Well it certainly looks like leaf spot disease. I planted four of these Montmorency Cherry trees this spring, they were all doing great until summer started. They have all stopped growing, even though I am watering them regularly with fertilizer. I put a bucket of water on each every few days. They have been looking great, until the summer heat came in. I live in the Midwest, Illinois. The last several days have been very close to the 100s, with brutal humidity. Suddenly, one of the cherry trees exploded with yellow spotted leaves. It had a few one day, which I pulled off. Too many to pull of the following day, and by day 3 its now about half of the tree covered in yellow spotted leaves. Its full scale, sick. Luckily, its the only cherry tree affected so far. This guide to cherry trees is almost completely unhelpful in this case. It basically says it could be overwatering, OR underwatering. OR, it could be leaf spot disease. OK https://greg.app/rainier-cherry-tree-yellow-leaves/ Given the fact that the tree appeared to be dying in front of my eyes, and having no guideance at hand I used every brain cell I had at my disposal, and decided it must be leaf spot disease. I then rushed out to the hardware store and got copper fungicide, which is professed to be the ONLY thing that can stop leaf spot disease on tart cherries. And so, following the directions, I sprayed the entire tree tonight, trying to get under the leaves also. A nearby tree is entirely unaffected right now, but I sprayed that one also. I left the other two unsprayed, on the off chance the fungicide might aversely affect the trees. Because I'm a gambling man. Was I right? You can see from the other pictures a nearby mulberry is affected by spots, although not as severe, as well as a Viburnum that was completely healthy yesterday and seems to have been hit by a Mack truck as we say here. I assumed it was the 100'F temperatures, and watered all three. If they are all suffering from overwatering, then that will be the death blow I'm sure. But, when your ship is sinking and action must be now, one must do something. Even if its ANYTHING right. And wait for people to tell you after the fact you did it wrong. Heh, well thats how it works. Thanks for comments.
