We have had excellent turf weather in the past week and it looks like good weather again this week- cool nights, mild days. The only problem seems to be a lack of rain where irrigation is not available, but diseases should be minimal at this time. A few reports of take-all patch in newly planted bentgrass followed the many days of rain earlier this month. There was also a report of Ascochyta leaf blight following the extensive rain. There is a long list of fungi that can cause tip blights and leaf blights when turf remains wet for long periods. These diseases may appear as irregular areas or circular patches, but often only the tips of the blades are affected and the disease disappears quickly after the return of drier weather. In the case of Ascochyta, the fungus produces numerous round, dark fruiting bodies filled with spores in the infected tissue. Sometimes these are visible with a handlens especially when swollen in wet conditions. Many common fungicides are effective against these fungi, but treatment is not usually recommended.
The cottonwood trees are shedding their seeds at this time. The seeds are attached to cottony fibers. Sometimes, in the morning dew, these can be mistaken for fungal mycelium and can appear to cover turfgrass areas causing what appears to be a disease outbreak. The cottonwood seeds can usually be felt when the cottony growth is rolled between the fingers. Fungal mycelium and spider webs will usually disappear when touched.
Submitted by: Dr. Gail Schumann