Potential of crop diversity for pest management I. Theoretical and empirical
ABSTRACT: Agronomous advantages of mixed cropping particularly from work in the tropics are well known. There has, however, been an unfortunate dearth of scientific input from entomologist and pathologists despite the recognition accorded insects and diseases as major limiting factors to increased yields in most tropical crops. The indication from the limited information is that intercropping frequently reduces insect herbivore infestations on the component crops. This, the first of a two-part review paper, gives some of the circumstantial evidence of reductions in the abundance of insect pests due to mixed cropping in relation to the diversity-stability theory. Examples from work by the author on pest abundance in a cowpea/sorghum mixture at Zaria are also given. The need for incorporation of alternative pest control strategies that reduce the current level of reliance on
pesticide is emphasised.