The field experiment was conducted to study the impact of application of Fusarium sp. formulations on chilli plant parameters. It consists of nine treatments with different formulations of Fusarium sp. and three replications in randomised block design. Among all the treatments the highest dry chilli yield was recorded (5.12 q/ha) in the plot sprayed with dust water formulations in combination with monocrotophos (0.05%) and the lowest yield was recorded in no spray (control). Along with this experiment in vitro study was also conducted to know the compatibility of different pesticides against naturally occurring entomopathogenic fungi by means of food poisoning technique, and the effectiveness of fungicide and insecticide was measured in terms of the radial growth. The result obtained was clearly revealed that among different fungicides Bordeaux mixture, captan and copper hydroxide have the great to complete inhibition effect on Verticillium sp. And among insecticides chlorpyrifos showed the great to complete inhibition on Metarrhizium anisopliae and Verticillium sp. Followed by malathion on Verticillium sp. Copper oxychloride and wettable sulphur was resulted as safer chemical for entomopathogens and among insecticides Metasystox, Dichlorovos was showed least toxic to Fusarium isolate and Verticillium lecanii followed by Dicofol an Acaricide. Form these two study we can easily correlate that entomopathogens in combination with insecticides can reduce the quantity of application of insecticides and simultaneously increases the yield.