A new race of stripe rust in durum wheat has been discovered in Mexico which is a cause for concern for California researchers and growers.

Jorge Dubcovsky, wheat breeder at UC Davis, encourages California wheat producers to carefully monitor their durum fields for infection rates and report any increase in infection relative to previous years.

Based on research in Mexico, upwards of 100 percent of some fields are infected with the new race of stripe rust which so far has not been reported in California.

According to Dubcovsky, the varieties Kronos, Kofa and Westbred 881 have increased susceptibility to the new race. Desert King showed 20 percent infection in one field in Mexico. Desert King-HP was said to perform better than Desert King due to the presence of the Yr36 gene.

Miwok is said to be resistant to this new race.

Growers with questionable samples should collect infected leaves and contact Dubcovsky, Oswaldo Chicaiza or Mark Lundy at UC Davis for information on further plant material inspection.