Common Name: leaf spot / melting out
Scientific Name: Drechslera poae & Bipolaris cynodontis

Leaf spot and melting out are common symptoms in bluegrasses and bermudagrasses caused by species of Drechslera and Bipolaris (formerly known as Helminthosporium). In the bluegrasses, this disease is most active during warm and humid weather, but in bermudagrasses, most damage occurs during cool and wet periods in the fall and spring. Leaf spot symptoms are expressed in the early stages of the disease, but if left uncontrolled, the pathogen may progress into the basal portions of the plant to cause ‘melting out’. Leaf spot symptoms initially appear as small, brown or black spots or flecks on the leaves or sheaths. As the lesions expand, the center of the lesions becomes tan with a dark brown or black border. The lesions may also be surrounded by a yellow halo. As the lesions expand, they coalesce and cause dieback of entire leaves or plants. Melting out symptoms appear as a reddish brown rotting of the sheaths, crowns, rhizomes, or stolons which initially leads to wilting, yellowing, or death of the foliage. Symptoms of leaf spot and melting out appear in irregular patterns, although localized ‘hot spots’ may be more severely damaged than others.
leaf spot / melting out
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Characteristic Description
Host Turfgrass (2)bluegrasses, bermudagrass
Month(s) with symptomsMarch to June, Sept to November
Stand Symptoms (4)irregular distribution across turf stand
Foliar Symptoms - Location/Shape (3)oval leaf spots
Foliar Symptoms - Color (3)yellow, tan, brown
Root/Crown Symptomsnone
Fungal Signsnone
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