Cherry leaf spot
Are there any organic fungicides that are effective on cherry leaf spot?
Polk County Oregon
Thank you for your question on cherry leaf spot. The fungicides that are recommended for cherry leaf spot (Blumeriella jaapii) are listed in this reference, and two of them, Cueva and Sulfur 6L, are listed as organic. (The "O" next to them.) However, neither is listed for home use. (The "H" next to them.)
This other OSU publication on home orchards, lists captan, chlorothalonil, myclobutanil, or propiconazole, none of which are organic nor for home use. The time for application for all of these is at petal fall or shuck split, when the fungus is active on the leaf. After that, the fungicide is ineffective, and the damage to the leaf is already done.
Hope this is helpful.
Is there anything that is available for home use? I have two cherry trees that are fairly well established and this is the first year we have had the problem. We would prefer to use something organic but will use whatever we have to as long as it is safe to use around the following creatures;
Dogs, Chickens, Mason, bumble and honey bees, A wide variety of wild birds.
We have a very creature laden yard so I am sure I am missing some but these are my largest concern.
Yes; the two that are approved for home use are Cueva and Sulfur 6L, but they are not organic. By spring, when they should be applied, hopefully you can have it applied before the bees are out (in the morning), and you can keep the dogs and chickens corralled somewhere else. I do appreciate your concern for the environment and your furry and feathered friends! But I cannot advise the use of chemicals that are not recommended by OSU for Oregon home orchards.
As the references say, the best thing you can do that is absolutely organic is to clean up and burn all of the downed fruit, leaves, branches, etc., so that the fungus does not linger in the materials, and do similar damage again in the spring.
Perhaps you can drop into your local Extension office in late winter (before you see any growth on your trees) to see if there are any new/other fungicides that can then be applied. Good luck!
Thank you so much, we will drop in and if there isn't anything new, move forward with one of the two you have mentioned. Have a great summer.
Thank you! You, too! (All of you!)