Influence of different spacing and nitrogen levels on incidence of pink bollworm (Pectinophora gossypiella) (Saunders) in cotton

Results demonstrated that the DCH-32 Bt genotype consistently exhibited a reduced PBW larval incidence (6.56 larvae/25 green bolls), lower green boll (19.36%) and open boll (18.01%) damages compared to the non-Bt genotype. Wider spacing (90 × 60 cm) resulted in diminished PBW infestation and boll damage (7.65 larvae/25 green bolls, 26.52% green boll damage, and 23.41% open boll damage) relative to closer spacing. PBW incidence increased with higher nitrogen application, though the highest seed cotton yield (1599 kg/ha) was achieved in the Bt genotype under closer spacing (67.5 × 45 cm) with 150% recommended nitrogen.