Leaf Spot and Melting Out in Turf
Leaf spot and melting out are different diseases with similar symptoms, caused by different fungi. Melting out (caused by Bipolaris sorokiniana) usually appears in April and May during cold, rainy weather. Leaf spot (caused by Drechslera poae) is a summer disease that requires long dew periods, warm evening temperatures, and plenty of rain.
What leaf spot and melting out looks like:
Both diseases first appear as an irregular pattern of off-color spots. The infected area can be several inches to several feet in diameter. An entire lawn can become infected. Close inspection of infected grass blades reveals dark green spots. These lesions eventually turn purple/brown. Multiple lesions on a blade often cause the grass blade to die. Once the infection reaches the crown and roots, the entire plant will die.
How to prevent leaf spot and melting out:
● Raise the mowing height to 3”
● Add nitrogen fertilizer in the fall (not spring or summer)
● Do not water in afternoons or evenings
● Keep thatch to less than ½”
● Keep from walking on blighted areas to limit spreading the disease
How to eradicate leaf spot and melting out:
Adam’s Healthy Lawn professionals may be able to apply a fungicide to control Leaf Spot or melting out. Timing of the treatment is critical for satisfactory results. The fungicide must be applied at the first sign of the leaf spot stage of the diseases. If the disease has re-occurred in the same location year after year, a preventative application can be made when disease-favorable weather arrives. Once large areas are blighted to the point of crown infection and/or plant death, it is often too late for treatments.
Talk to an Adam’s Healthy Lawn Expert!