Sour cherry tree infestation

Question: My sour cherry tree had black webbing on many of the branches 1-2 months ago. All of the ripening cherries are now spotted, rotting. I’d like help with identifying the problem and tips on how to get my tree back to healthy production for next year.

responder: Diane M  Replied June 30, 2024, 8:34 PM EDT
response: Your sour cherry tree may be suffering from  both black knot disease and brown rot.  However, our early spring and very wet weather may be contributing to the damaged cherries, so it's possible that's the issue and not the brown rot.  The black webbing on the branches 1-2 months ago is a strong indicator that black knot is affecting your tree.  It's ,a common fungal disease that affects cherry trees and  causes hard, swollen black galls to form on branches.  Brown rot causes discoloration and wrinkling of the fruit skin.  To deal with the black knot, prune out all infected branches, cutting at least 3 to 4 in iches below the visible knots.  Destroy all pruned clippings and consider applying a fungicide in early spring.  Brown rot is treated by removing all damaged fruit and pruning out infected branches.  Improving air circulation through proper pruning and avoiding overhead irrigation can help reduce humidity and the spread of both diseases.   For detailed information on black knot disease, see:https://extension.umn.edu/plant-diseases/black-knot

responder: The Question Asker Replied July 01, 2024, 9:35 AM EDT
response: Hi,Thank you for your response. I don't see evidence of galls on my tree, but from what I read in the link you sent, I understand that they may show up in the fall and winter. I have a few questions and hope you don't mind giving me more advice.  Should I remove all / most of the fruit now? If so, can I put it in my compost? Some of the leaves have a powdery substance on them - is this possibly due to all the rain and humidity we've had recently? My tree is a North Star variety. Do you have a recommendation for an organic fungicide? Should I wait until next February and March to prune? If I do find evidence of gall growths and prune them out, is it best to dispose of the infected branches away from my property?  Thank you for your time, Julie      Julie M. Longo : Senior Manager of Visual Design and Social Media University of Minnesota Law School413 Walter F. Mondale Hall 229 19th Ave. SMinneapolis MN 55455  612.625.5577   Need design help? Fill out this handy design form to get the process started.    Law-branded Assets:Digital Banners  Email Banners Law School Logos           On Sun, Jun 30, 2024 at 7:34 PM Ask Extension <<personal data hidden>> wrote:

responder: Diane M  Replied July 01, 2024, 8:18 PM EDT
response: It's best to remove all damaged fruit, including whatever has fallen on the ground.  Don't put it in the compost, as the fungus may spread and damage other trees.  The powdery substance may be powdery mildew, due to all of the rain we've been getting.  Remove infected leaves and prune for good air circulation.  You could try a copper-based or clay-based fungicide and consider disease-resistant cultivars for future purchases.  It's generally best to prune a sour cherry tree In the winter, but galls do not need to be pruned. For more information on this cultivar, see  https://trees.umn.edu/north-star-sour-cherry-prunus-north-star

responder: The Question Asker Replied July 02, 2024, 9:53 AM EDT
response: Thank you for your help. Julie   Julie M. Longo : Senior Manager of Visual Design and Social Media University of Minnesota Law School413 Walter F. Mondale Hall 229 19th Ave. SMinneapolis MN 55455  612.625.5577   Need design help? Fill out this handy design form to get the process started.    Law-branded Assets:Digital Banners  Email Banners Law School Logos           On Mon, Jul 1, 2024 at 7:18 PM Ask Extension <<personal data hidden>> wrote: