Cutworms

Cut Out the Cutworms

Working in the garden as a child I clearly remember my father pointing out a large clod of soil. He would flip it over and point out the cutworm hiding beneath. He would tell me that cutworms liked to hide there in the daytime. Come nightfall they would be actively feeding, and destroying the pepper and tomato transplants. The lesson was clear: I needed to do a better job cultivating otherwise all the cutworms in the world would soon call our garden their home.

The larvae or caterpillars of some moths are called cutworms because of the manner in which they cut down young plants as they feed. The adults are night-flying moths that feed on nectar, if they feed at all, and do no damage. It’s the larva that is the problem. They feed on plants by chewing through the stems of young seedlings and transplants. Their numbers vary greatly from year to year and, when numerous, can destroy as much as 75% of a crop. They are especially fond of cucumbers, squash, peppers and tomatoes but can do a number on corn and beans too.

Most cutworms pass the winter as partially grown larvae. Come spring they are already voracious feeders when transplants and seedlings are set out. Over wintering cutworms may live under garden debris, in clumps of grass and weeds or in earthen cells in the soil. As the weather warms in spring they remain hidden under debris, or in the soil, and emerge only at night to feed. Luckily there is only one generation per year. The moths crawl from their cocoon cases in the soil and climb up to the surface, following the tunnel made by the burrowing larva. If this tunnel is blocked, the fragile moth cannot escape the soil. The moths often seek out grassy or weedy areas to lay their eggs, and the larvae feed until cold weather and then hide for the winter in sheltered, dry places.

Now lets take a look at the many ways cutworms can be controlled organically. There are several methods of cultural control at your disposal, and if you use most of the methods throughout the gardening season you’ll get excellent results controlling these little critters. Always practice good garden sanitation: remove weed and debris piles. Avoid planting in freshly tilled sod. Till new garden spaces in late summer or early fall the year before planting. Cultivate shallowly (but frequently) throughout the season to destroy hiding places and injure or expose the cutworm to predators. Cultivate deeply in the fall to deeply bury the cocoons.

If diligent tilling and garden sanitation aren’t your thing you can get very good control by placing collars made from toilet paper or paper towel tubes around young plants. Bury the tube 1-2 inches deep and cut it to extend upward 3-4 inches. Organic chemical control works well with Bt spray (Bacillus thuringiensis). Bactur, Dipel, SOK-BT, and Thuricide are common brand names for Bt products.

Over the years I’ve encountered many other home made remedies for cutworms. I can attest that the following are not remedies at all: catching and placing toads in the garden, wrapping onion stems around the stems of transplants, placing rings of moist wood ashes around the plants, and placing a toothpick or 16d nail alongside each transplant stem.

Forget the nails and put you toothpicks away. Leave the toads alone and skip the granular insecticides (they don’t work) and the Bt spray. Keep your garden clean and cultivated and cutworms will be no bother to you or your crop.