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How to Manage Pests

The UC Guide to Healthy Lawns

Microdochium patch or Fusarium patch (pink snow mold) — Microdochium nivale

Turfgrass killed by Fusarium patch

Spore mass

Click on images to enlarge.

Hosts

Annual bluegrass (a common weed in turf), creeping bentgrass, Kentucky bluegrass

Symptoms

Fusarium patch develops as circular patches 1 to 6 inches (2.5 - 15 cm) wide. Leaves appear watersoaked and are reddish-brown on the outside progressing to a straw color in the center. Dead leaves may have gelatinous spore masses. White or pink fungal threads may be observed in the early morning, giving the turf a pink cast.

Conditions favoring disease

Cool temperatures (40° to 60°F) and moist conditions favor Fusarium patch. High nitrogen applications in the fall and neutral or alkaline soils also contribute to disease development. Fusarium patch survives in grass residues.

Prevention and management

Reduce shade and provide good soil aeration and water drainage. Irrigate at the recommended frequency for your turf species and avoid excess nitrogen fertilizer, especially in the fall. Maintain a soil pH between 6.5 and 6.7. You may need to have a professional soil analysis done to help you determine what amendments to add to maintain an ideal pH. High levels of potassium suppress disease. If Fusarium patch has been a serious problem in the past, have a licensed pest control applicator apply a fungicide in the fall before symptoms appear.

For more information on lawn diseases, refer to:
Pest Notes: Lawn Diseases: Prevention and Management


Statewide IPM Program, Agriculture and Natural Resources, University of California
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Agriculture and Natural Resources, University of California

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