Some Grape Troubi.es of Western New York. 431 



of the cluster separated in the same manner as that which takes 

 place in the case of shelling ; most of the berries parted regularly 

 from the stem as if cut with a knife. The berries on the neigh- 

 boring cluster parted in a different manner, for the connecting 

 fibres remained attached to the peducle, as shown in the figure. 

 Here was positive proof that improper nourishment caused a 

 marked weakening in the connection between berry and stem, and 

 undoubtedly it was merely a matter of a short time before the 

 berries would have shelled as completely as some others in the same 

 vineyard were doing. With the others, however, it seemed to be a 

 clear case of overbearing, which to the fruit is nothing more than 

 a want of proper food. 



15. Want of barnyard manure. — This cause for the trouble is 

 here mentioned because Mr. H. B. Clothier, of Forestville, N. Y., 

 assures me he has stopped the shelling by the use of barnyard 

 manure which was taken from the stables of horses fed with grain. 

 The use of stable manure, however, has not always been followed 

 by such satisfactory results, and it may and sometimes does do 

 injury by promoting an excessive growth of wood. 



16. Want of phosphoric acid. — The lack of this substance in 

 available form in the soil has been advanced as a possible cause 

 of the grapes shelling. The use of phosphorus to the plant is 

 very imperfectly understood. It is supposed to assist in the diffu- 

 sion of soluble albuminoids, or those compounds which contain 

 nitrogen. Nothing definite can be said of the relations existing be- 

 tween the shelling of grapes and the action of the phosphates. 



17. Want of potash. — Probably more vineyardists agree upon 

 attributing the shelling of grapes to a want of potash than they 

 do upon any other cause advanced. There are several facts which 

 favor the theory. 



Potash is an essential element of plant food. Experiments 

 carried on by Nobbe, Schroeder, and Krdmann* seem to prove con- 

 clusively that the office of potash in the plant economy is to assist 

 in the formation of starch. Plants of Japanese buckwheat were 

 grown in a solution free from all traces of potash. After a few 



*Versuchs-Stationen, xiii. 1870, p. 357; cited by Goodale, Physiological 

 Botany, p. 252. 



