Bihar hairy caterpillar

Bihar hairy caterpillar: Spilosoma (Diacrisia) obliqua

Symptoms of damage:

  • Young larvae feed gregariously mostly on the under surface of the leaves
  • Feed on leaves and causes defoliation
  • In severe cases, only stems are left behind

Identification of the pest:

  • Eggs: Laid in clusters of 50-100 on the lower side of leaves
  • 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.

Management:

  • Pre-monsoon deep ploughing (two/three times) will expose the hibernating pupae to sunlight and predatory birds
  • Removal and destruction of alternate wild hosts and weeds which harbour the hairy caterpillars
  • Mass collection and destruction of eggs and just emerged caterpillars
  • Place the twigs and leaves of calotropis, jatropha and papaya around the field to trap grown up caterpillars and destruction
  • Grow trap crops like cowpea, castor and jatropha on field bunds to attract the caterpillars
  • Conserve the biocontrol population of spiders, long-horned grasshoppers, preying mantids, robber fly, ants, green lacewing, damselflies/dragonflies, flower bugs, shield bugs, lady bird beetles, ground beetle, predatory cricket, braconids, trichogrammatids, NPV, green muscardine fungus
  • Use of NPV (nuclear polyhedrosis virus) on cloudy days at 500 LE/ha will be effective
  • Apply safe chemical insecticides at recommended doses only if the insect population crosses the ETL
  • Spraying of quinalphos 25 EC (2 ml/lit) or chlorpyriphos 20 EC (2.5 ml/lit) or Dichlorvos 76% EC (2.0 ml/lit) recommended when the caterpillars are younger.

 

Source-

  • TamilNadu Agritech Portal