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When making sure conditions are pristine during the height of the busy summer playing season, it is easy for superintendents to get caught up in daily chores and lose sight of the big picture.
In this instance, the big picture means next year and what steps should be taken now to guard against problems such as dollar spot and, especially in the northern climates, snow mold.
Next spring seems a long way off, but like the proverbial squirrel preparing for the coming winter, the smart superintendent realizes treating his turf now with fungicide applications can prevent problems next spring.
“Dollar spot and snow mold are essentially our primary concerns,” says David Libby, superintendent at Prout’s Neck Country Club, Scarborough, Maine. “Here on the coast of Maine we can go days at a time in a fog bank while it can be bright and sunny four miles inland, and winters can produce snow mold pressure for six to seven months.”
Libby’s staff are always on the lookout for symptoms of dollar spot. “My assistants are both weather junkies, so we are always looking at short- and long-range models to try and stay ahead of the curve,” he says.
Libby adheres to a preventative program for dollar spot, “as our use of foliar nutrition and a heavy reliance on PGRs make it more difficult to grow out of an outbreak.” He begins applications in mid-May when soil temperatures rise to levels conducive for uptake, and uses primarily systemic products.
“Should we stretch our interval too long, we will make a curative application of a contact or local penetrant and bump our foliar nitrogen up to facilitate a speedy recovery,” says Libby.
Libby’s snow mold applications begin in early October with systemic fungicides to bolster the immune system of the plant, and he makes a final application of a contact/local penetrant tank mix paired with an anti-desiccant as late as possible, usually just before Christmas.
“We have seen increased efficacy in recent years with the addition of PGRs to our snow mold treatments. I have no scientific data as to why we are achieving greater success with this addition, but in slowing the metabolism of the plant we seem to be elongating our window of control. Should we experience any breakthrough due to an abnormally long period of pressure, we will apply curative rates of mancozeb in the early spring to burn down any residing inoculates.”
A greater number of superintendents have changed their philosophy on controlling dollar spot in the last several years and have incorporated late-season applications to provide dollar spot-free turf during the winter and reduce the innoculum, which delays dollar spot incidence the following spring, says Kyle Miller, senior technical specialist for BASF Professional Turf and Ornamentals.
A season-ending fungicide spray can be timed with a snow mold application to save on manpower. Miller advises superintendents to make sure they include a top-performing dollar spot product in their mix, as most superintendents are focused on snow mold control.
“To be prepared for this application, superintendents need to choose their products and have them on hand for the application,” says Miller. “Most suppliers offer early-order discounts beginning in September and October, which is an excellent time to acquire the products you are targeting for this application.”
To control dollar spot next spring, Jim Goodrich, product sales specialist for PBI/Gordon, says superintendents should look at reducing the amount of overwintering by applying a late-season fungicide application prior to the first frost of winter.
“Controlling snow mold may be accomplished with a fungicide applied in late October or November or prior to prolonged periods of snow cover. By scheduling a late October or November snow mold application, a superintendent can have product on the ground before snowfall.”
Dollar spot is Eric Wygant’s greatest problem on fairways and tees. “If it gets ahead of me just a little I will battle it the rest of the season,” Wygant, superintendent at Shannopin Country Club in Pittsburgh, says. “Snow mold is not as much as a concern as it is something that we just need to be aware of because of where we live. If you do not treat it preventively you could have a big problem coming out of winter.
“Taking proper steps in the fall can help set you up to prevent dollar spot the next season. Maintaining healthy turf with adequate nutrient level in the soil coming into winter will go a long way to fight off diseases.”
Dollar spot can appear anytime during the growing season, says Matt Giese, technical manager for Syngenta. Steps should be taken to scout and observe not only prior outbreak dates but the environmental conditions at the time of the outbreak. Dollar spot development is dependent upon moisture, optimum temperature, and humidity levels, he says.
“By monitoring the conditions that can influence disease development, a golf course superintendent can make an educated decision about when to apply a fungicide before the disease appears,” he says. “Strong cultural practices to discourage dollar spot coupled with a preventive fungicide program is crucial for long-term control.”
Snow mold, on the other hand, generally occurs outside the growing season or during cold and wet conditions, Giese says. Pink snow mold, for example, occurs during cloudy, cool and wet conditions and sometimes in the absence of snow cover. Gray snow mold requires a minimum of 60 days of snow cover to develop an infection. Both pink and gray snow mold can be controlled with fungicides prior to conducive weather conditions, he says.
“Depending on the geography, these applications may occur as early as late August or as late as December in any given year,” Giese says. “For locations with prior snow mold history, these fall applications are most effective at limiting turf damage from snow mold infections. In some instances where favorable conditions persist for snow mold development, spring applications may be warranted for control of pink snow mold.”
Pine Tree Country Club superintendent Mike Posey hasn’t had to deal with severe dollar spot outbreaks since the Birmingham, Ala., course has A1/A4. “But in the Southeast we spray low nitrogen rates on our bentgrass so it can pop up from time to time,” he says. “At previous courses with more susceptible varieties it was a constant battle with the high humidity in the Southeast. It can actually be more prevalent in our Tifway fairways and roughs in the spring and fall when Bermudagrass is not growing aggressively enough to outgrow it. It is also very prevalent in low-fertility (N) Bermudagrass.”
Posey reports good luck on bentgrass greens with the Emerald first and last program.
“This year on the ‘first’ spray, I used Honor (Emerald+Insignia) since pythium root dysfunction was a major disease in the Southeast last year and Lane Treadway’s recommendation of a spring Insignia application coincides with my Emerald timing,” he says. “To me, Honor makes a lot of sense for the spring application in our area. The dollar spot will really start showing up in the fall on the Bermudagrass when your slow-release fertilizer starts wearing off and temperatures drop below optimum for the Bermudagrass growth. Most of the time I will just put down .5lb/N/1000 square feet to mask the dollar spot. Fungicide applications are too cost-prohibitive on such a large area.”
Posey calls the Southeast “the perfect storm for disease,” given the region’s high humidity, high daytime/nighttime temperatures and afternoon thunderstorms.
Megan Van Arsdale has followed “the rule of thumb” of not spraying DMI’s during the high stress periods of summer.
“I just like to remember that late summer does not mean you are in the clear,” says the superintendent at Danville Country Club, Lexington, Ky. “By late summer, the grass is stressed and tired, and I cannot stress enough that superintendents need to be on their A-games at all times. It is always important to spray proper rates to prevent disease – don’t get cheap towards the end of summer and stretch spray intervals or rates… it’s not worth it. Remember, how you leave the grass in the fall is what you start with in the spring.”
When timing fungicides applications, Sandy Queen, superintendent for the Overland Park Golf Division in Overland Park, Kan., is more concerned with the calendar than with weather conditions. “I try to have a couple of applications of DMI’s out before mid-May and I also try and have an application of chlorothalanil down, too,” she says. “This doesn’t always happen as I am now applying more curatively than preventively.”
Timing treatments is important, says Miller. “Generally speaking, we want to time our snow mold treatments just prior to the onset of cold and snowy weather,” he says. “This will allow the fungicide to provide season-long residual. Applying in the fall with numerous warm days remaining might enhance the breakdown of these fungicides, shortening their control period. Delaying applications until after snow has fallen may result in poor control if the product is not allowed to reach the turf.”
Each part of the country is different in regard to treatments and applications. The date of the first snowfall is used as a good indicator to time the last fungicide application. Superintendents employ historical weather patterns (normal year) and what products have been effective to most successfully control dollar spot and snow mold.
It’s too late to apply fungicides when infection symptoms already appear, says Tim Zech, president of United Turf Alliance. It is possible to arrest or prevent additional infections if the same environmental conditions exist.
“Existence of dollar spot may mean that you can expect more to come if the conditions remain favorable and if nutrient inefficiencies are not addressed,” he says. “It is too late to apply snow mold products if the ground is already frozen or snow has covered the turf.”
Wygant plans his treatments in the spring when dollar spot is just starting to get active in the soil. “If we can suppress it then there is less of a chance for it to get into the plant in the summer,” he says. “Other than applying when conditions are favorable for a proper application, treatments are done preventively to reduce the frequency we would have to treat on active dollar spot. Extended periods of high nighttime temperatures with high humidity could bring dollar spot on and then we would have to treat curatively.”
“I use the first and last program, and then I catch control with my applications of Daconil, 26GT, and 3336,” says Posey. “One of these products are sprayed every other week with a pythium preventative the weeks in between.” This usually starts in June and continues until September. Posey will also mix a low rate of Banner Maxx with the Daconil in his first June application and last fall application while the temperatures are still low.
The common thread for all treatments is the GDD model for early season dollar spot application, says Dr. Kathie Kalmowitz, BASF Professional Turf and Ornamentals technical specialist. “Of course dollar spot is more problematic in some areas over others, as is snow mold,” she says. “And yes, local environments or microclimates greatly impact disease development. Areas with more air movement and more sun exposure are less susceptible to disease.”
Given the number of dollar spot fungicides and their efficacy for dollar spot, most applications have an effect in reducing disease levels when timed late or when disease is present, Giese says. In these situations, complete disease control may not occur or may take longer and require more applications than a preventive program.”
In fact, research has shown limited benefits from fall applications or early spring applications to reduce dollar spot inoculum prior to typical preventive applications, Giese says. Fungicide residuals that expired prior to disease activity required subsequent applications and therefore effectively negated any benefit of early applications.
Snow mold applications can also be applied too early, or if fall weather conditions remain mild fungicide treatments may need to be repeated. Once snow cover has occurred, fungicides should not be applied on top of snow. Plant uptake and foliar coverage are essential to protect the plant throughout winter. Mid-winter thaws or open winters may allow treatment, but these are not conducive to plant uptake and should be used infrequently.
Zech advises superintendents to maintain a year-round focus on healthy turf, take soils samples to look for nutrient deficiencies, pay attention to soil temperatures, dig down in the soil and see what turf roots are doing, carefully balance nitrogen amounts, use a reasonable base program and spoon-feed if possible, look ahead at pending weather patterns, establish a prevention program and adjust it in advance of pending weather changes and agronomic changes.
There are ways to save on manpower needed for such treatments. “The best ways to reduce manpower hours are to make sure you have a properly trained and licensed applicator performing the treatment,” Goodrich says. “He will make sure the course is sprayed in the most efficient manner by reducing travel time from area to area and applying only to those areas designated for the application. Another way to reduce manpower is to properly calibrate the spraying equipment. If the equipment is calibrated incorrectly, it could result in too little chemical being applied, limiting the effectiveness of the application and thereby raising the need for retreatment.”
Get a bigger sprayer. Or better yet, get two bigger sprayers, Libby says. Often, superintendents overlook replacing the sprayer because it does a great job. Instead, they look to the new fairway unit or triplex upgrade. Actually, the easiest and most effective way to reduce man hours for applications is to keep healthier turf. “Take it easier on your turf, and it will lower your disease pressure and perhaps even your blood pressure.”
Apply the right products at the right time, Zech says. Tank mixing appropriate products saves a trip or two over the course. Good fertility and agronomic practices extends application intervals of control products or potentially avoid some sprays altogether.
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