Large Brown Areas in Grass

Asked February 16, 2013, 1:45 PM EST

Last fall brown areas began appearing in by bluegrass and fescue lawns. I treated for grubs, but the areas became larger. I then treated for fungus, but it may have been too late in the season. What can I do to stop the spread of whatever this is and to help regenerate new grass in these areas especially as Spring is coming?

Bernalillo County New Mexico

1 Response

It is my experience that brown areas in lawns are typically the result of non-uniform sprinkler irrigation rather than grubs or fungal infections. While grubs and fungal infections may affect lawns, let's rule out the most common issue first. If you can find at least 2 containers in your home that have flat bottoms and sides (such as coffee cans, tuna cans, cat food cans, etc.), place at least one in the brown area and one in a green area. Run your sprinkler system for a set time (10 or 15 minutes should do it). Then simply take a ruler and measure the amount of water in the containers. If there is a noticeable difference between the containers, sprinkler adjustments are in order. And, this may solve your problem. If the water amounts seem pretty much the same, I recommend bringing in a sample of the affected area to your county extension office once the growing season gets underway. Please cut out about a 3 in x 3 in piece of sod at the margin of the problem (half green and half brown). Include grass, roots, and a bit of soil. The Extension Agent can send this sample to the NMSU Plant Diagnostic Clinic and have it properly analyzed for pathogens. If there is one present, then you will be told what it is, what conditions favor it, and be provided with instructions on how to reduce or eliminate it. Most pathogens, such as fungal infections, are brought on by how we care for our lawns. So, usually a few cultural adjustments and possible a little assistance with a fungicide, can rid you of the problem. But, it's important to properly identify the problem, which can be challenging at times. I hope this helps!