They’re Big, They’re Fat, and They’re Green! Watch out for the Tomato Hornworm…hopefully, they are NOT coming to a garden near you.
If you’ve ever grown tomatoes, chances are good that you’ve dealt with these green caterpillar pests. They can ruin your tomato crop in record time! They also feed on other plants in the Solanaceae (nightshade) family: eggplants, peppers and potatoes. They blend in quite easily with the green foliage and feed non-stop, creating spotty and chewed leaves and fruit.
Tomato hornworms live according to the following life cycle:
- In late spring, large adult moths lay eggs on the undersides of foliage, which will hatch within a week. The adult moths are easily recognizable; they’re commonly called sphinx or hummingbird moths.
- Caterpillar larvae will hatch in late spring and feed for 4–6 weeks before creating a cocoon, overwintering in their pupal state in the soil.
- Moths will emerge in the spring, and will then lay eggs once again. More than one generation a year may be possible in warmer climates.
Tomato hornworm moth (female)
Hornworms can be up to 5 inches long – which can be quite a shock when you first come across one! They do the most damage in the caterpillar or larval stage. They are pale green with white and black markings, plus a horn-like protrusion stemming from their rear. (Don’t worry, they aren’t able to sting or bite!) The caterpillar also has eight V-shaped stripes on its green body. Tomato hornworms come from a mottled brown-gray moth (see picture, above).
The larvae blend in really well with the plant greenery. This is when you have to become a garden detective. Each morning, I inspect my garden, carefully looking at each plant. Just get used to a daily patrol, looking for hornworm eggs and small caterpillars. Here are some clues to look for:
- Hornworms tend to start feeding from the top of the plant; look for chewed or missing leaves.
- Look closely at the TOP of your tomato leaves for dark green or black droppings left by the larvae feeding on the leaves. Then look at the underside of leaves and you’ll likely find a hornworm.
- Look for stems missing some leaves and wilted leaves hanging down.
Tomato hornworm
Handpicking is the best control for getting rid of these pests. But, if you are squeamish (like me), just cut off the leave that the caterpillar is on and throw it away.
Insecticidal soaps will also kill hornworms, but the pests need to come into direct contact with the substance.
One way to prevent the worms is to till the soil at the beginning and end of each gardening season to destroy the larvae. Also, you can introduce beneficial insects, like ladybugs and green lacewings that feed on young hornworms or hornworm eggs. You can also use companion plants such as dill, basil and marigolds to deter them.
The Texas City Garden selected the home of M.C. Giusti for their April “Spot of Beauty”. This lovely home with a beautiful landscaped yard is located at 1705 11th Street. N.
The Garden Club selected this home for their May “Spot of Beauty”. This home with beautiful roses is located at 1702 Wayside Drive.
The Garden Club appreciates both of these homeowners for doing the part in Keeping Texas City Beautiful.
You could be next ~ We are always on the Look-Out!
