Chemical defoliation of fruit trees

Trees in most mature peach, nectarine, and plum orchards in the southern San Joaquin Valley cease growth by early to mid-October. Because the foliage often persists on the trees for another three to five weeks and interferes with the pruner's vision, it is impractical to start annual pruning immediately. Thus, any means of stimulating defoliation in mid-October that would allow an earlier start on pruning could become an important factor for progressive farm labor managers. Under normal conditions, many farm laborers are idle from mid-October through mid-November, because harvest of most other crops is nearly completed. The availability of defoliated trees by mid-October would provide work when the unemployment rate is high and would extend the period over which dormant pruning could be accomplished.