Dollar Spot is Still #1

Dollar spot is the most important disease in cool-season grasses across the country as more dollars are spent to control this disease than any other. It can be a problem from spring through fall, but is most problematic during the summer with high heat and humidity.

  • Apply early – As mentioned in the previous Talking Turf, early spring applications of DMI fungicides at average air temperatures of 60°F help to minimize dollar spot inoculum long term
  • Long-term cultural management strategies
    • Reduce surface moisture with morning mowing, rolling, dew-whipping, or dragging a hose
    • Light rates of fast release N will also help limit dollar spot. Rates as low as 0.1 lb. N/1000 sq. ft./14 days are recommended for greens with higher rates for fairways
  • Smith-Kerns model – this prediction model is gaining a track record for accuracy over the last year. However, all models may need fine-tuning for your specific site, cultivars, maintenance etc., and it is still critical to set your threshold fairly low in this model to stay ahead of the inoculum
  • Resistance management – fungicide resistance is always a concern with dollar spot so rotates modes of action and avoid overuse of SDHI’s, the newest group of fungicides containing eight different fungicides with this mode of action (FRAC code)
  • Bayer fungicides for dollar spot
    • Interface® Stressgard® – only fungicide available in the FRAC Group 2, so is critical for resistance management, and offers excellent curative and preventive control
    • Tartan® Stressgard – DMI (Group3 ) + QoI (Group 11) fungicide with excellent summer safety
    • Mirage® Stressgard – DMI fungicide (Group 3) that also provides excellent control of root-infecting pathogens
    • Exteris® Stressgard – the newest SDHI fungicide (Group 7) from Bayer that provides both quick knockdown and long-term residual control of dollar spot
  • The benefits of Stressgard
    • Stressgard has been extensively researched for over 25 years and has been found to consistently increase chlorophyll and photosynthesis, resulting in improved rooting, stress tolerance, and turf density - all critical to maximize your turf’s performance throughout the summer
  • For more information — See the attached Green Solutions Sheets for more information and contact your Bayer Area Sales Manager. Read and follow all label directions.

Dollar spot mycelium on fairway height creeping bentgrass. Photo: Zac Reicher, Ph.D., Bayer.

  Bayer Solutions - DollarSpot - COOL
Zac Reicher

by Zac Reicher , Ph.D., Green Solutions Team Specialist

Monday, June 3, 2019