Three species of Armillaria are found in oak woods in Italy: Armillaria mellea (Vahl:Fr) Kummer; Armillaria tabescens (Scop.:Fr.) Dennis et al.; Armillaria bulbosa (Barla) Kile et Watl. (= Armillaria lutea Gillet = Armillaria gallica Marx.P Rom.). Armillaria mellea is the most distributed species. It has been frequently isolated from declining oaks presenting drying of the cortex and of the branches in association to Ascomycotina and Deuteromycotina fungi and/or defoliating insects. The combined action of Armillaria mellea, acting at root level, and one or several fungal microorganism causing drying of the aerial part of the tree (such as Hypoxylon mediterraneum, Colpoma quercinum, Diplodia mutila, Phomopsis quercina) may be a risk factor for survivial of the tree. Armillaria bulbosa and Armillaria tabescens, less distributed than Armillaria mellea, were observed to be mainly saprophytic on coppices and wood residues.
