Introduction to Grass Diseases

Learning about lawn grass diseases and what causes them are vitally important for everyone who desires a great looking lawn. Anytime we begin a serious lawn improvement program, disease management must be factored in or we could experience lawn problems later on. Although viruses and nematodes account for some damage, the primary lawn disease culprits are specific types of pathogenic fungi.

Beneficial and Pathogenic Fungi

Beneficial fungi live in and around the soil and perform hundreds of essential functions necessary for plant health. For example, they are the primary agents that breakdown all types of organic matter into elements plants can use. Other types of fungi attach to roots and even help plant roots collect and absorb nutrients. Still other feed upon and suppress disease causing fungi.

However, there a few types of pathogenic fungi that can harm plants. They, too, maintain a constant presence in the soil, in and around the root zone. If the grass is susceptible to that particular pathogen and the environmental conditions are correct, the plant could become infected.

Conditions that Promote Grass Diseases

• A disease causing pathogen.
• A susceptible host plant.
• Correct environment conditions for disease development.

If just one of these factors are missing, grass diseases cannot occur.

To explain further, if a particular pathogen is present in the soil, but your grass type is not susceptible, then it will not become infected. In order for a disease to develop, the pathogen must have a susceptible host.

Each species of fungi have specific environmental conditions they are active in. The pathogen will remain dormant until the humidity, soil and air temperatures and soil moisture content is in the correct range. Due to the wide range of environmental conditions across the country, some regions will experience greater problems with certain grass diseases than other regions.

If a grass disease does begin, in most cases, as soon as the environmental conditions change to where it no longer favors disease development, then disease progression will stop. It could be a drop in humidity or a period of no rain that allows the soil surface to dry.

What We Can Do To Hinder Disease Development

Sound cultural practices are just as important. Routinely mowing your grass below its lowest optimum level places it under a lot of stress. Proper irrigation methods performed at the correct times reduces opportunities for disease development. Fertilization also plays in important role in grass disease suppression. Developing a good fertilization plan that takes into account the grass’ needs and the environmental conditions where you live will go a long way in preventing disease.

One of the most common mistakes people make is to over-fertilize during a disease period. Many people don't know what a disease looks like, so when one does develop, they add fertilizer and lots of water thinking that will help. Often, it just makes it worse. When it is all over, they are left with a major lawn repair job. But don't worry, this section will help you better understand what to do and how all these things link together.

Lawn Conditions that May Resemble Disease

There is also types of insect damage that can resemble disease, especially insects that feed on plant juices. If you treat an insect problem as if it were a disease, you will likely continue to have a problem. These pages will help you correctly identify disease damage and learn practices that will help prevent diseases from starting..