Sudden Heat Conducive for Diseases!

With the sudden increase in temperatures turf disease suddenly appear. After a relatively long cool spring the first high 80's to low 90's F plus temperatures bring the onset of several diseases.

Waitea Patch / Brown Ring Patch

The first case of this disease arrived this week from Northern Ohio. This follows the pattern for the last two years. If seems to be a minor problem when cool and then spikes with temperatures in the 80ºs to 90ºs F. This disease has been reported throughout the East, Midwest, and West coast. The case received this week showed aggressive thinning of the turf and is one of the most severing cases seen in Ohio. There are still questions about this disease, how if relates to some other diseases, the disease biology & life cycle, and best management.

In most cases the disease does not kill turf but thin the plants on the out edge. There are limited research studies on the disease and much of the work comes form California where Waitea Patch is fairly wide spread and occurs for a longer time then it in Eastern USA.

Trinity and Insignia are labeled for use on Brown Ring Patch / Waitea Patch (follow labeled instructions). In addition, some of the other products that have been reported to show a positive affect are Endorse 2.5 oz, Heritage 0.4 oz, Prostar 3 oz, Medallion 0.5 oz, or Banner 2 oz (per 1000 sq.ft.). There has been limited research and results have been variable.

Since this is a relatively newly defined/described disease and similar to other diseases caused by Rhizoctonia fungus, the following may help to understand the way these are classified and named at this time.

Common Disease Name: Current Pathogen Name

Brown Patch :Rhizoctonia solani
Yellow Patch : Rhizoctonia cerealis
Brown Ring Patch*/ or Waitea Patch**:Rhizoctonia circinata var circinata
Sheath and Leaf Spot or Warm Season Brown Patch: Rhizoctonia circinata var zeae

* Name for disease on bentgrass proposed to the Japanese society of Phytopathology. ** Preliminary name for disease on annual bluegrass.

Anthracnose and Basal Rot Anthracnose --- ALERT:

Wet conditioned + heat = high risk for Anthracnose.
Some other key risk factors are:

- high populations of Poa annua, especially if there is a history of the disease
- poor drainage
- soft greens and any low mowing or scalping
- turf under low fertility programs

If this disease has been a problem or is a concern implement an aggressive turf health management program immediately. One component would be timely and accurate fungicide applications but remember fungicides alone often will not control this problem. Use appropriate spray volume to place the fungicide where the pathogen is active.

OTHER DISEASES:

Dollar spot and if the wet and hot conditions prevail Pythium may be active. Scout the turf (foliage and root) thoroughly and frequently during these periods. Do not make assumptions. Summer is here!

Authors: Joe Rimelspach and Mike Boehm