Abstract
Two trees of avocado root rot were identified in an avocado plantation at the University of the West Indies Field Station, Trinidad. One of these was a slow decline typified by gradual death of branches and apparent loss in vigour of trees and the other was an acute root rot (rapid decline) associated with a comparatively rapid process of defoliation and death of whole trees. Observations indicated that plant parasitic nematodes and weakly parasitic fungi were probably the causal agents of slow decline. Phytophthora cinnamomi Rands and Pythium ultimum Trow. were isolated from roots of avocado trees with rapid decline, but pathogenicity tests indicated that isolates of these fungi were not pathogenic on West Indian cultivars.
