Response of Winter-injured Peach Trees to Pruning
Seven-year-old `Blake'/`Lovell' peach [Prunus persica (L.) Batsch] trees were subjected to four pruning levels (none, light, heavy, and dehorned) each at three times (April, May, and June) in a factorial arrangement following freezing injury in January 1994. Pruning had a significant effect on canopy height, canopy volume and fruit yields. Peach trees pruned in April or dehorned (severe pruning) had less canopy volume in the first fruiting season (1995) after the pruning treatments were initiated than trees pruned in May or June and light or heavy pruned trees. In 1995, yields were lower for trees pruned in June, nonpruned or dehorned trees in 1994. These treatments also produced fewer large fruit at harvest and thus reduced dollar returns per hectare in 1995. In 1996, fruit numbers and fruit sizes did not differ among treatments, but dehorned trees had lower returns per hectare because trees were smaller. The results of this study indicate that peach trees subjected to moderate winter injury should be pruned no later than 2 to 3 weeks after bloom using a heavy level of pruning. There appears to be no economic advantage to dehorn pruning even though canopy volume can be reduced resulting in a smallertree with high quality wood. The results clearly illustrate the long-term negative effect of dehorn pruning on yields resulting from reduced canopy volume. Mean number of cankers per tree increased over time from 1995 through 1998, but pruning treatments did not affect the number of cankers produced. Pruning treatments did affect the size of cankers and the number with visible gumming.