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kudzu9

Spraying for Peach Leaf curl

kudzu9
12 years ago

Last year I had Peach Leaf curl and wanted to spray...but the fall was so wet here in the Pacific NW that it never seemed like a good time. I am just starting to get budding and want to know if there is any harm to the tree in applying a copper-based spray right now.

Comments (7)

  • wildforager
    12 years ago

    Kudzu,

    Not to dodge your question, as I'm not sure of the answer but I have a tree that suffers from PLC as well. I'm working on grafting over it with J-plums and Pluots...and what ever else I can get to take. I've got a few different stone fruits on there now and they just shrug off the PLC while the rest of the tree suffers. If you're really set on having a peach and are interested in working over your tree, check out these varieties that are supposed to be PLC resistant.

    -John Muir
    -Oregon Curl Free
    -Avalon Pride
    -Autumn Rose
    -Indian Blood Free
    -Q-1-8
    -Charlotte
    -Kreibich Nectarine
    -Five Star Curlless
    -Clayton

    Good luck!

  • blazeaglory
    12 years ago

    Spray now or before flowers open at "pink" stage but definitely before green. Yes copper is alright. It would be good to spray after leaf fall as well.

  • blazeaglory
    12 years ago

    Wild. Usually PLC overwinters in the buds so when the disease is present Im not sure if it will show on new growth that is disease free. The disease should show up during the next growth cycle the following year, if Im not mistaken. I could be wrong though.

    I would like to know if there is a true resistant tree out there

  • wildforager
    12 years ago

    I have an Elberta peach that suffers badly with PLC. I've grafted Santa Rosa, Burbank & Toka plums as well as Black Velvet Pluot onto the tree. For several years these branches have no reaction while the rest of the peach branches are badly infected and curling. The variety Q-1-8 seems to be pretty resisitant. Check out the link below, hope you can see it. Its on facebook....

    Here is a link that might be useful: Q-1-8 vs Mary Jane peach

  • olpea
    12 years ago

    Wildforager,

    I didn't know Clayton was PLC resistant. Where did you come across that info.?

    Kudzu,

    The life cycle of leaf curl is that it overwinters in leaf scars and on the bark. The disease washes into the bud scales as they loosen in spring. Once in the leaf buds, it infects the leaf tissue systemically.

    Signs of the disease don't show up right away. At first the leaf tissue looks like it's emerging normally. After a while you start to see the distorted leaves with occasional red bulbous tissue. Defoliation of infected leaves occurs after that.

    Spraying in the dormant season breaks the cycle. In my opinion the optimum time is just before bud scales loosen. Spraying in the Fall is frequently recommended, and while I'm sure it's successful in most cases, it does run the risk of allowing the disease to reestablish itself on the bark of trees before Spring arrives, which happened to me once. The advantage of Fall spraying is that it generally provides decent protection if you don't get the chance to apply in the Spring before bud swell.

    Once green tissue is showing sprays will do little good to control the disease, since the tissue has had ample time to become infected. Still, you might gain a small benefit in spraying now.

    For reasons I don't understand, just because the leaf tissue is infected, does not necessarily mean it will develop into disease. It still takes humidity and rain as leaves emerge to cause disease in leaf tissue.

    I don't use copper much during the growing season, but my gut feeling is that at this early stage of leaf development, you could probably apply your copper spray without any significant harm. At worse case, I'd expect it would burn the tops of the emerging leaf tissue, but this is just a guess.

    I mostly use Chlorothalonil (sold in homeowner formulations like Daconil, Funganil, etc.) for leaf curl. It might be an advantage to you in this case because it's much phytotoxic than copper and slightly more effective against the disease.

  • olpea
    12 years ago

    I wrote:

    "It might be an advantage to you in this case because it's much phytotoxic than copper and slightly more effective against the disease."

    It should read:

    "It might be an advantage to you in this case because it's much less phytotoxic than copper and slightly more effective against the disease.

  • kudzu9
    Original Author
    12 years ago

    Thanks, everyone, for the input. I feel a lot more comfortable now dealing with this.

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