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Pink bollworm (Pectinophora gossypiella)

Pink bollworm, Pectinophora gossypiella (Saunders), is a small lepidopteran moth (family Gelechiidae) whose larvae bore into developing cotton bolls. Since the development of field resistance to Bt toxins, it has become the most damaging pest of Indian Bt cotton, capable of inflicting 20-30% yield losses on unmanaged crops.

Identification and symptoms

Eggs are laid singly on squares, bolls and tender shoots. Newly hatched pinkish larvae bore directly into the boll, feeding on developing seeds and lint. Affected bolls show small entry holes that close over and may rot internally; lint is stained yellow and locules contain damaged seeds. The "rosette flower" symptom — petals fail to open due to silken webbing — is diagnostic.

Host crops and life cycle

Cotton (Gossypium spp.) is the principal host. Indian field observations describe boll-stage damage building from roughly 60 days after sowing, with multiple overlapping generations through the season; diapausing larvae persist in stored seed cotton and crop residue.

Damage and economic impact

ICAR-CICR documents 20-30% yield loss on unmanaged Bt cotton. Field resistance to Cry1Ac was confirmed around 2009 and to the Cry1Ac+Cry2Ab Bollgard-II stack (Bt Cotton Bg Ii) around 2014-15, leaving farmers without effective transgenic protection against this pest.

Management

ICAR-CICR coordinates a multi-state IPM demonstration package combining timely sowing within the recommended window (Cotton Delayed Sowing Ipm), pheromone-trap monitoring, refuge maintenance (Refuge In Bag Cotton), inundative releases of Trichogramma bactrae and T. brasiliensis, ETL-based insecticide sprays, field sanitation and timely crop termination by December. Across 2018-22 demonstrations, the package reduced infestation by roughly 33-43% over farmer practice. Short-duration single-pick hybrids (e.g. Nuziveedu Navaneeth) and HDPS escape strategies (High Density Planting System Cotton) are increasingly used to vacate the field before peak moth pressure.

See also Bt Cotton Bg Ii, Refuge In Bag Cotton, Cotton Delayed Sowing Ipm, Amrit Pattern Cotton, Cotton Double Cropping Systems.

References

  1. Entomology Research. ICAR-CICR.
  2. ICAR Farmer Training Camps on Pink Bollworm Management. Krishi Jagran.
  3. Resistance development in pink bollworm against Bt cotton. Scientific Reports.