Summer Stress

This summer was difficult for cool season grasses in the Mid Atlantic area. With over nine inches of rain in the month of June, the roots didn't have to move deep into the soil to find water, since it was available close to the surface. This means they didn't have the depth or structure like they normally would, which showed when it was hot and dry in July. With the weak root structure the stress is noticed on areas of fairways that have rock close to the surface which heats the plant from below and wilts.

This also allowed the disease Summer Patch to become a big issue in the Bluegrass intermediate cut and the rough. This is a disease we preventatively treat for in the early spring, which we did the same this year as to prior years. The weather conditions this year were ideal for Summer Patch to develop even with the preventative treatments. Once the disease is present their are no curative fungicides to control Summer Patch. The only cultural control for Summer patch is allow the plant to grow out of it by raising mowing heights. From mid July to the end of August we didn't mow Intermediates for this reason. Below are a few pictures showing when the disease first became active as well as after we raised the mowing height to help put less stress on the plant.

This fall we will be seeding Ryegrass into the intermediates around the greens because it is not susceptible to Summer patch. We are also doing some sodding in the roughs with Tall Fescue where the Summer Patch was the worst. Any large clumpy areas in the roughs will be areified and seeded with Tall Fescue.  The Kentucky Bluegrass always bounces back and fills in from Summer Patch during the cooler growing months. This means it will still be present and susceptible to it but the Ryegrass and Tall Fescue will decrease the amount of area affected by it.
Here is a link to a great article going more in depth about Summer patch. https://www.extension.purdue.edu/extmedia/bp/bp-115-w.pdf

Number 15 on July 24th

Number 15 on August 31st