Lawn disease & fungal issues

Lawn diseases can cause major damage to a healthy lawn

Repairing a lawn after a major fungal issue can take multiple seasons. Fungi is the main culprit for diseases in home lawns.  These fungi are considered parasitic, and can steal everything the grass needs like water, nutrients, sunlight, and sugars that grass produces for itself.

Growing healthy grass is the first and best defense against disease invasion

While some turf species are susceptible to different fungal diseases, your lawn maintenance activities can greatly influence your lawn’s susceptibility to disease and ability to recover from outbreaks. For example, watering too much, improper mowing, and compacted can increase the potential for a disease outbreak, especially under specific environmental conditions. 

Fungal species can generally be categorized as one of three characteristic types:

Patches type disease – Patches of dead or dying spots in the lawn.

Ring disease – Rings of discolored or dead grass.

There are diseases that can create “mycelium” which looks like a stretched-out cotton ball or a thick spider’s web. 

Before treating your lawn, it’s crucial to identify the disease

The first step is to narrow down the possibilities by evaluating the prevailing climatic conditions and the turf species in your lawn. For example, red thread commonly invades Kentucky bluegrass lawns during the spring, especially in wet weather. Other fungal diseases are prevalent during hot, humid weather, such as brown patch. 

Cultural practices can help minimize disease outbreaks and reduce their severity; these should be considered as an option before traditional fungicides. When needed, fungicides may be applied as a curative treatment, or applied as a preventative treatment prior to disease outbreak. Keep in mind that in certain circumstances, incorrect application of fungicides can do more harm than good. 

Outside of cultural strategies, treatment options include bio-fungicides, “reduced risk fungicides” and conventional fungicides. 

Prevention of fungal diseases in turf can be attempted with biofungicides which are derived from Bacterial species and are branded as Ecoguard, Companion, Rhapsody, and Turf Shield.  These products are typically derived from animals, plants, and certain minerals. Generally, these options are preventive or for mild disease infestations. Biofungicides essentially make the ecosystem less friendly to fungal diseases without hurting your lawn. 

Reduced risk fungicides pose less risk to human health and the environment than conventional alternatives. For turf, EPA-approved reduced risk fungicides are available with the generic names azoxystrobin, boscalid, fludioxonil, mefenosam, and trifloxystrobin. 

Ultimately however, sound cultural practices and reseeding with improved varieties with demonstrated disease resistance provides the most efficient means of discouraging fungal diseases. 


Photo credit: Donald Groth, Louisiana State University AgCenter, Bugwood.org