454 FUNDAMENTALS OF FRUIT PRODUCTION 



Ottawa, Canada, red raspberries pinched back in early summer and thus 

 forced to branch, generally yield less than untreated plants. Since 

 Kenyon, Loudon, King, Hansell and Miller (red raspberries) do not branch 

 freely, they should never be summer pinched.*^ The main advantage 

 claimed for summer pinching is that it results in a lower, more compact, 

 bushy plant with mechanically stronger canes than those that are un- 

 headed and unbranched. Consequently they hold up their fruit better 

 and require less trellising. Dewberries which usually require trellising 

 are seldom summer pinched. It is generally agreed that if raspberries or 

 blackberries are to be summer pinched the operation should be performed 

 early, when the shoots are only 18 to 24 inches high or perhaps even 

 before this.^ Pinching higher or cutting back to this point at a later date 

 is likely to result in weak, late-maturing laterals that are especially sub- 

 ject to winter injury and are less likely to give rise the following year to 

 good fruiting shoots. Blackberries and black raspberries generally 

 respond better than red raspberries to summer pinching. Pinching the 

 ends of the growing shoots just before blossoming has been stated 

 to aid sometimes in the setting of fruit in the grape; it is thus a partial 

 remedy for "coulure."^ Bioletti*' mentions pinching as sometimes useful 

 also in protecting grapes from sunburn by causing the shoots, through 

 more rapid lignification, to remain more upright and to furnish more shade 

 for the fruit clusters. But little evidence is available concerning the 

 influence of summer pinching on fruit-bud formation in the grape and at 

 present it cannot be recommended confidently for any effect of this sort. 

 The early and repeated pinching back of shoots of the apple and pear 

 to stimulate the development of fruit spurs and fruit buds has been dis- 

 cussed freely. Thomas^^ states that " by pinching off the soft ends of the 

 side-shoots after they have made a few inches of growth — the sap imme- 

 diately accumulates, and the young buds upon the remainder of these 

 shoots, which otherwise would produce leaves, are gradually changed into 

 fruit buds. To prevent the breaking of these buds into new shoots by too 

 great an accumulation of the sap, partial outlet is left for its escape 

 through the leading shoot of the branch, which at the same time is effect- 

 ing the desired enlargement of the tree. ... It often happens, and espe- 

 cially when the pinching is done too early, that the new buds send out 

 shoots a second time the same season. When this occurs, these second 

 shoots are to be pinched in the same manner as the first, but shorter; and 

 third ones, should they start, are to besimilarly treated." Barry, ^Rivers^^ 

 and others recommend the same treatment for the same purpose and these 

 early authorities have been followed by many later writers. Recently 

 Ballard and Volck^" in California have shown that, by two or three repeated 

 summer pinchings, fruit spurs bearing fruit buds can be developed from 

 watersprouts of the apple in one season. They found also that normal 

 shoots throughout the tree respond in the same way to similar treatment. 



