104 Nebraska Agricultural Exp. Station, Research Bui. 12 
DESCRIPTIOX OF PLATE XVIII 
Jonathan tree infected by wild inoculation thru frost crack in 
trunk. 
A. Crown of tree. Infection did not extend into the crown. 
B. Two cross sections of trunk, one longitudinal section between 
the two cross sections and one between lower cross section and crown. 
Longitudinal sections show the depth of the frost cracic and accom- 
panying infection. 
C. Sections of two main branches showing a slight amount of 
infection. 
