Pest:Rice case worm

The adult is a small delicate moth with snowy white wings speckled with pale brown markings.The insect is a problem in all the rice tracts of the State. The eggs are laid on both the surfaces of leaves and leaf sheaths.The young larvae move in to the water droplets on the leaf and start feeding by scraping the green matter. As the larva grows it makes leaf folds and cut it loose from the leaves.The caterpillar remains in this chamber and moves with the case and actively feed on the leaves.Tubular gills are present on the body of the caterpillar.Caterpillar can breath only from water with the help of tracheal gills.This is why the pest infestation is found in fields with standing water.The larval cases contain water to enable the larvae for breathing. Dispersal of larva takes place by floating on water.

Total life cycle from egg to adult takes about 5 weeks- with egg period 5-6days and larval period 20 -22 days.Full grown larva pupates in the last case it makes after attaching it to the leaf sheath above the water level.

  • Pest 1
  • Pest 2
  • Pest 3
  • Pest 4
  • Pest 5
  • Pest 6
  • Pest 7
  • Pest 8
  • Pest 9
  • Pest 10
  • Pest 11
  • Pest 12
  • Pest 13
  • Pest 14
  • Pest 16
  • Pest 17
  • Pest 18
  • Pest 19


  • Larva scrapes the leaf tissues leaving only the papery upper epidermis.
  • Characteristic leaf damage has horizontal rows of green material leaving a ladder like appearance.
  • Only young stage of the crop is attacked by the pest.
  • Many of the rice field weeds are alternate hosts of this pest

Procedure for Observation

Randomly mark 4 one square meter plots in 0.4 Ha. Estimate the % of hills attacked in these plots and work out the average.


  • 5 % hills attacked.
  • Control Measures

  • Since the pest is semi aquatic, draining is the most effective method for the management of the pest. Addition of small quantity of kerosene to water in the field before dislodging the cases will help in killing the caterpillars which drop in to water.
  • Ensure good weed control.
  • Spray cow’s urine hot chilli mixture as explained under leaf roller management.
  • If infestation is severe apply.Carbaryl dust or spray Sevin 10 DP ,Carvint 10 DP,Hexavin 10 Dp @ 20 Kg/Ha Carbaryl 50WP,Sevin 50 WP @ 1.5-2 kg/Ha Alternatively spray Quinalphos 25 EC @ 1000 ml /Ha