Seashore Paspalum Roundtable Discussion February 27, 2015

Seashore Paspalum Roundtable Discussion

By Todd Lowe - USGA Florida Region Agronomist
April 27, 2009

A small group of turfgrass professionals from Southwest Florida met on April 3 rd at Forest Glen Country Club to discuss seashore paspalum management on golf courses. The group consisted of golf course superintendents, assistant superintendents, sales professionals, and others. Golf courses ranged from newly-planted seashore paspalum to those several years old, and different varieties were represented (SeaDwarf, SeaIsle 1, SeaIsle 2000 & SeaIsle Supreme). There was a wide range of golf club standards represented as well.

The meeting provided an open forum for golf course superintendents to discuss management-related issues concerning seashore paspalum in an informal setting. Certainly, this update cannot offer an exhaustive review of each course's program, but it is meant to show the highlights of each topic discussed.

Plant Growth Regulation: Primo (trinexapac-ethyl) is applied on a regular basis at each of the respective golf courses. Rates generally consist of twice as much as those applied to bermudagrass playing surfaces, with 6 to 8 oz/A/wk applied on most putting greens during the growing months, and higher rates on tees and fairways. Several courses also occasionally apply Trimmit (paclobutrazol) with Primo.

Diseases: Dollar spot and large patch are the most problematic diseases experienced. Dollar spot is more injurious on seashore paspalum than on bermudagrass; and large patch can be a persistent nuisance on seashore paspalum. Disease control ranged from occasional fungicide treatment to costly preventative fungicide programs, depending upon the standard of the course. In bermudagrass, dollar spot can be suppressed with additional fertilizer applications; but supplemental nitrogen seems to only slightly reduce dollar spot severity in seashore paspalum.

While seashore paspalum has notably better turf quality than bermudagrass, it also can get ugly at times. Issues like disease, drought, and micronutrient deficiency can cause sharp declines in turf quality; and attending golf course superintendents mentioned that communication should occur quickly and repeatedly to educate golfers when problems occur.

Mowing: Much of the discussion concerned mowing heights, which seemed to be similar to bermudagrass and depended upon the standard of each particular golf course. It is necessary to keep mowers sharp to cut the thicker leaves and stems of seashore paspalum and to reduce disease incidence. Increased mowing on putting greens is necessary to maintain acceptable speeds. Grooming was discussed as well; and one superintendent employs groomers on each of his mowers on a regular basis to decrease thatch production.

Fertility: Calcium nitrate was once thought to be a popular fertilizer for seashore paspalum, but many different types of fertilizers are applied to maintain good turf quality. Most superintendents remarked that while less nitrogen may be required by seashore paspalum than bermudagrass, similar fertilizer treatments are required in regards to application frequency. Micronutrient spray programs are often employed, with particular emphasis on magnesium and iron. Potassium was mentioned by most superintendents as an important nutrient.

Cultivation: Deep verticutting can be injurious to seashore paspalum, and most agreed that aeration was probably more important than surface cultivation practices. Among the most popular verticutting implements on putting greens included the carbide-tipped Dynablades. Also, sand topdressing was felt to encourage leaf bruising, which decreased turf quality and possibly encouraged disease. While the trend for ultradwarf bermudagrass is to incorporate light/frequent sand topdressing, less frequent topdressing was felt to be beneficial to most superintendents who were in attendance.

Bermudagrass Management: Bermudagrass control or management in seashore paspalum is an impossible task at this time, as no effective herbicide can selectively remove bermudagrass from seashore paspalum. Control programs include physical removal with a sod cutter and replacement with seashore paspalum sod. Fortunately, most golfers cannot identify bermudagrass patches; but there is some angst with golf course superintendents over common bermudagrass infestation increasing.

Small focus groups like these can be very valuable resources. Since there were no speakers, university professors, or turfgrass growers in attendance, all participants felt free to speak their minds and ask basic questions or just be candid with thoughts on the grass and its management. Most superintendents felt that similar meetings should be held on a regular basis. A Green Committee chair from a local club also was in attendance and remarked about the importance of such meetings, especially for seashore paspalum growers. With the increased popularity of this grass among golfers, he felt that many more such meetings will take place in the future.