Dull mower blade injury. (Purdue University extension photo)

Dull mower blade injury. (Purdue University extension photo)


MOWING: Keep the blade set high – 3 ½ inches is ideal. Short lawns have short roots and it takes about 60 days of good mowing to re-grow deep roots. Don't be afraid to mow at 4 to 4 ½ inches if the lawn is bumpy, the mower has a large deck or watering is only fair. It is a good idea to sharpen the blade(s) a couple of times per season.

Drought damage and heat reflection.

Drought damage and heat reflection.

WATERING: Water isn't cheap but neither is re-seeding or re-sodding drought damage. This time of year two inches of water per week (including rain) is often not too much. One inch may keep the lawn alive but if the temperature is over 85-90 degrees and windy, water use can exceed 3/4 inch in one day. How long to water in each spot depends on many factors but you can get an idea of output by using a number of straight sided containers as measures. Without the optional Hydretain (Moisture Manager) application I watered my own lawn three times per week for 45-50 minutes per zone. If water usage is high, I run my system manually in addition. If we get heavy rain I skip a few waterings. If your lawn is struggling and we get a moderate rain, keep on watering; it's your chance to catch up. Soil moisture can be estimated with a large screwdriver which should insert easily to a six inch depth. With practice you should be able to spot stressed and problem areas. Take a look at your lawn from a distance in the late afternoon. Looking toward the sun, watch for darker, gray-green or browning areas and footprints that lay flat and don't bounce back. These areas need more water while areas with adequate moisture will be lighter or brighter green in color.

Billbug damage to stem bases. (Ohio State University photo)   

Billbug damage to stem bases. (Ohio State University photo)


Ring Spot Disease. (University of Minnesota Extension photo)

Ring Spot Disease. (University of Minnesota Extension photo)

Summer Patch Diesease (Iowa State University photo)

Summer Patch Diesease (Iowa State University photo)

Summer Patch Disease ( North Carolina State Extension photo)

Summer Patch Disease ( North Carolina State Extension photo)


These small grubs are about 1/4 - 3/8 inch long and do noticeable damage from about July 1st to July 25th when they pupate. Look for browning plants that break off easily near the soil level. the stems will be hollow and filled with saw dust like material. Adult billbugs do not cause the damage but wander around the same neighborhoods laying eggs every year. 

This insect is most often a problem in: 

  • Older neighborhoods

  • Lawns with less than ideal watering

  • Stressed areas such as along walks and driveways

The best control is our season long insect control applied in early May every year.




1) Circular or oval rings or semi-circles of damaged turf (ring spot symptom).


2) Clusters of circles or whole damaged patches of turf (patch symptom).

3) Irregular patches with pale green, reddish, yellowish or tan stunted plants mixed with healthy plants often resembling drought or insect damage (especially along sidewalks).


  • Daytime temperatures in the 75 to 100 degree range with high humidity and overnight temps above 70 degrees

  • Plants that are under drought stress.

  • Saturated soil or leaf tissue wet for long periods of time in hot weather.

  • Ring spot showing up in the cooler part of the year is a different fungus and is often confined to rings only and is less severe.


1) Mow at no less than 3½ inches tall except for late October and the first mowing in spring, when mowing no closer than 2½ inches tall is OK. If you use a commercial type mower, mow at 4 inches. These diseases attack grass roots and tall mowing is essential to encourage deep roots and reduce heat stress.

2) Do not let your lawn go into drought stress. Plants with damaged root systems are weak and die after only a short time under stress. Prolonged deep infrequent irrigation is best with frequency determined by soil make-up and weather conditions. A major problem with home lawns is that the soil is often a thin layer of topsoil over tortured clay subsoil and construction debris making more frequent watering a necessity.

3) Fall core aeration is helpful as it encourages root growth. Plan to combine overseeding with aeration.

4) Reduce thatch to ¼ to ½ inch if it is greater than this amount.

5) Overseed and spot seed in an effort to establish resistant varieties. High quality named varieties of perennial ryegrass tend to be good. Many new varieties of bluegrass have good resistance but no variety is immune. Milborne Seeds Deluxe Mix, available at Midwest Landscape, is a good choice.

6) DO NOT USE Park, Merion, Plush, Ram I, Nugget, Newport, Kenblue, Delft or Argyle.

7) We do not recommend fungicides for home lawns.