Tuesday, November 6, 2007
171-7

Safening of Aryloxyphenoxy Propionate Herbicides by Triclopyr on Zoysiagrass.

Dustin F. Lewis1, J. Scott McElroy2, and Greg Breeden2. (1) Plant Sciences, University of Tennessee, 2431 JOE JOHNSON DR., 252 PLANT SCIENCE BLDG., knoxville, TN 37996-4561, (2) 2431 Joe Johnson Dr, University of Tennessee-Knoxville, University of Tennessee, Plant Sciences Dept./ 252 Plant Sciences Bldg, Knoxville, TN 37996-4561

Bermudagrass (Cynodon dactylon) is a difficult weed to control in zoysiagrass (Zoysia spp.) fairways.  Both are warm-season grasses that react similarly to herbicide treatments.  Although it has been reported that bermudagrass can be suppressed by using fluazifop and fenoxaprop, zoysiagrass injury can occur.  When these herbicides are tank-mixed with triclopyr, bermudagrass suppression occurs with decreased injury to zoysiagrass.  Other aryloxyphenoxy propionate herbicides could potentially provide greater control of bermudagrass in zoysiagrass turf.  Research was conducted to evaluate sequential applications of fluazifop (0.11 kg ai/ha), fenoxaprop (0.14 kg ai/ha), quizalofop (0.09 kg ai/ha), and cyhalofop (0.32 kg ai/ha) applied with and without triclopyr (1.12 kg ai/ha) to bermudagrass and zoysiagrass turf.  Fluazifop and fenoxaprop without triclopyr injured zoysiagrass unacceptably (>20%), but injured zoysiagrass <5% when applied with triclopyr.  Quizalofop alone injured zoysiagrass to an excessive level (>50%).  Cyhalofop alone did not injury zoysiagrass unacceptably (<20%).  While injurious alone, fluazifop, fenoxaprop, and quizalofop were all safened by triclopyr when applied to zoysiagrass turf.