Summer Pruning, a Continuing Look at 

 the Benefits 



Wesley R. Autio and Duane W. Greene 



Department of Plant & Soil Sciences, University of Massachusetts 



Since 1986, we have promoted the use of summer 

 pruning as a partial alternative to the use of Alar™ 

 in Mcintosh apple production in New England. We 

 have shown that it increases the development of red 

 color. Additionally, summer pruning results in 

 earlier development of red color, allowing an earlier 

 than normal harvest, and thus leaving fewer fruit on 

 the tree which may drop later in the season. (See the 

 article on page 20 of this issue for additional benefits 

 of summer pruning.) In previous Fruit Notes articles 

 [52(3):7-8; 53(2):1; 53(3):l-2) we discussed some of 

 the practices and economics of summer pruning. In 

 this article we shall continue this discussion by 

 including direct comparisons of the value of summer 

 pruning with the use of Alar and NAA as drop- 

 retarding chemicals. 



In 1988, seven 6-tree blocks (replications) of 25- 

 year-old Rogers Mclntosh/M.7 were selected at the 

 University of Massachusetts Horticultural Re- 

 search Center in Belchertown. Alar (1000 ppm) was 

 applied to 2 trees in each block on July 10. NAA (10 

 ppm) was applied to 2 trees in each block after the 

 first harvest on September 18. Two trees in each 

 block did not receive a chemical treatment. In each 



block one of the Alar-treated trees, one of the trees 

 scheduled to receive NAA, and one of the non-treated 

 trees were summer pruned on August 1. Commer- 

 cial harvests were performed on September 17 and 

 27. Twenty fruit were sampled at each harvest for 

 fruit weight determinations. Additionally, 1 bushel 

 of fruit was taken from each tree at each harvest, 

 kept at 32°F for 3.5 months, and graded. The 

 economic value of these treatments was compared by 

 constructing a partial budget. Fruit values of $15, 

 $12, $8, $2.50, and $1.50 per bushel for Extra Fancy, 

 Fancy, Number 1, Utility, and processing grades, re- 

 spectively, were used. From the value of the crop, 

 the costs of both summer and dormant pruning were 

 subtracted at the rate of $ 7 per hour. Costs of $75 per 

 acre for Alar and $8 per acre for NAA were sub- 

 tracted. A value of $10.50 per hectare for the labor 

 and equipment costs associated with spray applica- 

 tion was subtracted. Yield-related costs for harvest- 

 ing of $1 per bushel and for storing and packing of $4 

 per bushel were also subtracted from the total value. 

 The resultant number does not reflect profit but 

 gives a means of comparing the treatments. 



As we have reported previously, summer prun- 



Fruit Notes, Winter, 1991 



27 



