Dollar Spot

Tee box with dollar spot


Rough with dollar spot

mycelium on infected turf in morning hours

Pathogen- Rutstroemia Floccosum formerly known as Sclerotinia Homocarpa

Hosts- Bahia, Bermuda, st. Augustine, Zoysia, and several other cool season grasses

The spots you see all over the course are called dollar spot. This disease is characterized by round, bleached-out or straw colored spots, ranging from the size of a quarter to the size of a silver dollar. The spots appear as sunken areas in the turf. The spots are very visible in the morning when the grass is still wet, the grayish white, fluffy mycelium of the fungus can be seen sitting on top of the grass. This disease can be spread by mowers, humans, animals, and other maintenance equipment carrying the mycelium and infected tissue. This disease occurs when the temperature is between 60 degrees and 90 degrees. There are many different vegetative compatibility groups within Rutstroemia Floccosum that caused diseases at various temperature and humidity regimes.

Cultural management of dollar spot involves regulating the nitrogen level in the plant. One school of thought states, the number of infections will be greater with high nitrogen levels, but damage will be less severe than if nitrogen levels are low. This is the situation we are in, our nitrogen levels are keep very low, so the outbreak is widespread. Dollar spot can be managed with the use of many contact and systemic fungicides like myclobutanil, fenarimol, propizonazole, boscalid, and triadimefon applied every two or three weeks, or contact fungicides like chlorothalonil applied every seven to ten days.

This bottom line is this disease is not fun to look at, but it will not kill the bermudagrass. We will apply a little nitrogen to the course and we will be grown out of it before you know it.