Army cutworm

Euxoa auxiliaris

Army cutworm (Euxoa auxiliaris) is a species of moth in the family Noctuidae, known for its larval stage, which acts as a significant pest in agriculture. The army cutworm is found across North America, particularly in the western and central regions, where it affects a variety of crops including wheat, alfalfa, and vegetable crops. This pest is named for its behavior in the larval stage, where it moves in large groups, or "armies," from plant to plant, consuming the foliage and sometimes causing significant damage to crops.

Description

The adult army cutworm moth has a wingspan of approximately 1.5 to 2 inches (38 to 50 mm) with dull gray or brownish wings, which help it camouflage against the soil and plant debris. The larvae are greenish to brownish with dark stripes running along the body, making them difficult to spot on the plants they consume.

Life Cycle

The army cutworm has a unique life cycle that includes a migration pattern for the adult moths. In late summer and fall, the moths lay their eggs in the soil of crop fields. These eggs hatch into larvae, which remain active through the winter, feeding on plants. In the spring, the larvae pupate in the soil, and the adult moths emerge. After mating, these adults migrate to the Rocky Mountains, where they spend the summer before returning to the plains to lay eggs again. This cycle allows the army cutworm to have one generation per year.

Damage

Army cutworm larvae feed on the leaves of plants, often consuming large portions of the foliage. This feeding can stunt plant growth, reduce yields, and in severe infestations, kill young plants. The larvae are nocturnal, feeding at night and hiding in the soil during the day, which can make them difficult to detect and control.

Management

Management of army cutworm infestations involves a combination of cultural, biological, and chemical methods. Monitoring fields for early signs of infestation is crucial. Cultural practices, such as crop rotation and maintaining field hygiene by removing plant debris, can help reduce the habitat for the moths and larvae. Biological control agents, including natural predators and parasites, can also play a role in managing cutworm populations. Chemical control is often used as a last resort, with insecticides applied to affected areas when infestation levels exceed economic thresholds.

Impact

The army cutworm poses a significant threat to agriculture, particularly in regions where it is prevalent. The economic impact includes the cost of control measures and the potential loss of crop yields. Understanding the biology and behavior of the army cutworm is essential for developing effective management strategies to minimize its impact on agriculture.