Cause and signs of disease: Wheat leaf rust,
caused by the fungus Puccinia triticina (formerly recondita
f. sp. tritici), reduces wheat yields in susceptible
varieties when weather conditions favor rust development
and spread. The most characteristic signs of leaf
rust infection are the rusty-red spores in round to oval
pustules breaking through the leaf surface (Figure 1).
These spore masses are detected fi rst on wheat in
North Dakota in late May or early June, generally in the
southern-most counties, and on lower leaves where
higher humidity occurs.
Disease cycle: