|Evaluation of Solanum sisymbriifolium as a Potential Host for Colletotrichum coccodes and Verticillium dahliae|
Z. A. FREDERICK (1), T. F. Cummings (2), D. A. Johnson (1). (1) Washington State University, Pullman, WA, U.S.A.; (2) Washington State University, Pullman, ND, U.S.A.
The emphasis of Plant Pathology on disease management in agricultural systems has resulted in many positive outcomes for plant health. This success can be enhanced by understanding of how pathogens interact with their plant hosts in natural systems. One example is a wild relative of potatoes, <i>Solanum sisymbriifolium</i>, which can stimulate egg hatch of the Potato Cyst Nematode, <i>Globodera pallida</i> and <i>Globodera rostochiensis</i>, but does not support nematode reproduction. However the ability for <i>S. sisymbriifolium</i> to be a host for various pathogenic fungi of potatoes, such as <i>Verticillium dahliae</i> and <i>Colletotrichum coccodes</i>, has not been fully investigated. Given that <i>V. dahliae</i> and <i>C. coccodes </i>persist in soils through crop rotational cycles, the knowledge gained from this study would add to the continued success of crop rotations. Greenhouse trials were established to detect <i>V. dahliae</i> and<i> C. coccodes</i> from the stems of <i>S. sisymbriifolium</i> and three potato cultivars of varying susceptibility to <i>V. dahliae</i>. It was determined that<i> V. dahliae</i> genotypes that are aggressive on potato infected and reproduced in 50 percent of sampled <i>S. sisymbriifolium</i> stem tissues. <i>V. dahliae</i> genotypes that are aggressive on mint, along with all<i> C. coccodes </i>genotypes, were detected from 13 percent of sampled<i> S. sisymbriifolium </i>stems. Hence, utilizing <i>S. sisymbriifolium</i> in rotation just prior to potatoes would increase risks associated with the propagation of aggressive <i>V. dahliae</i> genotypes.