Seeing an old friend!

Sorry for the delay and lack of posts this week, but I have been on the road in the Mid-West and haven't been "in touch" with disease issues in the Northeast this week. A nighttime check of the email and a question from a Delaware superintendent sparked my interest in getting a late night post out.

The disease in question is bentgrass dead spot (an old friend of mine). This disease was first observed at the Maryland Diagnostic lab on August 21, 1998. The only reason that I know that date is that I started working in the lab on the 20th and this was one of the first samples that I had seen. That was the beginning of a six and a half year project in which we beat that disease to death and it just about killed me in the process too.

SO...here is what I told the superintendent dealing with the disease.

Sounds like you are doing exactly what you need to in order to keep it in check. The major problem with BDS is that it DOES NOT recover. My suggestion is to continue with fungicide applications on a 10 day interval (T-methyl, Insignia, Emerald, Dac + one of the aforemetioned...stay away from other strobilurins and bayleton) and start spraying ammonium sulfate with every fungicide application (0.125 lb N/1000). What will happen is that the symptoms will continue to be visible until things start growing actively in Sept/Oct. The fert will finally kick in and aid in recovery and the repeated apps of Amm Sulf will help lower pH and assist in recovery. After the first week of Oct, no fungicide apps are necessary as new infections will be minimal to none and recovery will occur anyway. If you have large spots now, these WILL NOT heal prior to winter and you may consider plugging them out. Any spot smaller than a silver dollar will likely heal before the end of the year. Sorry that I can bring better news, but this is the nature of the beast!

One of the benefits of the down economy is that very few new courses are being constructed and the use of methyl bromide to regrass greens is minimal. These are some of the requirements for dead spot to appear, so this is one of the reasons that this disease rarely makes an appearance these days. As Dr. Dernoeden used to say when samples of yellow tuft came into the lab..."Seeing this disease is like seeing an old friend."