These dirty devils are trying their darnest to eat up my tomatoes this year. Got about 10 off of six plants in 2 days. Then a few each day this week. The tomato worm is the first stage of those super large moths that fly around at dusk making you think they are hummingbirds. (they are about the same size). The worms start out real small but by the time most are noticeable they are usually about 3 or 4 inches long. They are green the same color as the tomato plant leaves and stem. They can eat an amazing amount of leaves in just one night. Some of these worms have a 'horn' on top of its head that is about a half inch long and looks like a needle. I don't know if they can sting with it or not and I don't intend to find out. I use two sticks to pull them off the plant then smash them with a rock.