and a hybrid between the two species above that often occurs on some grasses.
Dark reddish brown, large, oval or elongated pustules, full of powdery spores appear on both sides of the leaves, sheaths, stems and heads in spring. Leaf and stem surfaces appear torn from ruptured pustules.
The red brown spores will rub easily off the leaf onto your finger. The black spores at the end of the season don't rub off.
Puccinia graminis f.sp. tritici infects Barley, Cereal Rye, Durum Wheat, Triticale and Wheat.
Puccinia graminis f.sp. secalis infects Barley and Cereal Rye.
Requires a green host for survival and can't survive in soil or on crop residues.
Epidemics are more likely in seasons that have summer rains that allow volunteer Barley, Cereal Rye, Triticale or Wheat to survive over summer.
Requires warm, 15-300C, moist and humid conditions for infection.
The red brown spores are infectious whereas the black spores aren't.
New strains that are infectious on "resistant" varieties commonly occur.