Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/16/1997
Publication Date: N/A
Citation: Interpretive Summary: Ergot, caused by the fungus Claviceps purpurea, is an important disease of Kentucky bluegrass seed. During 1991-1993, field surveys indicated that 36-62% of fields of Kentucky bluegrass grown for seed were infested by ergot, although only about 2-13% of the fields had a high level of ergot. Recleaning of seed to remove ergot resulted in a 7.8% reduction in marketable yield. This is the first report quantifying the impact of ergot in Kentucky bluegrass seed production in central Oregon.
Technical Abstract: In 1991-93, ergot was detected in 36, 44, and 62%, respectively, of fields of Kentucky bluegrass grown for seed in central Oregon. Relatively few fields (2-13%) had a high level of ergot. Ergot severity (percent sclerotia by weight) in 1991-1993 was estimated at 0.85, 0.07, and 0.34%, respectively. Recleaning of seed to reduce ergot contamination and meet purity standards resulted in a 7.8% reduction in marketable seed weight. Weed grasses supporting ergot at the time of harvest of Kentucky bluegrass were species of Bromus, Secale, Festuca, and Poa. However, very few weed grasses were infected and they appeared to contribute little to ergot development in Kentucky bluegrass in central Oregon. Most infested fields (with more than one sclerotium/gm seed) or weed grass sites were located in the southern range of the production area.