Last year I suggested that there are differences in large patch susceptibility between Zoysia japonica and Zoysia matrella. A photo of large patch posted last month on the Turf Diseases Facebook page by Dr. Mike Richardson and follow up comments by Dr. Richardson and Dr. Kennelly on the relative lack of resistance they have observed has prompted me to write on this subject again, for all of my observations lead me to believe that there are differences in susceptibility to large patch among zoysia varieties and between zoysia species. Click on the thumbnail images to see photos of large patch on zoysia in Asia, and you will see that the symptoms are most evident on Zoysia japonica:
Why am I convinced that there is some resistance to this disease?
- I've noticed that when Zoysia japonica and Zoysia matrella are growing in the same general vicinity, large patch may be present on Zoysia japonica but not on the Zoysia matrella.
- Research at the Chiba Prefectural Agricultural Experiment Station in Japan has found that there are differences in resistance to large patch among zoysia varieties.
- Dr. Larry Stowell suggested there may be a mowing height effect on the disease where higher cut turf might be more susceptible but a greenkeeper at Japan assures me that at his course it is the Zoysia japonica at fairway height that gets more disease than the higher mown rough.
- Masahiro Kato has published on large patch resistance in zoysia and he found that the differences in resistance among varieties are related to differences in leaf sheath lamination structure.