8 BULLETIN" 203, U. S. DEPARTMENT OF AGEICULTURE. 



CONTROL OF BEET GALLS. 



From our present knowledge of the cause of the crown-gall of 

 beets, combined with the field observations already made upon this 

 disease, its elimination or control becomes comparatively simple. 

 As already suggested, a beet field badly infested with the crown-gall 

 organism may be freed from the pest by growing some other crop 

 in that field for two or more years before returning to sugar beets. 

 It is necessary onl}^ that the rotation crops other than beets shall 

 be such as are not readily attacked by the crown-gall organism. 

 In Bulletin No. 213 of the Bureau of Plant Industry, already men- 

 tioned, it is pointed out that the crown-gall organism will attack 

 a large number of plants in a great variety of families, but there are 

 plants which are attacked with difficulty, if at all, by this organism. 

 In the test mentioned in this bulletin the crop grown was oats, but 

 it is safe to say that any of the small grams, corn, kafir, milo, or 

 sorghum would do well. If only those crops are gro\\ai upon which 

 the organism can not feed and thrive, it must eventually die out 

 and the field be left free from the pest. The elimination of crown- 

 gaU is, therefore, a simple matter of wise crop rotation, which as a 

 matter of good farming should be practiced by every farmer regard- 

 less of the presence of crown-gall. 



SUMMARY. 



(1) There are at least two distinct types of sugar-beet gaUs. 



(2) The crown-gall of sugar beets is caused by a bacterium or a 

 number of closely related bacteria. 



(3) Sugar-beet galls appear to have an injurious effect upon the 

 quality of the roots. 



(4) The galls themselves are low in purity and therefore detri- 

 mental in the milling processes. 



(5) Sugar-beet gaUs sometimes cause the beet roots to decay, 

 but, so far as general field observations can determine, they do not 

 appear otherwise to affect the tonnage. 



(6) This disease may be held in check by a proper system of crop 

 rotation with grain-producing plants. 



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