Infection Foci of Armillaria mellea in First-rotation Hardwoods

Abstract

Infection foci of Armillaria mellea , often 10–20 m in diameter, were discovered in first-rotation plantings of oak and beech on former arable or heathland sites—they were commonly associated with thinning stumps containing the fungus. Since the foci were scattered and contained different mycelial types of A. mellea it seemed probable that they had arisen as a result of stump infection by basidiospores. There was evidence that many years had elapsed between stump infection and the production of rhizomorphs, and that subsequent growth of these depended upon the presence of suitable living roots. Larger oaks seemed little affected whereas many small and medium-sized trees had been killed.