Superintendent counters rapid blight

Like most golf course superintendents, Mike Caranci, superintendent for Candlewood Country Club in Whittier, Calif., defies the laws of nature every day. That presents Caranci a number of challenges to overcome to keep his course looking great and in the best playing condition possible.

The work that Caranci and his 23-person crew do is almost invisible to the golfers who enjoy more than 40,000 rounds played on the 350 open days per year. The golfers don’t know the well-planned course maintenance program that Caranci has developed over the past 17 years. They barely notice his crew performing the mowing, irrigation, preventive weed and disease applications, nor the dozens of daily fine grooming details necessary to create one of the best-conditioned courses in Southern California.

The Candlewood crew’s greatest challenge is keeping the Poa annua greens thriving year round in an environment that is not conducive to cool-season turf success.

While Poa annua on greens is the turf of choice at Candlewood, the environmental conditions that it must live in are far from optimal. For starters, the soil is naturally high in salts (greater than 3.0 dS/m) due primarily to the lack of frequent rainfall that would leach the salt through the soil profile. Water in the region also is naturally high in salts – compounding the detrimental soil condition.

A constant blade length of between 5/32 and 5/64 inch also challenges Caranci’s Poa annua greens. Additionally, the southern California heat of June through September, coupled with the greatest seasonal traffic occurring during the same period, makes constant turf monitoring and quick correction of additional stresses critical to the greens’ survival.

While these factors are course management concerns, if the additional stress of turf pathogens appeared, they could certainly spell disaster in this delicately balanced environment.

With more than 24 years of experience as a superintendent in Hawaii, Palm Springs and the Los Angeles areas, Caranci has seen, and fought, just about every turf disease common to those regions.

Caranci previously followed a preventive fungicide application program that included a rapid blight preventive treatment that consisted of a tank mixture of Compass at 0.5 ounce and Fore at six ounces per 1,000 square feet that provided 14 to 21 days control.

However, in late winter 2003 and continuing through early spring 2004, Caranci discovered that his preventive rapid blight treatment wasn’t doing the job.

“The turf just didn’t look right,” Caranci says. “I’ve had problems with brown patch and summer patch before, but this wasn’t the time of year that you normally see those. The turf looked really dry, even though it had proper irrigation and the temperatures were relatively cool – 60 to 70 degrees.”

Rapid blight appears as irregular shaped chlorotic or necrotic reddish brown patches that are five inches in diameter and may form larger dead areas up to five feet in diameter. Additionally, a close look at the turf reveals chlorotic leaves that appear mottled and water-soaked.

Having exhausted his options in correcting the situation and convinced that a disease had developed a resistance to his fungicide routine, Caranci turned to his distributor sales representative for help. His representative confirmed the disease that was attacking the greens, and helped re-evaluate his fungicide program to correct the situation.

The diagnosis was indeed rapid blight and the recommendation was Insignia fungicide, a BASF fungicide that has recently been labeled for golf course turf use in California. The product was shipped directly to the course and within 36 hours Caranci was making his first application.

“The greens looked really bad, but within seven days the turf showed a significant recovery and in 10 days the rapid blight disappeared altogether,” Caranci says.

At the time of the distributor sales representative’s visit, few were familiar with rapid blight as it was not identified through plant pathological systematics until 2003. Labyrinthula, an obscure microorganism that has features of both fungi and protozoans, had only previously infected marine plants such as seagrass, diatoms and algae. In December 2004 the University of Arizona received confirmation from the international organization that approves biological nomenclature that the species Labyrinthula terrestris had been accepted as the causal agent.

Rapid blight is becoming a problem for many courses in the southern United States where more than 100 golf courses in 11 states (Arizona, California, Colorado, Florida, Georgia, Louisiana, Nevada, North Carolina, South Carolina, Texas and Utah) have identified rapid blight infections on cool-season turf. In fact, the high salinity environment that rapid blight thrives in is common to courses in these states.

Additionally, maintenance practices such as aeration and frequent mowing, along with heavy traffic damages the leaf blade, provide an entry point for the disease.

Having learned how it attacks the turf, Caranci now follows a preventive fungicide program that includes a tank mixture of Insignia at 0.5 ounce and six ounces of Fore per 1,000 square feet applied every 14 days during the summer months (June through September) and applications every four to six weeks the remainder of the year at the same rate.

“Prevention really is the key and Insignia is very economical as its broad-spectrum control provides additional protection against other common diseases,” says Caranci. “With one package of Insignia, I can make two complete greens treatments.”

For more information on Insignia, visit www.turffacts.com.