Fighting Off the Tomato Worm

Nothing disrupts the visions of BLTs that are dancing in your head like finding a tomato worm in your vegetable garden. The tomato hornworm is ugly enough to give you bad dreams and lethal enough to eat the foliage from your tomato plants.

Tomato hornworms are easily recognizable garden pest. The worms are actually three- to four-inch long caterpillars. Most commonly, they are a light green color with black and white markings. They can also be brown, gray or black. The worm gets its name from a small red or black horn that protrudes from its tail end.

Tomato hornworms eventually become pale gray Sphinx moths, but the time to worry about them is when they are green and crawling. Hornworms feed on the foliage of tomatoes, eggplants, potatoes and peppers. The worms can also infest melon, squash and cucumber plants.

The adult moths lay hornworm eggs on the underside of leaves in the spring. When these eggs hatch, the young worms feed off the plant foliage for about a month before burrowing in the soil to pupate. When they emerge as moths, they will start the infestation cycle over again. In warmer climates, plants can have as many as four generations of tomato hornworms in a single growing season.

You will usually know you have a tomato hornworm problem when you see the worms on the stems or leaves or find evidence of the damage they cause. The worms also leave behind telltale black droppings on leaves.

How to Deal with These Pests

To treat tomato hornworms, hand pick any worms you find off of the plant and destroy them. Treat infested plants with an insecticide containing pyrethrins or carbaryl. Talk you local extension agent or garden supply store for pest control recommendations. Wasps are the natural enemies of the hornworm so welcome them to your garden.

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