New York Agricultural Experiment Station. 233 



are formed on the diseased areas and infection begins. It makes 

 its first appearance on the young canes oftentimes when they are 

 from six to ten inches high and at any point on them where the 

 spores may chance to fall. It is supposed that the germ tube of 

 the spores can enter only young and tender tissue, consequently 

 the spread of the disease is toward the tip of the cane naturally 

 following the tender growing part. Therefore we find the small 

 spots toward the top, while the larger, older ones are lower down 

 on the cane. The disease first appears on the new canes as small, 

 dark or purple colored spots, few at first but increasing rapidly 

 in number providing a diseased spot on an old cane is in close 

 proximity and the weather conditions are favorable for the pro- 

 duction and germination of spores. The new spots rapidly in- 

 crease in size, changing from the dark color to a brown or dirty 

 white in the center as the fungus feeds outward in all directions 

 and leaves the dead tissues behind. The slightly raised outlines 

 of the spot vary in color from dark-brown to bright puri)le. As 

 the cane grows older it throws out numerous layers of corky 

 tissue around the diseased spots in its effort to heal the wounds, 

 thus giving the diseased canes a rough, scabby appearance. If 

 badly infected the spots are so numerous on the cane that they 

 soon grow into one another and form large blotches or scabs 

 sometimes six or eight inches long, often entirely encircling the 

 cane and thus effectually girdling it. 



This minute plant lives on the juices contained in the cells of 

 the tissue that lies just beneath the outer bark, the most vital 

 part of the plant; here the threads of the mycelium cross and 

 interlace and ramify in all directions absorbing nourishment that 

 should go to build up the cane. As the disease advances it leaves 

 the cells of the tissue discolored and collapsed. Where a scab 

 spot nearly or entirely encircles a cane the supply of sap is cut off 

 and the cane withers and dies. It is not known that the fungus 

 works into the wood but its attacks occasionally cause the canes 

 to crack and expose the pith. 



While the anthracnose of the raspberry may be said to be pre- 

 eminently a disease of the canes, it sometimes attacks the leaves, 



