As many of you walk through your lawns you might see that your shoes are discolored with an orange tint. Rust disease is caused by a variety of different fungi and usually affects taller mown turf such as residential lawns, low budget athletic fields and golf course roughs. Common names for this disease are leaf rust, crown rust and stem rust. Rust will mainly affect bluegrass and perennial rye grass and for the most part this disease is mainly cosmetic although the spores will get on your shoes, pets and lawnmowers covering them with an unsightly orange tint. Rust can damage new spring-seeded lawns that will lose vigor during the important weather conditions such as a drought.
A majority of rust outbreaks will begin in late summer and early fall and I have started to see several properties that have it now. Low fertility, compaction, and shade will contribute to rust in lawns and it also likes constant night temperatures of 50-60 degrees and a long dew period at night of 10 hours.
The best way to control rust in your lawns is by maintaining a healthy stand of turf that is fertilized late in the summer with moderate amounts of nitrogen (.25-.5# / 1000 ft2). This application of nitrogen will encourage leaf growth and allow for normal mowing that will keep the spores from your turf grass. Although there are many fungicides that can take care of the rust disease we often do not recommend the extra cost since the disease will not typically harm your lawn. Be sure to avoid late evening irrigation so your lawn does not remain wet throughout the night.