(Megan Kennelly, KSU Plant Pathology)
If you manage zoysiagrass and have a history of large patch, you are undoubtedly already thinking about this disease, and maybe you just put out an application or are getting ready to do it soon.
There is some great info about large patch control at this link, starting on page 14.
We’ve done quite a few trials at KSU over the years, and our results match pretty closely with the efficacy data shown at the above link. Regarding timing, we’ve had good control from most application timings in September.
Large patch tends to be in the same areas from one year to the next, so one option is to map out “hot spots” and focus on those.
In addition to large patch management, it is also time for large patch inoculations for research. Yup, most of you want to get rid of large patch. Here at KSU, we want MORE! I’m working with PhD student Mingying Xiang and Dr. Jack Fry in collaboration with Texas A&M, Purdue, University of Arkansas, and other universities to screen zoysiagrass breeding lines for disease resistance and agronomic traits as part of a USGA-funded project. We recently inoculated plots with the fungus that causes large patch disease. We cultured the fungus in the lab, grew it out on sterilized oats in glass jars, and then hauled our tailgate-of-death-and-destruction out to the field. To inoculate, we put the colonized oats just below the thatch. We might see some symptoms this fall, otherwise we definitely should see patches by spring. We will measure disease severity using digital images and other methods. We are hoping to find some breeding lines with good resistance. As we all know, starting with a resistant variety is the foundation of integrated pest & disease management.
“My knees are getting tired from all this crawling”
No, that is not our snack. Those are jars of the fungus growing on oats. Yum!
We dig just barely down into the soil and place the oats, then put the flap of grass back down.
Even after one (rainy) night, there was already new mycelium growing off the oats.