What is Rust?
Rust is a disease that is caused by a fungus that occurs mostly on perennial ryegrass but can occur on Kentucky bluegrass and fine fescues. The disease is very common on newly seeded areas. The rust fungus that occurs on turf does not cause the rust diseases that occur on perennials, shrubs or trees. The turf rust is a different strain from the plant rusts.
Rust makes the turfgrass have a diffuse yellow, orange to reddish-brown color. The spores are easily noticed by the orange color left on shoes or pant legs. The disease usually appears in the late summer and fall when the grass is slowly growing. The rust fungus is strictly foliar and does not kill the turfgrass.
Conditions optimum for rust is high humidity, along with low soil moisture, low nitrogen fertility and other growth-limiting factors.
Rust can be controlled through sound cultural turf management. Use quality turfgrass seed blends with several varieties desired for your site. A diverse lawn helps reduce rust and other turf problems. Resistance to rust will vary according to environmental conditions and strain of rust.
Maintain lawns through sound practices of watering, mowing and fertilizing. Alleviate symptoms by watering slow-growing turf. The turf should be watered in the early morning so the leaf surface dries quickly. Apply adequate water (one inch a week in 2-3 applications per week).
Mow at recommended height of 2 ½ -3 ½ inches high.
Fertilize to encourage growth. Apply adequate nitrogen fertilizer but don’t over fertilize. Apply a fertilizer with both quick release and slow release nitrogen. A fertilizer bag will have three numbers on it. The first number is nitrogen. (Example: 26-0-3, 26 is the nitrogen.)
Chemicals or fungicides are not recommended or rarely suggested. Implementing sound turf management practices, as described, will help you to create and maintain a lush, healthy lawn for years.