Turf Troubleshooting Reference

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Symptoms observable throughout the growing season
Problem	Symptoms	Cause of Damage	Identification	*Management
Drought stress	Pattern may be Irregular or correspond with sprinkler layout	Lack of water, improperly spaced sprinkler system or faulty heads.	Use rain gauges or tuna cans to determine water application rates in various locations in the lawn	**Correct watering problems.
Compaction	Pattern may be irregular or follow walking or driving paths	Heavy traffic, walking on wet soil. Clay soils especially susceptible	When soil is moist, but not wet, push a long screwdriver into the soil and feel resistance at various places across the lawn.	Look for other signs of traffic, such as matted down, thin turf. **Use core aerator in spring and fall in these areas. The entire turf may benefit from yearly core aerification. Re-direct traffic.
Animal Urine	Dead circular patches 2 to 6 inches in diameter, bordered by tall, dark green grass	High concentration of nitrogen and other chemicals kills the grass in the center but causes lush growth on margins, where concentration is less.	Visual observation.	Limit availability of the area to animals. Diet modification may help (consult veterinarian)
Salt injury	Most likely to occur adjacent to sidewalks or street. Grass looks like it is drought-stressed.	Ice melting products accumulating on turf or in soil cause turf to be unable to absorb water properly.	Visual observation.	Use ice melting products sparingly and choose those less likely to damage plants. You may be able to correct minor problems by leaching salts from the soil in these areas with a lot of water. More serious problems will require replacement of the top portion of the soil.
Dull mower blade	Shredded leaf blades give the entire lawn a dull appearance.	The mower blade shreds instead of cutting the grass cleanly. Tips of grass blades dry out and die. The turf is more susceptible to drought damage.	Examine tips of grass blades closely. Look at mower to see if blade is sharp (first make sure it cannot start).	Sharpen mower blade regularly. Take precautions, such as removing the spark plug wire, to make sure the mower cannot start while working with the blade.
Iron or nitrogen deficiency	Symptoms are typically fairly uniform, although one area of the turf can be affected more than others. Grass is pale green to yellowish and grows slowly.	Lack of iron or nitrogen reduces the plants’ ability to produce food through photosynthesis.	Visual observation. Other plants in the yard may also exhibit yellowing.	If iron deficiency is suspect (especially if trees or other plants show yellowing between the veins) use fertilizer sources that include iron and elemental sulfur. Improvement may take time. If replanting a lawn, select varieties that process iron efficiently on affected soils. **For better nitrogen utilization, use slow release sources of nitrogen fertilizer. Follow recommended fertilization practices. Avoid compaction, drought , overwatering or other situations that can make roots unthrifty.
Fertilizer burn.	Bands or streaks or brown grass, often with lush green grass at the margins.	Excessive fertilizer in overlapped areas draws moisture from the plants	Compare pattern with recent fertilizer application pattern.	Apply half rate of fertilizer in each of two applications, going perpendicular directions each time, for more even application. **Avoid applying excessive fertilizer rates.
Herbicide damage.	Grass may brown slowly or rapidly, depending on the herbicide.	Incorrect use of an herbicide or application of the wrong herbicide.	Compare affected areas with areas to which pesticides were recently applied. Consider overspray or drift from adjacent areas.	Use only products labeled for the site. Read and follow labeling carefully, paying attention to wind, temperature extremes, etc. Replant affected areas if necessary.
Winter to early spring
Problem	Symptoms	Cause of Damage	Identification	*Management
Winter drying	Bleached or dead grass, especially in wind-prone areas	Cold, dry winds cause grass to lose moisture	Compare pattern of dry grass with wind or exposure patterns	Water during warm, dry periods in winter if soil is dry Water / ice damage
Flooding or ice damage	Flooding or ice suffocates turf.	Browning follows drainage patterns	Visual observation, including accumulation of water and ice	Adjust downspouts or change slope of the lawn as needed.
Snow mold	Spots are roughly circular, and 4 to 12 inches in diameter. Grass is bleached and matted. When wet a white to salmon-pink moldy growth is visible at edges of the patches.	Infection by a fungus during prolonged cool, wet weather	Visual observation. Laboratory analysis.	**Avoid mid-autumn fertilization. Use slow release fertilizer in dormant season (end of October). Mow until leaf growth has stopped. Rake in early spring and lightly fertilize to encourage new growth. Fungicides are available.
Late spring to early summer or late summer to early fall
Problem	Symptoms	Cause of Damage	Identification	*Management
Necrotic ring spot	Tan to reddish brown patches or rings, with blackened stem bases and roots. Patches may have green centers or exist in a snake-like pattern	Infection by a fungus	Visual observation of leaves, stems and roots. Laboratory analysis.	**Follow recommended fertilization practices and reduce thatch, if necessary. Fungicide treatment is possible, beginning in mid-April
Rust (especially late summer to early fall)	Orange pustules on leaves, that rubs off onto shoes.	Infection by a fungus.	Visual inspection / walking across the turf to see if reddish rust gets on shoes.	**Avoid evening watering. Aerate to relieve compaction. Mow regularly. Fungicide treatment is possible, beginning in early July.
Summer
Problem	Symptoms	Cause of damage	Identification	*Management
White grub	Localized patches of grass may appear drought stressed. As feeding progresses grass dies and affected areas enlarge rapidly, growing together. Damage may be worst in hot, sunny areas, especially near concrete or buildings. Heavily damaged areas may also include those near light poles, which may attract the adult chafer at night. Turf may feel spongy under foot.	The larvae of the masked chafer beetle (June bug) feeds on grass roots and rhizomes. Egg laying takes place in July and early August, with the majority of turf damage occurring from August to early October. Grubs move deeper into the soil for winter, and feed briefly in spring before pupating and emerging as adults in June. Other grubs are less likely to cause significant damage to turf in west central Nebraska.	Cut 6-inch square pieces of turf on three sides and peel back, to examine the top 2 inches of the root zone for the larvae. They are “C” shaped and creamy in color. As damage progresses, you can pull turf back like a carpet.	To prevent damage, you may apply a “season-long” control product in early July. The first week of August is normally the optimum time to apply rescue treatments. Two larvae per 6-inch sample square at this time, indicates a need for control. Use an appropriate pesticide based on the size of grubs present.
Sod webworm (can be present early spring to fall, but usually does the greatest damage in mid-summer)	Small ragged brown spots appear grazed upon close examination. Usually more uniform than damage by other insects.	Grey larvae with two rows of black spots. Adult moth is cigar shaped, and flies over turf and drops eggs.	Larva feeds above ground and creates silken tubes leading into the soil, where the larva hides during the day. Look closely at signs of grazing, along with the presence of small green fecal pellets. Look in the thatch layer and top inch of soil for larvae, silken tubes and webbing. Larvae can be flushed from the turf by mixing ¼ cup of lemon scented household detergent in 2 gallons of water and using it to drench two, one square yard sections of turf. Allow 10 minutes for larvae to emerge.	**Well managed turf withstands light infestations. Insecticides are available.
Bluegrass billbug	Leaves take on a straw brown color. Pattern may be irregular or in large patches.	Damage is caused by larvae of this insect. They feed initially inside stems before growing larger and moving to roots.	Watch for adult billbugs on concrete. These are slow moving shout beetles about ¼ inch long in April to June and September to October. Pull on stems. They break easily at the base. Cut into turf and peel it back to a depth of 2 to 3 inches and look for cream colored larvae that resemble puffed rice, up to ½ inch long. Adults can be flushed from the turf by mixing ¼ cup of lemon scented household detergent in 2 gallons of water and using it to drench one square yard of turf. Allow 15 minutes for insects to emerge.	Insecticides are available.
Leaf spot / melting out	Turf may appear to thin out. Grass blades have small dark purple to black spots (lesions). Older lesions have tan colored centers with dark brown to purplish margins. Affected leaves turn yellow and die.	Two different fungi.	Examine grass blades closely. Laboratory analysis can also be done.	Control thatch, if necessary. avoid evening watering. Follow University of Nebraska fertilization recommendation. Use slow release nitrogen fertilizers, to avoid stimulating lush growth. Fungicides are available, with application begun in April.
Necrotic ring spot / Summer patch	Tan to reddish brown patches or rings, with blackened stem bases and roots. Patches may have green centers or exist in a snake-like pattern	Infection by two different fungi. Differentiation between the two requires lab analysis but is usually unnecessary.	Visual observation of leaves, stems and roots. Laboratory analysis.	**Follow recommended fertilization practices and mowing practices and reduce thatch, if necessary. Syringe (water lightly) heat-exposed turf (especially south-facing slopes) to cool it in mid-day during hot periods in July and August. Fungicide treatment is possible, beginning in mid-April

*Read and follow pesticide product labeling carefully.

**Follow recommendations in NebGuide G517, “Kentucky Bluegrass Lawn Calendar,” available from University of Nebraska Extension Offices or on the Internet at the IANR Publications site. Click on “Horticulture,” then find the guide listed under “Turf.”

This guide was written and formatted by George Haws, University of Nebraska extension associate, May 2, 2005. The source of information was EC1557, Integrated Turfgrass Management for the Northern Great Plains, written by members of the University of Nebraska Turfgrass Science Team and edited by Frederick P. Baxendale, Ph.D., and Roch E. Gaussoin, Ph.D.; published by University of Nebraska Cooperative Extension in Lincoln, Nebraska; 1997.