Stem Rust of Barley
Puccinia graminis f.sp. tritici
Puccinia graminis f.sp. secalis
and a hybrid between the two species above that often occurs on some grasses.
Description: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.
Species Affected:Puccinia graminis f.sp. tritici infects Barley, Cereal Rye, Durum Wheat, Triticale and Wheat.
Puccinia graminis f.sp. secalis infects Barley and Cereal Rye.
Biology: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.
Life Cycle:Origin and History:
Grain yield loss can be total.
Management and Control:Sow resistant varieties. HYPERLINK \l "_Disease_Susceptibility_of_Barley Va" Disease Susceptibility of Barley Varieties. No variety is totally tolerant so other measures should also be practised to reduce inoculum loads.
Control volunteer and out of season Barley, Cereal Rye, Triticale and Wheat.
Control Stem Rust in Cereal Rye, Triticale and Wheat crops.
Seed treatments are not effective and foliar treatments with fungicides are rarely economic.
Avoid planting Barley in spring.
Related and Similar Species:Leaf Rust of Barley (Puccinia hordei) has smaller, lighter brown and more circular pustules that do not noticeably rupture the leaf surface and only appear on the sheaths late in the season.
Leaf Rust of Wheat (Puccinia recondita) has smaller, lighter brown and more circular pustules that do not noticeably rupture the leaf surface and only appear on the sheaths late in the season.
Stem Rust of Wheat (Puccinia graminis)
Stripe Rust of Wheat (Puccinia striiformis)
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