NECROSIS OF THE GRAPE VINE 



In drawing the ordinary implements of grape-culture through the 

 vineyard, occasional vines are caught and broken off or their roots 

 are torn loose, so that nearly every year new vines must be set out 

 to replace them. Viticulturists, in a few localities, have noticed that 

 not all of the vines that have to be replaced are broken loose but that 

 they have " just died," while in those sections where the grape-root 

 worm is present all such losses are laid to this insect pest. 



INTRODUCTION 



From a careful examination of vineyards in three of the large grape- 

 growing regions of the State (Chautauqua, Keuka Lake and Niagara 

 Triangle), the writer feels safe in saying that a large percentage (per- 

 haps 50%) of vines whose death is attributed to root worm, or "just 

 died," is due to some other cause. The fact that vines die in a similar 

 manner in regions in which there is no root worm goes far to show 

 that the root worm may not after all be responsible for everything 

 attributed to it. Examination of such dead vines fails to reveal any , 

 root trouble or any insect or borer in the stem, but if microscopic 

 examination of a thin section of the stem be made it will be found 

 that a fungus is growing there, plugging up the sap tubes, slowly 

 destroying the living tissue and eventually killing the vine. 



Since there appears to be an organism responsible for the dying of 

 these vines, it becomes the duty of the plant pathologist to learn the 

 life history of the organism, the conditions of its life and growth, its 

 means of entrance into the stem of the vine as well as to devise or 

 discover preventive measures. From conversation with vineyardists 

 (many of whom have been met at the various fairs), the writer has 

 found that nearly all are acquainted with the general characters of 

 the disease but that relatively few practical growers recognize this as 

 a disease, much less give any thought to a means of prevention or 

 control. 



It requires much time to work out in detail all of the points in the 

 life history of a fungous parasite, but the importance of this disease 

 to the vineyardist seems to warrant the publication of a preliminary 

 report in order, first, to call attention to the disease; second, to obtain 



