Field trials were conducted to assess the efficacy of Beauvaria bassiana and Metarhizium anisopliae against chironji ( Buchanania lanzan ) stem borer, Plocaederus obesus Gahn (Coleoptera: Cerambycidae). These fungi treatments were compare with conventional prophylactic insecticide treatments. Buchanania lanzan trees with early phase of borer infestation were marked and the treatments were applied sequentially. Different delivery methods were adopted viz. swabbing of saturated conidial- mud slurry over the tree trunk, pouring saturated aqueous suspension of conidia through grub entry holes and soil incorporation of fungal spawn, after removing the grubs and cleaning out the frass material. The effectiveness of treatments was assessed, based on the extent of recovery of infested trees. All the treatments were superior to the untreated control in reducing borer infestation. Variations among the treatments could be observed with a higher coefficient of variation of 47.15 per cent. The efficacy of B. bassiana and M. anisopliae were on a par, but the delivery methods varied significantly. Pouring conidial suspension affected a 16.0–25.0% recovery of the infested trees followed by swabbing conidial slurry with a 17.0–20.0% recovery and soil application with 13.0–14.0% recovery of trees. Conventional insecticidal treatments remained superior with 38.0–43.0% recovery of infested trees. However, implementation of fungal application in integrated control of P. obesus should be considered. Fungi would not only be safer to non target organisms, but it would also be more effective in the long term pest control programme.