Earlier studies by Fokunanget al. (2000b), have shown that pathogenicity and virulence of C. gloeosporioides f.sp. manihotis on cassava genotypes were correlated with sporulation density and germ tube development. Greenhouse and field evaluation of cassava cultivars for resistance to CAD confirmed the results from the screening test. According to Friend (1981), plant resistance is mainly associated with phenol metabolic changes, which is a common resistance reaction in many plants . The increased resistance in cassava cultivars to anthracnose disease was investigated by Van der Bruggen and Maraite (1987). Their results showed that the increase in resistance of cassava to CAD was associated with an increase in peroxidase activity around the dark brown lesions form ed. The peroxidase participates in the last stage of lignin synthesis and also plays a role in the development of the brown margin of the lesion s which is a defence mechanism of the plant against the pathogen (Van der Bruggen et al., 1990).