Surface Disinfestation of Wheat Seed and Inoculation of Seedling Roots with Single Macroconidia of Fusarium acuminatum. J. P. Hill, Associate Professor, Department of Plant Pathology and Weed Science, Colorado State University, Fort Collins 80523. C. R. Armitage, D. Kautzman-Eades, and P. Hanchey. Former Graduate Student, Research Assistant, and Professor, Department of Plant Pathology and Weed Science, Colorado State University, Fort Collins 80523. Plant Dis. 71:130-131. Accepted for publication 18 September 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0130.

Seed of seven wheat cultivars were surface-disinfested with squential treatments of detergent, Tween 20, ETOH, NaOCl, and mercuric chloride under negative pressure. The surface-disinfested seed were germinated in petri dishes containing potato-dextrose agar. Five days later, uncontaminated wheat seedlings were transferred to test tubes containing water agar and the largest root was inoculated with a small piece of water agar containing a single, germinated macroconidium of Fusarium acuminatum. After 6 days, inoculated roots were excised, surface-disinfested for 1 min in a solution of ETOH and NaOCl, and placed in petri dishes containing PDA. Five days later, roots were assayed for the presence of F. acuminatum. The pathogen was isolated from almost all inoculated roots, and there were no significant differences among cultivars. Most inoculated roots were symptomless. Staining and microscopic examination revealed that the fungus grew profusely over the entire root and repeatedly penetrated between epidermal cells. Hyphae grew intercellularly within the cortex. No evidence of vascular tissue penetration was found.

Keyword(s): foot and root rot, Fusarium culmorum, F. graminearum, winter wheat.