The HAREC ergot spore trap site was set up in one of our perennial ryegrass research plots on April 24th. Thanks to Ms. Victoria Skillman, Faculty Research Assistant in Dr. Frost’s Plant Pathology Lab at HAREC, for helping us with our spore trapping efforts!

A pulse of ergot spores were observed at the HAREC site on the first day of trapping, April 24th, as well as on April 25th. Updated HAREC spore counts through May 6th should be available by the end of this week.

A predictive model for ergot ascospores 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.

Accumulated degree-days as of May 2 were 259 in Hermiston, OR (solid line). According to the model, most ascospores are produced in the Lower Columbia Basin when accumulated degree-days are between 414 and 727.

At this time in 2018, accumulated degree-days were 278 (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).