Golf courses in Florida are breathing a collective sigh of relief as yet another summer has passed, but, even more so, as hurricane season comes to a close. While several storms have given us glancing blows this summer, we are pleased not to have had as much activity as has occurred the previous two summers.

Even without the threats of a major hurricane, summer months can be quite stressful on bermudagrass putting greens. In particular, the rainy summer months bring extended cloudy weather. Low sunlight is stressful to bermudagrass turf, especially for putting greens that are mowed at heights near 0.1-inch. If low mowing and aggressive cultivation are implemented during extended cloudy and warm weather, significant turf injury can occur. Our region has experienced an increase in rainfall over the past several weeks (see previous update) but, luckily, I have not had any S.O.S. calls in regards to major turf loss on putting greens over the past several weeks.

A stress that continues to be active on most recent visits has been plant-parasitic nematodes. Fortunately, these pests do not inhabit the entire golf course, but significant turf thinning occurs in nematode-affected areas over the summer months. The most effective nematicide on the market (Nemacur) is no longer available and courses are forced to use other alternatives for control. Curfew (1,3-D) also is effective at suppressing nematodes, but it is more costly and has additional restrictions for application. University of Florida Turfgrass Nematologist, Dr. Billy Crow, recently reported a new compound that produced extraordinary results in a field trial. We are hopeful that these results can be repeated and that, if safe and effective, the EPA registers it in the future.

Nematodes are active during summer months and cause turf thinning to occur.

Weeds are a constant problem on Florida golf courses, but are particularly troublesome in summer months as increased rainfall encourages weed seed germination and makes timely herbicide applications difficult. The herbicide MSMA has been a reliable chemical for controlling weeds on golf courses for nearly 30 years, but we have recently learned that this chemical is in jeopardy, as the EPA may choose to cancel its registration. There are effective alternatives for many turfgrass weeds in Florida but most of these alternatives are more costly. Also, some very troublesome weeds like dallisgrass and tropical signalgrass are not controlled by these alternatives. Hopefully, MSMA can be saved with perhaps some new restrictions for its use.

Source: Todd Lowe, tlowe@usga.org or 941-828-2625