2 MISC. PUBLICATION 5 41, U. S. DEPT. OF AGRICULTURE 



BEETS 



The beet (Beta vulgaris L.) is grown primarily for its fleshy roots, 

 although the young, succulent tops are also often used as greens. The 

 choicest of the garden varieties have a rich red color and moderate- 

 sized, smooth roots that are sweet and of fine texture. The field, or 

 sugar, beets are yellow to white and are grown for the production 

 of sugar. 



Early garden beets are usually marketed in the fresh, crisp condi- 

 tion and should be free from disease. The tops are especially sus- 

 ceptible to decay by the bacterial soft rot organisms (p. 2), and 

 occasionally by the gray mold fungus, during transit and marketing. 

 Cercospora leaf spot sometimes disfigures the tops of garden beets, 

 and it causes severe damage to the sugar-beet crop. Any leaf disease 

 which reduces the normal leaf area of the plant, such as curly top 

 (virus) or rust (Uromyces ~betae (Pers.) Lev.), is likely to cause 

 dwarfing and poor development of the roots. The growing roots are 

 subject to black rot, crown gall (Agrohacterium tumefaciens (E. F. 

 Sm. and Town.) Conn), fusarium rot (Fusarium spp.), and rhizoc- 

 tonia root rot (Corticium solani (Prill, and Del.) Bourd. and Galz.). 



The late beet crop is topped and either marketed immediately or 

 stored for winter use like potatoes. Beet roots without mechanical 

 wounds and free from disease will remain firm and crisp for several 

 months if stored in a cool place. The mature roots are not subject 

 to many diseases. Occasionally they are affected by black rot, blue 

 mold rot (Penicillium sp.), fusarium rot (Fusarium spp.), internal 

 black spot, and scab. 



(See 5, 91. ) 2 



Bacterial Soft Rot 



(Erwinia carotovora (Jones) Holland and other organisms) 



Bacterial soft rot is not as common on the roots of beets as it is on 

 other root crops, such as carrots and turnips. However, it is the chief 

 cause of loss of leaves and stems of beets when they are shipped and 

 marketed as young bunch beets. 



Breaks in the protective skin of plant tissues, moderate temperatures, 

 and an ample supply of moisture are predisposing factors for this 

 rot. Young beets are easily bruised in harvesting, and the leafstalks 

 also are often wounded when the beets are tied into bunches. 



The first symptoms of this rot on leafy tissues are darkened, water- 

 soaked areas which tend to increase rapidly in size. The affected tis- 

 sues soon become soft and slimy and often have a very disagreeable odor. 



(See also Spinach, Bacterial Soft Hot, p. 16.) 



Black Rot (Heart Rot) 



(Phoma betae (Oud.) Frank) 



Black rot sometimes affects garden beets, but it is most important 

 on sugar beets. Usually only slight loss is caused in garden beets, 

 but sometimes the crop is practically destroyed in fields of sugar 

 beets. Lack of rainfall during the critical period in the life of the 

 beet plant is particularly favorable for the development of this disease. 



2 Italic numbers in parentheses refer to Literature Cited, p. 33. 



