Spring Dead Spot of Bermudagrass in Tulsa
Spring Dead Spot, or SDS, is one of the worst-looking and most aggravating afflictions your Bermuda lawn may go through. When your lawn starts to green up, you might see little dead spots or big dead spots, circular dead areas or dead half-circles, ranging from a few inches to over a yard in diameter. While the rest of your lawn greens up beautifully, these areas remain dead. You may even see weeds like crabgrass invading the dead areas. The worst part is, these dead spots may be back year after year, in the same place. SDS can be a devastating problem on golf courses and sports fields.
The Disease: SDS is a soil disease. In Oklahoma, it’s caused by two fungi, Ophiosphaerella herpotricha and Ophiosphaerella korrae. Infected plants or soil can be transported by many agents – animals, people, equipment, even running water. The infection usually begins in September, when temperatures are mild, and can remain active as long as temps stay above 50°. In the spring, activity resumes and then subsides when temps get over 70°, although SDS may remain dormant, in the same spot.
Repairing the damage: If you do nothing, the surrounding healthy grass will likely fill in the area by late summer. Most people don’t want to wait that long! To speed things up:
- Rake out the dead area.
- If a depression is evident, add some topsoil to fill it in.
- If the area is large, consider laying a piece of sod to help it fill in.
- Water, mow and fertilize!
What it affects: For the most part, SDS affects Bermuda grass only in Oklahoma. Fescue does not get SDS and zoysia is very rarely affected. Bermuda that is weakened or under stress for any reason may be more susceptible. Unfortunately, over-cared-for lawns are sometimes the most susceptible. If you put down high-nitrogen fertilizer late in the year to try to extend the green color, your grass may have a higher chance of getting SDS. But sometimes there seems to be no rhyme or reason.
Certain Bermuda varieties are less susceptible to SDS. For example, more cold-tolerant cultivars seem to have fewer SDS problems than non-cold-tolerant varieties.
OSU recently developed 2 new Bermuda cultivars – Latitude 36 bermuda (OKC 1119) and Northbridge bermuda (OKC1134.) Both varieties have increased cold-hardiness and earlier spring green up (which seems rather fitting, since back in 1954, 2 guys from OSU, Wadsworth and Young, were two of the first people to investigate the pathogen SDS.) Patriot, Midlawn and Premier are also pretty cold-tolerant. However, there is no Bermuda grass that can be considered immune to SDS.
SDS control: There are some fungicides available that may offer partial control. These are only available to licensed commercial applicators. Most lawn care companies in our area do not offer this service because the material’s effectiveness is partial and sporadic and the material itself is very expensive and requires 2 separate applications in the fall, or one in the fall and one in the spring.
Look-Alikes: Spring Dead Spot can look like other lawn problems – drought stress, chinch bug damage, grub damage or winter damage. Just remember that the symptoms of winter damage and SDS both are that the bermuda does not green up in the spring with the rest of your grass. With chinch bugs, grubs or lack of water, the grass greened up and then turned brown. And, whether it’s SDS or winter damage, both are repaired in the same manner.
More detailed info:
Managing Spring Dead Spot Disease of Bermudagrass - OSU fact sheet
Springdeadspot.com - website dedicated to the ongoing research, education and extension of information regarding SDS
Photo is from OSU Extension website.