Several species of fungi cause rusts of turfgrasses. Typical symptoms include yellow specks on the leaf blades followed by development of yellow, orange, dark orange-brown, or red rust pustules on either or both leaf surfaces. Infection may also occur on stems and leaf sheaths. Severe rust infections can kill leaf blades and may cause the turfgrass to appear thin or weak. Weedy species can infest weakened turfgrass. Affected areas of the lawn may show a reddish, brown, or yellow tint. Rust diseases are more severe on slow-growing or stressed grasses (shade, drought, poor nutrition, and incorrect mowing height are possible causes of stress). The fungi overwinter in diseased grass and can be spread by wind. Rusts typically occur on bluegrasses, ryegrasses, and fine fescues.

Management Options

Non-Chemical Management

Plant mixtures of improved bluegrass varieties.
Provide proper culture (including adequate, balanced fertilization) to maintain vigorous, healthy turfgrass.
Water in the mornings so grass can dry quickly. Deep, infrequent watering is best.
Correct conditions which stress grass. For example, prune trees and shrubs to increase light penetration.
Mow regularly at recommended height. Remove clippings when rust infections are severe.
For more information on proper care of lawns see EB 0482E, Home Lawns.

Select non-chemical management options as your first choice!

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

Treat in early spring and fall when grass is growing slowly and the climate favors rust development. Do not repeatedly apply the same fungicide or fungicides with the same active ingredient as tolerant strains may result. Carefully check product labels.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

ferti-lome F-Stop Lawn & Garden Fungicide RTS
Active ingredient: myclobutanil | EPA reg no: 7401-505
ferti-lome Liquid Systemic Fungicide II R-T-Spray
Active ingredient: propiconazole | EPA reg no: 53883-184-7401
Scotts Lawn Disease Control
Active ingredient: azoxystrobin | EPA reg no: 100-1275-538
Spectracide IMMUNOX Multi-Purpose Fungicide Spray Conc
Active ingredient: myclobutanil | EPA reg no: 9688-123-8845
This list may not include all products registered for this use.

Images

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Caption: Rust Photo by: R.S. Byther

WSU Extension

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