Controlling peach leaf curl and other fruit tree fungus - Ask Extension
Hello, gardeners! You've been very helpful in the past and now and have a clarifying question. I have a beloved peach tree that suffers from peach lea...
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Controlling peach leaf curl and other fruit tree fungus #888132
Asked October 17, 2024, 6:55 AM EDT
Hello, gardeners! You've been very helpful in the past and now and have a clarifying question. I have a beloved peach tree that suffers from peach leaf curl unless we treat it. You told me I should treat it in the fall in addition to the spring. Gardener's supply told me I should use horticultural oil in addition to the copper I have. I am curious: should I use a mineral-oil-based hort oil, or should I use Neem oil -- or neither? Also, we have just one peach tree and one plum tree (new, just planted, but hte previous one we planted there got "poop on a stick" fungus) that I was thinking to treat. We normally use paint brushed to paint the branches (not a sprayer). Will this work? Any advice on how to do this, specifically? Thank you!
Chittenden County Vermont
Expert Response
Hi Rachelle,
Thank you for contacting the UVM Extension Master Gardener Helpline about your fruit trees.
I was only able to find one reference that mentioned anything about using horticultural oils in combination with a copper fungicide to treat peach leaf curl and it did not specify what type of oil. Here it is:
"Also, “The safest, effective fungicides available for backyard peach trees are copper soap (copper octanoate) or copper ammonium and are known as fixed copper fungicides. Apply either of these copper products with 1% horticultural oil to increase their fungicidal effectiveness. Bordeaux mixture also works but it is a home-made copper sulfate and lime mixture that must be carefully mixed just prior to treatment of the tree. The synthetic fungicides chlorothalonil, ziram, carbamates and ferbam are also very effective. ”https://bygl.osu.edu/node/1895 See the full article for much additional information."
Here is an article that explains the difference between mineral based oil and plant based oil if you choose to use either.
https://upshur.agrilife.org/files/2011/03/Using-Oils-as-
Pesticides.pdf
Every other article I researched only mentioned using a copper based fungicide to treat peach leaf curl.
I believe what you are calling "poop on a stick" is black knot disease. I wasn't able to find anything about painting vs. spraying for black knot. Most of the articles only mentioned treatment once the black knot is knot is present. Here is one link that mentions prevention.
https://extension.umaine.edu/ipm/ipddl/publications/5091e/
Here are a couple of other references for black knot.
https://extension.umn.edu/plant-diseases/black-knot
https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource000566_Rep588.pdf
I hope some of this is helpful for you!
Thank you for contacting the UVM Extension Master Gardener Helpline about your fruit trees.
I was only able to find one reference that mentioned anything about using horticultural oils in combination with a copper fungicide to treat peach leaf curl and it did not specify what type of oil. Here it is:
"Also, “The safest, effective fungicides available for backyard peach trees are copper soap (copper octanoate) or copper ammonium and are known as fixed copper fungicides. Apply either of these copper products with 1% horticultural oil to increase their fungicidal effectiveness. Bordeaux mixture also works but it is a home-made copper sulfate and lime mixture that must be carefully mixed just prior to treatment of the tree. The synthetic fungicides chlorothalonil, ziram, carbamates and ferbam are also very effective. ”https://bygl.osu.edu/node/1895 See the full article for much additional information."
Here is an article that explains the difference between mineral based oil and plant based oil if you choose to use either.
https://upshur.agrilife.org/files/2011/03/Using-Oils-as-
Pesticides.pdf
Every other article I researched only mentioned using a copper based fungicide to treat peach leaf curl.
I believe what you are calling "poop on a stick" is black knot disease. I wasn't able to find anything about painting vs. spraying for black knot. Most of the articles only mentioned treatment once the black knot is knot is present. Here is one link that mentions prevention.
https://extension.umaine.edu/ipm/ipddl/publications/5091e/
Here are a couple of other references for black knot.
https://extension.umn.edu/plant-diseases/black-knot
https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource000566_Rep588.pdf
I hope some of this is helpful for you!
