Effect of plant spacing and fertilizer levels on insect pests in Bt cotton hybrids

Field experiments were conducted to study the effect of plant spacing and fertilizer levels on pest infestation in Ht cotton hybrids. RCH 2 Bt hybrid recorded lower aphid and jassid infestation. Closer plant spacing of 90×45 cm was observed with more population of aphids and hoppers, however fertilizer applied @ 200: 100: 100 kg NPK/ha enhanced the sucking pest population. Bt hybrids had recorded zero damage due to American and spotted bollworms. Stem weevil infestation was occurred during 2006 and Bt hybrid MECH 184 was found to be highly susceptible to stem weevil. Natural enemies population was fond to have direct correlation with sucking pest population.