Spray your maters with BT (Home Depot $5) and send Mr. Hornworm to insect heaven! BT merely quenches their appetite; they stop eating!

Did he have the little white cocoons on his body? Mercy, they're ugly things!

only one of them, and I inspected all my plants and didn't find any more. I could have missed some though.

Do they generally travel in packs? ;)

I don't use Bt, or anything other than my fingers. I pick them off and rear them indoors before the wasps can get them. Since I only have 15 pruned, staked plants, they haven't been a problem for me. Last year I found the first one on August 6, and it was less than 1/2 inch long.