New Yokk Agricultural Experiment Station. 955 



that might grow for several years without showing marked evi- 

 dences of disease. Development of the disease is slow, so that 

 infected arms or vines may live four, five or even more years, but 

 with a constantly increasing loss of vitality. Under such conditions 

 any severe strain on the vine, like a particularly hard winter, may 

 result in its death; and while the vine still lives the yields of the 

 whole plant or of the affected arm are reduced below the profitable 

 point. Such vines or arms should be hunted out and removed, and 

 new healthy wood be secured to take the place of that diseased. 



This is not difficult, for the new growth from 



Remedy. near the ground or below its surface, even on a 



badly infected vine, is usually free from the disease, 



and can be kept so if the affected portions of the vine and adjacent 



ones are promptly and thoroughly removed. 



The remedy for the disease is therefore quite simple: The 

 diseased vines should be marked in early summer, when they are 

 easily recognizable- from the yellow leaves, and all affected wood 

 removed and burned. By carrying a piece of old cotton or linen 

 cloth when cultivating the vineyard, it is but the work of seconds 

 to attach to the diseased vine a strip of cloth to direct attention to 

 it when trimming. Often the removal of a single arm eradicates 

 the disease, but in other cases the whole trunk will be found affected. 

 If the characteristic discoloration or dry rot of the wood of the 

 main trunk is apparent the whole vine should be sawed off at a point 

 below the last indications of rot. In many cases it will be best to 

 cut the vine off close to the ground so that renewals will come from 

 below the surface. If all sources of infection are removed, such 

 renewals are sure to be healthy and to develop rapidly into strong 

 vines. In some years it might be safe to leave infected wood to 

 bear fruit while the renewal canes are growing, but when conditions 

 are favorable for infection such a procedure would be very unwise. 

 In any case each renewal should be inspected carefully some time 

 during late summer to see that it has not been infected; for if it has 

 been attacked by the fungus, even slightly, it should be rejected. 

 To insure one healthy renewal it is well to leave two or three 

 suckers at the base of the stump from which to select when tying up. 

 At the regular trimming time precaution should be made not to 

 leave for bearing wood any canes that show lesions of the disease. 

 Detection of these is easy with a little care, as they are usually 

 conspicuous at this time, being reddish in color and slightly elevated. 



Spraying should be effective in preventing the spread of this 

 disease, and where black rot is prevalent the first application for this 

 disease, when the shoots are eight or ten inches long, should protect 

 these shoots from infection with the dead-arm fungus. Where 

 growers realize the necessity of spraying to control root worm, and 

 own spraying machines for this work, the use of an early application 

 of bordeaux to assist in eradicating the dead-arm disease would be 

 well worth while. 



