Lawn and Turf: Rusts

Biology

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

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• 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.

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.

Approved Pesticides

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

• ferti-lome F-Stop Lawn and Garden Fungicide
  Active ingredient: myclobutanil [EPA registration number: 7401-505]
• ferti-lome Liquid Systemic Fungicide II R-T-Spray
  Active ingredient: propiconazole [EPA registration number: 53883-184-7401]
• Scotts Disease EX Lawn Control
  Active ingredient: azoxystrobin [EPA registration number: 538-330]
• Spectracide IMMUNOX Multi-Purpose Fungicide Spray Concentrate
  Active ingredient: myclobutanil [EPA registration number: 9688-123-8845]
• This list may not include all products registered for this use.