430 



Bulletin 76. 



to a healthy growth of the Concord grape. Either of these causes 

 might tend to produce shelling. 



That insufficient nourishment does cause grapes to shell is 

 clearly shown in Figure 4. This Catawba cane was found in the 

 vineyard of Messrs. King & Robinson near Trumansburg, N. Y. 

 The first thing which attracted my attention was the light red 

 color of the berries upon the central cluster. They were just 



Fig. 4. — Obstructed flow oj sap the cause of shelling. 



turning, while the clusters on either side were colored a dark 

 red. Upon closer examination the cause of the trouble became 

 apparent. It will be seen in this illustration that the two outer 

 clusters hang directly down from the underside of the cane. The 

 stem of the central cluster, however, is attached on the upper 

 side of the cane and the weight of the fruit has caused the stem 

 to bend at a very acute angle, thus seriously interfering with the 

 flow of sap. 



Another interesting point was soon noticed. The lower berries 



