Effect of temperature and heat units on zoysiagrass response to herbicides during post-dormancy transition

Abstract In the transition zone, turfgrass managers generally utilize dormancy period of warm-season to apply herbicides for managing winter annual weeds. Although this weed control strategy is common in bermudagrass, it has been less adopted zoysiagrass ( Zoysia spp.) due variable injury during post-dormancy transition. Previous research reported that air temperature could affect and crop safety from herbicides. Growth chamber studies were conducted evaluate response glyphosate glufosinate as influenced by three different regimes after treatment. A field study was at four-site years assess influence heat unit accumulation on seven growth study, injured more than reduced time reach 50% green cover reduction, regardless rate when incubated 7 d under levels. When sprigs 10 C, reduction slowed both herbicides; however, rapidly 27 C. After incubating treated plugs having 5% C 14 d, glyphosate-treated reached 22 similarly nontreated but 70 required glufosinate-treated plugs. Zoysiagrass dependent, unacceptably regime. Diquat, flumioxazin, glufosinate, metsulfuron+rimsulfuron 200 or 300 growing-degree-day base 5 (GDD 5C ) application timings, foramsulfuron oxadiazon did not injure GDD . The relationship leaf density turf dependent mowing height metrics are injurious Research indicates injures glyphosate, speed magnitude herbicide increases with temperature.