Pathology and control of soil-borne fungal pathogens of potato

Abstract

Several soil-borne fungal pathogens continue to cause problems in potato production worldwide. The reasons for these problems are illustrated by reference to the pathogensVerticillium dahliae, Rhizoctonia solani, Spongospora subterranea and a group normally considered to be tuber-borne, includingColletotrichum coccodes, Helminthosporium solani andFusarium species. Generally, the long-term persistence of survival structures, the difficulties in reducing inoculum and lack of good sources of resistance hinder attempts to improve control of soil-borne fungal pathogens. Post-harvest fungicide treatment of seed or ware potatoes does not entirely alleviate storage problems. In the foreseeable future there is no alternative to the use of integrated measures from the time of planting seed to movement from storage. Key research areas that arise as a means of better controlling most of these pathogens are: the role of intraspecific variation in pathogenesis and ecology, problems of detecting and quantifying inoculum, and the need for improved methods for biological control.