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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #221832
Title: Ascosporic fertilization of Epichloe typhina in Dactylis glomerata seed production fields in Oregon and implications for choke management

Author
item Alderman, Stephen
item RAO, S - OREGON STATE UNIVERSITY

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/28/2008
Publication Date: 4/21/2008
Citation: Alderman, S.C., Rao, S. 2008. Ascosporic fertilization of Epichloe typhina in Dactylis glomerata seed production fields in Oregon and implications for choke management. Plant Health Progress.doi:10.1094/PHP-2008-0421-01-BR

Interpretive Summary: Epichloe typhina, cause of choke disease in orchardgrass is a newly emerged fungal pathogen that causes significant yield loss in orchardgrass seed production fields in Oregon. There is currently no effective control of this disease. In experiments to determine the spores responsible for fertilization of the fungus, conidia and ascospores were found to fertilize the fungus. Fertilization by the windborne ascospores, which are produced in large numbers, not only accounts for the rapid and widespread development of choke in orchardgrass, but represents a key point in the fungal lifecycle where control measures may be most effective.

Technical Abstract: Epichloe typhina, cause of choke disease of orchardgrass is a newly emerged fungal pathogen that causes significant yield losses in orchardgrass seed production fields in Oregon. Experiments were conducted to determine whether ascospores of E. typhina could function as spermatia and fertilize stromata of E. typhina. Ascospores or conidia applied to unfertilized stromata, individually contained in plastic tubes with filtered and humidified air, fertilized stromata and produced viable ascospores. Control treatments in which water was applied to stromata remained unfertilized. As far as we are aware, this is the first report of ascosporic fertilization in the genus Epichloe. Ascosporic fertilization accounts for the rapid development of spread of E. typhina among orchardgrass fields in Oregon.