322 GRAPES, STRAWBERRIES, BUSH FRUITS 



trating the energy of the plant into a few well-developed 

 clusters. The fruit of the grape is borne upon canes of the 

 present season's growth, which are produced from buds 

 on canes of the past season's growth. The spur system, 

 which simply consists in the pruning back of each cane of 

 the past season's growth to one or two buds, is the simplest 

 system and probably the most common method of pruning. 



The renewal system is generally practiced by the com- 

 mercial growers of our native species. Four of the past 

 year's canes are retained. Each of these is pruned part 

 way back, leaving from six to ten buds on each. Two 

 of these are trained upon the upper wire about five feet 

 from the ground and two upon the lower about three feet 

 from the ground. The buds upon these canes produce the 

 new shoots that bear the fruit. 



The grape should be pruned either during the late winter 

 or very early spring, as injury may be caused by pruning 

 in late spring after the sap has begun to flow. Some- 

 times summer pruning is practiced, which consists in cutting 

 back some of the most vigorous canes, rubbing off all 

 suckers that have started from the base of the roots, 

 and pinching off the side shoots of the canes that are to 

 be reserved for the following year. 



Insects and Diseases. -- The black rot is the most 

 serious fungous disease of the grape, although the downy 

 mildew and the powdery mildew are also often injurious. 

 The grape cane borer, the flea beetle, the rose chafer, the 

 grape berry moth, the leaf hopper, and the phylloxera, or 

 root louse, are destructive insects of this fruit. 



The grape rot appears as brown, circular, decayed spots 

 on the berries, which soon spread over the entire fruit. 

 Infected berries soon shrivel and turn black. The downy 



