300 



PRINCIPLES AND PRACTICE OF PRUNING 



rapid. It continues until the new growth can elaborate 

 more food than is needed for its maintenance. 



Hence if vines are pruned immediately after the leaves 

 drop the cuttings are in best possible condition for prop- 

 agation. A month later they will not be so good for 

 such purposes, but the largest proportion of food will have 

 been saved in the roots to develop the new spring growth. 

 If pruning is delayed until spring, large quantities of the 

 reserve food will be lost in the prunings. Therefore, 

 vines pruned then will develop poorer shoots, but a 

 better set of fruit. 



Vidal also concludes* from three years' experiments that, other 

 conditions being equal, the time of pruning modifies only slightly 



the number of 

 bunches borne. 

 With extremely 

 late pruning the 

 bunches are more 

 vigorous and the 

 proportion of im- 

 perfect bunches 

 and aborted flow- 

 ers is less. The 

 individual ber- 

 ries are larger, 

 heavier and more 

 numerous. The 

 growth is more 

 rapid for late 

 pruned vines and 

 continues for a 

 longer time. The 

 vegetation is at 

 times diminished 



FIG. 259 VINES HEADED BACK FOR VARIOUS SYS- 

 TEMS OF PRUNING 



A, The spur and the fan systems; B, the four-arm re- 

 newal system; C, the two-arm Kniffin, Munson, um- 

 brella and overhead systems. 



and at times in- 

 creased by spring 

 pruning just as in 

 winter pruning 

 These positive or 

 negative variations in vegetation progress or retrogress in more or 

 less regular order with the progression of the time of pruning. The 

 prunings were made at intervals between January 1 to about Ap-il 

 1"). With vines pruned after mid-February, the later the pruning 



Compt. Rend. Acad. Sc-i. No. 17, Page 1,192. 



