Q.no plums on trees
We have three plum trees that don’t produce plums. Any suggestions? Also, in spring the trees get nice green leaves that have started getting holes in the leaves although we sprayed.
Noticed last year that the leaves went brown and dropped off.

There can be a few reasons for no fruit on your trees.
This is an excellent article that will help you pinpoint the issues.
https://www.gardeningknowhow.com/edible/fruits/plum/plum-trees-not-fruiting.htm
Neem Oil is a good treatment for the insect issue.
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm