422 Bulletin 76. 



appearance. The following are the more important of these pos- 

 sible causes : 



1 . Insects. 



2. Fungi. 



3. Blight of the foliage. 



4. Stems shrivel before the berries mature. 



5. Berries prematurely ripe. 



6. Premature ripening of the wood. 



7. Overbearing. 



8. Too much wood and foliage. 



9. Too rich land. 



10. The kind of soil. 



11. Too much cultivation. ^ 



1 2 . Excessive drought . 



13. Excess of moisture after drought. 



14. A weak root system. 



15. Want of barnyard manure. 



16. Want of phosphoric acid. 



17. Want of potash or of some other element. 



18. Excessive heat. 



19. South wind. 



20. West wind. 



Such a variety of opinions regarding the causes that produce 

 the shelling of grapes should include some at least which offer 

 the true solution of the problem. Before considering the list in 

 detail, it may be convenient to divide these opinions into groups, 

 basing the division upon the close relationship existing between 

 many of them. They fall readily into four groups, as follows : 

 I. Injuries caused by parasites : embracing Nos.1-3. 

 II. Improper condition of the vine : embracing Nos. 4-9. 



III. Condition of the soil : embracing Nos. 10-17. 



IV. Condition of the atmosphere : embracing Nos. 18-20. 

 The various opinions will be considered individually so that 



their real value may be properly estimated. 



