As many of you know Poa Annua (Poa) is an undesireable turfgrass plant. With the majority of the greens at Hyde Park being over 90 years old, the populations of Poa can be almost 60 percent. Poa is undesireable because it is a shallow rooted plant that prefers moist shaded conditions. It is a prolific seed producer, creating a bumpy surface particularly in the spring time and in the summer it declines rapidly due to heat and fungal pathogens from Summer Patch and Antracnose to name a couple.
The yellow or unhealthy area is Poa, while the healthy area is green and composed of creeping Bentgrass
So what are the yellow rings? The yellow rings are symptoms of Summer Patch, a fungal root pathogen that infects the Poa plant in the spring, while the signs of the infection are only noticeable in the summer under stress conditions. We target this pathogen in the spring with multiple applications of acidifying fertilizers, and fungicides to slow the demise of the Poa. Curative applications have been erratic in controlling this disease at HP.
In the short- term we will continue to monitor the progress of the Summer Patch, trying to offset the effects on playability through sand topdressing, fertilization and promotion of creeping Bentgrass.
In the long-term, encouraging Creeping Bentgrass will improve the playability and health of the putting greens. The building blocks of a healthy putting surface include; added sunlight, aggressive topdressing and aerification, improving air movement, proper moisture management, and the addition of internal drainage to the putting surfaces.