[newton] 



WHEAT STEM RUST 



187 



A 



.1 



-■■l-l 



XV XI XVII IX XIX XXIV XII XXXII XXX XXI XX(X XVIII Ml I 



♦^ 



■^ <-D-^ ^-E— > 



..Il 



I 



.11 



yv. XII XXM1. XVIII XI. III. XVII XXtt XXX XXI I »» XXIV Xtt- 



-> <- 



^ ^-c- 



Fig. 3. Frequency of occurrence and order of virulence of forms isolated. 

 Comparative frequency indicated by height of columns. Forms arranged from left 

 to right in order of virulence to all differential hosts (upper figure) and to bread 

 wheats (lower figure). 



