Is Bleach Good for Fungus in Zoysia Grass?

Zoysiagrass Fungus

• The fungus that typically infects zoysiagrass is known as large patch or brown patch and caused by Rhizoctonia solani. It is sometimes also referred to as Rhizoctonia blight, and causes unsightly brown circular patches in warm-season lawns such as zoysiagrass. When active, this fungus causes grass to turn orange around the outside of the brown ring. There are several other closely related species of Rhizoctonia that may cause similar symptoms and colonize grass throughout a variety of growing and environmental conditions.

Dangers to Soil

• Bleach is an effective fungicide, but unfortunately causes dangers to soil that make it unwise for use in this situation. Bleach has a high pH of 11 and is composed of sodium hypochlorite, so it contributes lots of sodium to the soil when it breaks down. Because fungicides when applied to lawns are usually done so as a drench, too much bleach ends up in the ground, causing pH to rise and soil to become salty when the bleach breaks down. This in turn is bad for the lawn.

Management Strategies

• Instead of using bleach to get rid of fungus, try other cultural practices. Collect lawn clippings unless you have a mulching mower that chops them up into pieces ¼ inch in length or smaller. Don’t allow lawns to get overly shaded, or overly soggy by watering too frequently. Instead of frequent sprinklings, water deeply to a depth of six inches, once a week. Generally, most fungicides available to homeowners are not effective, so stick with cultural management strategies.

Bleach as Fungicide

• Despite the danger of changing soil pH, bleach is still quite useful in the home garden as a fungicide. Because commonly used tools such as rakes, shovels, trowels or shears can transfer fungus if not cleaned properly, bleach is an effective means of disinfecting. Prepare a solution of nine parts water to one part bleach, and dip tools in the solution. Before rooting cuttings in the greenhouse, you can even dip them in a bleach solution of the same concentration before rooting to prevent pathogens from taking hold.