New York Agricultural Experiment Station. 185 



'' Cane Knot. — We have sought for Bailey's^^ cane knot of 

 blackberry but have not found it. Among wild blackberries we 

 have found cane knots caused by an insect. A few inches above 

 the ground the canes bore swellings from one to two inches in 

 length and having a diameter about one-half greater than nor- 

 mal. The swellings were mostly smooth but some were cracked 

 owing to the canes having broken over at that point; and a few 

 specimens collected at Barker showed eruptions of soft, spongy 

 tissue. Inside the swellings there were the whitish larvte of 

 the gouty gall-beetle, Agrilus ruficolUs. These larvae were boring 

 in the pith. In many cases they had also girdled the cane by 

 boring around it just under the bark. Undoubtedly, the larvse 

 were the cause of the swellings. These observations were made 

 in May. 



On the Station grounds we have observed enlargements on 

 blackberry canes near the ground which were due to mechanical 

 injuries made by tools used in cultivation. 



Other Diseases. — At Portland a powdery mildew was ob- 

 served on a few canes of the variety Snyder. It was probably 

 the same fungus as that found on black raspberries (see page 

 208). As in the case of the raspberry, only rusted plants were 

 attacked. 



Anthracnose, Glaeosporium venetum, has done very little dam- 

 age to blackberries. 



Crown gall or root knot occasionally attacks blackberries, but 

 is rarely destructive to them. 



CHERRY DISEASES. 



Fruit Rot {Monilia fructigena P.). — On account of the ex- 

 tremely dry season the loss from fruit rot has been much less 

 than usual. A few correspondents report losses of 15 to 20 per 

 ct. 



Black Knot {PloicrigMla morhosa (Schw.) Sacc). — Black knot 

 attacks sour cherries in Western New York, but is easily kept 



** Bailey, L. H. Blackberries. Cornell Univ. Agr. Exp. Sta. Bui. 99: 

 427-428. Illus. 



