GRAPE PRUNING AND TRAINING 



307 



when about a foot longer than desired. It is most prac- 

 ticed when the disbudded or shoot-thinned canes have 

 grown excessively long because of the concentration of 

 food in them. Development of laterals is its chief effect. 

 These may be used to form fruit spurs the following sea- 

 son. It is usually done about midsummer ; sometimes twice 

 or thrice. Suckering is the removal of shoots that appear 

 from or near the ground surface. It is most necessary with 

 grafted vines. Water sprouting is the removal of sterile 

 shoots where not needed. Pinching is the removal of the 

 growing tip with finger and thumb. It tends to increase 

 the size of the leaves below. Usually it is done when 

 the shoots are 15 to 18 inches long. Thus the shoots 

 have ample time in which to mature. Defoliating is the re- 



FIG. 266— DIAGRAM OF ORDINARY TRELLIS 

 Note braces A, B, C and devices D used for tightening the wires. 



moval of leaves to expose the fruit better to the sun so as to 

 increase color. It may be largely superseded by an im- 

 proved form of the vine. 



L. Ravaz* summarizes the results of investigations in heading 

 in grapes by declaring that if employed shortly after the flowering 

 season production is increased, but at the expense of quality. 



218. Pinching grapevines.f — Experiments by G, Riviere to de- 

 termine the effect of pinching the flowering shoots of grapevines 

 just before flowering to "no leaves and to 1, 2, 3 and 4 leaves re- 

 spectively beyond the second bunch of grapes, showed upon analysis 

 more or less chemical difference in the composition of the must 

 according to the nuinber of leaves left. The sugar content de- 

 creased approximately in proportion to whether 4, 3, 2, 1 or no 

 leaves were left on the shoot beyond the bunches — 14.5.8 gm. where 

 4 and 70 where none. On the other hand, the acid content increased 

 from 36.3 gm. where 4 leaves were left to 60.5 where none. With 

 the variety studied (Chasselas Dore) it seems advisable where 



* Ann Ecole Nat. Agr. Atontpelier N. Ser. 

 t Soc. Nat. Hort. France, 1907. 



(1912), No. 4, Page 285-323 t pi. 



