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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #246002
Title: Summary of choke control studies-2008

Author
item Alderman, Stephen
item RAO, S - Oregon State University
item SPINNEY, R - Western Farm Service
item BOREN, P - Western Farm Service
item CACKA, J - Western Farm Service

Submitted to: Seed Production Research at Oregon State University
Publication Type: Experiment Station
Publication Acceptance Date: 2/28/2009
Publication Date: 3/31/2009
Citation: Alderman, S.C., Rao, S., Spinney, R.L., Boren, P.K., Cacka, J.F. Summary of choke control studies-2008. Seed Production Research at Oregon State University. 2009. p. 19-25.

Interpretive Summary: Choke, caused by the fungus Epichloe typhina, is an important seed limiting disease of orchardgrass, and there are currently no controls for choke. This is the first study to evaluate the efficacy of a wide range of fungicides on the sexual reproductive stage of E. typhina. Fungicides caused a significant reduction in the choke reproductive bodies, although this reduction would likely have little no impact on disease spread. This study indicates that fungicides directed at the reproductive phase of the choke fungus would not likely result in significant choke control.

Technical Abstract: Choke is an important seed limiting disease of orchardgrass. There are currently no controls for choke. The objective of this study was to evaluate fungicides for efficacy in control of the sexual reproductive stage of choke in orchardgrass. In large plot studies, a copper fungicide caused a significant 8% reduction in the fungal reproductive body (stroma) fertilized, although not likely large enough to impact choke development and spread. In an evaluation of 10 fungicides in experimental plots, a small but significant reduction in choke was observed relative to untreated control plots. Unfortunately the reduction in choke is likely too small to impact disease development. Insecticides proved effective in lowering the survival of a fly associated with fungal fertilization, but the impact of the is on the epidemiology of choke will require further investigation.