Cause The fungus, Pyrenophora graminea (asexual stage: Drechslera graminea), survives exclusively on or in seed but is not in all seed lots. Infected seeds can appear healthy. Soil temperature and moisture level during germination and emergence are important in determining whether infected seeds result in seedling infection. Infection is enhanced by intermediate moisture levels and temperatures below 60°F. If moisture is high during heading, conidia may be produced on infected seedlings.
Symptoms Yellow striping is visible on second, third, or older leaves. Stripes turn brown, and infected leaves die as the disease progresses. Infected leaves may look frayed as they die.
Infected plants are stunted, and flag leaves may be a light tan. Spikes may emerge twisted and brown or not emerge at all. Heads may be infected, resulting in few seeds and shriveled, discolored kernels.
Cultural control
- Use pathogen-free seed.
- Some spring barleys are resistant to some isolates of this pathogen.
Chemical control
- Use a seed treatment. Dividend Extreme at 2 to 4 fl oz/100 lb seed for spring barley. Do not graze green barley forage until 30 days after planting. See label for reentry restrictions.
- Demethylation-inhibiting (DMI) Fungicides (Group 3) are labeled for use.
- Bumper 41.8 EC or Bumper ES at 4 fl oz/A on a minimum of 14-day intervals for no more than two (2) applications, one (1) application maximum if harvesting for forage or hay. Do not apply within 45 days of harvest for grain and straw; 30 days for forage or hay. 12-hr reentry.
- Miravis Ace B at 4 fl oz/A at flag-leaf emergence (Feekes stage 8) but not after Feekes 10.5.4. Do not apply within 7 days of harvest for forage or hay. 12-hr reentry.
- Tilt at 4 fl oz/A on a minimum of 14-day intervals for no more than two (2) applications, one (1) application maximum if harvesting for forage or hay. Apply when the flag leaf is 50% to fully emerged, up to late head emergence (Feekes 10.5). Preharvest interval is 7 days for forage and hay. 12-hr reentry.
- Strobilurin fungicides (Group 11) are labeled for use. Do not make more than one (1) application of any Group 11 fungicide per season.
- Headline at 6 to 9 fl oz/A. Apply no later than 50% head emergence (Feekes 10.3). Preharvest interval is 14 days for hay and forage. 12-hr reentry.
- Quadris Flowable at 9 to 12 fl oz/A applied prior to disease development, up to late head emergence (Feekes 10.5). Do not apply more than two (2) applications of any Group 11 fungicide per season. Do not apply within 7 days of grazing. Preharvest interval is 7 days for forage and hay. 4-hr reentry.
- Premixes of Group 3 + 11 fungicides are available for use. Do not apply more than one (1) application of any Group 11 fungicide per season.
- Quilt or Quilt Xcel at 10.5 to 14 fl oz/A on a minimum of 14-day intervals for no more than two (2) applications. Can begin when the flag leaf is 50% to 70% emerged and continue up to late head emergence (Feekes 10.5). Preharvest interval is 7 days for forage and hay. 12-hr reentry
Reference Mathre, D.E. 1997. Compendium of Barley Diseases. St. Paul, MN: AS Press.