Is there any way to prevent hornworms?
Tomato hornworm is the caterpillar of one of the Five-spotted hawk moth. The only way to prevent them is to deny access to the plant by the moth. The adult is 3-5 inches long so cover the plants with netting small enough to keep them out. Examine plants daily, especially if you see adults moths in your flowers at dusk. The eggs are like a pearl and white to light green. They are 1-2mm (large for an insect egg) and are deposited one at a time, often on the upper leaf surface. Also look for hornworm "frass" a term that just means excrement. If small black round clusters show up on your plants, you have a hornworm hiding somewhere! More info here: http://entnemdept.ufl.edu/creatures/field/hornworm.htm