The data of a survey carried out in southern Italy on the presence of Armillaria species on woody plants are reported. The investigation concerned mainly oak woods, but was also extended to orchards, conifer plantations and spontaneous woodlands. Armillaria species were identified on the basis of the morphological characteristics of the diploid cultures observed in vitro and by means of mating tests performed with haploid testers. Basidiomes found in autumn also proved to be useful in recognizing species. The 191 isolates collected from the 46 surveyed localities were shown to belong to the following three species: Armillaria mellea (42,4%), Armillaria gallica (46,1%) and Armillaria tabescens (11,5%). The first species of Armillaria proved to be highly pathogenic, mainly on orchard trees and in young conifer plantations. The second species was frequently found in declining oak woods, and the third species only occurred, mainly as a saprophyte, in deciduous oak woods.
