Cause A fungus, Rhynchosporium secalis, which overwinters in infected residues, weeds, grasses, volunteer barley, and seed. This fungus produces spores on residues, which are spread by splashing water.
Symptoms Oval to elongate spots with light centers and dark brown to black edges develop on leaves, leaf sheaths, and sometimes on floral bracts or awns. Large spots may kill leaves. If seedlings are infected, lesions do not develop; seedlings wilt completely.
Cultural control
- Rotate crops.
- Destroy old stubble by plowing deeply or burning.
- Destroy volunteer barley or other infected grass species.
- Plant resistant varieties. Some varieties such as Gwen, Hundred, and Kold are resistant to some strains of the fungus.
Chemical control Economic returns from fungicides are best when weather is wet just before and after Feekes stage 8.
- 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 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 or hay. 12-hr reentry.
- Miravis Ace A (Group 7) at 10.3 fl oz/A beginning at flag-leaf emergence (Feekes stage 8) but not after full head emergence (Feekes 10.5.4). Do not apply within 7 days of harvest for forage or hay. 4-hr reentry.
- Strobilurin fungicides (Group 11) are labeled for use. Do not make more than two (2) applications of any Group 11 fungicide per season. Do not make more than one (1) application of any Group 11 fungicide before alternating to a labeled fungicide with a different mode of action.
- 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 within 7 days of grazing. Preharvest interval is 7 days for forage and hay. 4-hr reentry.
- Vertisan (Group 7) at 14 to 24 fl oz/A on 7- to 14-day intervals through flowering (Feekes 10.5.1). Do not make more than two (2) sequential applications before alternating to a labeled fungicide with a different mode of action (non-Group 7). Preharvest interval is 0 days for forage and hay. 12-hr reentry.
- Premixed fungicides are available for use. Do not make more than one (1) application of any Group 11 fungicide before alternating to a labeled fungicide with a different mode of action.
- Miravis Ace (Group 3 + 7) at 13.7 fl oz/A. Apply between Feekes 10.3 and 10.5.4. Harvest interval is 7 days for forage and hay. 12-hr reentry.
- Priaxor (Group 7 + 11) at 4 to 8 oz/A. Do not apply after 50% head emergence (Feekes stage 10.3). Preharvest interval is 14 days for forage and chopped feed. 12-hr reentry.
- Quilt or Quilt Xcel (Group 3 + 11) at 10.5 to 14 fl oz/A when the flag leaf is 50% to fully emerged. Applications may be made no closer than a 14-day interval and may be applied up to Feekes growth stage 10.5. Do not make more than two (2) applications per season. Preharvest interval is 7 days for forage and hay. 12-hr reentry.
- Stratego (Group 3 + 11) at 7 fl oz/A or Stratego YLD at 2.3 fl oz/A. Do not apply after flag-leaf emergence (Feekes stage 8). Do not make more than two (2) applications per season. Do not apply within 40 days of harvest. See label for grazing, forage, and hay restrictions. 12-hr reentry.
- Trivapro (Group 3 + 7 + 11) at 9.4 to 13.7 fl oz/A. Apply from Feekes 8 through Feekes 10. Do not make more than two (2) applications per season. Do not apply within 7 days of harvest for forage or hay. 12-hr reentry.