"Surfactant WK" for thinning peach blossoms

The surfactant, "Surfactant WK" (dodecyl ether of polyethylene glycol), was applied to peach trees [Prunus persica (L.) Batsch] at full bloom three co nsecutive years. Blossoms died rapidly so that within 1 week dead blossoms could be distinguished easily from live blossoms. There were significant, l inear relationships between concentration of "Surfactant WK" applied and pe rcent blossoms removed, which was determined 1 to 2 weeks after treatment ( R-2 = 0.78***), and fruit set, which was determined 4 to 5 weeks after trea tment (R-2 = 0.86***). Trees were hand thinned according to commercial prac tices after treatment. Cropload, fruit weight and yield were similar across treatments at harvest indicating no negative effects by the chemical on pr oductivity. "Surfactant WK" caused slight limb damage and overthinning at t he highest concentrations. Based on the effectiveness, consistency, and lac k of significant phytotoxicity, "Surfactant WK" demonstrated acceptability as a blossom thinner for peach trees in the southeastern U.S.