152 Elementary Principles of Agriculture 



solutions of formaldehyde, or other special prepara- 

 tion.* 



223. Potato Scab may be prevented by soaking the 

 seed potatoes in a two- or three-per-cent solution of 

 formaldehyde for one or two hours. This destroys the 

 fungus in the scabs and cracks on the potatoes. 



224. Cotton-root Rot is a serious disease of cotton on 

 heavy clay lands. The disease does not attack cotton on 

 loose, sandy soils. This fact has suggested the practice 

 of early and deep breaking of land to prevent the growth 

 of the fungus. Results are favorable to the practice. 

 Rotation is also a means of holding this disease under 

 control. The destructive effects of the cotton-root-rot 

 fungus is often confused with damage due to alkali. The 

 soft, spongy condition of the roots of plants killed by 

 this fungus is very characteristic. This fungus also 

 attacks okra, orchard trees, shade trees, etc., in fact 

 nearly all classes of plants except members of the grass 

 family, such as corn, small grains, sorghum, etc. 



*See full directions in Farmers' Bulletin No. 250, United States Department 

 of Agriculture. 



