Cutworms are the caterpillars of moths that fly at night, eat nectar and generally do no damage. The cutworms, on the other hand, wreak havoc in the vegetable garden. Usually during the night, the worms will encircle the stem of a young transplant, eating through it. You will find the severed plant on the ground in the morning. There are several ways to get rid of cutworms in your vegetable garden.
Use a rototiller or spade to turn over the soil in mid to late summer. This prevents the cutworms from laying the eggs of next year's population.
Turn the soil again in the fall to expose larvae or deeply bury the immature cutworms. This prevents them from surviving winter and emerging in spring to gnaw on your plants.
Let weeds grow in spring until they are a few inches high, then use a rototiller or manually turn them with a spade so their vegetation is under the surface of the soil. After that, wait a week to 10 days before planting seeds or transplants. This will starve the cutworms.
Cultivate the vegetable garden once or twice a week. Turn over the soil with a spade or disturb the surface by raking with a garden claw. This will expose hidden cutworms to their predators, mostly birds. Encourage birds to visit your garden by providing water nearby in the form of a bird bath and put up bird feeders near your garden.
Dig in the soil about 1 foot around damaged plants until you find the cutworm, then you can manually destroy it. Turn over lumps of soil or rocks and you'll likely find the offending worm snoozing in the soil.
Wrap the stems of transplants with a collar of paper, cardboard or aluminum foil. Completely encircle the stem and ensure that part of the collar is beneath the surface of the soil. This prevents the cutworm from gnawing on the stem. This option is the best way to avoid damage to your young plants. Once the plants grow larger, you can safely remove the protective collar. Cutworms prefer tender, young vegetation.
Plant a decoy crop such as sunflowers--a favorite of cut worms--around the perimeter of your garden. Find the worms in the soil around the damaged sunflowers and manually destroy them.