Virginia Turf
@vaturf, #vaturf
Large Patch in Zoysiagrass Lawns
This scenario comes from Fairfax Co. Virginia Cooperative Extension Agent Adria Bordas. Drs. Goatley and McCall, one of our Master Gardener Volunteers did some traveling in September and upon returning home discovered brown patches in their lawn. They mowed the grass and expected the patches to clear up. However, they have continued spreading and now they count over 200 brown spots in their lawn. There's no evidence of grubs or weevils, no pattern or history of chemical use. It looks like and behaves like a disease. However, I have never encountered disease problems in zoysia and don't understand what or why it would be present in September/October. Do either of you have any thoughts on this (see attached photos)?
Virginia Cooperative Extension materials are available for public use, reprint, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University. Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, s Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; M. Ray McKinnie, Administrator, 1890 Extension Program, Virginia State University, Petersburg. Disclaimer: This information is for educational purposes only. Any commercial products named in this publication are for informational purposes only. Virginia Cooperative Extension does not endorse these products and does not intend discrimination against other products which also may be suitable.
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Virginia Turf
@vaturf, #vaturf
Mike Goatley (@vaturf) responds: Great images! That looks like classic ‘large patch’ on zoysiagrass. The disease is incited by Rhizoctonia solani... same causal agent as brown patch on tall fescue, but instead of the warm, wet weather timing on fescue it attacks warm season grasses during their cool, wet 'stress' periods of fall and spring. The arrival of some fall moisture provided an ideal environment for the disease. The lesions on the leaves in the 3rd image are classic ‘brown patch' symptoms that you are used to seeing on tall fescue. The turf usually recovers (as appears to be seen in 1st image with green stems reappearing in the patch area) but symptoms can remain for a long time because of how slow zoysia grows. I will let Dr. McCall dive further into the diagnosis and control alternatives. David McCall (@vtturfpath) responds: Yes, this absolutely looks like large patch to me. It has been fairly active over the last few weeks with the rains in the area. Mike is correct that it usually doesn’t cause a lot of long‐term damage, but will be visible for quite some time. Depending on expectations, it may be worthwhile to treat the lawn with a fungicide this fall (very soon). It won’t have much impact for this fall since it is about to enter dormancy, but should benefit in the spring. If you don’t treat this fall but want to instead treat in the spring, the treatment should go down very soon after breaking dormancy. If making a curative application in the spring, expect to stare at the damage for four or five weeks! Consult the Virginia Pest Management Guide for Lawns (pubs.ext.vt.edu) for a complete list of possible fungicide treatments available to homeowners. There are several formulations of azoxystrobin available to homeowners. Heritage G is an excellent granular product that is available for homeowners at specialty lawn and garden centers. Combination products that include a QoI product (active ingredients such as azoxystrobin or fluoxastrobin) plus a DMI‐class fungicide (active ingredients such as propiconazole or myclobutanil) are also strong. These are four common fungicide active ingredients available to homeowners. Also remember that lawn care professionals have a wide array of registered products available to them for treatment if the homeowner wishes to use an outside source.
Virginia Cooperative Extension materials are available for public use, reprint, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University. Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, s Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; M. Ray McKinnie, Administrator, 1890 Extension Program, Virginia State University, Petersburg. Disclaimer: This information is for educational purposes only. Any commercial products named in this publication are for informational purposes only. Virginia Cooperative Extension does not endorse these products and does not intend discrimination against other products which also may be suitable.
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