Turfgrass Disease Triangle: What is it?
Turfgrass disease is made of three components. These components can be viewed as the three sides of a triangle. All three sides of this triangle are required to have a successful disease. Without one component in the turfgrass disease triangle, the disease will fail to thrive. Our goal is to grow the best, healthiest grass we can. By studying and understanding this triangle, we will be able to understand and target the disease itself while promoting healthy grass growth.
What is the Turfgrass Disease Triangle?
The first side of the turfgrass disease triangle is the host. In order for a disease to be successful, it requires a grass plant. It is essential that this grass plant is weak and susceptible to disease. A plant that is entirely healthy is not a viable host since the disease cannot take hold. Improper maintenance can cause a healthy turf plant to become susceptible. For example, your healthy grass will begin to grow weaker if mower blades have not been sharpened and you are tearing the grass instead of cutting it. This weak grass creates the opportunity for the second side of the triangle to take hold.
The second side is the pathogen. This is the element that causes the disease. The pathogen alters the appearance of the damaged plant. Disease can show up in many different ways on different grasses. For example, diseases can appear as field patterns, symptoms, and signs. Firstly, field patterns are visible on your lawn as rings, circles, or even linear patterns of disease. Secondly, symptoms are the plants’ response to the disease. These can show up as leaf spots, blight (deterioration), dieback, or root rot. Finally, the signs are a representation of the actual disease on the plant. Appearing as thread-like masses, hardened masses, or spores, these signs are an excellent way to identify the specific disease. However, the pathogen is not effective without the third side of the triangle.
The third side is the environment. This refers to three separate components; temperature, moisture, and soil pH and fertility levels. Since certain diseases develop and grow at different temperatures, examining the environment is essential. In another way, some diseases prefer moisture and humidity while some diseases grow best in dryer areas. Soil pH and fertility levels can either promote or impede the growth of diseases, depending on the levels. You can learn how to test your soil pH levels here. Therefore, putting these three components together will be extremely helpful to understanding the growing environment of the disease. In addition, knowing the optimal environment for fungal growth will help identify the disease accurately.
Using the Turfgrass Disease Triangle to Combat Disease
Since we know that none of the three sides to the turfgrass disease triangle can cause and maintain disease without the other two, we know what it takes to combat turfgrass disease. With our ultimate goal being encouraging healthy grass growth thereby eradicating disease, studying this triangle will help immensely. We know that manipulating the three sides of the triangle will strengthen the susceptible host, remove the disease-causing element, and improve the growing environment for the grass.
First, we look at how to alter the host. Since strengthening the immune system of your grass will help combat these diseases, overseeding with disease-resistant grass varieties is a good place to start. Additionally, adding fertilizer to your lawn will bring back essential nutrients your grass could be missing.
Second, we alter the pathogen. Simply applying fungicides can severely diminish and eradicate many diseases. However,
it is extremely important to correctly diagnose the disease. Otherwise, you may run the risk of applying the wrong fungicide due to an incorrect diagnosis and may actually exacerbate the fungal growth.
Third, we work on altering the environment. Adjusting your watering habits or improving soil drainage could be all you need to avoid providing the optimal environment for fungal growth. Additionally, thatch removal, fertilization, proper maintenance, and aeration are all excellent ways to improve the environment in which your turfgrass grows. It is essential to understand the optimal environment for the specific fungus that you are dealing with. This way, you are able to fully remove it by adjusting the environment to promote grass growth instead.
The Importance of Correctly Identifying the Disease
An incomplete or inaccurate diagnosis of turfgrass disease can ultimately result in exacerbating the symptoms. Not fully understanding the growing conditions and original cause of the disease could negatively impact your grass. In order to effectively remove the disease, you must have a complete understanding of the three sides of the turfgrass disease triangle. Use this triangle to research and adjust the three elements to encourage healthy turf. Otherwise, the disease may recur and continue to damage your lawn year after year.
Using the turfgrass disease triangle to your advantage can help you combat disease, understand the causes, and correctly diagnose the issue. Keep all three elements of this triangle in mind and your grass will thank you for it!