Submitted to: American Society of Sugarbeet Technologists
Publication Type: Proceedings
Publication Acceptance Date: 1/1/2001
Publication Date: 3/1/2001
Citation: Hanson, L.E., Hill, A.L., Wickliffe, E., Schwartz, H.F., Panella, L.W. 2001. Fusarium in sugar beet and dry bean. American Society of Sugarbeet Technologists.
Interpretive Summary: Sugar beets and dry beans are included in a rotation system in many parts of the country. Both crops are susceptible to diseases caused by Fusarium species, in particular, fusarium yellows, caused by F. oxysporum formae speciales. While the forms of F. oxysporum that cause disease on the two crops are reported to be different, little is known about the interaction of the pathogen with the non-host crop. An understanding of the interaction of pathogens with multiple crops in a rotation system is important in disease management. We investigated the potential of dry beans and sugar beets to serve as hosts of pathogens of the other crop. For both crops, F. oxysporum isolates pathogenic to the alternate crop could grow and replicate on the roots without producing symptoms. In addition, five sugar beet isolates produced mild symptoms on dry beans and in a rotation might complicate efforts to control Fusarium yellows on either crop. In addition, isolates from sugar beet were found to be genetically diverse.
Technical Abstract: Fusarium species can cause a number of problems in sugar beet and dry bean, including yellows and wilts. The most important of these diseases are caused by Fusarium oxysporum. We surveyed beets to determine which Fusarium species were associated with yellowing of the plants. Sixty-five percent of the Fusarium isolates obtained were F. oxysporum. Six other species were identified. Seventy-one F. oxysporum isolates from sugar beet were tested for pathogenicity on sugar beet and for the ability to colonize dry bean roots. Of the isolates tested, 14% were highly virulent, 11% were moderatley virulent, and 75% were non-pathogenic on sugar beet. Five isolates caused stunting of dry bean. All isolates could be isolated from the roots of dry bean, indicating that dry bean can serve as a symptomless carrier for the beet pathogens. The pathogenic isolate could not be distinguished from the non-pathogens using RAPDs, and isolates were genetically diverse.