Built in refuge for the management of Pink Bollworm, Pectinophora gossypiella Saunders (Gelichidae: Lepidoptera) in Bt cotton

Field experiment was conducted at the Main Agricultural Research Station, University of Agricultural Sciences, Raichur during 2012-13 to identify and evaluate the suitable refuge strategy systems for pink bollworm resistance management in Bt cotton (Gossypium hirsutum L.) cultivation. The experiment was laid out in randomized complete block design with nine refuge systems : 0 % N-Bt (BIR), 5 % N-Bt (BIR), 10 % N-Bt (BIR), 15 % N-Bt (BIR), 20% N-Bt perimeter refuge, 100% Non Bt, 50% Non Bt, 10% structured refuge and 20% structured refuge as treatments with three replications in replacement series. Significantly lowest incidence (3.55 larvae/plant) and number of bolls with exit holes (11.22) due to pink bollworm was recorded in 0% BIR (41.25 q/ha) followed by 5 % N-Bt (BIR) with yield of 38.74 q/ha and this was on par with 10 % N-Bt (BIR) with yield of 37.79 is next best refuge systems with Bt cotton for higher production and greater economic benefits.