Dollar spot is a fungus that affects both bermuda grass and zoysia grass. If you’re finding small brown spots about the size of a silver dollar (a few inches across), it’s likely dollar spot. Another tell tale sign of dollar spot is a lesion on the grass blade, particularly on the edge of the blade of grass. Occasionally these lesions will go all the way across the blade which will cause the entire tip of the blade to die and turn brown. In extreme cases these spots can bunch together masking itself as brown patch. You’re also much more likely to notice dollar spot when you’ve closely mowed your bermuda or zoysia lawn.
If your lawn has fallen victim to dollar spot there are a couple of different reasons to consider.
Your nice and hardy bermuda grass is much more likely to develop dollar spot during a drought. These dry soil conditions are the perfect breeding ground for this fungus. Even a sufficient source of moisture like a morning dew, fog, or weekly watering will keep dollar spot at bay.
In the spring and fall, when temperature conditions are 60ºF-80ºF, is when disease development is most likely. Normally the nights are cool and the days are warm when the conditions are just right for this fungus to run rampant.
If you’ve correctly diagnosed the problem the first thing to try is watering the grass. Be sure to water the grass early in the morning so it will dry quickly. This will give the bermuda or zoysia ample water to grow and reduce the severity of the disease. If after 2 weeks your lawn isn’t recovering it’s time to move on to a fungicide. The chemical for the job is Daconil 2787. Be sure to read all safety labels and follow them closely.
To keep your lawn from getting dollar spot in the first place be sure to fertilize your lawn and irrigate deeply at least once per week. Since dollar spot thrives in the absence of nitrogen it’s ideal to get a hardy dose of fertilizer on your lawn. This should already be in your yearly lawn maintenance schedule.