Ergot ascopores are still being detected on most days at all spore trap sites.

Ascospore production by the pathogen is favored by:

  • moderate temperatures (≤80°F)
  • high soil moisture, rainfall, and/or irrigation.
  • conditions that delay or interfere with pollination, such as cool, wet weather, can increase the period of susceptibility in grass seed crops.

It is recommended that growers scout fields as grass seed crops approach anthesis.

Protective fungicides should be applied prior to the onset of anthesis to protect unfertilized flowers from infection.

Cultivars with prolonged flowering periods may require multiple applications.

Please refer to the PNW Plant Disease Management Handbook for more information (https://pnwhandbooks.org/plantdisease/host-disease/grass-seed-ergot).

Ergot ascospores have been detected in the Grande Ronde Valley at spore trap sites KBG2 and KBG3.

It is recommended that growers scout fields as grass seed crops approach anthesis.

Protective fungicides should be applied prior to the onset of anthesis to protect unfertilized flowers from infection.

Cultivars with prolonged flowering periods may require multiple applications.

Please refer to the PNW Plant Disease Management Handbook for more information (https://pnwhandbooks.org/plantdisease/host-disease/grass-seed-ergot).

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 10 were 387 in Hermiston, OR (black solid line).

At this time in 2017, accumulated degree-days were 302 (orange dotted line). Based on weather forecasts, the degree-day model will reach 414 over the weekend.

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).

Ergot ascospores have been detected in the Columbia Basin at spore trap sites KBG4 (a commercial Kentucky bluegrass field near Paterson, WA) and in Central Oregon KBG1 (an artificially-infested Kentucky bluegrass field at the OSU Central Oregon Agricultural Research  Center).

It is recommended that growers scout fields as grass seed crops approach anthesis.

Protective fungicides should be applied prior to the onset of anthesis to protect unfertilized flowers from infection.

Cultivars with prolonged flowering periods may require multiple applications.

Please refer to the PNW Plant Disease Management Handbook for more information (https://pnwhandbooks.org/plantdisease/host-disease/grass-seed-ergot).

Ergot ascospores have already been detected in the Columbia Basin at spore trap sites KBG5 (a commercial Kentucky bluegrass field west of Eltopia, WA), PRG1 (an artificially-infested perennial ryegrass field at the OSU Hermiston Agricultural Research and Extension Center), and PRG2 (a commercial perennial ryegrass field near Hermiston).

It is recommended that growers scout fields as grass seed crops approach anthesis.

Protective fungicides should be applied prior to the onset of anthesis to protect unfertilized flowers from infection.

Cultivars with prolonged flowering periods may require multiple applications.

Please refer to the PNW Plant Disease Management Handbook for more information (https://pnwhandbooks.org/plantdisease/host-disease/grass-seed-ergot).

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.