RHAMNUS IX THE DISSEMINATION OF CROWN RUST. 9 



niunity in northwestern Iowa realize the harmful effects of the Rham- 

 nus hedge and up to the present time have dug up 240 rods of it 

 (fig. 7). This eradication has been accomplished by means of a 

 stump puller, which removes the bushes but allows the soil to remain 



OfiT tft/ST /NFECT/ON 



<SP/?Etf0 E/PO/f 

 BUCKTHORN HEDGE 



CO/?A/ 



Fig. 4.— Sketch map of about 5 square miles surrounding the hedge of buckthorn I Rhamnus cathartica) 

 near Hinton, Iowa, showing the location of the oat fields and the percentage of infection which had 

 » occurred to the end of June 7. (Compare with fig. 2.) 



around the roots. Unless this soil is removed, the plant will continue 

 to live and put out leaves, and these may bear heavy secidial infec- 

 tion. However, the shrubs pulled in this way seldom survive until 

 the second spring after being removed. 



42199—23 2 



