Turfgrass Fungus - Causes and Remedies

One of the most frustrating things for a meticulous gardener and homeowner is for their lawn to have problems with fungal diseases. Lawns are particularly susceptible to problems because they are monocultures—millions of the same plant in the same place, without diversity. Whenever you have many of the same plant without variety, there is always a greater potential for problems. Fungi are one of the most common causes of turf diseases. Fungi spread by spores that are carried by air and water. The microscopic, lightweight nature of the spores makes the spread of fungi wildfire-fast. How do you know if your lawn has fungal problems? After all, there are a variety of bacterial and insect problems that plague turfgrass in addition to fungi. Insect damage is less uniform in variety. It would be spottier and less symmetric. Some fungi have noticeable structures (mushrooms) on top of the lawn. Other fungi cause noticeable symptoms, but no large, above-ground structures.
Common Types of Turfgrass Fungus

Fairy Ring: Fairy Ring fungus causes a circular or semi-circular band in the grass. If the symptoms are not all over the lawn, water and fertilizer can mask the fungus by greening up the rest of the lawn. You can also treat fairy Ring fungus by aerating and breaking up the fungal mat. That will improve air and water penetration. If the fungal ring has grown large, you may have to dig out the soil and replace it with uninfected soil and re-seed. There are some fungicides, but they are expensive and do not always work well. Cultural controls work better than fungicides, generally.

Dollar Spot: This fungal disease is caused by the fungi Lanzia spp. and Moellerodiscus spp. It produces the effect of dead circular spots of six inches to two feet in diameter. When the grass is wet, you can see the cobweb-like strands of fungus in between the blades of grass. To control this fungus, keep your lawn properly fertilized and watered. The fungus thrives in warm temperatures and high humidity, but low soil moisture. Fertilizing and watering schedules do a lot to control this fungus.

Necrotic Ring Spot: This fungal disease appears as rings of dead grass surrounding tufts of healthy, green grass. More prevalent when the weather is cool.

How to Prevent Turfgrass Fungal Problems

It is a lot easier to prevent fungus problems than to cure them. Most plants have problems when they are stressed. Turfgrass becomes stressed when the water conditions and nutrient availability are not optimum. Compaction and thatch buildup are other problems. To keep fungal problems from taking hold, learn what type of grass you have in your lawn and care for it appropriately. Most grass needs one to two inches of water a week. More or less water can cause stress. It is important to not over-fertilize. Excess nitrogen can cause weak growth in grasses. Thatch and compaction can be addressed by punch-core aerating in the spring and the fall, followed by topdressing with a compost/topsoil mix.

If your lawn is attacked by fungus, despite your best efforts, you can hire a professional to apply fungicide. You can also use corn gluten (which also serves as a pre emergence herbicide) to attract a type of fungus that feeds on other fungus. This is a biological control that can help keep your soil healthy. The key to lawn fungus control.healthy lawns fungus control is healthy soil. Regardless of your plant problems, if you notice a problem, you need to correctly identify it in order to fix it. Turfgrass fungus is no exception. With proper care, and treatment in the case of problems, you can have a luscious, green lawn, free of turfgrass fungal problems.

Casey Coke is a Marketing Manager for Natural Environmental Systems, LLC. The company is a global supplier of microbial products including compost starter and other organic soil conditioners.