12- 



Its Place in Massachusetts Apple Orchards 



Performing dormant- type pruning during the summer has a place 

 in young apple orchards as a means of tree training. However, 

 summer pruning is laborious and certainly of doubtful value under 

 Massachusetts conditions as a direct stimulus for flower bud ini- 

 tiation on axillary spurs and shoots. To the contrary. Dr. G. E. 

 Stembridge at Clemson University, Clemson, South Carolina, obtained 

 substantial flower bud initiation following stubbing of 4-year-old 

 Delicious/106 in early summer, 1974. Furthermore, many of the 

 axillary spurs and shoots produced by late summer pruning initiated 

 flower buds in 1975. Stembridge stated in correspondence that he 

 thought the extra flowers produced by summer pruning were relatively 

 inconsequential to the productive capacity of the tree. A more 

 important consequence of the summer pruning was the removal of 

 unwanted vigor and better light penetration. In South Carolina, 

 growing conditions are probably more favorable for flower bud ini- 

 tiation following summer pruning than in Massachusetts. To the con- 

 trary, the problem of controlling vigor is probably less acute in 

 Massachusetts than in South Carolina. 



Basically, Delicious is our only cultivar with which we have 

 problems of adequate fruitfulness on young trees whereas tree crowd- 

 ing and low fruit Ca is a problem with different cultivars in many 

 bearing orchards. Mid-July through early-August seems a suitable 

 timing for summer pruning to restrict vegetative growth; when prac- 

 ticed to increase fruit Ca, early August may be best. 



Many answers are needed concerning the responses of our major 

 cultivars before we can suggest this procedure on other than a trial 

 basis only. Summer pruning is very laborious when done with hand 

 shears, thus one of the questions is, "Can it be performed with a 

 mechanical tree hedger?". 



It certainly is possible that Rome and Cortland, which produce 

 part of their crop on 1-year-old wood, may not show favorable 

 responses to summer pruning if a high percentage of current season's 

 shoots are removed. Furthermore, we need to know the influence of 

 summer pruning on sun scald of fruit, and fruit maturity and keep- 

 ability in storage. 



Research on summer pruning is being conducted in many fruit 

 growing areas and many questions concerning the practice will be 

 answered. Meanwhile, we urge caution to the growers currently 

 experimenting with summer pruning . 



**************** 



