Cause:
A fungus, Puccinia graminis, that overwinters on stubble, straw, certain wild grasses, wheat, rye, triticale, and volunteer barley. Alternate hosts are species of barberry. The disease is not usually a problem in Oregon or Idaho.
Symptoms:
The red rust or summer spore stage (uredinia) is evident on stems, leaf sheaths, glumes, awns, and leaves as elongate pustules containing reddish brown spore masses. The black rust or autumn spore stage (telia) looks like the red stage except for the black color.
Cultural
control:
Eradicate barberry in grain areas of northeastern Oregon.
Anything that delays crop maturity, such as cultivars, herbicides, or planting practices, makes barley more vulnerable to stem rust.
Chemical
control: Use under severe disease pressure or when raising an unusually susceptible variety.
Bumper 41.8 EC at 4 fl oz/A. Highest yields are normally obtained when applied to the emerging flag leaf. May be applied until the ligule of the flag leaf emerges (Feekes growth stage 8). Do not feed treated forage or cut green crop for hay or silage.
24-hr reentry.
Folicur 3.6F at 4 fl oz/A as a single application. Do not apply within 30 days of harvest. 12-hr reentry.
Quilt at 10.5 to 14 fl oz/A on a minimum of 14-day intervals. Can begin when the flag leaf is 50 to 70% emerged and continue up to Feekes growth stage 10.5. Do not feed treated forage or cut green crop for hay or silage. Make no more than two (2) applications of Quilt/A/year. Crop tolerance/phytotoxicity notes on label. Preharvest interval is 45 days. 12-hr reentry.
Tilt at 4 fl oz in not less than 15 gal/A water (ground) or 5 gal/A water (air). Apply when the flag leaf is 50% to fully emerged. Do not apply within 30 days of harvest for forage, 40 days for grain and straw and 45 days for hay. 12-hr reentry.
Biological
control:
Ballad Plus at 1 to 4 quarts/A on 7- to 14-day intervals. Efficacy unknown in the Pacific Northwest. Can be applied up to and on the day of harvest. 4-hr reentry.
Content edited by:
Cynthia M. Ocamb on
January 1, 2009
