Host range of Phytophthora sp. causing leaf fall disease of nutmeg (Myristica fragrans Houtt.)

Leaf fall disease caused by Phytophthora sp. has become a serious problem in major nutmeg growing areas of Kerala during South-West monsoon period. Host range study was carried out to find out the infectivity of Phytophthora isolates of nutmeg on other known hosts of Phytophthora spp. including arecanut, coconut, cocoa, rubber, black pepper, cardamom, camboge, vanilla, rose, coreopsis, eucalyptus, colocasia and citrus. Phytophthora isolates of nutmeg showed characteristic symptoms on rubber, vanilla, rose, coreopsis, eucalyptus and citrus, whereas, cocoa, black pepper and colocasia developed hypersensitive reaction and the pathogen failed to cause infection on arecanut, coconut, cardamom and camboge.