|Case, Austin -|
|Brick, Mark -|
|Otto, Kristin -|
|Schwartz, Howard -|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 5, 2013
Publication Date: September 1, 2013
Citation: Webb, K.M., Case, A.J., Brick, M.A., Otto, K., Schwartz, H.F. 2013. Cross pathogenicity and vegetative compatibility of Fusarium oxysporum isolated from sugar beet. Plant Disease. 97(9):1200-1206. Interpretive Summary: Fusarium yellows of sugar beet, caused by Fusarium oxysporum f. sp. betae, causes significant reductions in root yield, sucrose percentage, and juice purity. F. oxysporum f. sp. betae can be highly variable in pathogenicity and genetic diversity. Little is known about factors that determine host specificity between forma specialis of Fusarium. To further investigate the diversity of the Fusarium oxysporum f. sp. betae from sugar beet, 51 isolates were characterized utilizing vegetative compatibility testing, which indicated that Fusarium oxysporum f. sp. betae is highly diverse. Furthermore, pathogenicity testing indicated that sugar beet may be acting as a carrier of pathogens for other hosts commonly found in crop rotations.
Technical Abstract: Fusarium oxysporum f. sp. betae, which causes Fusarium yellows in sugar beet, can be highly variable in virulence and morphology, with further diversity derived due to the wide geographic distribution of sugar beet production. Little is known about factors that determine pathogenicity to sugar beet and how these may differ between non-pathogenic F. oxysporum. Sugar beet is often grown in rotation with other crops including dry edible bean and onion, with F. oxysporum able to cause disease on all three crops. Fifty one F. oxysporum isolates were collected from symptomatic sugar beet throughout the United States production region. To investigate diversity of the F. oxysporum population and how crop rotation may influence pathogenic variation, these isolates were characterized for pathogenicity to sugar beet, dry edible bean and onion, as well as vegetative compatibility. Pathogenicity testing indicated that sugar beet may harbor pathogens that cause disease on hosts grown in rotation with sugar beet, particularly onion. None of the isolates tested were pathogenic to dry edible bean. Furthermore, vegetative compatibility testing supported previous reports that F. oxysporum f. sp. betae is polyphyletic and that pathogenic isolates cannot be identified from non-pathogenic F. oxysporum using vegetative compatibility.