Cutworms are soil dwelling caterpillars. They are the caterpillars of Noctuid moths, the turnip moth [Agrotis segetum] being one of the most common ones. These caterpillars eat the roots of plants like vegetables and eat holes in root vegetables like carrots and potatoes. After dark they will feed above ground on the foilage of small or low growing plants. Lettuce are especially vulnerable, with the plant collapsing after the stem has been eaten. The cutworms often work their way down rows.

The Caterpillars are dull brown or green with dark lines and dots on their back. The adult moth is small and has brown front wings and white to yellow hind wings. Eggs are laid in June and July, these then develop into caterpillars, which feed for 1-2 months before pupating. A second generation appears in August/September. These caterpillars then overwinter in the soil over winter. They can cause damage to winter vegetables and ornamental plants like primroses.

Protecting against Cutworms

If netting such as Just Insect Net Cover is placed over plants in the spring, this will help prevent the moths laying eggs on or near plants. Also a pheromone trap such as Just Moth Trap can be used for the Turnip moth [Agrotis segetum] to monitor the levels of moths in the area. This should be hung in the garden from May onwards. To control Cutworms nematodes can be used to kill the caterpillars in the soil. The product Just Cutworm Killer can be watered into the soil where the Cutworms are present. This should be done in daylight hours as the Cutworms will sometimes work above ground at night.