MILDEW. 139 



sites, ever ready to fasten on enfeebled and failing vegetation, 

 finding conditions more or less favorable to their development, 

 begin to appear. Having become once established, tbey prey 

 upon the vine, make it yet more feeble, and hasten its destruc- 

 tion. There are some vines of so delicate and feeble a constitu- 

 tion that parasitic fungi find in them a congenial soil, and may 

 be surely expected, sooner or later, to appear ; but in vines of a 

 robust constitution, Uke the Chnton, Concord, and many others, 

 where we find these parasitic fungi in the form of mildew present, 

 we may be sure that some cause is at work which has enfeebled 

 and injured the health of the vine. Overbearing is a very com- 

 mon cause of sickly and enfeebled viues ; injudicibus pruniug, 

 especially late fall pruning, and severe summer pruning are, in 

 this climate, also a prolific source of injury to the vigor of the 

 vines. It may be necessary, in order to restore the vines to 

 health, to destroy the fungi that are feeding upon them ; but, 

 unless the other enfeebling causes are removed also, and the vine 

 wholly restored, these fungi will continue to appear year after 

 year, in spite of aU. applications of sulphur or other substances 

 destructive to them, and in the end the vine wUl perish. 



Mildew should, therefore, be usually regarded as an indication 

 of want of perfect health in the vine, and the cause of that 

 failure of health be dUigently sought for, and, if found, promptly 

 removed. Some of the causes have been indicated, but there are 

 others, and some of these it is not possible to remedy. The vines 

 of Europe thrive here for a few years, but the extremes of tem- 

 perature in our climate are too severe for their constitutional 

 vigor ; they become gradually enfeebled, mildew makes its ap- 

 pearance, destroys the foliage so that the wood cannot ripen, 

 sad the next winter they are irretrievably ruined. Flour of 

 sridphur dusted upon the leaves is the best known agent for the 

 destruction of the mildew. 



