Q.Something or things are eating all the leaves on our plum trees. Mineral oil, insect sprays, don’t stop them???
The issues you mention with plum tree problems, does not explain our problems. Something is eating all the leaves down to the stems. I have sprayed with mineral oils, insect replelants, but nothing can stop them. Our pear thes make to many pears for us to give away. But, we are plumless….HELP!
Certified GKH Gardening Expert
Without photos I can only take guesses, and those guesses would be some type of insect. If there are brown spots, black spots, or other symptoms, then it will be easier to diagnose.
If pesticides don't work, then it could be fungal, in which case, you need a fungicide.
I would recommend getting with your local extension service to test your soil, and they will be able to tell you exactly what is wrong. You will have to bring them samples, photos, or anything else they ask for but they will get to the root of your issue.
This link will help you to find the closest one to you: https://www.gardeningknowhow.com/extension-search