TURFGRASS DISEASE IDENTIFICATION (P2)

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Ectotrophic Root Infecting Fungi

Summer Patch

Causal Agent: Magnaporthe poae

Susceptible Turfgrass: Annual bluegrass, Kentucky bluegrass, and fine-leaf fescue

Symptoms: Summer patch appears as circular or irregularly shaped patches that measure from several inches to several feet in width. Initially, patches appear as slow-growing thinned or wilted turfgrass. Mature patches are bronzish-yellow to straw-colored and can coalesce as they increase in size. The leaves of the plant turn yellow to brown from the tip to the base. The roots turn moderate to dark brown. Summer patch can exhibit a ring-like appearance where a less sus ceptible grass species survives inside the diseased patch.

Ectotrophic Root Infecting Fungi

Conditions Favoring Disease: Root infection is initiated when soil temperatures exceed 65°F; however, foliar symptoms of summer patch are favored by temperatures over 85°F during the day and over 70°F at night. It is also commonly found in areas that are sunny, exposed, and with high soil moisture, high soil pH, compaction, poor drainage, and low mowing height. This disease is typically more severe in turfgrass that has been fertilized with nitrate-nitrogen.

Management Tips:

  • Use acidifying fertilizers.
  • Increase the height of cut.
  • Reduce soil compaction through aerification and use of lightweight equipment.
  • Syringe when the temperature is over 85°F.
  • Improve the drainage of the turf.
  • Convert to resistant species, such as tall fescue, bentgrass, or perennial rye.
  • Apply effective fungicides preventively in early to late spring. Do not expect 100% disease control.

Occasionally occurs in: AK, AL, AZ, CA, GA, KS, LA, MA, MN, MO, MS, NC, NM, NV, NY, OK, OR, SC, SD, TN, TX, WA, WI.

Frequently occurs in: CT, DE, IL, IN, KY, MD, MI, NE, NJ, OH, PA, VA.

Labeled products:

Take-all Patch

Causal Agent: Gaeumannomyces graminis var. avenae

Susceptible Turfgrass: Bentgrass

Symptoms: Take-all patch symptoms initially appear as small, circular reddish-brown spot patches. Symptoms will progress to wilted, circular patches that are brown or bronze-colored and measure up to several feet in diameter. Symptoms are most evident during periods of stress induced by hot, dry weather. Infected plants have dark-brown roots.

Take-all Patch

Conditions Favoring Disease: Take-all patch is most common on newly established turf and severity decreases as the turf stand matures. It will occur on sites that have light textured soils, low organic matter content, manganese deficiency, and pH above 6.5. Take-all patch typically occurs in cool, wet conditions and in areas with a high soil pH—most severe at pH 6.5 or above. This disease is more severe on less fertile and sandy soil.

Management Tips:

  • Use acidifying fertilizers.
  • Apply moderate to high levels of phosphorus, potash, and minor elements where these nutrients are depleted from the soil.
  • Improve the drainage of the turf.
  • Reduce thatch.
  • Apply appropriate systemic fungicides in the early spring after the first mowing and in the late summer or fall.

Occasionally occurs in: AL, AR, AZ, CA, FL, GA, IA, KS, LA, MO, MS, MT, NC, ND, NE, NM, NV, OK, SC, SD, TN, TX, VT.

Frequently occurs in: CO, CT, DE, ID, IL, IN, KY, MA, MD, MI, MN, NJ, OH, OR, PA, RI, WA, WI, WV, WY, VA.

Labeled products:

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