The Effects of Ethephon on Thompson Seedless Grapes and Raisins

Ethephon applied at veraison, or seven to 10 days before or after this stage, increased soluble solids .6 to 1.2°Brix in five of six trials. A concentration of 150 ppm was generally the most effective. Except for one trial, response was similar for application dates. Raisin grades were improved with ethephon in two of the three trials in which raisins were made.