Observations on Armillaria occurrence in declining oak woods of southern Italy

Abstract

In order to assess which Armillaria species predominates on declining oaks in southern Italy, surveys were carried out in numerous oak woods and additional Armillaria isolates were collected. Most of the collected isolates were found to belong to A. gallica, while A. mellea and A. tabescens were observed to occur less frequently. The fact that A. gallica was found to be particularly widespread in the most seriously declining oak woods could confirm the opportunistic behaviour of Armillaria and suggest that it may depend on the remarkable weakness of the oak trees in very unfavourable site conditions.