Florida courses fight nematodes

Retirees aren’t the only ones who flock to Florida for its weather and golf courses. Parasitic nematodes also have an affinity for the warm sun and sandy soils of the Sunshine State.

Many of Florida’s courses feel the sting of turfgrass rootfeeding nematodes that cause severe damage to the fairways, tee boxes and greens; kill large patches of turf; ruin appearances; and interfere with play.

Heron Creek Golf & Country Club in North Port, Fla., located 25 miles north of Fort Myers, has been battling these parasites since it began operation in 1998. Heron Creek is a 27-hole golf course designed by Arthur Hills.

According to Tom Rainey, the course superintendent, it’s a challenge to keep the course in top playing condition – especially since it receives heavy play year-round. Providing members with excellent playability is Rainey’s top goal.

Greens treated with Curfew

Prior to Application: Topdressing immediately prior to injection with subsequent surface brushing after the injection can be beneficial for masking injection slits. Putting greens that are drier than normal (less than 50 percent field capacity) prior to application must be irrigated. Flag sprinkler heads and other known underground obstructions in and near areas to be treated. Root enhancement will be optimal with adequate fertility. Apply 0.5 to 1 pound of nitrogen per 1,000 square feet within two weeks of injection. Immediately Following Application: Watering: Don’t let greens dry out. Based on environmental conditions, at least five to 10 irrigation events of at least 0.1 inch are required the day of treatment. Then for the first 72 hours following injection, irrigation timing and water quantities should be similar to those used when a putting green is being established. After the third day, gradually return to normal watering for another 24 to 48 hours (four and five days after treatment). Avoid puddling and flooding of the treated turf. Putting greens that are drier than normal (less than 50 percent field capacity) or allowed to dry out soon after injection will experience severe phytotoxicity, disrupting playability. Rolling: Roll the putting green twice after the initial post-treatment irrigation and prior to mowing. The first rolling should be in the same direction as the slits and the second at a 45-degree angle to the slits. Rolling after injection and after the first irrigation event is beneficial to putting surface uniformity as long as proper personal protective equipment is worn during the 24-hour re-entry interval. Mowing: The first two mowings after injection should be conducted in the same direction as the slits. As is normally done after core-aerifying, consider raising the mowing height for two to three days after treatment. Aerifying: Aerification should not occur for seven days prior to or seven days after treatment. Stewardship: Adhere to all personal protective equipment guidelines when performing any management practices on treated turf within the first 24 hours after injection. Install pesticide application/no trespassing signage at treatment area exit and entry points. Notify Dow AgroSciences and all proper agencies in the event of spill or exposure issues.

Nematode pressure
When Rainey was hired two years ago by the club, he was immediately aware of the intense nematode problem.

“One of the key visual indicators of heavy nematode pressure is that the turf always looks really dried out – all the time, no matter how much you water, the turf looks thirsty,” says Rainey.

In addition, he also noticed the turf didn’t respond to fertilizer. Turf samples confirmed root growth had been severely impacted by the nematode pressure.
“There weren’t any,” Rainey says. “Nematodes had damaged all the roots.”

The story is the same at golf courses across Florida and other coastal states in the Southeast.

The Club at Pelican Bay in Naples, Fla., is no exception. The private, par 72 championship course is built on a sandy ridge along the Gulf of Mexico. Bob Bittner, a certified golf course superintendent and director of golf course operations, has been with The Club at Pelican Bay for 26 years – before the course even opened for play. He has been dealing with severe nematode pressure for many years.

“It is a constant battle,” says Bittner. “Every time we test the course, it always indicates that we need to treat for nematodes.”

With intense management, some courses are able to nurse the turf along with frequent irrigation, abundant use of fungicides, careful fertilization and higher mowing heights to keep the turf alive. But these practices lead to higher operating costs and increased maintenance time. In addition, playability becomes an issue, especially on sensitive putting greens.

“We have to treat,” says Bittner because of his course’s severe problem and the high expectations of club members. “It is really the only option we have. I treat all 27 fairways, tee boxes and selected rough areas once a year. I close nine holes for two weeks and treat while we are doing other cultural practices.”

How it works
Curfew soil fumigant is injected below the soil surface to manage parasitic nematode populations. Because it is a restricted use pesticide, it must be applied by a certified applicator. The equipment utilizes specialized knives to open the turf, allowing Curfew to be placed at least five inches below the soil surface through tubes located behind the knives. Presswheels close the cut seams and seal the fumigant under the turf. The injection slits heal and disappear about 14 to 21 days after the application.

Curfew works rapidly to manage plant parasitic nematodes. Once injected into the soil as a liquid, the active ingredient volatilizes as a gas and moves through the soil profile. As it moves through the soil, Curfew makes contact with the nematodes, effectively controlling a wide range of plant parasitic nematode populations.

The liquid fumigant, which has been effectively used in other types of soil fumigations for more than 30 years, has a 24(c) registration for Alabama, Florida, Georgia, Mississippi, North Carolina and South Carolina and is labeled for use on fairways, greens and tee boxes.

According to Raymond Miller, Dow AgroSciences sales representative, the company worked with certified applicators to refine the application process and modify the equipment for use on greens.

“The application method for greens utilizes smaller equipment, closer knife spacing and specialized rollers to protect the surface of the greens,” Miller says.

The new application method was made available for commercial use beginning with the 2004 golf season.

For Tom Rainey at Heron Creek, this is the first year the course was treated with Curfew. Heron Creek treated 27 holes during consecutive two-week intervals.

In preparation for an application of Curfew soil fumigant, Rainey increases irrigation on the turf that is scheduled for treatment.

“Moist soil helps minimize the damage to the turf by the slicing and also slows the dissipation of the fumigant,” explains Rainey.

Rainey says Dow AgroSciences provides him with a fumigation kit, which includes pink flags to mark all sprinkler heads, signage to post around all entrances to the course notifying people that they cannot enter the treated area, and an information pamphlet to distribute to members and neighbors of the course.

“It’s all about information and education,” Rainey says. “We gave our members plenty of notice before the Curfew application. We put it in the newsletter, posted it around the clubhouse, and held a town hall meeting with Raymond Miller from Dow AgroSciences to help educate members, answer questions and alleviate any concerns.”

Immediately following the treatment, all treated areas need to be thoroughly irrigated. The irrigation is critical to the treatment. It aids in sealing Curfew in the soil to optimize its activity.

“We also mowed and rolled in the direction of the slits to reduce scarring and help the slits heal faster,” he says.

The treated areas remain closed for 24 hours as required by the label.

The results
“Within 10 days of treatment, we had enormous root growth on turf that showed no roots just before the application,” says Rainey.

Bittner agrees.

“Curfew provides relief from the nematodes for a period of time,” Bittner says. “It gives us a chance to get some root growth. The turf is more tolerant to stress and able to absorb fertilizer. We definitely get a healthier plant.”

For Rainey and Heron Creek’s 27 full-time maintenance staff, healthier turf means they can reduce their turf management practices.

“Once we see strong root growth, we can back off on irrigation, and I know we’ll see a savings in herbicide and fertilizer usage,” he says.

At Pelican Bay, Curfew improves playability and that is something members notice. But both Rainey and Bittner understand that nematodes are here to stay.

“It’s a vicious cycle. Nematodes destroy the turf, we treat with Curfew, we get healthy turf, which then attracts the nematodes,” Bittner says.

“When you get healthy roots, it’s like putting out a buffet for nematodes,” adds Rainey. “We know they’ll be back. But annual Curfew treatments can keep you ahead of them and can help you build a healthy root system.”

Editor’s note: This article was contributed by Dow AgroSciences.