A predictive model for ergot ascospores was recently developed for the Lower Columbia Basin of Oregon.

The model 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 produced in the Lower Columbia Basin when accumulated degree-days are between 414 and 727.

Accumulated degree-days as of May 8 were 366 in Hermiston, OR (black solid line).

At this time in 2017, accumulated degree-days were 276 (orange dotted line).

For more details on the model and how it was developed, please see our recent publication in the journal Plant Disease (https://doi.org/10.1094/PDIS-05-16-0609-RE).

This year we have seven spore traps deployed in three grass seed production areas that include two sites in the Columbia Basin of Oregon (Umatilla County), two sites in the Columbia Basin of Washington (Benton and Franklin Counties) two sites in the Grande Ronde Valley (Union County), and a site central Oregon (Jefferson County).

We have expanded our spore trapping efforts northward this season, with a spore trap site in a Kentucky bluegrass field east of Eltopia.

These data will be used to refine and validate regional models and inform growers of spore production through the season.

The Ergot Alert Newsletter is brought to you by Oregon State University and sponsored by the Washington Turfgrass Seed Commission, the Oregon Seed Council, the Columbia Basin Grass Seed Growers, the Jefferson County Seed Growers Association, and the Union County Grass Seed Growers Association.

A predictive model for ergot ascospores was recently developed for the Lower Columbia Basin of Oregon.

The model 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 produced in the Lower Columbia Basin when accumulated degree-days are between 414 and 727.

Accumulated degree-days as of April 30 were 259 in Hermiston, OR (black solid line).

At this time in 2017, accumulated degree-days were 200 (orange dotted line).

For more details on the model and how it was developed, please see our recent publication in the journal Plant Disease (https://doi.org/10.1094/PDIS-05-16-0609-RE).

The HAREC ergot spore trap site was set up in one of our perennial ryegrass research plots on April 23rd.

Each spore trap site consists of a Burkard 7-day volumetric air sampler and a WatchDog data logger that measures air and soil temperatures, relative humidity, and soil moisture.

The samples are collected from the air sampler weekly and returned to the lab for analysis.