Updated spore counts from our spore trap sites are now available below.

In general, spore production has tapered off at most sites, though a considerable number of spores are still being captured at KBG-1 (central Oregon) and KBG-4 (upper Columbia Basin).

Spore production should decrease as daily temperatures begin to regularly exceed 80°F.

Field scouting for honeydew at this time can help identify infected fields which may present difficulties during harvest and seed cleaning operations.

Prioritize monitoring efforts in fields that were infected last year, as well as fields in close proximity to previously infected fields.

Honeydew and sclerotia have been observed in non-treated, artificially-infested plots in Madras, OR.

Cultivars with late emerging flowers may still be exposed to airborne spores or honeydew.

In contrast to airborne ascospores, honeydew is contact-, splash- or insect-dispersed.

Infections that occur later in the season can result in the presence of honeydew at harvest, which can make swathing and combining more difficult.

Fields with honeydew should be monitored for development of sclerotia (before and after swathing).

Late season scouting and field monitoring will help to develop harvesting/seed cleaning schedules and identify potential problem fields or areas that will need increased monitoring in the 2019 season.

Updated spore counts from our spore trap sites are available below.

It is important to remember that the spore counts presented below are intended to show daily trends in spore production and do not necessarily indicate inoculum pressure in your field(s). Spore production can vary from field to field, and inoculum pressure tends to be higher:

  • in older fields with a history of ergot in the previous season
  • in new fields planted next to established fields with a history of ergot
  • in fields with high numbers of sclerotia (for context, KBG1 and PRG1 are artificially-infested fields at COARC and HAREC, respectively)
  • when air temperatures are between 50 and 80°F
  • after precipitation or rain events

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).

Graphs of daily spore counts from our spore trap sites are now available and will be updated as more data is collected.

To date, spore counts are relatively high compared to last year, and we continue to detect spores at all 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).

We are still detecting ergot ascopores 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 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).