My Grass Blades Are Dead in the Middle

Dollar Spot

• Dollar spot is a fungal disease of turf grass caused by species of Lanzia and Moellerodiscus pathogenic fungi. The disease is common on bentgrass, Kentucky bluegrass, annual bluegrass, bermudagrass, fine-leaf fescues, perennial ryegrass, zoysiagrass and many other species of turf grass. Spores of the dollar spot causal fungus typically spread through lawnmowers, traveling sprinklers and other lawn care equipment. The fungus that causes dollar spot is also known to survive in many temperatures, so the disease can be active throughout the season.

Symptoms

• The only way to tell for sure if dollar spot is the cause of the dead tissue on your grass blades is to look for other symptoms that commonly occur alongside the dead tissue. Grass blades first discolor to a yellow or light green tint, but the discoloration is so subtle it often goes unnoticed. Depending on the exact species of fungus causing the infection, the discoloration deepens and either takes on an hour glass shape or spans the width of the grass blade. In early mornings, when the grass is covered with morning dew, you may notice fine, white cobweb-like growths of fungal mycelium over infected patches.

Natural and Preventative Control Methods

• Planting disease-resistant species of turf grass is the first and most important way of preventing infection. Cultivating several strains of bluegrass, for instance, can prevent infection because bluegrass turf grasses show varying degrees of resistance to dollar spot. For existing lawns, stress conditions caused by drought, alkaline soils, improper mowing and fertilization techniques and other factors leave your grass more susceptible to infection, so always keep your lawn in good health and vigor. Also, avoid thatch buildup because a heavy thatch layer can block sunlight, air and nutrients that would otherwise protect your grass from infection from reaching grass blades.

Chemical Options

• Adjusting cultural practices and allowing your grass to outgrow damage caused by dollar spot is typically the only management practice needed to restore your turf grass to full health, but a persistent dollar spot infection may require a chemical fungicide. Some fungicide chemicals commonly recommended for dollar spot infection include iprodione, chlorothalonil, fenarimol, triadimefon, mancozeb and propiconazole. Dollar spot fungal species are known to develop varying degrees of tolerance to fungicide chemicals, so it bears repeating that fungicides should only be used when absolutely necessary. When necessary, use only the smallest amount of fungicide needed to remove the dollar spot fungus and restore turf grass to full health.