A sentinel plot of Kentucky bluegrass was established at the OSU Central Oregon Agricultural Research and Extension Center and artificially-infested with ergot sclerotia in Fall 2025. Today we observed sclerotia in various stages of germination in the sentinel plot, indicating that airborne ascospore production has started or will begin soon.

This timing is also coinciding with flowering in many Kentucky bluegrass cultivars. Protective fungicides should be applied at the onset of flowering and throughout anthesis to protect unfertilized ovaries from infection. Cultivars with prolonged flowering periods may require more than one application. More information on registered products for ergot control in grass grown for seed can be found in the PNW Plant Disease Management Handbook.

Established fields that experienced ergot in the previous year are at a higher risk for ergot than first-year fields or fields with no prior history of ergot infection. However, airborne ascospores can travel from one field to another, meaning that even first-year fields may become infected when located near infested fields.

Updated spore detection results are posted below for the lower Columbia Basin of Washington.

Updated spore detection results are posted below for the lower Columbia Basin of Washington and the Grande Ronde Valley.

Updated spore detection results are posted below for the lower Columbia Basin of Washington and the Grande Ronde Valley.

Updated spore detection results are posted below for central Oregon, the lower Columbia Basin of Washington, and the Grande Ronde Valley.

Updated spore detection results are posted below. Spores were detected at two sites near Madras, OR and at two sites east of Pasco.

Updated spore detection results are posted below. Spores were detected at one site near Madras, OR and at three out of six sites east of Pasco.

Updated spore detection results are posted below. Spores were detected at two sites near Madras, OR and at three out of six sites east of Pasco.

Updated spore detection results are posted below. Spores were detected at two sites near Madras, OR and at one out of six sites east of Pasco.

Updated spore detection results are posted below. Spores were detected near Madras, OR and at two out of six sites east of Pasco.

A predictive model for ergot ascospore presence was developed for the Lower Columbia Basin of Oregon that uses accumulated degree-days (beginning January 1, with a base temperature of 50°F and upper threshold temperature of 77°F) to forecast when ascospores are likely to be present.

According to the model, most ascospores are detected in the Lower Columbia Basin when accumulated degree-days are between 414 and 727. Based on this model, the degree-day threshold was reached on May 16, 2024 in Hermiston, OR (accumulated degree days = 420).

In 2023, the degree-day threshold was met on May 19.