ARS | Publication request: Potential control of choke in orchardgrass with the fungus Dicyma pulvinata

Submitted to: Seed Production Research at Oregon State University
Publication Type: Experiment Station
Publication Acceptance Date: March 1, 2010
Publication Date: March 31, 2010
Citation: Alderman, S.C., Rao, S., Martin, R.C. 2010. Potential control of choke in orchardgrass with the fungus Dicyma pulvinata. Seed Production Research at Oregon State University. 129:6-8.

Interpretive Summary: Dicyma pulivinata was recently identified as a potential biocontrol fungus for the plant pathogen of Epichloë typhina, the causal agent of choke disease in orchardgrass. This report summarizes recently published results of greenhouse and field trials concerning the use of D. pulvinata for control of choke. The data indicate potential of D. pulvinata as a biocontrol of choke, although additional field trials will be required to determine the timing of application and effect of environmental conditions on efficacy.

Technical Abstract: The fungus Dicyma pulvinata colonizes the reproductive structure (stroma) of the plant pathogenic fungus Epichloë typhina, which causes choke disease in orchardgrass seed production fields in the Willamette Valley, OR. In greenhouse trials, D. pulvinata significantly (P < 0.05) reduced the reproductive capability of E. typhina. However, in field trials, a significant (P < 0.05) reduction in reproduction capability occurred in one trial initiated in mid May, but not in a second trial initiated in early June, although D. pulvinata was detected on 92% of the inoculated stromata. Dry conditions following the second inoculations are believed to have hindered D. pulvinata development. Under field conditions, D. pulvinata may have potential as a biocontrol agent of E. typhina if applied when stromata start to emerge during mid late April to early May when rain and high humidity conditions are typical. There are currently no effective chemical or cultural controls for choke in orchardgrass.