New York Agricultural Experiment Station. 145 



In the Hudson Valley, particularly in the vicinity of High- 

 land, Milton and Marlboro where currants are grown extensively, 

 necrosis is an important disease. In this region, it occurs to a 

 greater or less extent in almost every currant plantation and is 

 regarded as one of the chief hindrances to currant culture. Since 

 the disease does not attack the roots new shoots continue to appear 

 so that the plants are rarely killed outright; but as the plants 

 grow older more and more of the canes succumb until, finally, 

 there are so few fruit-bearing canes left that the plantation ceases 

 to be profitable. While the virulence of the disease varies some- 

 what from year to year it is never wholly absent from a planta- 

 tion in which it has once become established. 



Necrosis occurs frequently, also, in central and western New 

 York, but is rarely destructive, even in large plantations. The 

 reason for this is not clear. 



SUMMER PKUNING A THEORETICAL METHOD OF 



CONTROL. 



Because of the damage done by necrosis there has been a steady 

 demand for information concerning means of controlling it. The 

 writer has advised making two or three systematic inspections of 

 the plants during the spring and summer and promptly cutting 

 out and burning all diseased canes found. 1 We call this the 

 summer-pruning method. It depends for its success on the as- 

 sumption that the diseased canes can be readily detected before 

 the causal fungus has produced spores, thus making it possible to 

 remove the affected canes before the disease has had a chance to 

 spread. 



Prior to the investigations of Grossenbacher and Duggar, the 

 spore forms of the fungus were unknown, but it had been ob- 

 served by Fairchild and the writer that canes killed by the fungus 

 usually bear no spores of any kind until they have been dead a 

 long time. Moreover, all attempts to make the fungus produce 

 spores in artificial cultures have failed. Hence, the fungus came 



i Stewart, F. C. Currant cane blight kept in control, Amer. Agr. 69: 820. 

 28 Je. 1902. 



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