Impact of intercropping on natural enemies of insect-pests in cotton

A field study was carried out at Agronomy Farm, B. A. College of Agriculture, Anand Agricultural University, Anand during 2002-03 and 2003-04 to assess the impact of intercropping on natural enemies of insect-pests infesting cotton. Cotton (cultivar H-10) crop was intercropped alternately with maize, sesame and soybean. Experimental results of two years' study concluded that cotton intercropped with maize, sesame and soybean enhanced the population of various natural enemies of insect-pests attacking cotton. Cotton intercropped with maize registered relatively higher number of entomophagous insects followed by cotton + sesame and cotton + soybean. Population of natural enemies increased in all the intercropping treatments as evident from the relatively more numbers of biocontrol agents over cotton as sole crop. Plots treated with insecticides exhibited minimum number of natural enemies suggesting its detrimental effect on the beneficial fauna. The suppression of sucking pests and bollworms incidence, with an increase in seed cotton yield in the intercropping treatments, was attributed to an increase in arthropod natural enemies, which suppressed the insect-pests infesting cotton.