Cabbage moth

Mamestra brassicae

Overview:

Mamestra brassicae, or the Cabbage Moth, is a prominent pest that targets cruciferous crops, including cabbage, kale, and broccoli. Belonging to the Noctuidae family, this moth is known for its impact on yield and quality of these crops.

Detailed Appearance:

The adult Cabbage Moth has a wingspan ranging from 3.5 to 4.5 centimeters (1.4 to 1.8 inches). Its forewings are brownish-gray with distinct patterns, and hindwings are lighter in color. The larvae are caterpillars that vary in color, from green to brown, with a series of white, yellow, or pink stripes along their bodies. Fully grown larvae measure around 4 centimeters (1.6 inches) in length.

Life Cycle:

The life cycle of Mamestra brassicae involves egg, larva, pupa, and adult stages. Adult moths lay eggs on the undersides of leaves. Hatching larvae feed on the foliage, causing extensive damage. After completing their larval stage, they pupate in the soil. Adult moths emerge to continue the cycle.

Identifying Infected Crops:

  1. Leaf Damage: Look for irregularly shaped holes in leaves caused by the feeding activity of Cabbage Moth larvae. Severe infestations can lead to skeletonized leaves.

  2. Larval Presence: Identify the presence of green to brown caterpillars on plants. Cabbage Moth larvae often hide during the day, making evening inspections more effective.

  3. Silken Webbing: In some cases, larvae may create silken webs on the surface of leaves, providing additional clues to their presence.

  4. Feeding Patterns: Examine the edges of leaves for irregular feeding patterns, as the larvae tend to consume leaf tissue in a non-uniform manner.

Additional Identification Features:

  1. Proleg Arrangement: Cabbage Moth larvae have five pairs of prolegs, which are fleshy structures on the abdomen. These prolegs contribute to their distinctive crawling movement.

  2. Head Capsule: The head capsule of Cabbage Moth larvae is brown, and it contrasts with the body color.

  3. Resting Position: Larvae often assume a characteristic "C" shape when at rest.

Management: In addition to previously mentioned strategies:

  1. Insecticidal Soap: Use insecticidal soap, applying 30 to 60 milliliters (2 to 4 tablespoons) per liter (1 quart) of water, to control larvae by direct contact.

  2. Floating Row Covers: Use floating row covers to physically exclude adult moths from laying eggs on the plants.