|Barley crown rust|
Crown rust is a new disease of barley. It was found first in a barley breeding nursery near Clay Center, Nebraska in 1992. Since then, crown rust has been found throughout the upper Midwest, with greatest incidence in the central Red River Valley of North Dakota and Minnesota. In that region the alternate host, common buckthorn (Rhamnus cathartica), grows abundantly in shelter belts and riparian areas. Since 1993, outbreaks of crown rust have occurred on barley and forage grasses at several localities in this region. The extent of yield losses in barley caused by this disease have not been determined. Crown rust poses a threat to barley production, because the first infections in barley occur early in the season from local inoculum.
Disease Cycle and Control:
Barley crown rust can infect rye as well as barley. In addition, it also infects a number of grasses in nature including quackgrass (Elytrigia repens), slender wheatgrass (Elymus tranchycaulus), western wheatgrass (Pascopyrum smithii), foxtail barley (Hordeum jubatum), and several wheatgrasses (Elytrigia spp.) and wild rye grasses (Elymus spp. and Leymus spp.). The fungus readily forms telia on these hosts, which serve as a reservoir of overwintering teliospores. Quackgrass may be the most important reservoir for overwintering telia. This ubiquitous, perennial weed is very susceptible to the rust and is often found growing near Rhamnus.
Developing effective control strategies will depend upon how important this disease becomes in barley production. As with other cereal rust diseases, resistant cultivars will probably provide the most effective and economical control. Sources of resistance to crown rust have been identified in barley germplasm from diverse regions, but most malting barley cultivars currently grown in the northern Great Plains of North America are susceptible to crown rust. It is too early to know how quickly new races of barley crown rust may arise, but experience with oat crown rust suggests that the barley crown rust fungus may be able to overcome race-specific resistance quite rapidly.
Jin, Y., Steffenson, B. J., Oberthur, L. E., and Baenziger, P. S. 1992.
Jin, Y., and Steffenson, B. J. 1993. Natural occurrence of barley crown rust
Jin, Y., Steffenson, B. J., Wesenberg, D. M., and Bockelman, H. E. 1993.
Jin, Y. and B.J. Steffenson. 1999. Puccinia coronata var. hordei var. nov:
Jin, Y. and B.J. Steffenson. 2002. Sources and genetics of crown rust
Argrama, H., L. Dahleen, M. Wentz, Y. Jin, and B. Steffenson. 2004. Mapping
Contact at Cereal Disease Laboratory: Dr. Yue Jin