The Rhinoceros beetle Oryctes rhinoceros (L) is an important pest reported from all the coconut growing countries of the world. Application of chemical pesticides is expensive and may cause environmental pollution. Therefore an on farm trial was conducted by Krishi Vigyan Kendra, Palakkad, Kerala, India in an area of one hectare, in Thachampara, Kanjirappuzha, Pookkottukavu and Ottappalam areas in Palakkad district during kharif 2011-2012. Efficacy of three ecofriendly methods : application of common salt @ 2kg/palm, 2 times a year, filling the innermost two leaf axils with naphthalene balls + sand and incorporation of dry leaf powder of weed Clerodendron infortunatum Lin.@10% w/w basis in manure pits, and application of Metarhizium anisopliae @ 300 ml/l of water/m2 area (108 spores/ml of water) in manure pits coconut basins and other breeding sites during wet conditions. Observations after three weeks of treatment showed 100% mycosis of O. rhinoceros grubs by M. anisopliae and after 6 months, reduction of pest attack from 85% to 10%. The farmer’s practice and recommended practice were less effective with a final pest attack of 83% and 43% respectively. Therefore M. anisopliae can be effectively used as a bio control agent against rhinoceros beetle.