catapillars

[wickedinhere]

I came home today and noticed one of my apple trees looked kinda funny but didnt really pay attention to it. I was up front watering some freshly planted flowers and walked over to the tree and it was covered with 45 catapillars. I got all of them off of the tree but they pretty much ate all the leaves. I have 20 apple trees and a few pear trees and i need to spray them with something can someone suggest what i should use?

 

[Bird]

I'd probably use Ortho Malathion Plus concentrate. Home Depot has it, and Walmart sells it for about a dollar a quart cheaper than Home Depot.