COMPARATIVE RESISTANCE OF Bt. AND NON-Bt. COTTON VARIETIES AGAINST PINK BOLLWORM, PECTINOPHORA GOSSYPIELLA SAUND LARVAE
Pink bollworm (PBW) Pectinophora gossypiella is an imperative insect pest of cotton which is not only responsible for yield reduction but also damages the lint quality by causing yellow spots on fiber that results in reduced market value of cotton. Although, the Cry protein in Bt. cotton provides an insecticidal activity against many lepidopterous insect species but evolved resistance of bollworms particularly PBW has raised an importance in the field of Entomology. Therefore, this study with comparative varietal preference of PBW on Bt and non. Bt was designed. A total number of 12 different cotton varieties were included (IR-901, MNH-886, NIBGES-3701, CIM-602, FH-142, TRAZAN1, CRIS-129, CRIS-134, CRIS-342, CRIS-613, FH-1000 and FH-901) in the study to investigate the infestation of PBW at district Sanghar, Sindh, Pakistan. In results, the maximum (1.30±0.18) attack of larvae was recorded in IR-901 and minimum (1.15±0.18) in CIM-602 Bt. cotton varieties. However, in non-Bt. cotton, maximum population (1.42 ±0.19) of PBW larvae was observed on FH-901 and minimum (1.15 ±0.24) on CRIS-129. It was concluded from the study that the attack of PBW was observed on all cotton varieties less discrimination in preference by pest was investigated on Bt, and non-Bt. varieties of cotton. Therefore, a depth research is further required to know the reasons of resistance evolved by pest on Bt. cotton verities.