Question
what do you put on the trunk to stop the worms from crawling up the bark?

Answer
Dear Pam, The best way to control tentworms (and borers which cherry trees are also susceptible to is to spray with Spinosad.  Spinosad is an organic compound which kills bugs which eat your tree but doesn't harm people, pets, or beneficial insects.  One thing to understand about tentworms is that if they have already made a tent or web in the tree, it is useless to spray into the web, because they aren't feeding there any more.  Spray the leaves around the worms as this is the next area they will go to feed.  The Spinosad will cause them to stop feeding almost immediately, and causes death within a few days.  Also spray the trunk with Spinosad and this will prevent them going up the trunk and also prevent borers from eating your tree.  I hope this information helps.  Feel free to write me any time.  Melissa