61 



reach maturity. So far as heat and cold are involved in temperatures, 

 this criterion is probably nearly correct, the amount of heat necessary 

 to insure a crop of corn being also sufficient to mature most of the va- 

 rieties of cultivated grapes which have been derived from our native 

 northern species ; but the numerous failures in profitable grape cul- 

 ture prove that other factors besides those of heat and cold have an im- 

 portant influence upon the health of a vineyard. 



To those who are conversant with the history of the progress of grape 

 culture in the United States for the past 30 years and have acquainted 

 themselves with the cause of varying failures and successes, it must 

 seem difficult to account for the fact that grape-growers in general have 

 been slow, and apparently unwilling, to recognize the true reason for 

 most of the failures which occur. In some of the earliest reports of the 

 Department of Agriculture the statement was dwelt upon that the 

 greatest obstacle to complete success in grape culture could be referred 

 to the deterioration of the plants consequent upon the injury they sus- 

 tained from mildew on the leaves. This explanation of failure was not 

 generally considered as conclusive. Both grape-growers and authors 

 of treatises on grape culture, especially the latter, usually referred fail- 

 ures to some other cause or causes, which were expressed by the phrase 

 "improper treatment," and this was considered a sufficient answer to 

 all inquiries regarding failures. 



This profound explanation was generally accompanied by the further 

 advice that by giving vineyards " proper treatment" they would be ex- 

 empt from failure or loss. When called upon to define " improper " and 

 "proper" treatment, the answers would be often contradictory, and 

 more frequently unsatisfactory. This want of recognition of the true 

 source of trouble has been greatly against progressive grape culture. 

 Yarieties ot grapes much lauded for their superior qualities have been 

 procured at great expense and extensively planted, the result only add- 

 ing another disappointment to the planter. The main cause of failure 

 has been frequently pointed out, and from time to time the Department 

 has published lists of those varieties best adapted to general culture, 

 as also those which require special localities, and further experience 

 has borne conclusive evidence of the value and accuracy of these re- 

 ports. It was distinctly shown, and it is now clearly admitted, that the 

 distinguishing feature of a good grape climate is that where there is 

 entire absence of mildew on the foliage or on the fruit of the vines. 

 While making this statement prominent it is not forgotten that heavy 

 losses are occasioned by rot in the berry. This disease is not, however, 

 confined to varieties subject to leaf mildew, but it is equally prevalent 

 in those which are rarely attacked by it. We need no stronger proof 

 of the influence that the presence or absence of mildew on the leaves 

 of our native grapes has upon the determination of their value than 

 to turn to the list of the varieties which are most extensively cultivated, 



