Help!! I can't stop the death of my yard!

Asked September 2, 2016, 12:04 PM EDT

My lawn is covered with St. Augustine that I try to take good care of. However, I've had a brownish/gray spot that has slowly spread in size over the last month. We have had good rainfall here in Waco during that time frame (so much so, we've had wild mushrooms sprouting in other areas of the lawn) and I water my lawn using a sprinkler system for 5 minutes every 2 days over this affected area (I've set the irrigation controller to run at 9 pm to avoid burning the lawn during the heat of the day). My front yard faces to the east, so it gets good sunlight for most of the day. I've been told by some this is a fungal infection while others tell me it's root rot. I'm trying to find the correct course of action to treat my lawn so I can return it to health before fall/ winter arrives and it dies on me for good.
Please, please take a few moments to help me on this issue, this is an area that my expertise is lacking and my wife is looking to me for answers.

Joseph Scott

McLennan County Texas

1 Response

There are two fungal diseases that affect St. Augustine in this area:

Take-All Root Rot. When the disease is active, the first symptom is often a yellowing of the leaves and a darkening of roots. The area of discolored and dying leaves may be circular to irregular in shape and up to 20 feet in diameter. A thinning of the turfgrass within the affected area occurs as roots, nodes and stolons become infected and the plants decline. Unlike brownpatch, the leaves of take-all infected plants do not easily separate from the plant when pulled and the stolons will often have discolored areas with brown to black roots. The roots are sometimes so rotted that damaged stolons are easily pulled from the ground. Roots and stolons of brownpatch infected plants usually have a healthy appearance. Regrowth of the grass into the affected area is often slow and unsuccessful as the new growth becomes infected. During the stressful high temperatures of the summer months, the weakened, infected turfgrass will continue to decline. If you can grab a handful and it all comes up like pulling up a carpet…that’s Take-All.

Brown Patch. The first symptom appears as a small, circular, water soaked dark grass that soon wilts and turns yellow or brown. As the fungus grows outward from the center, there is a grayish-black colored ring of wilted grass around the perimeter that is called a smokey ring. The patch begins small, a few inches in diameter and can grow to over fifty feet in diameter. As they expand and merge with other patches the shapes become irregular. Another symptom is the leaves of the grass are easily pulled from the stolons. This is because the fungus has destroyed the tissue at the base of the leaf. The stolons are not usually killed unless the infection is severe and the warm, humid weather continues. If this is the case the roots and crowns will rot and the grass dies. If the stolons are not killed, the grass in the center of the patch may recover in a few weeks and put out new growth.

I treat them the same way. Rake out infested area, spread Peat Moss over the that area (preferably in spring), Apply either Honor Guard (propiconazole) ½ oz to a Gallon of water OR Heritage granule at 3 lbs per 1000 sq ft. You must treat it twice, for one label its 7 days later and its 14 days for the other, I cant remember which is which. Again you have to treat it twice. Remember to water early in the day (2 am) and not at night or afternoon (9pm), try to use slow release nitrogen products on your lawn. Watering at night only magnifies the fungal problem.