Studying a Fungicide Program
There is an excellent article that appeared in Golf Course Management (April, 2016 issue) entitled “Sharpening your axe” by Dr. Michael Agnew. In the article, he speaks to the stepwise thought process that goes into planning a fungicide program. It is worth your time to read the article.
I wanted to focus on the diseases that occur on your golf course greens and fairways and those that appear. At this time of the year, it is a good to reflect and document diseases that you might have expected and those that appeared. Your first inclination is that diseases that you might have expected and did not see, that your fungicide program was effective. And in most cases it probably was. But is it also possible that you might have overkilled the disease? That your program consisted of multiple fungicide combinations or overlap that resulted in the disease not appearing? The opportunity exists when looking at the disease and the time of year that it occurred you could possibly reduce the number of fungicides to control the disease.
For example, dollar spot, which is probably the most common and chronic disease on cool-season golf course turf. Yet it is one of the easier diseases to control. There are a slew of fungicides that are available to control this disease. With most of the fungicides that control dollar spot, they have a more broad-action activity against other diseases. So if you are on a preventative program and you are using a fungicide that controls dollar spot preventively for 14 to 21 days. Now seven days later you target a different disease but the fungicide that controls dollar spot too, are you 1) getting overkill, and 2) exposing yourself to dollar spot resistance eventually to one of the fungicides?
A second consideration is which diseases are a chronic problem versus a more acute issue. Again taking dollar spot as an example, dollar spot may be occur from May through October. A disease that is chronic like dollar spot is easier controlled preventatively, and generally more cost effective. Preventative rates are generally much lower than curative rates. In fairway situations it is common to try to stretch out your control period because of the frequency and thus the cost of preventative treatments. When looking at the past records were there disease outbreaks, or in this example dollar spot occurring that corresponded at times when a fungicide treatment was being stretched? If this were the case than “stretching” a treatment should be done.
Conversely, if you are looking at a disease that occurs infrequently and/or the duration is short lived, a curative fungicide treatment program should be put in place. One or two treatments a year for a disease does not warrant a season long preventative program. However, if the disease is especially devastating like Pythium blight that may occur infrequently, anticipating its occurrence based on weather and current conditions is warranted.
Here I have tried to take one small part of a fungicide program and try to express that a thorough thought process is needed. Using the article mentioned above develop your fungicide program in a manner that you understand it and what you are trying to accomplish.
About the author
Dr. Karl Danneberger is a professor of Turfgrass Science at The Ohio State University. Dr. Danneberger's contact information can be found here. You may also follow Dr. Danneberger on Twitter: