University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Orange Lawns Again Starting to Appear

August 7, 1997

Last year, rust was a common disease on lawns. Many lawns turned orange as a result of rust disease. Once again, this disease is starting to appear in the stateline area.

Rust is a common late summer disease on lawns. Rust starts with orangish pustules (or raised spots) on leaf blades of turfgrasses, which are not really noticeable at first. However, rust may continue to develop until it casts an orangish brown look to the lawn.

Look closely at the leaf blades of grasses in your lawn and you may see the orange pustules. The spores easily rub off on your hand. With a high level of disease, it's not uncommon to track rust spores, or orange powder, into the house.

Rust typically develops in the late summer-early fall period when lawns are growing very slowly. Rust is also aided by low fertility (in particular nitrogen), which is also common by late summer. Cool nights with heavy dew and light, frequent rainfall add to the ideal conditions for rust to develop. Rust can spread via air, water, shoes, equipment, and sod.

Control rust through sound lawn maintenance, including proper fertilizing, watering, mowing, and thatch management. Early September is an excellent for fertilizing, which combined with water, should get lawns growing faster. With improved lawn vigor, the rust should disappear. If seeding or overseeding areas in the next few weeks (ideal time), choose quality lawn seed blend of several cultivars of the species desired for the site. A diverse turf stand helps combat rust and numerous other turf problems.

If rust is severe on a particular site every year or if a new stand of grass is affected, fungicides may be needed in addition to following sound cultural practices. Suggested fungicides available through garden center outlets should contain either chlorothalonil, maneb, or mancozeb. Refer to labels for rates and application intervals.

For most lawns, however, increasing the vigor is usually enough to take care of rust.


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