Defoliator pests often cause severe damage to commercially valuable timber trees, such as teak, grown in plantations,affecting the quality and quantity of the wood produced. Twenty-five isolates of an entomopathogenic fungus,Metarhiziumanisopliae(Metsch.), derived from different forest habitats were tested for their efficacy against the Teak Defoliator,Hyblaea pueraCram. The median lethal concentration (LC50) for the isolates ranged from 0.65 to 947.41105conidiamL1. Four isolates, viz. MIS2, MIS19, MIS7 and MIS1, were promising, having low LC50values. A median lethal time(LT50) of 3.8 d was recorded for the isolates MIS2 and MIS7 when the moth larvae were exposed to a spore load of 107conidia mL1. Formulations composed of “MIS2 žMIS7ž0.5%Pongamia pinnataseed oil” and “MIS2 žMIS7”proved to be superior against the Teak Defoliator, causing 94.73% and 93.93% mortality, respectively. Application of theformulation “MIS2žMIS7ž0.5%P. pinnataoil” resulted in 63.6% and 56.2% reduction in infestation in nurseries andplantations, respectively, while the formulation “MIS2žMIS7” recorded 56.18% and 51.60% reduction. Our results indicate thatM. anisopliaeformulations could be an effective means of managing Teak Defoliator in plantations, particularlywhen combined withP. pinnataoil.