Symptoms. In warm weather, when the soil is dry but the canopy is moist, the fungus colonizes the older leaves. This causes the leaves and their stems to die faster. Plants are killed in irregularly shaped patches. The patches are an inch to a few feet in diameter. The patches are first reddish-brown, then yellow, next light brown, and finally darker brown. . Leaves have oblong reddish-brown leaf spots or may turn completely yellow. The disease progress up the stem with older leaves affected first. Within the leaf spots are spiny black spots, which are the fungal fruiting bodies.
During cool, wet periods (60o-75o F) in late spring and early summer, a basal rot develops. This can affect individual plants scattered throughout the turf, or clusters of plants in patches that can reach 6 inches or more across. An individual plant can have infected and uninfected tillers. The edges of the patches are irregular. The patches are a grayish-green color, and fade to tan.
The basal rot begins as a watersoaked spot on the stem. These spots then become bleached and ultimately grow completely around the stem. The leaves turn yellow, then light brown, and die, starting at the tips, and progressing down the leaf. The central, youngest leaf remains green the longest. It later may turn yellow, orange, and then red. A black rotting of the base of the plant occurs. This causes the top to be easily pulled from the roots.
Prevention. Adequate fertilizer and water are important to control this disease, especially in hot, humid weather. It is especially important to avoid potassium and phosphorous deficiencies or excessive nitrogen. Avoid fertilizing during drought or hot weather. Water early in the day, as deeply and infrequently as possible. Avoid soil compaction and aerate soil by spiking.
Some cultivars of annual bluegrass are less susceptible than others. Turfgrasses other than bluegrass are not as susceptible.
See current recommendations for chemical control measures.
By Pamela S. Mercure, IPM Program Assistant, University of Connecticut, 1998
References:
Smiley, R.W. 1983. Compendium of Turfgrass Diseases. APS Press, St Paul, MN.
Smith, J.D., N. Jackson, and A.R. Woolhouse. 1989. Fungal Diseases of Amenity Turfgrasses, Third Edition. E. & F.N. Spon, London.
Turgeon, A.J. 1996. Turfgrass Management, Fourth Edition. Prentice Hall, Upper Saddle River, New Jersey.
This information was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.
The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.