BLACKBERRY CANE-KNOT 



295 



which almond, peach and apricot plants were grown, large num- 

 bers of the young trees contracted the disease. Making incisions 

 in the root or stem near the surface and inserting a particle of 

 gall also communicated the disease. Seeds taken from diseased 

 trees and planted in uncontaminated soil produced none of it 



Treatment. A paste consisting of two parts 

 bluestone, one part copperas and three parts 

 quicklime largely prevented the spread of the 

 disease. When trees have become affected the 

 galls at the crown can be removed and the 

 wound painted with this preparation. By this 

 means orchards have been kept in bearing 

 which otherwise would have failed. Great care 

 should be taken not to introduce the disease 

 into a plantation. It may be readily spread 

 by water, especially with irrigation, by the 

 wind and by tillage. If plants which show 

 galls are received from a nursery, Professor 

 Tourney considers it insufficient to simply re- 

 move the ones which are diseased. He recom- 

 mends destroying the entire lot. 



CANE-KNOT. (Fig. 48.) 



Bailey, Bull. Cornell Exp. Sta. 99: 427. 



This is a disease of the same insidious, 

 treacherous habit as the one just described. 

 It is most common on blackberries, though 

 perhaps not confined to them alone. It is 

 manifest by numerous rough, warty knots upon 

 the canes. These knots somewhat resemble the 

 black- knot of plum in appearance, but with 

 small, whitish eruptions surrounding the central knot. It is not 

 common, but seems to be widespread, and in a few cases, at 

 least, has wrought serious injury. A similar diseased condition 

 is sometimes to be observed upon the canes of red raspberries, 

 as a result or accompaniment of anthracnose. 



The only treatment that can be recommended at present is to 



Fig. 48. Cane-knot 

 of blackberry. 



