Cutworms, known as the caterpillar stage of night-flying moths in the Noctuidae family, are pests that can harm plants. During the day, they hide beneath litter or soil, emerging at night to feed on plants. They get their name because they often cut down the stems of seedlings. Some cutworm species climb plants and feed on leaves, buds, and shoots. Although they usually stay hidden during the day, they can also feed below the soil surface.

It’s easy to mistake cutworms for grubs, but they are actually caterpillars. They can be confused with armyworm and African bollworm larvae. The adult moths, which are night-flying, do not cause any damage.

Life Cycle

Cutworms are a threat to all field crops, especially during the early growth stages of seedlings. Their life cycle generally follows a pattern, but the duration of each stage may vary. Depending on the species and temperature, the eggs, laid in soil in lightly vegetated or bare areas, hatch within 2-14 days. The larvae, or cutworms, are active and feed on host plants until they mature.

Pupation occurs in the soil, and adult moths emerge from overwintered or early-season pupae. While some species can have 3-4 generations in a season, others may only have one. Under favorable conditions, the life cycle takes about 8-11 weeks, depending on the species.

Identification

Cutworms have distinct characteristics that differentiate them from one another. They can be brown, tan, pink, green, gray, or black. Some are uniform in color, while others have spots or stripes. Their body length can reach up to 50 mm. When disturbed, they curl up into a tight “C” shape and remain still when picked up. They are often found just below the soil level or around damaged plants during the day.

In cloudy or dark conditions, they may be seen on the soil surface. Sometimes, their body colors blend in with the soil, making them easy to overlook. Adult moths are medium-sized, brown or black insects with various patterns and shades of gray, brown, black, or white. They typically have a body length of about one inch and wingspans up to 1.5 inches across. The forewings are darker than the hind wings.

Feeding and Damage

Cutworms cause damage by climbing young plants and feeding on leaves, creating small holes or skeletonizing them. This usually occurs at night or on cloudy days. Older cutworms may cut through stems at ground level and feed on the top growth of fallen plants, usually in the late afternoon or at night. During the day, they hide under the soil or in debris. Even if only the lower part of the plant is destroyed, the top often withers and dies. In many cases, entire plants are destroyed by cutworms, and they can cause significant damage quickly.

Management and Control

To manage and control cutworms, several methods can be employed: Chemical and non-chemical methods.

Chemical Methods

Chemical methods involve applying insecticides to the soil. Effective insecticides for eliminating these pests include PROFILE 440EC (60ml/20l), RANGER 480EC (60ml/20l), PENTAGON 50EC (20ml/20l), and LOYALTY 700WDG (10g/20l). Seed treatment can be done using SHIELD 600FS (3ml/1kg). It’s best to apply the insecticide in the late evening for optimal effectiveness.

Non-Chemical Methods

Non-chemical methods can also be used, such as introducing beneficial parasites and natural enemies like fireflies, birds, and parasitic wasps. Early plowing can reduce the number of eggs deposited by cutworms. Handpicking the cutworms is another option for control.

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