fungus problems.

On the above spray soon as leaves fall, mid winter, and month before bud break and until first ones they break.

Here is a link that might be useful: Tiram


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RE: Peach leaf curl questions.

I don't know about chlorathalinal, but it usually takes at least an inch (2" for pesticides I use) of rain to require respray in week following application. I'm also not sure how this fungicide is working against PLC- if it's destroying the existing fungus in the tree or preventing new fungus from elsewhere establishing on the peach. Any insights on this, Olpea.

I have found that with brown rot it is often enough to spray just one time in a peach tree in a season when I use Indar, which suggests to me that most of the destructive fungus is already in the tree with brown rot.

Nothing in the literature I've read backs me up on this, though, at least not specifically. I have a site where they hate having me spray but could not grow a single peach on any variety they have because of severe brown rot. Now a single spray solves the problem, including varieties that don't ripen for a couple months after spray. I have a hunch that a single spray could work for PLC as well, just by reducing innoculum. Of course, the fact that Chlor. is a preventive and not an irradicant might mean otherwise.


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RE: Peach leaf curl questions.

  • Posted by olpea zone 6 KS (My Page) on
    Sun, Sep 16, 12 at 17:23

Gator,

I'm not sure what you mean in some of what you mention above.

I'm not aware of any chlorothalonil product that requires a license. I use a chlorothalonil product called Echo. It has 90% active ingredient and does not require a license. However Echo is packaged for commercial production (a water dispersible granule in 20 lb. bag).

Daconil is packaged as a homeowner formulation and is sold in small quantities at farm stores around here.

In regards to PLC, it doesn't matter what the spray interval is for chlorothalonil because, except under extremely heavy pressure, one spray will take care of PLC. I spray for PLC one time prior to bud swell. There would be absolutely no reason to spray it three times in a week.

Chlorothalonil is slow to break down, so it retains it potency for quite some time. It is also fairly impervious to wash off. I once got some overspray on a window. The film lasted all summer long.

Labels for chlorothalonil recommend a spray in late fall and another in early spring (before bud swell) under heavy pressure. I've found one spray before bud swell completely eliminates PLC here, even under the wettest spring conditions.


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RE: Peach leaf curl questions.

Thank you Olpea. You are a great asset here. Nice to know, even though I am not managing PLC.


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RE: Peach leaf curl questions.

Whew! Thanks Olpea! I thought I'd be spraying a lot, since we get fog and rain here. So Daconil will work just as well. Good to know. Many thanks, Mrs. G


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RE: Peach leaf curl questions.

  • Posted by olpea zone 6 KS (My Page) on
    Sun, Sep 16, 12 at 21:39

Thanks for the nice comments. They mean a lot especially coming from someone as experienced as Hman and someone as enthusiastic as Mrs. G.

I noticed I missed the question about chlorothalonil destroying existing fungus and/or preventing new fungus.

Although chlorothalonil is classified as a preventative fungicide, it's preventative from the perspective of leaf infections. Since it has no systemic action, it has no curative potential once leaves are infected because they are infected systemically.

However, leaf buds are infected from fungus on the bark. The fungus on the bark is not systemic rather on the surface of the bark crevices. Chlorothalonil will kill fungus on the bark, as well as prevent new fungus from developing as long as its fungicide residues remain on the bark.

Regarding Daconil, it will work fine Mrs. G, despite it's lower active ingredient. Labels generally adjust for this and typically call for adding more of a weaker concentrate so that the final spray solution has the same amount of active ingredient as one mixed with a stronger concentrate. In the case of Echo, because it has a high % active ingredient a much smaller amount is required for a finish spray.


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RE: Peach leaf curl questions.

Olpea, and H-man these answers are so important to me as I knew nothing of peach leaf curl when I planted my first peach trees. One tree my 'Elberta' had a horrible case of PlC this summer. Not one piece of fruit was deformed or fell off. All new leaves grew in and the tree is beautiful. BUT now I know the fungus is already in the tree, so my first spray will be this Nov. then Jan, then before bud swell. My two newer peaches will get the same treatment. I hope this is correct. Mrs. G


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RE: Peach leaf curl questions.

Fungonil is what I purchased. It is good for stone-fruit. Tried to buy Equus and Bravo,but couldn't. Thanks Olpea and H-man! Mrs. G


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RE: Peach leaf curl questions.

At the big box you won't find bravo. You have to look at ingredients as they usually have a chlorothalinal formulation.


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RE: Peach leaf curl questions.

I happen to know for a fact that Hi-Yield Bordeaux also works.
I had a peach that ALWAYS had terrible PLC (before I knew what it was). Last winter was the first time that I tried to control it. Two sprays during the dormant period and this year it was GONE!


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RE: Peach leaf curl questions.

"had a horrible case of PlC this summer. Not one piece of fruit was deformed or fell off. All new leaves grew in and the tree is beautiful"

Your quote reminds me I went to a guys house earlier this summer and he had a mature peach tree that he multi-grafted. It had PLC and I asked him what did he treat it with, he told me "absolutely nothing, just leave it".

There are two peach trees in a parking strip down the street from me that have PLC. They fruit well, drop the PLC leaves, and put out new ones.

My question is; why put the time/money/effort into spraying for PLC when it doesn't effect the fruit ever or the tree in most cases?


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RE: Peach leaf curl questions.

  • Posted by olpea zone 6 KS (My Page) on
    Thu, Sep 20, 12 at 21:15

Mike,

In severe cases PLC can affect the fruit with major scarring. Once, it was bad enough on one of my trees to affect some of the fruit.

The larger problem is that the defoliation weakens the tree, but it really depends on the extent of the defoliation. Around here it's generally bad enough that I think it contributes to the quick decline common of unmanaged peach trees.

It also affects fruit quality. It takes a lot of energy to regrow leaves, some of which would have gone into the fruit. Furthermore the loss of photosynthesis from defoliation reduces the amount of carbohydrates in the fruit, which affects both fruit size and sugar content.

PLC is one of the easiest diseases to treat and the payoff in better fruit quality and healthier trees is generally worth the effort.


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RE: Peach leaf curl questions.

Thanks Olpea....


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RE: Peach leaf curl questions.

Here, severe PLC seems always to ruin the quality of peaches on afflicted tree. It is a matter of severity of the infection. If a tree completely defoliates the fruit will not be any good, in my experience.

I do think it is always a good idea to try to calibrate the damage threshold before taking action against a pest. That is standard IPM.


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RE: Peach leaf curl questions.

I heartily agree with 'Harvestman' my tree hasn't recovered, looks terrible, straggly and weak. The smallest thin branches are dried out and won't recover.
My tree was defoliated, fruit blossoms fell off as well, so not fruit whatsoever.
Still looking for an answer regarding 'Serenade'? Has anyone any information at all on this product, as the suggestions from the forum to prevent PLC are difficult to find here in my area of Ontario, Canada.


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RE: Peach leaf curl questions.

Serenade is certainly not recommended by Cornell for PLC and the organic rec is copper. They do mention Serenade as a possible help for control of apple scab, so it's not off their radar. Why would you even suspect it is affective against PLC? Any actual research is probably findable.

Anecdotal testimonials would be suspect because of the variability of pressure and susceptibility season to season, site to site, cultivar to cultivar.


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RE: Peach leaf curl questions.

I know that copper certainly didn't control it on my nectarines.


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RE: Peach leaf curl questions.

Hilton, did you apply before bud break?


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RE: Peach leaf curl questions.

since my last post I have done some research and discovered that Lime Sulphur is still available in my area.
So, harvestman, What do you think? Use it when dormant? Can I use it on all my other fruit trees?


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RE: Peach leaf curl questions.

Hman - yes, when the trees were totally dormant.


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RE: Peach leaf curl questions.

beeman, I've only used chlorathalinol for PLC and have no experience with lime-sulfur. my spray approach is to try to have at least a month between last spray and eating fruit but i've no big issue with synthetics.


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RE: Peach leaf curl questions.

Looks like the UC cooperative extension ran a peach leaf curl control trial this past spring. The results can be found at the link below. Chlorothalonil is mentioned in the introduction of the trial results, but it doesn't look like they actually tested it.

Here is a link that might be useful: peach leaf curl trial


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