Leaf rust, caused by the fungus Puccinia recondita, was found yesterday morning in two fields around Crookston, MN. The wheat in both fields is in the five-leaf stage and is just closing the rows. The small oval-shaped dark red to tan pustules could readily be found on the lower leaves. The incidence in both fields was probably 20% with severity ranging from a trace to a percent on the infected leaves with an MR to R response. The detection of leaf rust at this time in the growing season is worrisome because much of the wheat is very late and chances for an leaf rust epidemic and economic losses caused by leaf rust increase if the disease gets established this early in the growing season.

Scout fields and consider the use of a systemic fungicides to control leaf rust if you can readily find leaf rust present across your fields. An application of, for example, half the labeled rate of propiconazole (Tilt, PropiMax) can stop the leaf rust from developing further in this young crop. The fungicides labeled for wheat can be tank mixed with most herbicides but always read and follow label directions.