Powdery mildew

  • April 6, 2023 at 12:57 am #193
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    Powdery Mildew
    Posted by Nathaniel Bouman
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    Nathaniel Bouman
    Powdery Mildew
    November 13, 2017 07:30PM Registered: 8 years ago
    Posts: 75
    I’ve got a bad powdery mildew problem in my apple orchard. The stokes red are particularly bad off (the whole orchard is 3 years old) and it’s affecting the growth of the trees. Most of the smaller branches are sheathed in white on the stokes red. It’s a problem that really took off during the drought of 2016 (no rain but it stayed humid enough here). I was too inexperienced to catch it then and then this past season my attempts at control were kind of haphazard. I tried:
    potassium bicarbonate
    sodium bicarbonate
    stylet oil
    sulphur
    neem
    milk
    Serenade
    Trees seemed to perk up after the stylet and bicarbonate (potassium or sodium didn’t seem to make much difference) but nothing got rid of the ghost twigs on the most badly affected varieties.
    I hate trying to treat this because it’s taking time away from working on whole tree health.
    Has anyone encountered this kind of problem? Can you recommend a protocol for cutting down this pathogen? Do I have to engage in radical pruning?

    Nat Bouman
    Growing cider varieties in Zone 5b
    On B.118 at 18X24
    Susquehanna County, Pennsylvania
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    Karn Piana
    Re: Powdery Mildew
    June 12, 2018 09:33PM Registered: 4 years ago
    Posts: 77
    There is research on the use of Hops resin acid extracts as an effective counter to powdery mildew (Pseudoperonospora Humuli) . There is a conversation where this comes up in a thread titled Holistic Approach to Fire Blight in this forum if further rabbit holing is desired.

    Karn Piana
    Zone 7 Semi-Arid Steppe
    Northern New Mexico
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    Glenn Aldridge
    Re: Powdery Mildew
    October 08, 2019 02:51AM Registered: 6 years ago
    Posts: 8
    Had a tough season with Powdery Mildew here in Nassau Count, Long Island NY.. Not surprising, as the humidity was heavy as usual. I’m wondering if anyone has any experience with spraying milk or whey for powdery mildew. I’m told the grape growers are having success with it.

    Also, can report that I used pheromones for Oriental Fruit Moth with great success…. It is expensive, but it works.

    Tks in advance
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    Nathaniel Bouman
    Re: Powdery Mildew
    October 08, 2019 03:18AM Registered: 8 years ago
    Posts: 75
    I’ve tried milk. Started with powdered milk and rehydrated to make “milk” and then added to tank to make a 10% solution. I sprayed early in the PM season and mid growing season. I noticed no appreciable difference, sadly.

    Nat Bouman
    Growing cider varieties in Zone 5b
    On B.118 at 18X24
    Susquehanna County, Pennsylvania
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    Chris Vlitas
    Re: Powdery Mildew
    October 08, 2019 10:43PM Registered: 9 years ago
    Posts: 47
    Edited for brevity

    Edited 1 time(s). Last edit at 09/30/2022 05:39PM by Chris Vlitas.
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    Mike Biltonen
    Re: Powdery Mildew
    October 09, 2019 05:33AM Registered: 10 years ago
    Posts: 276
    Just remember that there are different species of “mildews” out there. Not all react the same to “milky” sprays. That said, I know that veg growers have had success spraying a yogurt or whey spray rather than just milk. Its the probiotics that works. In some cases mildews can be superficial, while others can be more invasive meaning that they infiltrate the cuticle of the fruit or veg. For apple, I would begin to work with a stronger probiotic yogurt spray, potassium bicarb or stylet oil (or combo) for better control. Bear in mind that the inoculum overwinters in the bud scales and is first active right after bud break. Start early, don’t wait for normal PM weather.

    Mike Biltonen, Know Your Roots
    Zone 5b in New York
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    Chris Vlitas
    Re: Powdery Mildew
    October 09, 2019 06:06PM Registered: 9 years ago
    Posts: 47
    Edited for brevity

    Edited 1 time(s). Last edit at 09/30/2022 05:38PM by Chris Vlitas.
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    Glenn Aldridge
    Re: Powdery Mildew
    October 17, 2019 02:09AM Registered: 6 years ago
    Posts: 8
    My sincere thanks to you all for your advice! I think I will try the SeaCrop in part of the orchard, and whey in another to begin with…. Luckily, I can get whey from our Amish friends, so the probiotics should be intact (no pasteurization).

    I will report back next year on my findings

    Glenn Aldridge
    Restoration Farm
    Nassau County, Long Island, NY
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    jim gerlach
    Re: Powdery Mildew
    June 20, 2020 04:49AM Registered: 7 years ago
    Posts: 3
    There is some good research on the efficacy of whey with powdery mildew on wine grapes in Australia. I’ll see if I can find the paper. We do not have issue with mildew but I used whey in a spray last late summer/fall. Go with a very dilute concentration and make sure you get good mixing. It will severely burn pears.

    Jim Gerlach
    Nashi Orchards
    Vashon Island, WA

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