Observations on the Course of Red Ring Disease of Coconuts Caused by the Nematode Rhadinaphelenchus cocophilus (Cobb, 1919) Goodey, 1960 in Naturally Infected Trees

Abstract

In another publication (Fenwick, 19G3) data are presented on the distribution of infection in coconut trees infected with the nematode Rhadinaphelenchus cocophilus (Cobb, 1919) Goodey, I960. The data favour the hypothesis that the disease can start either in the root system and proceed by upward extension to the stem and thence to the petioles, or alternatively in the upper parts of the tree and proceed by downward extension through the stem to the roots, but this conclusion is arrived at by inference from the condition of trees at one given time. There is no information available on the condition of the trees at any previous time nor on what would have been their condition if allowed to stand. The writers therefore decided to make observations on a number of infected trees at weekly intervals in order to learn more about the course of the disease. To this end, trees were selected in which it was considered that the disease was in an early stage and observe its spread to other parts of the tree.