Flag Smut of Wheat

History and Importance:

•Losses 5-20%

•First report 1868 (Austrailia)

•Sporadic

•Sori between leaf veins

•Epidemic ---100% losses

Disease Cycle:

The flag smut fungus infects young wheat plants in the fall but symptoms do not develop until later in spring. The fungus grows within the plant becoming systemic. At heading and flowering growth stages, the fungus produces spores with rapture through the leaf or stem tissues and can be seen as black-gray blisters. The spores produced by the fungus at this stage are called teliospores. These are hardy and can survive in the soil for a long time or on stored seed.

Symptoms:

Flag smut causes whitish or yellowish to dark grey longitudinal stripes between veins of infected plants. The stripes may appear as blisters between veins. These later may rupture exposing spores of this fungus making the stripes look very black. Infected plants are stunted and have fewer tillers. The leaves on infected plants become distorted/twisted and may be split longitudinally along the blisters.

Management:

•Copper carbonate

•Seed treatment----Thiram @ 3 g/kg seed, Topsin-M @2 g/kg seed.

•Seeds are soaked in water (1:1 w/v) in a galvanised tub which is tightly covered with a transparent polythene sheet and placed under the sun. 

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flag-smut-of-wheat.pptx (1.32 MB )