PRUNING BEARING APPLE TREES 13 



This table shows that heavy pruning has rather consistently reduced yields. 

 All varieties when heavily pruned show less gain in the second or differential 

 pruning period than the unpruned trees and less than the lightly pruned trees 

 except in the case of Gravenstein. Comparisons of the lightly pruned trees with 

 the unpruned trees are conflicting. Rhode Island Greening and Baldwin show 

 greater gains when lightly pruned, while the unpruned Russet and Gravenstein 

 trees gained more than the lightly pruned trees. Too much reliance should not 

 be placed on these differences, but it may be safe to conclude that light pruning 

 has had little effect on the yield of these trees while heavy pruning has reduced 

 yields. 



Effect of Pruning on Size, Color, and Blemishes 



It is generally believed that it is very difficult or impossible to control insects 

 and diseases in unpruned trees and that red varieties do not color well unless 

 pruned. Data are available from only two of these orchards. Both have been 

 sprayed according to the usual program with power outfits. No attempt has been 

 made to measure the amounts of spray mixture used, but the time required to 

 spray unpruned trees was no greater than that to spray pruned trees. It seems 

 fair to assume that the rate of discharge of liquid was fairly constant and that 

 there could have been no great differences in the amount of spray material used. 

 Not all the data that have been collected are presented here because little would 

 be added to the record. The trend is the same as shown in the tables that are 

 given. 



Whenever time permitted, the apples from these orchards were graded accord- 

 ing to the Massachusetts or the United States Grading Laws. The rules followed 

 in different years were not exactly the same, but each year the apples were sep- 

 arated into three grades and culls. Of course, the same rules were applied in 

 each year to all apples from trees with different pruning treatment. Some of 

 these results are shown in Tables 10 and 11. 



Table 10. — Effect of pruning on grade and size of fruit — Clark 

 Orchard, 1933. 



Percentage of Apples in Percentage of Apples in Each Size, 



Each Grade first and second grades only 



