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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #247036

Title: First report of Dicyma pulvinata on Epichloë typhina and its potential for E. typhina control

item Alderman, Stephen
item RAO, SUJAYA - Oregon State University
item Martin, Ruth

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/3/2009
Publication Date: 2/28/2010
Citation: Alderman, S.C., Rao, S., Martin, R.C. 2010. First report of Dicyma pulvinata on Epichloë typhina and its potential for E. typhina control. Plant Health Progress. doi:10.1094/PHP-2010-0216-01-RS.

Interpretive Summary: Choke is an important and widespread disease of orchardgrass seed production for which there are currently no chemical or cultural controls. A potential biocontrol agent for choke was discovered and under greenhouse and field conditions it was found to significantly reduce the level of choke. This is the first report of the biocontrol fungus Dicyma pulvinata on the choke pathogen, Epichoë typhina and demonstration of potential biocontrol of E. typhina by D. pulvinata.

Technical Abstract: The hyperparasite Dicyma pulvinata is reported for the first time on Epichloë typhina, which causes choke disease in orchardgrass seed production fields in the Willamette Valley, OR. In an orchardgrass field near Corvallis, OR, D. pulvinata was found on 7% of E. typhina stromata. Infected stromata had fewer perithecia and appeared shrunken, desiccated, and pale gray to grayish-white, in contrast to the orange colored uninfected stromata with mature perithecia. In greenhouse inoculations, D. pulvinata significantly (P < 0.05) reduced perithecial formation on E. typhina. However, under field conditions, a significant (P < 0.05) reduction in perithecial development occurred in one trial initiated in mid May, but not in a second trial initiated in early June, although D. pulvinata sporulated on 92% of the inoculated stromata from each trial within 72 hrs after their incubation in moist chambers. Under field conditions, D. pulvinata may have potential as a biocontrol agent of E. typhina if applied as stromata start to emerge during mid late April to early May when rain and high humidity conditions are typical. Development of D. pulvinata would likely be limited by low humidity conditions that often occur during mid to late June in the Willamette Valley. There are currently no effective chemical or cultural controls for choke in orchardgrass.