Brown Patch

Question 1

Brown Patch

Cause:

Answer 1

Rhizoctonia solani

Question 2

Rhizoctonia solani

Hosts

Answer 2

All turfgrass species but is most harmful to

Colonial Bentgrass

Question 3

Rhizoctonia solani
Symptoms:

Answer 3

• Brown Patches of blighted turf
• irregularly shaped Leaf lesions with tan colored center and reddish-brown border
  
  • ** Lesions can be present in absence of brown patches of turf

Question 4

Rhizoctonia solani

Signs

Answer 4

• Smoke Rings - active hyphae on the edge of the patches
• Hyphae have:
  
  • Right angle branching
  • Septa near branching
  • pinched at branching
• Hyphae has Multi-nucleate cells
• Dark Brown Sclerotia

Question 5

According to the predictive model, what are the conditions that make Rhizoctonia solani “turn on” ?

Answer 5

• Warm Nights
  
  • Soil temps > 61 degrees
  • Air temps > 59 degrees
• Extended Leaf Wetness
  
  • 95% relative humidity for > 10 hours
  • 0.1 “ of rain or irrigation in preceeding 36 hours

Question 6

Rhizoctonia solani

Predisposing Factors

Answer 6

• Thatch
• Drought stress
• Height of Cut is too low or too high
• N input is too low or too high
• High seeding rates

Question 7

Rhizoctonia solani

Fertility Management:

Answer 7

• Soil Test and adjust
• Adequate N input but avoid overstimulating by spoonfeeding

Question 8

Rhizoctonia solani

Chemical control

Answer 8

• Azoxystrobin
• Pyraclostrobin

Question 9

*R. solani *is most devastating to what turfgrass species?

Answer 9

Colonial Bentgrass