PLATE 3 
A. —Encircling type of apple-blotch canker on Oldenburg at a node. 
B. —Canker excision. Canker shown in A, cut out with a sharp knife. The cut is 
not deep enough to injure the cambium. 
C. —Results of canker excision in young Oldenburg tree. Cankers cut out in April, 
photographed in November. Wounds healed perfectly. Paraffin coating was 
unnecessary. One canker was overlooked, as indicated by the fresh cut. 
