OCCURRENCE AND PATHOGENICITY OF ARMILLARIA TABESCENS ON ALMOND IN GREECE

Armillaria tabescens was detected in almond orchards in three different localities of central Greece (Fthiotis county). Mycelial fans of the fungus were observed in the roots and the base of the trunk of dead or dying trees. Symptoms of gummosis were also evident on the bark of infected trees. One of the orchards had been established on land cleared of a Quercus coccifera forest. A. tabescens was identified from basidiocarps developed in vitro, as well as in haploid–haploid mating tests with testers from France. This is the first report of A. tabescens on almond in Europe. Although the fungus has been characterized as a weak parasite or even non-pathogenic to other hosts, it caused considerable damage in almond orchards. In inoculation trials, it was shown that one-year-old almond trees were susceptible to three Armillaria species tested: A. mellea, A. gallica and A. tabescens. The most virulent species in these tests was A. mellea while the least virulent was A. tabescens. The pathogenicity tests verified the ability of A. tabescens to be pathogenic to almond.