On
putting greens, summer patch may begin as small (2 to 3 inch) circular patches that progress to larger (up to 12 inches) pat
ches if conditions favor disease development. More often, large patches will appear suddenly with no indication of previous disease activity. In severe cases, the patches may coalesce and destroy large areas of
turf. The patches initially take on a yellow color, then turn tan or a straw-brown color as the plants die.
On greens with mixed annual
bluegrass/bentgrass populations, the
bentgrass usually will colonize the center of patches of affected annual bluegrass, creating a ring-shaped appearance. This is the easiest way to
identify summer patch.
Since summer patch is a root disease, cultural practices that promote good root growth will
aid in reducing disease severity. Increased aeration and improved drainage on compacted and poorly-drained soils will alleviate some root inhibition. Here are a few pointers:
- Avoid light, frequent applications of water.
- Avoid heavy nitrogen fertility, especially in the spring.
- Use slow release sources of nitrogen fertilizer.
- Reduce thatch when the layer is over ½ inches thick.
- Core aerate compacted soils in the fall, and if necessary, repeat core aeration in the spring.
