ii8 Diseases of Truck Crops 



Soft Rot 

 Caused by Bacterium teutlium Met. 



This disease was originally described by Metcalf . * 

 It is not known whether the garden beet is seriously 

 affected by it. The trouble, however, is of economic 

 importance where sugar beets are grown extensively. 



Symptoms. The disease in its initial stage is char- 

 acterized by a soft rot at the lower portion of the 

 root. At this stage the crown and leaves remain 

 normal, but later the outer leaves die and fall off. 

 The disease is primarily a root trouble; the decayed 

 tissue is soft, yellowish gray, and cxantains a sour 

 smelling liquid which exudes at the least pressure. 

 It is most prevalent in wet and poorly drained lands. 

 The cause of soft rot is a bacterial organism, Bac- 

 terium teutlium,. 



Control. Since the disease works on the root 

 underground it is clear that no exterior treatment 

 will be effective. Thorough drainage, careful culti- 

 vation, and crop rotation are the only methods of 

 control known. 



Crown Gall 



Caused by Pseudomonas tumefaciens Sm. and Town. 



Crown gall is a very important disease because of 

 its cosmopolitan nature. It prevails widely and 

 attacks a large number of hosts. 



» Metcalf, Haven, Nebraska Agr. Expt. Sta. 17th Ann. Rept.: 69- 

 112, 1904. 



