Indiscriminate,excessive and continuous use of pesti- Indiscriminate, cides creates a powerful selection pressure for altering the genetic make-up of the pests. Naturally resistant individuals f in a pest population were able to survive onslaughts of the pesticides, and the survivors could pass on the resistance traits to their generations. This resulted in a much higher percentage pest population being resistant to pesticides(Biyela et al. 2004; Levy 2002). The number of weed species resistant to herbicides was estimated to be 270, and plant pathogens resistant to fungicides were 150. Resis- tance to insecticides was common, and more than 500 insect species have acquired resistance to the pesticides. Due to these limitations of chemical pesticides and their hazardous effects on human beings, animals and on fields like loss of fertility due to its excess use and killing of beneficial soil microflora, researchers turned towards the search of new potential agents against insect pest having minimum or no side effects.