Bihar Hairy Caterpillar
Spilosoma obliqua
📖 Description
Bihar Hairy Caterpillar is a polyphagous pest of pulses, oilseeds and cereals across the Indo-Gangetic plain, particularly destructive in Bihar, eastern Uttar Pradesh, West Bengal, Jharkhand and Odisha. Outbreaks typically occur from July to October, often starting on sunhemp or wild hosts and migrating into crops. The larvae are gregarious in early instars and can completely defoliate large fields within a week. The pest’s polyphagous nature and ability to migrate in waves make area-wide management essential. Light trapping of adults, mechanical collection of egg masses and Bt/NPV applications form the backbone of sustainable management.
⚠️ Symptoms to watch for
- Skeletonization of leaves in early instars, complete defoliation in later instars, damage to pods and developing seeds, scattered appearance of larvae 'crawling in waves' across field, yield loss 30-60%
🩹 Treatment
- Handpick egg masses and gregarious early instars, dust young larvae with malathion 5%, install light traps @ 1/ha, spray NSKE 5% in early evening, apply Bacillus thuringiensis @ 1 g/L
🌿 Organic treatments
- Bacillus thuringiensis @ 1-2 g/L, NSKE 5%, neem oil 5 ml/L, collect and destroy egg masses and gregarious larvae, set up bonfires at dusk to attract adults, spray NPV (Spilosoma NPV) @ 250 LE/ha
🧪 Chemical treatments
- Quinalphos 25 EC @ 1.5 ml/L, Chlorpyriphos 20 EC @ 2 ml/L, Emamectin benzoate 5 SG @ 0.3 g/L, Dichlorvos 76 EC @ 1 ml/L, Novaluron 10 EC @ 1 ml/L
🛡️ Prevention
- Deep summer ploughing to expose pupae, destroy alternate hosts (weeds, sunhemp volunteer), avoid late sowing of pulses, install light traps at onset of monsoon, intercrop with non-host (marigold), plant early-maturing varieties to escape peak larval period
🪴 Affected plants
- Sunhemp, Mungbean, Blackgram, Soybean, Maize, Sorghum, Cotton, Castor, Groundnut, Pulses, Vegetables
🦋 Natural predators
- Trichogramma, Telenomus, Carabid Beetles, Spiders, Birds, Frogs, Predatory Bugs
🌱 Host plants
- Crotalaria juncea, Vigna mungo, Vigna radiata, Glycine max, Zea mays, Ricinus communis
🔄 Lifecycle
- Female lays 600-1500 eggs in clusters on leaf undersides, covered with yellowish hairs.
- Eggs hatch in 5-10 days.
- Larvae feed for 25-35 days through 6 instars.
- Pupation in soil, lasting 12-20 days.
- Adult lifespan 6-12 days.
- Total life cycle 45-75 days; 3-5 generations per year.
📅 Season
- July-October (kharif), peaks Aug-Sep
🔎 Appearance
- Larva is a hairy caterpillar with a yellowish-brown body covered in long black and white hairs; a black stripe runs along the back.
- Adult moth is white with yellowish abdomen and black spots on wings and thorax (hence 'hairy caterpillar' common name).
💥 Damage level
- Severe
🔁 Reproduction rate
- Rapid
🗺️ Geographic regions
- Indian Subcontinent
- South Asia
- Southeast Asia
Have an Insect to Identify?
Upload or take a photo of an insect on your plant and our AI will identify it and recommend treatments.
📷 Diagnose from Image