It can be heartbreaking to plant and care for a crop of tomato plants, only to come out one morning to find your plants have been ravaged by pests. Unfortunately, many tomato worms, such as the cutworm, pinworm, fruit worm and tomato hornworm can destroy an entire row of plants overnight. The best plan starts with prevention, and taking fast action when you see a worm on your plants will ensure that you get the problem under control so that you will be the one to enjoy your ripe, home-grown tomatoes, and not a squirmy invader.
Till your soil heavily in the late fall, after harvest, to kill larvae and destroy eggs. If you had a problem with an infestation, you may wish to apply an insecticide to the soil.
Rotate your crops every year. If the problem is recurring, putting your tomatoes in the same spot season after season can exacerbate it. Rotating crops will help discourage worm reinfestations every year.
Companion plant. Many common herbs such as chives, rosemary, lavender and marigolds repel pests. If you have a problem with a particular type of worm, look into companion planting to find out what common garden plants may discourage them. Plant these plants with your tomatoes in the same garden plot.
Wrap the base of your tomato plants with aluminum foil when transplanting them to prevent cutworms. Cutworms like to curl up around the stem at the soil line, or slightly below it, and within a few hours in the night they will sever the plant by cutting straight through the stem. An aluminum foil cuff will discourage them. Be sure the cuff extends a couple of inches below and a couple of inches above the soil line when you are transplanting your tomatoes.
Attract beneficial insects to your garden, such as lady bugs and praying mantises. These insects will feed on most common pests and keep the population down. You can attract them by setting out plants and flowers that attract them near your tomatoes, or by purchasing live eggs or larvae of beneficial insects from a gardening store and releasing them in the garden.
Check your plants regularly for signs of eggs, larvae, leaf tracks, bite marks, holes in fruits or live worms. Be vigilant so you can nip problems in the bud before they get out of hand. Hand-pick worms off of plants, dispose of leaves with signs of eggs or larvae, pluck fruits that are infested or remove and destroy entire plants when an infestation begins to prevent it from worsening.
Spray your plants with a strong blast of your hose. Often a hard blast of water is all you need to remove many different types of eggs, larvae and worms.
Make a simple, homemade worm repellent by mixing 2 teaspoons of mild dish soap in water, or making a hot pepper tea. Spray it all over your plants. Worms who want to eat your tomato plants don't like the taste of soap or hot pepper any better than you do.
Apply an insecticide if all else fails. Check with your local extension office for recommendations based on the kind of worms attacking tomatoes in your garden.