Germinating sclerotia have been observed in artificially-infested sentinel plots at the Central Oregon Agricultural Research and Extension Center (COAREC). Grass seed growers and crop consultants can assume that ergot spores are currently present in the area. Spore trap updates from COAREC (and other locations in the Pacific Northwest) will be available soon.

Sources of sclerotia include established (2nd year or older) grass seed fields with a recent history of ergot. First-year fields are not likely to be sources of inoculum unless planted with seed infested with sclerotia. However, Kentucky bluegrass stands of all ages can potentially become infected with the disease.

Only unfertilized flowers are susceptible to infection, but the ergot pathogen has a wide host range among grasses. Other hosts include cereal rye, wheat, triticale, wheatgrass, and fescues. Cereal crops and grassy weeds can serve as alternative hosts and sources of inoculum in grass seed production systems.

Some Kentucky bluegrass varieties are in the early (~boot) stages of anthesis (flowering) and may be subject to exposure to ascospores. For maximum ergot control, fungicide applications should be timed to occur at the beginning of, or immediately prior to, anthesis. Since fungicides for ergot are protective and not curative, applying earlier is better than later. Cultivars with long anthesis periods may require (an) additional application(s).

More information on fungicide options for ergot in the Pacific Northwest can be found in the Pacific Northwest Disease Management Handbook: https://pnwhandbooks.org/plantdisease/host-disease/grass-seed-ergot .

Acknowledgement: This research is funded by the Eastern Oregon Kentucky Bluegrass Working Group, the Jefferson County Seed Growers Association, the Oregon Department of Agriculture Alternatives for Field Burning Research Financial Assistance Program, the Oregon Seed Council, the Union County Seed Growers Association, and the Washington Turfgrass Seed Commission.