Rhizomes of zoysiagrass (Zoysia spp.) were subjected to controlled freezing tests in Jan. and Mar. 1993 and 1994 to determine their low-temperature tolerance. In 1994, `Belair', `Korean `Common', `Meyer', and `TGS-W10' rhizomes survived temperatures as low as -18 °C, while rhizomes of `Sunburst' survived -14 °C. `Cavalier', `Crowne', `Palisades', `Emerald', and `El Toro' were killed at -10 °C or warmer temperatures. Entries surviving exposure to -14 to -18 °C in 1994 controlled freezing tests received post-winter survival ratings in the field of 6.7 to 8.7 (9 = 100% green). Entries killed at higher freezing test temperatures were slower to recover after winter in the field, with ratings of 2.0 to 3.0. Shoot number produced after freezing was a better measurement for assessing low temperature tolerance than was shoot mass. Controlled freezing tests, using regrowth as a measure of hardiness, appear to be useful for identifying low temperature tolerance of zoysiagrasses in the early years of a field study.
J.H. Dunn, S.S. Bughrara, M.R. Warmund and B.F. Fresenburg
J.H. Dunn, D.D. Minner, B.F. Fresenburg and S.S. Bughrara
We evaluated the effect of fertilization treatments in combination with clippings disposal on perennial ryegrass (Lolium perenne L.) in two adjacent locations. Clippings left on turf during mowing decreased dollar spot (Sclerotinia homoeocarpa F.T. Bennett) in both locations during three summers compared with clippings removed in mower baskets. However, brown patch (Rhizoctonia solani Kuhn) increased during July and Aug. 1995 when clippings were left on turf. Dollar spot was more severe with N (kg·ha–1·year–1) at 120 compared to 240; brown patch was more severe at 240. While clippings disposal had significant effects on disease incidence, implementation may not be practical because of the contrary responses of the observed diseases to this management approach.