New York Agricultural Experiment Station. 253 



on the more important commercial varieties. Delaware seems to 

 have a certain amount of resistance, at least the disease has rarely 

 been found on that variety. The variety Pocklington seems to be 

 particularly susceptible, but as this variety is not grown extensively, 

 data on this point are difficult to obtain. 



distribution. 



So far as the writer's observations go, no district in the State is 

 free from the disease, nor does there seem to be any great difference 

 in the prevalence of the disease in the different districts. The writer 

 has rarely visited a vineyard in the State in which at least occasional 

 diseased vines could not be found. Perhaps the least of the disease 

 is to be found in the Keuka Lake region. This is only a general 

 impression as no accurate estimates of percentages of diseased vines 

 have ever been made in this section. 



The observations of Shear (1911) extend the known distribution 

 of the disease to practically all the vine-growing sections of the 

 eastern United States. Lately Bubak (1911) has reported a vine 

 disease occurring in Hungary the cause of which is described as 

 a fungus closely related to the causal organism of the dead-arm 

 disease. Since no such disease has been reported either from France 

 or Germany it seems quite evident that the disease is indigenous 

 to America and apparently confined to it at the present time. 



LOSSES. 



The insidious nature of this disease makes a determination of 

 its extent and destructiveness almost impossible. One may mark 

 1 per ct., 2 per ct., or occasionally 5 per ct. of diseased vines in a 

 vineyard at a single inspection. Sometimes as many more can 

 be marked the following year. How long this might continue remains 

 to be seen. 



The loss, of course, is considerable. Besides the dead vines there 

 are many others declining in vitality which each year bear fewer 

 and fewer pounds of grapes until finally they die or are removed. 



SYMPTOMS. 



(a) The dead arm is the most strikingly obvious symptom of 

 the disease. Fig. 5 (Plate VI). Almost as frequently the entire 

 vine dies, in which case suckers usually spring up about the base. 



