Tomato hornworm caterpillar - how to recognize and control it

Everyone wants to grow the great tomatoes in his garden. But what if something seems to devour your plants? It can be a tomato hornworm. Learn how to recognize and fight those pests.

They feed on Nightshade (Solanaceae) family, like tomatoes, tobacco, eggplants, pepper and potato. Can be found on leaves, stems and fruits, a few can destroy plant. Moths lay eggs on the leaves, after a few days larvae hatch. Those catterpillars feed and grow. Fully grown they pupate and overwinter in the soil. In a warmer climates 2-4 generations can grow up during one season. Tomato hornworm is often confused with tobacco hornworm, since both feed on the same plants.

How to recognize tomato hornworms?

picture of the tomato hornworm Photo by Muffet

How to find out that your tomatoes are attacked by hornworms? First, you can see that plants have an areas chewed on. Huge piles of black droppings attached to the leaves are a telltale sign of a hornworm presence. Those bugs are difficult to spot, since they blend very well with the plant. How do they look like? Large (4-5 inches), green catterpillars sport a black horn on their rear ends, true to their name - hornworms. Eight V-shaped lateral white or grayish markings are characteristic (see picture on the left). You can usually find those insects on the downside of stems or leaves. They look scary, but are completely harmless to the humans. Your kids may even enjoy seeing this interesting pest.

How to get rid of tomato hornworms?

picture of the tomato hornworm Photo by wormwould

There are a few ways to fight hornworms:

  • Collect the catterpillars by hand and drown them in the bucket.
  • Use organic bacterial insecticide containing Bacillus Thurgiensis. It's completely safe for plants, people and other insects. Make sure to prepare dose of BT you will use at once.
  • Use chemical insecticide - this is not necessary. You will be better off not using chemicals on crops you are planning to eat.
  • Rototill the soil in the fall or early spring to destroy the burrowing pupae.
  • Hornworms have a natural enemy - parasitic wasps whose larvae feed on catterpillars. When you notice white cocoons attached to the bug (see picture on the left), let it be. Next generation of wasps protecting your garden will pupate soon.