VIRULENCE OF 1990-1994 COLLECTIONS OF USTILAGO-AVENAE AND USTILAGO-KOLLERI FROM MANITOBA AND SASKATCHEWAN

Surveys for loose smut [Ustilago avenae] and covered smut [U. kolleri (syn. U. hordei, U. segetum)] of oat were conducted during 1990-1994 i n farm fields in Manitoba and Saskatchewan, and smutted oat panicles w ere collected at 21 sites. Fourteen of the collections were identified as U. avenae and seven were identified as U. kolleri. The virulence o f the collections was evaluated in the field at Glenlea, Manitoba, dur ing 1995 on the Canadian oat differential set. Eight races were charac terized among the fourteen collections of U. avenae, while six races w ere characterized from the seven collections of U. kolleri. The U. ave nae collections were virulent on 7-10 hosts of the differential set; t hose of U. kolleri were virulent on 4-7 differential hosts. None of th e smut collections was virulent on the oat differential lines Markton and Camas or the currently registered cultivars Dumont, Robert, Tibor, and AC Preakness.