The biochemical parameters studied were peroxidase and polyphenol oxidase activity; resveratrol, total phenols and sugars. The resistant genotypes contained higher resveratrol (95.75 mg/g), peroxidase (0.084 0D. Min −1/g −1) and polyphenol oxidase activity and total phenols. The healthy leaves in all genolypes showed higher quantities of above biochemical factors than diseased leaves. The diseased leaves and susceptible genotypes (Pusa Seedless, Cardinal, AK x PS. 72–51 and BA x BS. BS. 74–10 contained higher total and reducing sugars. The per cent increase in resveratrol, peroxidase and polyphenol oxidase activity upon infection was higher in resistant genotypes.