Disease seen in some lawns

Earlier this week, we were called to a home in Pewaukee because of some suspicious looking dead patches.  At first, we thought it was an overspray of roundup.  Once we saw the area in person we soon realized that it was a fungal disease.

How can we tell the difference?  With a fungal disease there are various distinct markings on the leaf blades and also if inspected early in the day we can often see mycelium (fuzzy stuff).  Each sort of plant disease has very distinct characteristics in how they look either to the naked eye, or under a microscope.

What should be done?  On a residential lawn, usually nothing.  As soon as conditions change, the disease progression will stop.  The damage is often very minor and the lawn will recover just fine on its own.  One of the reasons why the damage is minor is because your lawn is created from several types of grass.  Often a disease only attacks one type and the others are unscathed.

In other scenarios, such as a golf course, where there are monocultures of grasses planted, pristine conditions are demanded and because of the way the turf is maintained overall, the application of a fungicide may be necessary to halt its progression. 

For a home lawn situation however, it is not prudent to apply fungicides for a problem that is really quite temporary, likely to pass with a change in weather, and not cause significant damage.  If there is resulting death to patches or areas of a home lawn from the presence of a fungal disease then repair to these areas is the better option, along with a review of other components of the area (compaction issues, irrigation practices, fertility levels, mowing height, to name a few).