I have a plum tree and it has an insect problem. Doesn't really hurt the tree and doesn't hurt the fruit, but is annoying to say the least. Right when the flowers fall off and the leaves get going strong I have an army of little caterpillars descending out of the tree on silken threads. I have not been able to identify these little buggers. I don't know what adult it becomes. They are a quarter inch long, purple with black faces. Legs in front and back.