Dealing with Those Terrible Tomato Worms

While many pests are hated by gardeners, tomato worms are uniquely troublesome. The larva of the hawk moth, they are very difficult to remove once they have invaded the tomatoes. They seem to appear suddenly and be impossible to control. They eat leaves and fruit voraciously, and in warmer climates can persist through several generations.

The best method of pest control for these larva is constant vigilance. One source suggests checking tomato plants by hand twice a day. Remove the worms and smash them. Planting some bell peppers in the area will give an early indication that these worms are present. Another sign of the worms’ presence will be small piles of droppings on the leaves.

Controlling the Worm

Solutions for the problem of the tomato worm (also called tobacco worm and potato worm, and very similar to the tomato hornworm) are varied and creative. Several sources point out that braconid wasps are parasites which will kill the worms; the wasps will burrow in and lay their eggs. Other suggestions are companion planting with the tomato plants; borage and marigold are particularly recommended. Removing the moths at the outset, or rotating tomato crops, might also help minimize the incidence of worms.

Hand-picking off the worms is by far the most effective method of controlling the infestation once it is established. If a worm is already the carrier for wasp eggs, the wasp larva will be protruding from it like grains of rice, or the worm will have a white sac on its back. In this case, killing the worm would kill the wasps that will kill future worms. Leave the worm to its waspish death.

If you choose to use a pesticide instead of hand-picking off the worms, the suggested one is generally Dipel, a Bacillus thurengiensis product. Other pesticides are available but are not recommended for the home gardener, and are not organic.

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