The use of conventional synthetic insecticides to manage mites population poses great difficulties owing to their cryptic nature and has, therefore led to growing interest in novel and effective alternatives like microbial bio-control agents. Successful usage of entomopathogenic fungi for pest control under field conditions includes delivery techniques, infectivity and persistence of their inoculum in the environment. Microplot experiment on chilli mite, Polyphagotarsonemus latus Banks revealed that the oil based formulation of B. bassiana (Bb 112) was significantly superior to all other treatments and recorded the highest cumulative mean population reduction of 39.80 percent. Two field experiments conducted against chilli mite, the cumulative mean percent reduction in the first field trial at Kumarapalayam and the second one at Ambilikkai showed that oil based formulation of B. bassiana, Bb 112 @ 108 spores mL-1 sprayed with CDA sprayer was significantly superior to other treatments with 39.27 and 45.86 per cent reduction respectively.