Pest:Rice swarming caterpillar

Spodoptera mauritia Noctuidae

The adult is a moth with grayish brown forewing with wavy lines and dark spot.The insect occurs more commonly in wet lands.Eggs are laid in masses on tender leaves.Egg masses are covered with buff coloured silken hairs.The larva has six instars.Towards the close of the sixth instar the caterpillar enters the soil for pupation.The total life cycle from egg to adult occupies 26-30 days.Several species of graminaceous weeds growing in rice fields serve as alternate hosts of rice swarming caterpillars.

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  • Pest 1

Symptoms

  • The caterpillar damages rice by feeding on leaves.
  • The pest appears in the field sporadically in large swarms and eat away the crops in the entire field and move to other fields.Hence it is called as Swarming caterpillars or Army worms.
  • If the nursery and early stages of the crop are attacked the plants are reduced to mere stumps.The pest is severe generally during puncha season.

Procedure for Observation

Walk diagonally in a 0.4 Ha area and make 25 sweeps and collect the caterpillars and count. Sweeping need be conducted only during vegetative phase of the crop.

ETL

  • 4-5 caterpillars per sweep.

    • Control Measures

  • Flood the field to bring the hiding caterpillar during day time to the surface of water which will be eaten by the birds.
  • Let in to the field herds of ducks and allow the ducks to feed on the caterpillars.Provide perches for the birds in the fields.
  • Migration of caterpillars from one field to another can be prevented by making trenches around the fields.
  • Ensure control of weeds which serve as alternate hosts for the insect.
  • Sweep with hand nets, collect the caterpillars and kill them.
  • Chemical control can be obtained by applying any one of the following. Carbaryl 50WP 2 kg/Ha Quinalphos 25 EC 1000 ml/Ha Trichlorfon(Dipterex 50EC) @ 1000-1500 ml/Ha