CONTROL OF THE SUGAR-BEET LEAF-SPOT. 17 



Besides the roots proper, one may harvest a large quantity of leaves and tops. How- 

 ever, there are many farmers sufficiently blind to overlook the precious quahties of 

 these portions of the plant, and allow them to remain and rot on the field without 

 rendering other ser\dce than that of supplying a portion of certain mineral elements 

 * * * which have been absorbed by the root during its development. The 

 money value of these leaves when used as a fertilizer is certainly less than that which 

 would be derived fi-om feeding to cattle. Beet leaves and tops contain, it is true, a 

 certain amount of salts which are useful to the soil, but on the other hand many of 

 these mineral substances can be more advantageously utilized by feeding the leaves 

 to cattle and collecting the manure; their fertilizing properties are not subsequently 

 lost by the passage through the animal's body and during the interval the stock has 

 been benefited by receiving a good, wholesome, green fodder at the very period of the 

 year when it is most relished and is eaten with avidity. * * * Experience shows that 

 the best results are obtained by feeding siloed beet leaves during early spring. * * * 

 Many farmers allow sheep to run over their fields and eat the leaves during their 

 passage. Under all circumstances such customs should be prohibited, as large quan- 

 tities of leaves are necessarily trod under and are thus destroyed, which in reality 

 means a waste, as far as their nutrient value is concerned. 



All average crop of leaves and tops is stated as being about 4.8 tons 

 to the acre. 



CONCLUSIONS. 



(1) The leaf -spot of the sugar beet is caused by Cercospora hrticola 

 Sacc, which lives through the winter upon the old beet tops of the 

 precedmg season. 



(2) Results thus far obtained mdicate that the organism is unable 

 to survive a passage through the alimentary tract of cattle, sheep, 

 and pigs. However, it is impossible to prevent waste in feedmg the 

 beet tops, and consequently all material is not eaten and may be 

 returned m a viable condition in the manure to the land. 



(3) For a thorough control of the leaf-spot the beet tops should be 

 removed from the fields while still green and should be made into 

 silage. Cercospora beticola is killed when the beet tops are siloed. 



[Cir. 121] 



