How Do Lawn Diseases Develop and Ways to Prevent Them

lawn disease

If there is a disease that can develop where you live, the spores of that disease are probably in your lawn already as they will move from lawn to lawn mainly through wind movement. Some diseases are soil borne, meaning that they already exist in the soil. All diseases are waiting for the right environmental conditions to develop to infect the turf.

Development of Lawn Disease

It is important to understand how a disease develops. The term used to explain how a disease develops is called the Disease Triangle. It is basically the same concept as the Fire Triangle. There are three basic components that are required for a fire to develop – fuel, heat and oxygen. If one of the three is removed, the fire is extinguished. In the Disease Triangle, the three components are host plant, pathogen and environment.

In regards to lawns, the host plant is the turfgrass in your lawn. The pathogen, as was mentioned earlier, already exists in the lawn as a dormant spore. Think of a spore as a tiny seed, waiting for the right conditions to begin its development. These spores can be fungi, bacteria or viruses. The right conditions is the environment that favors its development.

There are diseases that develop in cool weather, warm weather and hot weather. A critical component is moisture. Too much water or high humidity generally favors more disease development. Along with weather, the environment includes the growing conditions for the turfgrass. Soil pH and fertility can lead to an unhealthy plant, which can be more easily colonized by a disease. Lawns that are mowed too short will result in a weaker plant and more susceptible to disease development. Too much or too little fertilizer can also lead to disease development.

Preventing Lawn Disease

The amount of thatch that has developed in a lawn can also lead to disease development as thatch can act like an incubation chamber for many diseases. The best way to inhibit the development of a disease in your lawn is to follow proper cultural practices of mowing high, based on your turf species, watering deeply, but infrequently, core aerate the lawn once a year and follow a proper nutritional program to ensure the health of your lawn. Of these practices, the most important one is mowing.

Here are the recommended mowing heights for the most common turfgrasses:

• Bermuda Grass 1/2 to 1-1/2”
• Zoysia Grass 3/4 to 1-1/2”
• Centipede Grass 1-1/2 to 2”
• St Augustine Grass 3-1/2 to 4”
• Tall Fescue Grass 3 to 4”
• Bluegrass 2 to 3”
• Perennial Ryegrass 2 to 3”
• Fine Fescue 2-1⁄2 to 3-1⁄2”

Proper watering is also very important. Many people with an automatic sprinkler system water too much. Reduce the number of days you water and invest in a rain sensor so the system doesn’t run while it’s raining or if rain fall has been plentiful. Training a lawn to be more water efficient starts with reducing the frequency of watering, but increasing the length of time each zone is watered based on sprinkler head type and size of the area being watered.

sprinkler system

There are disease control materials available to treat most diseases, but the control is usually temporary and the disease often comes back. That is why Spring-Green recommends improving the growing conditions as the best approach to preventing diseases from developing in your lawn. There are some situations where, due to intense environmental stresses, a disease control program may be the best choice. Contact your neighborhood lawn care professional to determine the best approach to reduce disease development in your lawn.