Question
Is there any pesticide that can be used to control or eradicate the worms on my catawa tree.  I dont fish therefore the worms are truly just a pest and turn my beautiful 100 year old, 70 foot high tree into a scragly mess each summer. Any info you could provide will be much appreciated.  Thanks

Answer
The easiest way to kill any type of caterpillar is with products that contain Bt, Bacillus thuringiensis (Green Light Worm Killer, Dipel, Caterpillar Attack, etc.). Your biggest problem is how you'll get the spray up in the tree. If you have good water pressure, use one of the long-necked hose-end sprayers designed for trees. Apply insecticide to the catalpa in late July and repeat every two weeks until late August.
You could also use an insecticide called Sevin liquid. BT has to be ingested by the caterpillar and sevin is a contact insecticide. If you use sevin also spray the trunk to catch any caterpillars that crawl down the trunk to pupate.