ASSESSMENT OF ERGOT AND BLIND SEED DISEASES OF GRASSES IN THE WILLAMETTE VALLEY OF OREGON

The levels of ergot and blind seed among grasses grown for seed in the Willamette Valley of Oregon between 1986 and 1989 were assessed. Seed samples, representing nine grass species, were obtained from the Oregon State University Seed Laboratory (seed lab) or, in 1988 and 1989, were collected from commercial fields before harvest. Grower management information was obtained for 179 and 218 fields in 1988 and 1989, respectively. The correlation coefficient between seed lab samples and field samples with ergot in 1988 and 1989 was 0.90 and 0.61, respectively. Ergot was observed in 2-34% of the colonial bentgrass, creeping bentgrass, Kentucky bluegrass, and chewing festuca seed samples examined. Significantly (P = 0.05) more samples infested with ergot were observed in 1988 than in 1989. The percentage of ergot in burned and nonburned fields was similar in 1988 and 1989, and the incidence ranged from 4 to 11%. The correlation coefficient between seed lab samples and field samples with blind seed in 1988 and 1989 was 0.90 and 0.91, respectively. Blind seed was detected in 8-10% of the tall fescue and in 2-3% of the perennial ryegrass seed samples examined. Blind seed was detected in 38% of fields open burned and 0% of fields not burned in 1988. In 1989, 6% of the fields open burned and 4% of the fields not burned contained blind seed.