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 or in new fields planted next to established fields with a history of ergot.

In general, ascospore production by the pathogen is favored by:

• moderate temperatures (between 50°F and 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, and 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).