Verticillium wilt of potatoes caused by three Verticillium species

摘要

In the past few years, a renewed interest in Canada and the United States has arisen regarding Verticillium albo-atrum Reinke & Berth. and Verticillium dahliae Kleb., the causal agents of Verticillium wilt of potatoes. These pathogens can also contribute to the potato early dying disease complex involving soilborne nematode species (5). In the eastern regions of Canada, Verticillium albo-atrum (Vaa1) has been traditionally recognised as the major causal agent of Verticillium wilt of potatoes (6). However, during the past 10 years, V. dahliae (Vd) has also been isolated from some fields with plants expressing wilt symptoms and/or premature senescence (1). In addition, V. tricorpus Isaac (Vt) has been detected in plants with one or both of these diseases symptoms and a second putative sub-species of V. albo-atrum (Vaa2) has been identified (8). Disease control generally involves use of healthy seed tubers, chemical treatments and crop rotation (7). However, control success is dependent on ensuringwhich pathogens are involved in the disease syndrome (3). The presented study examined the roles of the three pathogens in the occurrence of plant wilt and/or premature senescence in field studies that involved inoculation of healthy tubers and plants with these pathogens.