Pythium Blight and Leaf Spot in Bermudagrass Greens

Pythium blight and leaf spot are foliar diseases that can quickly and extensively impact bermudagrass golf greens under cool and wet conditions. Symptoms of Pythium blight and leaf spot are similar with both diseases occurring at the same time in the fall, winter and spring. Proper lab diagnosis is important since fungicide control methods for Pythium are dramatically different from leaf spot.

• Foliar Pythium:
  • Low temperature Pythium blight - caused by Pythium graminicola and P. ultimum when daytime temperatures are below 55-60°F, and high humidity plus extended periods of leaf wetness can incite severe damage and potential turf death in 24-48 hours
  • Symptoms - small, sunken, red-orange to dark gray spots and streaks which can coalesce into greasy looking patches. These symptoms often appear as streaking due to the movement of Pythium spores by equipment or by surface water drainage
• Leaf spot:
  • Symptoms: attacks oldest leaves first during times of slow growth, forming leaf lesions that are dark to purplish and may look water-soaked
  • Leaf spot and ensuing melting out occurs in spots or streaks (spreads by spores/conidia) which progress to irregular patches of dead turf and algae
• Cultural practices to limit damage - like with most diseases, anything to improve plant health and reduce turf stress including improving root zone characteristics, raising mowing height or skipping mowing and rolling instead, maximizing sunlight and air movement, etc.
• Prevention with fungicides - during cool and wet conditions with daytime highs below 55-60°F:
  • Pythium-specific fungicides provide both preventive and curative ability
  • Phosphonate fungicides for preventative control and to maintain plant health under cool, stressful growing conditions
  • Do not water in fungicides because the target is a foliar disease
• Envu options for bermudagrass greens:
  • Banol^® rotated with Segway^® or Serata^® - preventive and curative control for Pythium blight and limit risk of resistance with rotations
  • Prevent both Pythium blight and leaf spot – Signature^® XTRA Stressgard^® plus tank mixing mancozeb, Interface^® Stressgard or Densicor^® prevents Pythium diseases, promotes plant health and will also control leaf spot, algae and Microdochium patch. Castlon™ is our newest QoI fungicide and provides simultaneous control of both leaf spot and Pythium blight for 14 days when applied at the high label rate
• Need more info? – follow all label directions and contact your Envu Area Sales Manager if you need assistance