Pink boll worm  (Pectinophora gossypiella)   

Identification

The pink boll worm is one of the most destructive pests of cotton. The pest is active from July-October/ November. The adults are dark moths with  blackish spots on forewings. The margins of hindwings are deeply fringed. Wing span is 8-9 mm. The caterpillars are creamy yellow when young and turn pink when grown, 8-10 mm long with distinct brown head. Eggs are laid on the underside of tender parts of the plant (shoots, flower buds, leaves and green bolls). The egg, larval and pupal periods lasts for 4-15, 8-42, 8-12 days, respectively. The life cycle is completed in 3-6 weeks.   

            The damage is caused by the caterpillars by feeding on the flower buds, panicles and bolls. The holes of entry close down by excreta of larvae which are feeding inside the  seed kernels. They cut window holes in the two adjoining seeds thereby forming "double seeds" and finally damage them. The attacked buds and immature bolls drop off. Lint is destroyed, ginning percentage and oil content are impaired. The pest hibernates in “double seeds” and can be located in the cavities (hibernacula) impairing the development of the bolls.

Management  

• Clean cultivation and destruction of crop residues ( fallen leaves, twigs etc.) before the onset of season.

• Plough deeply to expose the hibernating larvae/pupae.

• Avoid late sowing of the crop. Early sowing helps in early maturity facilitating escape.

• Hot water treatment of the seeds up to 60oC kill the hibernating larvae. Treat the seeds with aluminium phosphide.

• Use of tolerant  varieties (Khandwa-2, JKH-1, Abdhita, Sujay and Desi cotton).

• Withholding irrigation water to avoid prolonged late boll production/formation to reduce the build up of over-wintering population.

• Release of egg parasitoids Trichogramma chilonis or  Bracon gelechidae or Elasmus johnstoni or pupal parasitoid Microbracon lefroyi would keep in check the population of PBW.

• Encourage the activities of predators Chrysoperla carnea/ Scymnus sp. or Triphles tantilus or Pyremotes ventricosus (mite) or release them in the fields.

• Use pheromone baited traps with insecticides to kill the pest/ monitor pest population.

• Apply bacterial formulations Bt.K @1 kg/ha.

• Application of insecticides like chloropyriphos 20 EC or endosulphon 35 EC or triazophos 40 EC @ 2.5  Ltr/ ha spray.