Monday, November 5, 2007 - 9:50 AM
72-9
Spray Adjuvants Influence Bispyribac-sodium Efficacy for Annual Bluegrass Control In Cool-Season Turfgrass.
Patrick McCullough, Dept. of Plant Biology and Pathology, Rutgers Univ., 59 Dudley Rd, New Brunswick, NJ 08901 and Stephen Hart, Foran Hall, 59 Dudley Rd., Rutgers State University Accounts Payable, Rutgers University, Department of Plant Biology & Pathology, New Brunswick, NJ 08901.
Field and laboratory experiments were conducted in New Jersey to investigate the influence of spray adjuvants on foliar absorption and efficacy of bispyribac-sodium for annual bluegrass control in creeping bentgrass and perennial ryegrass. In laboratory experiments, 14C-bispyribac-sodium without an adjuvant had 25% foliar absorption by eight hours after treatment while absorption increased to 45, 46, and 75% when applied with crop oil concentrate, non-ionic surfactant, and methylated seed oil, respectively. In creeping bentgrass fairways, annual bluegrass control increased with bispyribac-sodium rate while the addition of a non-ionic surfactant and methylated seed oil enhanced control 10 to 15% from the herbicide without an adjuvant. In perennial ryegrass, annual bluegrass control ranged 29 to 93%, 45 to 100%, and 76 to 100% from five rates of bispyribac-sodium applied with no adjuvant, methylated seed oil, and a non-ionic surfactant, respectively. Spray adjuvants did not exacerbate perennial ryegrass discoloration from bispyribac-sodium while the addition of adjuvants exacerbated creeping bentgrass discoloration one week after the second application in one of two years. Overall, spray adjuvants appear to enhance bispyribac-sodium efficacy for annual bluegrass control in cool-season turf.