PRUNINd WITH SPECIAL REFERENCE TO PARTICULAR FRUITS 469 



apply to the priming of many other fruit phmts, but not to the same 

 extent that they do to the grape. In practice perhaps the best way of 

 determining the severity of pruning is, following a suggestion of Hed- 

 rick,2^ to figure the problem for each vine on a mathematical basis. He 

 says in reference to varieties of the Labrusca and Labrusca-hybrid types: 

 "A thrifty grape-vine should yield, let us say, 15 pounds of grapes, a 

 fair average for the mainstay varieties. Each bunch will weigh from 

 a quarter to a half pound. To produce 15 pounds on a vine, therefore, 

 will require from 30 to GO ])unches. As each shoot will bear two or three 

 bunches, from 15 to 30 buds must be left on the canes of the preceding 

 year. . . . Pruning, then, consists in calculating the number of bunches 

 and buds necessary and removing the remainder." As some of the fruit- 

 ing shoots may be broken off incident to the work of cultivation, spraying 

 or other vineyard operations, it may be well to leave a few extra fruit 

 buds; this matter, however, can be overdone easily. 



Special mention should be made of the variation in the relative 

 amounts of pruning to be given vines of any given variety, not only with 

 their age and the conditions of soil moisture and fertility but, in grafted 

 vines, with the stocks on which they are grown. Certain stocks have the 

 reputation of producing shy-bearing vines, though actually they are 

 unproductive only when pruned too closely. 



Another point already mentioned is the provision that should be made 

 for the production of properly placed new shoots on which fruit buds for 

 the following crop can form. In practice this "proper distribution" 

 generally involves their location as near the head of the vine as possible, 

 so that the fruiting wood is not pushed out unnecessarily each season; 

 thus the plant is kept compact. In many varieties this is secured by 

 retaining the lowest or basal cane (fruiting shoot of the preceding season) 

 on each arm or spur and pruning away those originating farther from the 

 head. In certain other varieties, however, the fruiting shoots develop 

 only from buds at nodes some distance from the base of the canes and the 

 more basal buds remain dormant when the heading back is light enough 

 to permit the development of fruiting shoots. Pruning varieties with 

 such growing and fruiting habits in the way just described would quickly 

 carry the bearing surface of the vine far from its head and necessitate 

 frequent resort to pi-uning like that called dehorning in tree fruits. The 

 usual method of handling vines of this type is each year to prune lightly 

 or moderately certain canes for fruit production, leaving them with the 

 requisite number of fruit buds and to prune severely other canes so that 

 all their fruit buds are removed and they are forced to develop vegetative 

 shoots from their basal buds. These vegetative shoots then become the 

 fruiting canes of the following year, while those that have borne fruit 

 are entirely removed. These much shortened canes are spoken of as 

 "renewal spurs." 



