Distribution of clones of Phellinus noxius in a windbreak on Ishigaki Island

Abstract

SummaryThe distribution of clones of Phellinus noxius, the causal agent of brown root rot, was studied in a windbreak on Ishigaki Island of Japan. In total, 99 isolates obtained from infected trees of Calopbyllum inophyllum, Casuarina equisetifolia and Bauhinia racemosa were analysed by means of a somatic compatibility test on a sawdust‐rice‐bran medium, an antagonism test on PDA with guaiacol solution, and by esterase analysis with isoelectric focusing. Results obtained from the three methods were almost identical, although the somatic compatibility test was less precise than the other methods. Isolates from neighbouring infected trees belonged to the same clone in many cases. On plots of 150–400 m2, 1–5 clones were found. Single clones covered an area of up to 20 × 20 m. A total or 25 different clones were recognized within the sample sites. This suggested that multiple basidiospore infection existed in the site, although infection centres spread by vegetative growth across root contacts of neighbouring trees.