TURFGRASS DISEASE IDENTIFICATION (P10)
Other Fungal Diseases
Causal Agent: Colletotrichum cereale (formerly Colletotrichum graminicola)
Susceptible Turfgrass: Annual bluegrass and creeping bentgrass
Symptoms: Anthracnose is most destructive during warm weather. It causes irregularly shaped patches that are yellow to brown in color. Leaf lesions that are yellow with black centers may also occur. Anthracnose also causes a basal stem rot from late winter to fall. Infected shoots are easily detached. The dead foliage and stems also become covered with acervuli—tiny, spined, black fruiting bodies—that require magnification to identify.
Conditions Favoring Disease: Anthracnose favors temperatures over 78°F. It occurs in areas that experience more than 10 hours a day of leaf wetness for several consecutive days. Conditions that stress turfgrass plants, such as soil compaction, poor drainage, low mowing height, and low amounts of nitrogen fertility also contribute to this disease.
- Increase the height of cut.
- Minimize stress by using walk-behind mowers.
- Decrease the amount of foot traffic.
- Maintain adequate nitrogen and a balanced fertility level.
- Irrigate the turfgrass just enough to prevent wilting.
- Do not core aerate while disease symptoms are present.
- Core aerate and overseed in the fall.
- Convert from annual bluegrass to less susceptible varieties of turfgrass in the fairways.
- Make preventive fungicide applications where the disease is a chronic problem.
Occasionally occurs in: AL, AR, AZ, CA, CO, FL, GA, IA, ID, LA, ME, MN, MS, MT, NC, ND, NE, NH, NM, NV, NY, OR, SC, SD, TX, UT, VT, WA, WY.
Frequently occurs in: CT, DE, IL, IN, KS, KY, MA, MD, MI, MO, NJ, OK, PA, RI, TN, VA, WV.
Bentgrass Dead Spot
Causal Agent: Ophiosphaerella agrostis
Susceptible Turfgrass: Creeping bentgrass and bermudagrass
Symptoms: Bentgrass dead spot begins as small, sunken reddish- brown or orange-rust spots about 1/2 inch in width, growing to about 3–4 inches. Typically, there’s some tan tissue in the center and reddish-brown leaves at the edges, possibly developing a green center if left untreated. Distinctive black fruiting bodies of the fungus are readily seen with a hand lens.
Conditions Favoring Disease: Open, sunny locations and hot, dry weather favor development. Dead spot most often strikes greens that were newly constructed or renovated and that were built with large amounts of sand. Disease is not known to occur in native soils. The disease naturally declines and it is rarely seen on greens older than six years.
- Maintain balanced fertility.
- Avoid turf stress and excessive traffic.
- Apply water-soluble fertilizers to stimulate growth of surrounding healthy creeping bentgrass.
- Apply contact and/or systemic fungicides on a preventive basis.
Occasionally occurs in: FL, MO, TX.
Frequently occurs in: CT, DE, IL, IN, KY, MA, MD, MI, NC, NJ, NY, OH, PA, RI, VA, WV.