1320 THE FRUIT INDUSTRY ix XEW YORK STATK 



The disease may be controlled by the use of bordeaux mixture. 

 The two last applications recommended for black rot are espec- 

 ially valuable. 



DEAD AR,]\I DISEASE 



The dead arm disease is one of comparatively recent appear- 

 ance. It is not found 011 European varieties; although, if intro- 

 duced into Europe, it might prove very serious. The disease 

 occurs in all parts of the state, lout seems to be more common in 

 the Chautauqua belt and on the Concord variety. 



The disease is caused by a fungous parasite, Cryptosporella riti- 

 cola. The fungus passes the winter in small black fruiting 

 bodies on the dead parts of affected vines. In the early spring it 

 spreads by means of spores to the young shoots, and later in the 

 season to nearly matured berries, producing a black rot. The 

 spots on the shoots are small, black, and oblong. The fungus 

 passes slowly into the Avood, and, if the shoot is not cut off too 

 soon, gains entrance to the arms or trunk of the vine. A slow 

 dry rot follows, the vine showing evidence of this condition by 

 the small leaves, often yellowish in appearance and crimped 

 about the margin. Eventually the vine dies. 



The disease may be controlled by marking affected vines when 

 the first symptoms appear and removing them at pruning time. 

 Suckers brought up from beneath the surface of the ground almost 

 invariably develop into strong, healthy vines. The first applica- 

 tion of bordeaux mixture recommended for black rot is valuable in 

 protecting the shoots from infection. 



