You Are Here: Management Updates 2003 Archive May 23, 2003

Date: May 23, 2003
Category: Diseases
Subject: Fusarium Patch, Yellow Patch, Take-All Patch, Bacterial Wilt, Drought

The cool, wet weather has resulted in some expected diseases, but they sometimes have symptoms that make diagnosis confusing, especially when the weather warms up for a day or two and then returns to cooler temperatures.

• Fusarium patch (pink snow mold): Look for dime- to quarter-sized spots that are coppery to greasy looking, very similar to hot weather Pythium blight. And like Pythium blight, the fungus can be streaked with mowers, feet and water. Iprodione is a good curative fungicide. Excess N favors the disease which can continue as long as the weather is cool and wet. Place a plug of turf in a plastic bag overnight to look for the pinkish mycelium on the leaf blades if you are unsure of the diagnosis.
  
• Yellow patch (cool season brown patch): Cool, wet weather, high N, and excess thatch favor this disease. You are unlikely to see the "smoke ring" associated with hot weather brown patch. It usually only affects the leaves, but can be very unsightly with prolonged wet weather. Medallion™ and ProStar™ are particularly effective fungicides. Warm, dry weather is the same as a fungicide application for both yellow patch and Fusarium patch.
  
• Take-all patch: This root disease is favored by cool, wet weather on young bentgrass and in areas where the pH is high. Improve the root environment (reduce thatch and compaction), reduce pH where necessary with ammonium sulfate, and use Heritage watered-in. You might not see the symptoms until the weather gets warmer when the impaired root system fails to support the tops of the plants.
  
• Bacterial wilt: This disease is restricted to annual type Poa annua plants, mostly found in very old push-up type greens with poor root systems. There is no cure or control. Try to improve the root environment and overseed with bentgrass.
  
• Drought: There is no fungicide to spray for this one! In thatchy, compacted greens, be sure to use a soil probe or cup cutter to make sure that you are actually watering deeply. In addition, we have seen some mowing injury and fertilizer injury. When large areas are uniformly affected, this usually points to a physical problem rather than a fungal disease.

Lab closed: Please mark your calendars. The UMass Turf Disease Diagnostic Lab will be closed June 30 - July 3 and through the holiday weekend. I will be going to Wisconsin to make arrangements for my move. I will post alternative diagnostic lab information on this web site and on my phone during that week. Always call ahead before sending samples the rest of the summer to make sure that I am here to receive them. Thanks.

- Submitted by: Dr. Gail Schumann