First report of Verticillium wilt of pomegranate caused by Verticillium dahlme in Greece

In March 2008, typical symptoms of a wilt disease were observed on two-year-old pomegranate trees (Punica grana-tum) cv. Wonderful in an orchard of the region of Kilkis (Central Macedonia, Northern Greece). Diseased plants were stunted and showed twigs dieback and yellowing of the leaves. Characteristic discoloration of xylem vessels with brown to black streaks was observed in cross sections of infected trunks. Verticillium dahliae Kleb. was consistently isolated from discolored vascular tissues on potato dextrose agar (PDA). The identification of the fungus was based on morphological characteristics of conidia, conidiophores and microsclerotia (Hawksworth and Talboys, 1970). Pathogenicity tests were carried out on six-month-old trees cv. Wonderful. Five trees were inoculated by dipping roots in an aqueous suspension of 10 super(6) CFU ml super(-1). Inoculum was obtained from two-week-old cultures grown on PDA at 24C by adding sterile tap water and homogenizing them with a blender. Inoculated trees were planted in sterile soil and kept in a growth chamber at 24C with a 12 h photoperiod. Wilted leaves with interveinal yellowing and vascular discoloration appeared on inoculated trees 40 days after inoculation. The five control plants, dipped in sterile water, remained healthy. V. dahliae was reisolated from all inoculated plants, fullfilling Koch's postulates. To our knowledge, this is the first report of V. dahliae as agent of pomegranate wilt in Greece and elsewhere in the world.