What’s that question? It is the one posed most frequently by delegates to this week’s Sustainable Turfgrass Management in Asia 2012 conference: How can we control bermudagrass in seashore paspalum? The conference saw 210 delegates from 20 countries assemble at Thailand’s popular beach resort of Pattaya to discuss turfgrass management and learn from speakers including Dr. Doug Karcher (University of Arkansas), Dr. Lane Tredway (a former contributor to this website), Boonthong Ngamsaprang, and Sittichai Dusadeeporn (Golf Course Superintendent and General Manager of Golf Course Maintenance and Construction, respectively, at Thailand’s award-winning Siam CC).
Dr. Tredway mentioned the disease suceptibility of seashore paspalum, in particular to the dollar spot pathogen, but of even more concern to the delegates was how to control bermudagrass. The problem is the same from China to Vietnam to Indonesia — seashore paspalum is planted, over time bermudagrass invades the seashore paspalum turf, and the bermudagrass area generally becomes more and more, while the seashore paspalum area shrinks.
There are few options for bermudagrass control, all of which are disruptive to play, and none of which are completely effective:
- physical removal of bermudagrass and replacement with seashore paspalum sod
- non-selective herbicides applied to bermudagrass and replacement with seashore paspalum sod
- selective herbicide applications that don’t entirely eradicate bermudagrass and can be phytotoxic to seashore paspalum
- salt applications that don’t kill bermudagrass
- over-irrigation of the turf, creating high soil moisture content in which bermuda struggles and seashore paspalum persists
The best advice I heard at the conference? Remove the dew in the mornings so that the expanding bermudagrass patches won’t stand out so much (bermudagrass leaves hold a lot of dew compared to waxy seashore paspalum leaves that don’t hold much dew).
This discussion at the conference is indicative of a larger problem — seashore paspalum is overused in Southeast Asia; it is, except in special cases, not well-adapted as a golf course turfgrass in this part of the world, and it is completely unsuitable as a low-maintenance turfgrass in Southeast Asia. In well-drained soils, even under intensive maintenance, when the mowing height is more than about 6 mm, bermudagrass or manilagrass overtake and eventually replace seashore paspalum. Under minimal maintenance, seashore paspalum simply disappears and is replaced by better-adapted species.
I, and the hundreds of golf course superintendents in China, India, and Southeast Asia who are managing seashore paspalum, will be glad to hear any suggestions on reasonable solutions for this pernicious problem.