By Mike Jiggens
TAKE-ALL patch, dollar spot, anthracnose and the need for adequate air movement on putting greens were but a few of the topics discussed in July during Plant Science’s annual “Turf Academy” series at five Ontario golf courses.
USGA agronomist Adam Moeller led the series over five consecutive days at Maple City Country Club in Chatham, St. Thomas Golf & Country Club in Union, Lakeview Golf Course in Mississauga, Vespra Hills Golf Club in Minesing and Dalewood Golf Club in Port Hope.
At each location, Moeller was joined by the host superintendent and a contingent of neighbouring superintendents for an early morning walking tour of the golf course, during which issues pertaining to that specific golf course were discussed in detail.
While at St. Thomas, Moeller pointed out some incidence of take-all patch on the course’s chipping green.
“It’s not the most devastating disease out there in the world,” he said. “Some courses, especially new courses, battle it a little longer than others. Typically, it’s not much of an issue after 10 years or so on greens, but it can still happen.”
Moeller said there have been reports of take-all patch on older pushup greens that are a mix of poa annua and bentgrass. Bentgrass and sand are the two big items associated with take-all, he noted.
“If you’re a new course with bentgrass, it’s definitely a disease you need to worry about.”
St. Thomas superintendent Wade Beaudoin said his chipping green has a pH level “on the high side” at 7.8 or 7.9. Take-all patch is known to be more problematic in soils that are high in pH.
“Anything you can do to knock down the pH in these soils is good long term,” Moeller said, adding it won’t mean the end of take-all or summer patch, “but it’s typically more severe the higher the pH.”
When building on calcareous soils, knocking back the pH levels becomes a challenge. Cultural programs which adopt acidifying fertilizers are helpful in reducing high pH levels, Moeller said.
Damage is usually seen in the summer, but sometimes problems will show in the spring. Moeller said at the time of the late July turf academies that curative applications could be done then, but it’s often just a matter of preserving the current root mass as opposed to stopping the disease which is already “pretty much done.”
A significant problem with take-all patch on fairways and approaches is the expense associated with preventing the disease.
Two applications in both the spring and fall are recommended when greens are relatively new, especially if they have already have a history of the disease. Otherwise, in most cases, a late April or late May application is suggested, Moeller said.
“It’s (take-all patch) a major challenge. It’s one of the bigger issues with bentgrass, but it typically goes away after about 10 years.”
If it hasn’t disappeared after 10 years, it’s usually on its way out, he added.
In most instances, take-all patch is associated with greens which have been seeded rather than sodded. Moeller said he suspects sod growers tend to successfully manage the disease.
He suggested to the superintendents attending the St. Thomas academy that for the remainder of the summer they practise an extra wilt watch but not to give affected areas a “ton” of water.
Solid tine aeration preserves the root mass and alleviates stress and is non-disruptive and gentle on the turf. Moeller recommended not getting overly aggressive with aeration practices.
In spite of widespread damage to several golf courses precipitated by last year’s harsh winter, five or six of St. Thomas’ greens “didn’t have a lick of damage on them,” Beaudoin said. Due to the design of the golf course, which features dramatic changes in elevation, some greens have poorer growing environments than others, including those in valley settings which receive little or no air movement. A recent tree removal program at the golf course has helped matters considerably, allowing for better air movement and sunlight penetration.
Moeller said growing environments are the limiting factors on whether rebuilding or regrassing can occur. As growing environments improve, the damage from a severe winter can be minimized.
“If you tackle the growing environments first, maybe the greens get better enough where you don’t have to go down that route.”
The main issue associated with improving growing environments isn’t so much the expense of doing it, but rather the disruption and loss of revenue it brings.
Moeller said dollar spot on greens usually goes unnoticed by golfers, but superintendents are quick to spot the disease.
“It’s more of a self-induced problem and we worry about it more than we should.”
On fairways, however, there are resistance issues with dollar spot for which superintendents should be concerned, he said.
Some superintendents might be on too much of a calendar-based program, and they consequently see resistance build up over time because they spray more often.
Knocking down dew as best as possible is a cultural means of helping to keep dollar spot at bay, but doing that over 30 acres of fairway is “easier said than done.”
Resistance to de-methylation inhibitor (DMI) fungicides could translate into what was once 28 days of expected control becoming only 21 days.
“It works, but is not lasting as long.”
Moeller said if an effort is made to cut back on some DMIs over a couple of years, one can selectively control some of the populations which have resistance to DMIs, and better control can be achieved after a while because those resistance isolates will have been killed off.
“But it takes a long time to do that, and what else can you use if you can’t use DMIs?”
Moeller said Penn State University plant pathologist Dr. John Kaminski recommends that a superintendent with a history of dollar spot problems following the second or third true mowing of the season should make an application with any material he feels works well for control. It is typically the lower cost material which can knock down some of the populations and make dollar spot more manageable throughout the rest of the season. It might simply be a couple of hot spots on the fairways.
Most superintendents at the July 22 St. Thomas academy said anthracnose had only recently made an appearance at their golf courses. Most issues related to its recovery are golfer and traffic-related.
“Any time there’s turf loss on a green of this age, you lose a lot of perennial poas (the better poas which perform better over time), and you’re likely to get the annual poas (which produce a lot of seed heads and check out at the first sign of heat, wilt quicker, are more prone to future winter injury and are more prone to anthracnose).
Moeller said this is why he has seen continual battles with anthracnose which keep popping up.
“It’s not where it’s wiping the grass out entirely, but you keep seeing it and you’re treating for it, but it doesn’t seem to really go away.”
Nitrogen fertility through both a granular and soluble program is key, with an emphasis on spring fertilization. Moeller said he recommends never going beyond a half-pound or three-quarters of a pound at any one time.
“You just see more growth than what you want and then start battling on clippings.”
After that, soluble nitrogen “is your friend” with anywhere from one-tenth of a pound to two-tenths every seven to 14 days.
“It’s a very generic program, but it works well for most people” when combined with Primo Maxx or its generic equivalent, he said, adding the combinations will provide a constant feed in helping to manage against anthracnose.
The latest research from Rutgers University shows that potassium is an important consideration in the control of anthracnose. Some, however, have abandoned potassium because there is also research that suggests it may increase snow mould potential.
“I don’t discredit that research,” Moeller said, “but I don’t think your potassium levels are going to be that high where you see more snow mould. The Rutgers research is showing that if you maintain a one-to-one or even a two-to-one nitrogen to potassium ratio in your regular program, anthracnose is a little bit less of an issue.”
He said if there is already plenty of potassium in the soil, it may not be all that beneficial, but, as long as moderate to high levels of potassium are being maintained, it should help to manage anthracnose. Research suggests that 100 pounds or so per acre works well against the disease.
Aeration and topdressing
Beaudoin said he topdresses a little more infrequently than he used to.
“We’re probably three weeks-ish and relatively light,” he said.
Moeller said topdressing can be overdone and isn’t always the solution. It can be common for a new superintendent who inherits greens with issues to want to aggressively aerify.
“You can overaerify greens pretty quickly and you can overtopdress greens. You aerify too much and suddenly you take out that organic matter, and you need some for traffic support. You lose all that structure in the top inch or so and you see the holes collapsing along the edge throughout the day. General wear and tear builds up on these greens, and as a result you don’t have the traffic tolerance.”
He said too much aeration, too much verticutting and too much topdressing, especially on a new green or a newly-established area, can have a detrimental effect. Topdressing and aeration should be based on growth rate, he added.
Beaudoin said it was his plan to aerate Sept. 4-5 with three-eighths of an inch coring tines on 13 of his greens. The others were to undergo a drill and fill at three-quarters of an inch double drill and fill, followed by a half-inch solid “to squish the holes together.” Spacing was to be 11/2 inches using three-eighths of an inch hollow tines.
Moeller said if there are only two inches or so of sand built up in a modified zone and there is more organic matter than what is needed, a half-inch at minimum is recommended to ensure ample movement and to allow backfilling of sand into the channels.
“Once you start going below a half-inch, it’s really difficult to fill those holes with just brushes and sweeping.”
More “bridging” occurs once below a half-inch.
Moeller said it is important for a golf course to deal with one lab for soil testing, and not bounce from one to another, noting there is a tendency to get different variations in numbers from one lab to another because testing protocol may differ.
Frequency of testing should depend on how greens perform over time and whether a course’s programs have changed. As an example, he said a golf course may have switched to a different topdressing sand or is aerating more frequently. Under such conditions, testing perhaps once a year is recommended. If routines haven’t changed all that much, testing every other year is probably sufficient.
“If you haven’t tested in a while, it would be good to do it just to have a baseline. You might find out you’re way low on potassium and that’s why you’ve got anthracnose issues or something along those lines.”
The walking tourincluded a look at St. Thomas’ 15th green which, only a couple of years ago, had significant shade and lack of air movement issues. Situated in a valley setting, the hole was once heavily shaded by surrounding trees and received little or no air movement, and was a precipitator of the club’s recent tree removal program.
Moeller said when greens peter out during heat spells, it can almost always be attributed to a lack of air movement. He said Beaudoin did an exceptional job of clearing trees from the area to permit better sunlight penetration to the green, but air movement remains an issue. He recommended a fan be installed at the site to do what nature is unable to achieve.
Fans will permit consistent playability. More golf courses are opting for gas-powered fans over electric models due to the cost of having remote areas of a golf course serviced for electricity. He said there is no point in installing anything smaller than a 50-inch oscillating fan.
“That will give you enough movement from the back to the front.”
Even a 50-inch fan, Moeller admitted, will be tough to provide ample air movement all the way to the front of a green, but a portable model can be placed almost on the collar with its angle of attack adjusted to ensure it’s low enough to move air across the entire green.
A fan may be required for only three to four weeks during the summer, and it can be rotated to a couple of green sites in need. Both heat and humidity levels need to be considered as determining factors as to when fans are required.
“If it’s hot and dry, still run them, but even if it’s a little bit cooler yet humid, I wouldn’t hesitate.”
A green which is in shade for a significant amount of time in the afternoon and then suddenly exposed to sun for an extra three to five hours will present issues.
“You’ve got to be on top of that with moisture because that grass is going to wilt a lot quicker than what it once did.”
Strategic tree removal equates to better quality greens, he said.
Some golf courses have memorial tree programs in place, but the planting of new trees, even though well intentioned, can create problems in future years. Moeller said the USGA opposes memorial tree plantings on golf courses from an agronomic standpoint.
“You’re much better off having a tree memorial fund which goes toward general tree care, and possibly planting in some situations, but it’s just for overall management.”
He said opposing memorial trees makes for sensitive discussions with members, but he urged superintendents to discuss the matter with their respective clubs to stress what is best for the long-term betterment of the golf course.
“A golf course should not look like a cemetery.”