One hundred and six trees suffering from Red Ring disease were examined and the distribution of worms plotted. The results indicate that infection can start in either the root system or in the upper part of the tree. The distribution of worms in 21 of the trees examined was consistent with the disease starting in the base of the tree; and 5 trees exhibited conditions consistent with infection starting in the upper part of the tree. Of thirteen trees, more than 20 years old, one was found to be infected in the top only; the other carried an infection in the roots and lower stem. It is concluded that the disease can start in either the top of a tree or in the root system but for reasons given in the text, it is not possible to say which is the more frequent.