RESPONSE OF WINTER INJURED PEACH TREES TO TIME AND SEVERITY OF PRUNING

Authors: Miller, Stephen; BYERS, ROSS - VA TECH VPI AND STATE UNI

Submitted to: Annual Cumberland Shenandoah Fruit Workers Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/1/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Peach trees in the mid-Atlantic region and west to Illinois are often subjected to low winter temperatures which result in significant damage to fruit buds and the tree's woody tissue. Peach growers are generally uncertain how to prune these winter injured trees. In January 1994 peach trees in the eastern panhandle of West Virginia experienced three successive nights of low temperatures which resulted in 100% bud kill and moderate injury to woody tissue. In the spring a replicated study was begun applying four levels of pruning at three timings (April, May, and June) to determine the best time and how severely these winter injured trees should be pruned. The results 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. No economic advantage could be detected from "dehorn" pruning (a severe level of pruning) which is sometimes recommended. This information will be valuable to extension fruit specialists and peach growers in areas where winter injury is a common occurrence.

Technical Abstract: The objective of this study was to examine several pruning levels in the spring of 1994 at various times after a January freeze on tree survival, quality of regrowth, yield, and fruit size in the subsequent year. Seven- year-old 'Blake'/'Lovell' peach trees were subjected to four pruning levels (none, light, heavy, and dehorned) each at three times (April, May, and June) in a factorial arrangement. Dehorned pruned trees had the lowest canopy growth among all levels of pruning. Canopy fruiting wood quality ratings taken in March 1995 were greater for trees pruned in April or May, than trees pruned in June. All levels of pruning produced higher wood quality ratings than non-pruned trees. Returns per tree and per acre were highest for early pruned trees (April and May) and trees which had received either light pruning or heavy pruning in 1994. The results of our 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 as a method of handling winter injured peach trees even though it may produce a high quality of wood since canopy volume is severely reduced leading to a significant reduction in the number of fruits produced.