Hi, I'm Stan DeFreitas, Mr. Green Thumb. We're at Willow Tree Nursery in St. Petersburg, Florida. When we talk about tomatoes, one of the biggest problems is that of the hornworm. You know, you look at your favorite tomato, and you'll turn that tomato over, and underneath that tomato you're going to see a nice little worm. Actually, it's usually about two and a half to three inches long, and the hornworm looks, well, like a large green worm with a horn on the end of it. It has a nasty habit of eating up a lot of your tomato plants. Now, what can you do? Well, you can either spray them, or you can use one of the dusting materials. This happens to be Dipel, D-I-P-E-L, or Thuricide. Now it's made from the Bacillus thuringiensis, which is a bacteria toxin. Now, it's a good guy, though. You know you talk about bacterias being bad, and yes they can be, but there are good bacterias. This particular bacteria actually kind of stops the caterpillar from eating, and the bacterias actually eat the caterpillar alive. Now that sounds gory, but the good news for you is that you could harvest your tomato on the same day--and harvest it and eat it on the same day--because it doesn't have toxicity to you. So that's a good thing. It's an organic-based material. Dipel or Thuricide, are the trade names, or look for the chemical name: the Bacillus thuringiensis. Now you either can pump it up in a little pump sprayer like we have here and spray it underneath and on top of the plant--make sure you get good coverage. Or, if you use a dusting type material like we have here, make sure you get a good coating all over the plant. The nice thing about this that's not like a lot of chemicals where you really have to worry about suiting up with gloves and respirators and all those type of things, this is an organic type based material, so it's on the safe side, and that's a good thing for you and I. If you want to kill those caterpillars, and you also want to stay in the organic gardening club, remember Dipel, or Thuricide, or the Bacillus thuringiensis. I'm Stan DeFreitas, for askmrgreenthumb.com.