Yellow patch, also called cool-season brown patch, is primarily a problem on bentgrass putting greens from November through April. The disease often results in superficial ring patterns in the turf but in certain years may cause extensive damage.
Yellow patch is the most common cold-weather disease of bentgrass in Kansas.
Figure 1 . Yellow patch on a bentgrass green. Turf inside the ring may show no adverse effects, resulting in a frogeye appearance. In other instances, turf inside the ring is discolored a light yellow. This gives the disease a more patch-like quality.