At Leslie Park, we view ourselves as stewards of the golf course. We have the privilege, as well as the responsibility, to manage it in such a way that will make it an asset for the Ann Arbor golfing community, while also enhancing wildlife habitat, protecting indigenous vegetation and protecting community water resources.
Leslie Park uses pesticides (fungicides, herbicides, insecticides, and plant growth regulators) in a solely curative way. This means that we only apply a pesticide in the presence of a confirmed pathogen. Before deciding to use a pesticide, golf course staff consults a thorough Integrated Pest Management (IPM) program. The primary principle of IPM is the pest triangle. This is based on the assumption that in order for a pest to become a problem, three conditions must be met: 1) the pest has to have a host that is susceptible to the pathogen; 2) the environmental conditions for the pest must be present; 3) the pest must be present.
Spraying a chemical will eliminate the third leg of the triangle, but we always try to impact the other two legs so that a pest infestation will not occur. If we can choose a turfgrass or other plant that is not subject to a disease or pest, we always use that plant. The most common way for the golf course to impact the pest triangle is to alter the environment. For example, dollar spot is a fungus that attacks turf at a temperature between 60 and 85 degrees, but it also requires at least 12 hours of leaf blade wetness. Often, we will drag a rope between two golf carts first thing in the morning to get rid of the dew. This will cut down on the time the leaf is wet and thus the amount of dollar spot that we have in our fairways.
Another important concept of IPM is to establish an economic threshold of injury. We have to realize that we never will be completely free of a certain pest. The trick is to determine at what point the injury from a pathogen becomes too severe and must be corrected. Our tolerance for dollar spot on greens is lower than it is on tees. Tees have a lower threshold than fairways, which have a lower threshold than roughs and out of play areas.
An often-overlooked aspect of IPM is the monitoring of chemical applications. At Leslie Park, we keep track of the chemicals we apply and the effectiveness of those applications. This helps prevent pesticide resistance and helps determine whether the cost and effort are justified.
When possible, the course tries to use pesticides with lower toxicity and has begun to experiment with nontraditional pesticides such as Civitas. Civitas is a synthetic paraffin wax that acts as a plant protectorant and, when used in conjunction with a traditional pesticide, allows us to use half the recommended rates with similar results to using the full rate of the pesticides. We also have tried some bacterial additives that target the dollar spot pathogen.