This is a hands-on practical guide to the use of Trichoderma as a biocontrol, as part of sustainable disease control measures for Ganoderma disease in oil palm plantations. The manual provides background information on Ganoderma (basal stem rot), the most devastating disease of oil palm in Southeast Asia, as well as on the benefits of Trichoderma fungi in safe guarding yields. The disease is caused by soil-borne fungi, Ganoderma spp, which are found in West Africa and South America, as well as Southeast Asia.