You Are Here: Management Updates 2000 Archive October 20, 2000

Date: October 20, 2000
Category: Diseases
Subject: Dollar Spot, Leaf Spot, Bentgrass Dead Spot

DOLLAR SPOT has been especially severe this year. The cool, wet weather allowed turf to outgrow fungicide protection more quickly than usual. Without the midsummer growth slowdown that is typical in hot weather, fungicides lasted minimal amounts of time. In addition, the abundant moisture favored the growth of the dollar spot fungus as well as many other foliar pathogens. "Spring" LEAF SPOTS also continued throughout the summer and into the fall.

Dollar spot on putting greens has been confused with the new BENTGRASS DEAD SPOT (BDS) disease where it is severe. BDS is identified by the distinct spots that generally kill the turf right down to the soil similar to ball marks. Infected leaves often contain abundant black fruiting bodies in late summer and fall. In contrast, dollar spots often coalesce (grow together) and will affect both bentgrass and annual bluegrass (Poa annua). If you are not certain, try closing a cup cutter plug of the diseased turf in a plastic bag with a moist paper towel overnight. If white mycelium appears at the edge of the spots, it is dollar spot and not BDS.

- Submitted by: Dr. Gail Schumann