What to Do About Rust on Turf

Irrigation

• The growth of the disease-causing fungal spores is favored by warm temperature ranging between 70 to 75 degrees Fahrenheit and prolonged moisture on leaf blades. Following healthy irrigation practices will reduce outbreak of disease. Generally, 1 to 2 inches of water is necessary to keep roots sufficiently moist. Irrigating lawns infrequently but deeply encourage healthy root growth. Water the grass during the early part of the day to allow blades to dry thoroughly.

Fertilizer

• Lawns that are not receiving enough nitrogen are more prone to rust disease. Fertilize cool and warm season grass four times a year with ½ to 1 lb. of nitrogen per 1,000 square feet. This amounts to 4 to 6 lbs. of nitrogen over the entire year. Do not use an excessive amount of fertilizer because this can burn the grass. Reduce fertilizer amount to half for grass growing in shade. Apply minimal amounts of fertilizer to cool season grass during summer.

Mowing Height

• Mowing the lawn regularly and at the right height is among the cultural practices that help to reduce chances of rust in lawns. Also, remove all clippings to minimize the spread of fungal spores to healthy lawn areas. Avoid mowing very low because this tends to remove the food producing area of blades. Mowing high affects the aesthetic quality and usefulness of grass. As a general rule, grass needs frequent mowing during active growth periods. This is spring and fall for the cool season grasses and summer for the warm season species. Mow only enough to remove a third of the total leaf length.

Fungicides

• Maintaining optimal cultural requirements is usually enough to bring symptoms of rust under control. In severe cases and as a last resort, the use of products containing strobilurin help contain infection. Start application of fungicide on earliest sign of disease on newly seeded lawns. Repeat applications are generally not required to control disease.