Asked May 04, 2021, 3:47 PM EDT
Macomb County Michigan
Adjusting the pH of soil, especially over a large area like a lawn, can be a challenge. Soils have a high buffering capacity and generally need ongoing applications. A pH of 7.1 wouldn't be something we would normally recommend adjusting for cool-season turf. https://turf.purdue.edu/changing-soil-ph-under-turf/
On May 4, 2021, at 5:58 PM, Ask Extension <email@example.com> wrote:
Our turf disease specialist does agree that this looks like symptoms of melting out. The fungicide azoxystrobin is registered for control of melting out on residential lawns. They also indicate that daily irrigation of 1/10 of an inch of water from an irrigation system will prevent the disease from becoming a problem. Other cultural controls that can prevent the spread are summarized in this post from OSU (https://u.osu.edu/athleticfieldmanagement/2017/04/03/leaf-spotmelting-out/):
- Mow the turf high (2.5 – 3 inches) to provide leaves that produce food for the plant and maintain a healthier lawn.
- Avoid excessive nitrogen fertilization in spring which promotes lush growth. The use of fall and late fall fertilization is recommended. Once in the melting out phase maintain the lawn with a complete fertilizer at modest rate to encourage healthy turf and recovery. Often a starter fertilizer is recommended.
- Do not over water the turf if the lawn is irrigated.
- Manage thatch by frequent and heavy core cultivation (aeration) of the lawn. This will also promote a deeper healthier deeper root system.
- Plant resistant cultivars of Kentucky bluegrass. For information on these refer to the National Turfgrass Evaluation Program
- Fungicides can be applied but for best results need to be made early in the disease cycle or as a preventative treatment. This is done based on a history of the disease in the lawn. Unfortunately the most effective fungicides are no longer registered for use on residential lawns.