Ethrel sprays were applied to Concord grape vines on September 4, 11, 19, and 26, 1968 in concentrations varying from 10 to 2000 ppm. At daytime temperatures averaging 69.7°F Ethrel promoted the abscission of berries in six days or less at 250 ppm and higher. Daytime temperatures of 63°F or higher prior to normal harvesting appeared necessary to activate berry abscission in six days or less. Concentrations of 250 ppm and higher induced leaf yellowing and accelerated leaf senescence. Berries removed easier when shaken off at 77°F than at 62°F. Grapes receiving a foliar application of 250 ppm of Ethrel 14 days before harvest removed easier than those receiving 500 ppm Ethrel applied six days before harvest when both were shaken off the same day. Ethrel resulted in no differences in fruit soluble solids, titratable acidity, pH and color determinations. There was no response from dipping only clusters in Ethrel. A minus 11°F on December 30 caused serious bud damage on vines sprayed on September 4 at 2000 ppm, compared to non-sprayed vines.