Bihar Hairy Caterpillar in Groundnut: Identification, Lifecycle, Symptoms & Effective Control Methods

Telugu name: Bihar gongali purugu
Scientific name: Spilosoma obliqua

Identification of the pest:

Eggs: Laid in clusters of 50-100 on the lower side of leaves. Eggs are creamy yellow.
Larva: Orange coloured with broad transverse band with tufts of yellow hairs that are dark at both ends
Pupa:  Forms a thin silken cocoon by interwoven shed hairs of the larvae             
Adult: Crimson coloured moth with black dots and a red abdomen. Pinkish wings with numerous black spots

Life cycle:

• Female moths lay eggs in clusters on the underside of leaves and hatch in 3-4 days.
• The caterpillar is covered with long hairs, giving it a characteristic "hairy" appearance. taking about 20-25 days to develop.
• Pupation occurs in the soil within a loose cocoon.
• The moths are medium-sized, with white wings and black spots. They are nocturnal and live for 5-7 days.
• A complete lifecycle takes about 30-40 days

SYMPTOMS

• Young larvae feed mostly on the under surface of the leaves
• Feed on leaves and causes defoliation.
• In severe infestation, whole plant eaten away leaving only the stems.

FAVORABLE CONDITIONS

• Warm and humid weather is favorable ,especially during the monsoon.
  Economic Threshold Level (ETL)
• 5-10 larvae per square meter or defoliation of 10-15% of the crop foliage.

MANAGEMENT

Cultural Control

• Early sowing of crops can avoid peak infestation.
• Use intercropping systems (e.g., groundnut with pigeon pea) to reduce pest intensity.
• Pre-monsoon deep ploughing to expose the hibernating pupae to sunlight and predatory birds.
• Collect and destroy eggs and young caterpillars.

Mechanical Control

• Handpick and destroy egg clusters and early instar larvae in small fields.
• Use light traps to attract and kill adult moths.

Biological Control

• Release parasitoids like Trichogramma chilonis.
• Encourage natural predators such as spiders, ladybird beetles, and predatory bugs.

Chemical Control

• Spray neem oil (2-3%) or neem seed kernel extract (NSKE, 5%).
• For effective control of Caterpillar in groundnut bio pesticide like “LARVEX 250 ml / acre” can be used.

FAQ’S

1. How can I spot a Bihar hairy caterpillar infestation in my groundnut crop?
Look for egg clusters under leaves and caterpillars feeding in groups. Early signs include skeletonized leaves and rapid defoliation. Inspect regularly during early crop stages.
2.What natural methods can control Bihar hairy caterpillars?
Deep ploughing destroys pupae, while neem oil sprays and handpicking larvae can control small infestations. Encourage natural predators like birds.
3.When is the Bihar hairy caterpillar most active?
They are most active during the rainy season. Monitor fields closely during this time, as their population can grow rapidly in favorable conditions.
4.Are chemical solutions effective for controlling these caterpillars?
For effective control of Caterpillar in groundnut bio pesticide like “LARVEX 250 ml / acre” can be used.
5.How do Bihar hairy caterpillars spread in groundnut fields?
They hatch from eggs laid on the underside of leaves, and young larvae feed in groups before dispersing. Wind and nearby infested fields can increase their spread.