77 



Townsend isolated pathogenic bacteria from the galls of peach, hard 

 galls of apple, hairy root of apple, hop, rose, and chestnut. He says: 

 "The organisms obtained from the galls of these different plants are cross 

 inoculable and are very similar, if not identical in shape, structure and 

 habits of growth on media with the organisms from the Paris daisy gall." 



Sometimes Crown Gall reveals itself by the hairy appearance of the* 

 roots, especially in seedlings. Experiments in Virginia and other south- 

 ern States "proved conclusively that seedlings with hairy roots produced 

 trees affected b}^ crown gall, and that by selection of the seedlings and by 

 discarding those with the hairy root appearance the trouble could be very 

 much reduced." (Report State Ent. and Plant Pathologist, Virginia, 

 1908-1909, p. 57). 



Treatment. — No remedial treatment of Crown Gall has been effective 

 in controlling this disease. The method that shows the greatest promise of 

 controlling this disease is to plant only nursery stock that is perfectly free 

 from the disease. Experiments have proved that scions cut from diseased 

 trees readily inoculate healthy seedlings. As the bacteria travel in the sap 

 it is plain that care should be taken to prevent injuries to the growing 

 trees at the surface of the ground during the cultivation of the orchards. 



