Cotton Pink Boll Worm

Pink boll worm is widely distributed serious pest. Completely pan tropical in distribution, including the subtropical regions. In India, it is distributed in W. Bengal, Assam, Orissa, Bihar, U.P, Haryana, Punjab, Madhya Pradesh, Gujarat, Maharashtra, Rajasthan, Andhra Pradesh, Tamil Nadu etc. American cottons are damaged more than the indigenous varieties. Infestation occurs when the crop is in the mid stage and continues till end. It is a monophagous pest.

Appearance:

Adult is a small moth. Wings are fringed and reddish brown with numerous black spots. Larvae are whitish color during early stage and as it grows turn pinkish with dark brown head and prothoracic shield.  Pupation is in flimsy cocoon in boll, often in seeds, hollowed out by the larva. Some larvae undergo hibernation and are responsible for the infestation of the following crop.

               Adult                                         Early stage Larva                 Later stage larva

Life cycle:

Adult lays around 125 eggs on the tender leaves, hatch in 4-5 days, larval period last for 25-35 days, pupates in a thin silken cocoon in the lint or within soil or in kapas. The insect hibernates in the larval stage in North between March - July and emerge from July onwards and attack the host. The adults have 4-6 generations up to October- November.

Nature of damage:

• Larva soon after hatching enter the square, flowers or the boll.

• Larvae enter the developing bolls through tip portion and entrance hole is closed as the boll matures.

• Larvae inside the boll feed on seeds and fibre forming tissues which leads to the retardation of lint development.

• Larvae feed on the seeds and move to adjacent seeds and locules by making a hole through the septum.

Damage symptoms:

• Infestation of flower buds causes shedding of buds.

• Flower infestation lead to the formation of rosette flower.

• Reduction of lint development, destruction of seed and weakened lint.

• Infested bolls open prematurely exposing the saprophytic fungi to grow on them.

• If seeds are used for sowing, the germination is reduced.

             rosette flower                                               Infested bolls