Application of (2-chloroethyl)phosphonic acid (ethephon) reduced fruit removal force (FRF) as much as 50% depending on concentration and time of application. Reduction in FRF allowed reduced mechanical harvesting vibration frequency which reduced damage to berries during harvest and thus increased shelf-life. Mechanical harvest was further facilitated by ethephon-induced color development and hastening of abscission which reduced the number of machine harvests required.
Received for publication September 3, 1974. Michigan Agricultural Experiment Station Journal Article No. 6952. The authors would like to thank J. W. Nelson, Michigan Blueberry Growers Association for help with plot harvesting and P. Jones and R. Bodke for allowing portions of the research to be done in their plantations with their mechanical harvesters.