Effects of simulated chlorsulfuron drift on fruit yield and quality of sweet cherries ( Prunus avium L. )

Field experiments were conducted at the Irrigated Agricultural Research and Extension Center, Prosser, Washington, in 1992 and 1993 to study the effects of simulated chlorsulfuron (2 chloro‐ N [[(4 methoxy‐6 methyl 1,3,5‐tnazin 2 yl)amino]‐carbonyl]benzenesulfonamide) drift at different reproductive growth stages of three cherry ( Prunus avium L ) cultivars, Rainier, Chinook, and Bing Branches of each cultivar were treated at side‐green, full bloom, postbloom, and pit hardening growth stages with 0, 251 1 × 10 7 , 83 8 × 10 7 , 27 9 × 10 −7 , 9 3 × 10 −7 , and 3 1 × 10 −7 M chlorsulfuron In single‐exposure expetiments, Chinook was adversely affected by the lower levels of chlorsulfuron Bing was not affected by levels of chlorsulfuron below 27 9 × 10 7 M The yield and quality of fruit decreased significantly with the increase in chlorsulfuron concentrations applied at full bloom and postbloom stages Reduction in yield was correlated with the severity of injury symptoms on leaves In the multiple exposure experiments, fruit yield, fruit size, and color were significantly reduced by increasing chlorsulfuron concentration and number of exposures Average firmness of fruit increased with increases in chlorsulfuron concentration The data suggested that multiple exposures of a susceptible cherry cultivar to low levels of chlorsulfuron at full bloom and postbloom stage can reduce fruit yield and delay maturity of cherries while increasing fruit firmness