There are basically three approaches to pest control on golf courses. The first is perhaps best described as the back-in-the-day approach where blanket applications (aka “spray and pray”) were made to control just about everything – weeds, bugs, fungus, moles, gophers, etc. – whether or not the critters in question were actually there. The idea was to get them before they took up residence and caused problems.
The second approach is much different. It involves a philosophy of treat only when and where necessary, which minimizes the use of control measures and targets pests using spot treatments. With this method, a moderate degree of damage tolerance is often required.
The process is both reactive and proactive, treating after the invasion has already occurred and anticipating future infestations. One of the big advantages of this approach is money savings for pesticide products.
The third type of pest control involves a hybrid of the first two approaches with adjustments made based on the current season and previous pest control experiences.
There are sound reasons for using the spot treatment approach. First, it saves money, and the money-saving math is easy. If only 5 percent of the turf stand is infested, the money that would have paid for the product(s) to unnecessarily treat the remaining 95 percent can be redirected toward other projects such as equipment purchase and soil improvements. Is it reasonable to expect an infestation of surface-feeding insects, say chinch bugs, to infest the entire turf area? The answer is probably no; it is not reasonable to treat a section of turf where you do not expect chinch bug problems.
When formulating new insecticides, manufacturers strive to develop products that have few, if any, undesirable side effects. One such side effect involves the harm that can come to nontarget organisms. Because spot treatments target pesticide applications directly to the pest, injury to beneficial natural enemies and nonpest species is minimized.
In addition to the advantages outlined above, spot treatments save time. By not treating an entire fairway at predetermined intervals, treatments take only a fraction of the time needed to treat larger areas. And, since time is money, less time spent applying insecticide reduces labor costs for the overall budget.
Thresholds and IPM
Utilizing either the spot treatment or a hybrid approach requires establishing a treatment threshold to quantify pest injury. In the cereal grains or fruit crop industries, there is a clear financial incentive for establishing an economic threshold. For these crops, the issue is how many insects, weeds or diseases can be tolerated in terms of production and profits.
For nonedible ventures such as golf and sports turf, treatment or action thresholds focus on creating and maintaining a functional and aesthetically pleasing turf surface. Establishing a threshold or line in the sand for high-value turf is difficult, as many factors (public or private course, previous pest control attempts, product availability and restrictions, local ordinances, available budget, etc.) can influence the situation.
Treatment thresholds reflect the number of insect pests needed to cause unacceptable damage to the turf. These thresholds are estimates, not hard rules, that apply to every situation.
They are best used to help turfgrass managers make better informed pest management decisions, and will vary depending on pest species, abundance, and life stage; turf species and cultivar; vigor and value of the turfgrass; relative effectiveness and cost of control measures; and the time of year.
The function and location of the turf will play a role in determining the treatment threshold for a given insect pest. For example, when considering control measures for white grubs, grass species with deep and expansive root systems will generally experience less damage than grasses with shallow roots, so the treatment threshold will be a bit higher. When spot treating, focus on high-priority areas that are important in terms of placing people and products where they are needed the most. Tees, greens, approaches and clubhouse turf are usually the most noticeable, yet can vary greatly from course to course.
Keeping integrated pest management (IPM) in mind and utilizing all available tools and techniques when selecting a management approach is helpful. An important aspect of the IPM approach involves planning ahead to avoid or minimize future pest problems. Decisions made during the establishment and maintenance of a turf area can significantly influence pest development.
Among these key decisions are selection of turfgrass species and cultivar, weed and disease control strategies, irrigation, fertilization, thatch management and other cultural practices that affect the health and vigor of the turfgrass. As a general rule, stressed or poorly maintained turf will exhibit pest damage sooner than healthy turf, and will be slower to recover following insect or mite injury.
Read more: The do’s and dont’s of pesticide safety
Monitoring is key
As opposed to blanket treatments, spot treatments rely heavily on frequent scouting and monitoring to identify the areas of concern. Scouting is a day-to-day activity, whereas monitoring takes on a more of a long-term perspective. Effective scouting begins with a thorough understanding of biology, behavior and damage caused by turf pests in the region of the country where the golf course is located.
Knowledge of the signs (the actual pest) and symptoms (the appearance of the affected turf) is crucial to effective scouting. Fortunately, many books and online sources are available for identifying signs and symptoms.
Scouting can be accomplished on a routine basis as golf course workers go about their daily activities or as a separate dedicated activity.
There are advantages and disadvantages for each approach. Scouting by the golf course workers could add time to each job, but create a more seamless transition. A dedicated IPM/scouting program may require hiring an additional individual with scouting experience, but will upgrade the course’s overall IPM program.
Maybe history wasn’t your favorite subject in school, but it’s certainly as useful as math is for determining how much fertilizer to apply to a fairway. Knowing where certain pests have been a problem over the years can be very helpful in predicting future pest infestations on specific areas of the course.
Many techniques for recording course history are available, including electronic note-taking, old-school notebooks, and asking long-time golf course workers and other superintendents in the area for their opinions.
One technique that has been especially effective for some courses is to develop pest activity maps, photographs or line drawings of each hole where insects, weeds and diseases have been problematic over the years.
There are exceptions to the virtues of choosing spot treatments as the primary method of pest control. Certain pests are so reliably invasive and so unacceptably destructive that preventive course-wide applications are justified. White grubs and annual warm-season weeds are two examples that fall into this category.
Read more: Proper pesticide application