Mr. Felix Horne, from Action Lawn Care, brought in some samples of St. Augustinegrass yesterday which appeared to have very suncken, wilted patches. It is down on a plantation where take all root rot (Gaeumannomyces graminis) has been an issue and pH has been high in areas. This is important because take-all patch typically occurs in areas with a high soil pH – most severe at pH 6.5 or above. It is also more severe on less fertile and sandy soils.
Under the microscope, some of the roots were dark colored and looked stubby. There is actually some large patch (Rhizoctonia solani) mycelium here too. Under the compound microscope, you can see the hyphae and hypopodium referred to as “puzzle pieces.” We see more into the summer. Home lawns with this disease will really show damamge and is hard to control.
Here are some management tips for take all root rot:
- Use acidifying fertilizers.
- Apply moderate to high levels of phosphorous, potash and minor elements where these nutrients are depleted from the soil.
- Improve the drainage of the turf.
- Reduce thatch.
- Fungicides are available to control the disease. Consult the current Georgia Pest Management Handbook.