Tomato plants can be affected by a wide range of problems, but none are quite as pervasive as worms. A number of green worms can affect tomato plants, ranging from cutworms and hornworms to fruitworms. In some cases, protecting tomato plants against certain worms is simple. In others, the problems can prove quite difficult. The key to ridding your tomato plants of green worms is to identify the worm and apply the correct solution.
Examine the base of your tomato stem for chew marks. Worms that feed on the stems of tomatoes are usually cutworms. Though not all cutworms are green, some species of cutworms are. If you find a worm that is green, up to 2 inches long and fat, you have probably found a cutworm.
Remove weeds that grow in or along your garden to remove cutworm habitats where moths lay eggs. Till your garden before planting to destroy overwintering larve.
Wrap the stem of your plant at the soil line with tin foil, wax paper or cardboard to prevent cutworms from eating at that location. The wrapping should be 3 inches wide and should extend into the ground 1 inch and above the ground 2 inches.
Spray the leaves and stems of your tomato plant with Bacillus thuringiensis (Bt). Bt is an insecticide made from bacteria found in the gut of caterpillars. When reintroduced to the stomachs of caterpillars, the insecticide kills them.
Pick a tomato from your plant and look it over for holes. These holes are signs of fruitworms, which may be green, pale yellow or red, with stripes running down their sides. Fruitworms make holes in fruit that are at least pea-sized. Smaller holes may be the work of pinworms, which are not green in color.
Pour a mixture of 1 gallon Bt and 1 teaspoon liquid detergent an insecticidal sprayer.
Spray your tomatoes late in the evening. The spray will knock fruitworm eggs and larve off tomato fruits.
Repeat the process every evening for 5 consecutive days.
Explore your plants for signs that the leaves and fruits have been completely stripped. Stripped plants are the work of tomato hornworms. If you find a tomato hornworm, it will be gray-green in color with V-shaped dashes on their sides and a red horn protruding from their back ends.
Mix a bucket full of water and dish washing detergent.
Hand-pick hornworms off your tomato plants.
Throw hornworms into the bucket of water to kill them.
Spray tomatoes with a vegetable insecticide formulated for use against caterpillars.