COURSE CARE
Pick A Patch February 27, 2015

Pick A Patch

By Bob Vavrek, Senior Agronomist
July 16, 2008

Despite a cool spring, we knew that it was only a matter of time before hot, stressful weather would arrive across the upper Midwest. Right on the heels of the heat and high humidity were brown patch, take-all patch, and summer patch. Each disease has been seen with regularity during the past few weeks and each has its own unique personality.

Brown patch tends to be more of an annoyance than a serious threat to golf courses in northern states. Ask around and no one seems to have ever seen it actually kill turf. Besides, it's easy to diagnose and fairly easy to control with most contact or systemic fungicides.

Summer patch is the forgotten disease on many courses. Still a serious threat to turf, but it has been overshadowed by more glamorous and ominous sounding diseases, such as Waitea patch, bentgrass dead spot or rapid blight. After all, you get no sympathy from the neighboring superintendent when you mention you have plain old summer patch on fairways. On the other hand, rapid blight sounds really serious. First of all, it's a blight - a blight beats a patch, just like a full house beats a straight every time. Furthermore, it's rapid and what could possibly be worse than a blight that's rapid. That name alone has to make the green committee increase the fungicide budget by at least $5K to $10K.

Last, but definitely not least, is take-all patch. It never takes it all, but that name scares many into thinking that some year…it just might. Diagnosis isn't all that easy. In many cases you send a half-dead sample to a lab and ask if there is any take-all disease on this turf and the answer is usually yes. No smoke rings, no mushrooms, no black spiny acervuli and no webby mycelium to count on. Even when you are confident of the diagnosis and have tracked the disease on a few of the same greens for several years, it disappears and appears on other greens this season. The same goes for fairways, the disease was right there like clockwork during the 3 rd week of June for the past three seasons and darn if it doesn't show up somewhere else this year.

Maybe take-all scares people because it only affects bentgrass. Bentgrass is good. We would probably care less if it was only affecting Poa annua , since we pay good money to kill Poa with growth regulators and herbicides.

Take-all has to be the fungicide distributor's dream disease. Treatments require high rates of expensive fungicides applied to turf during late fall and early spring, well before any symptoms are observed. Better yet, it's kind of hard to tell if the treatments are working since the disease can be here today and gone tomorrow. However, it is easy to sell the preventative program to the golfers; after all it's called take-all patch, not take-some patch.

Source: Bob Vavrek, rvavrek@usga.org or 262-797-8743