!N"ew Yoek Agricultural Experiment Station. 207 



tunity to study this case thoroughly no statement is made as 

 to its cause. 



BLACK KNOT. 



A considerable number of specimens of this disease were found 

 in an old vineyard at Middle Hope. At a distance of from six 

 inches to two feet above the ground the stems showed warty 

 excrescences of spongy texture. (See Plate XVII.) No knots 

 were found on the roots or at the crown. These excrescences 

 bear a striking resemblance to the black knots on plums and 

 cherries caused by the fungus Ploiurighiia morbosa (Schw.) Sacc, 

 but they have an entirely different origin. European investigators 

 hold that they are due to the action of frost.^ 



The disease appears to be rare in the Hudson Valley, but in 

 Central and Western E'ew York it is met with frequently. It is 

 also reported from Pennsylvania,^*' California^' and Canada.^ 

 From American writers on plant diseases it has received very 

 little attention, although it has a considerable literature in French, 

 German and Italian. 



PEACH DISEASES. 



WINTER INJURY. 



The Hudson Valley peach crop of 1899 was almost a complete 

 failure owing to the hard freeze in February which killed nearly 

 all of the fruit buds. There were very .few orchards that bore 

 any fruit. In many orchards the tAvigs also w^ere much injured 

 and in some the trees were killed outright. The severe attack 

 of leaf curl in 1898 probably made the trees unusually suscep- 

 tible to winter injury. 



25 See Frank, A. B. Die Krankheitcn der Pflanzen, 1: 209-210. Breslau, 

 1895. 



26 Galloway, B. T. Botanical Div. U. S. Dept. Agr. 'Bui. 8: G3. 



27 Woodworth, C. W. Cal. Exp. Sta. Bui. 99: 2. This, however, may be 

 a different disease. 



28 Fletcher, -las. Canada Experimental Farms Kept, for 1889: 87. 



