Insect Pests of Vegetable, Ornamental and Spice Crops (2+1)

Cutworms

Lecture - 8

9. Cutworms

• Common name: Cutworms
• Important species:
• Agrotis segetum
• A. ipsilon
• A. flammatra
• A. Spinifera
• Family: Noctuidae
• Order: Lepidoptera
• Distribution: Cosmopolitan reported from China, India, North Europe, Canada, Japan, South America and New Zealand. In India cutworms are more serious in northern region than in south.
• Host range: polyphagous

Damage:

• Caterpillars are damaging
• Cut the seedling at ground level
• Drag the seedling into the soil
• Reduce the plant strand
• Some time replanting is required
• Caterpillars also nibble the tubers of plants

Identification:

Eggs: globular in shape, 0.5 mm in diameter, ribbed and whitish in colour.

Caterpillars: smooth, stought, cylindrical, 40-50 mm long, blackish- brown dorsally and grayish green laterally with dark stripes. They coil up at the slight touch.

Pupae: 18-22m long and reddish brown in colour.

Adult: Moths are medium sized, stought, dark greenish brown with reddish tinge and have grayish brown wavy lines and spots on the fore wings. Hind wings are hyaline having ark terminal fringe which is darker in female than in male. Wings expanse is 45-50mm.

Life cycle:

• Each female lays on an average 300-450 eggs in clusters of 30-50.
• Incubation period is 2-13 days
• Larval period is 10-30 days
• Pupal period is 10-30 days.
• Total life cycle is completed in 30-68 days depending on the climatic conditions.

Salient features:

• Moths appear soon after dusk, mate and lay eggs on ventral surface of leaves or moist soil.
• Freshly ploughed fields are preferred for oviposition.
• Tiny caterpillars feed gregariously on foliage for a few days and then segregate and enter into the soil.
• The caterpillars are nocturnal
• Loss caused is much more than what is actually eat
• Pupate in soil

Management:

• Flooding of fields. ( Caterpillars are exposed to birds and other enemies )
• Deep ploughing & stirring of soil.
• Hand picking & destruction of caterpillars found just under the damagd plant.
• Soil application (drenching) of chlorpyriphos @ 0.1%
• Mixing of insecticidal dust.
• Poison baits containing wheat bran + carbaryl + molasses be spread on the ground to attract and kill larvae.