RESEARCH BULLETIN NO. 12 
THE UNIVERSITY OF NEBRASKA 
BU LLETIN 
OF THE 
AGRICULTURAL EXPERIMENT STATION 
OF 
NEBRASKA 
STUDIES OF THE ETIOLOGY AND CONTROL OF 
BLISTER CANKER ON APPLE TREES 
By J. Ralph Cooper 
Distributed December 15, 1917 
TYPICAL BLISTER CANKERS 
LINXOLX, NEBRASKA, U. S. A. 
