The gardening public today is much more organically oriented than was my generation. There are some really neat products which fit the bill to help the organic gardener deal with pest issues.
BT, Bacillus thuringiens is one of them. It is marketed under many trade names including Dipel, Thuricide, Bt Caterpillar Killer, Foray to name a few. It is a microbial insecticide that is easy on the environment, yet very effective at controlling tomato worms, cabbage loopers, and many other leaf and needle feeding caterpillars which can ravage our vegetable gardens this time of year.
BT is a naturally occurring bacterial disease, which is effective at controlling these insects, yet has no environmental consequences to beneficial insects and we who eat the fruits of thy labor.
So check out this product if you have to deal with leaf eating caterpillar larvae.