154 Elementary Principles of Agriculture 



dilute solutions of formaldehyde, or other prepar- 

 ations. 



222a. Preventing Smuts in Grain Crops. Full directions for 

 treating small grains to prevent smut may be obtained from 

 Farmers' Bulletin No. 507, U. S. Department of Agriculture, or 

 other bulletins from your State Experiment Station. Other 

 bulletins give information on the control of smut of sorghum and 

 other crops. Every class in agriculture should make tests on smut 

 prevention. 



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. It is 

 plain therefore that, if such plants as the small grains, 

 corn, etc., are grown on the land, the fungus will be 

 starved out, so that cotton or other susceptible plants 

 may be again grown. It is important that weeds that 

 might harbor the fungus should be destroyed. Fields 

 will rarely become seriously infested with this fungus if 

 proper rotations are made. No variety of cotton has yet 

 been discovered that resists the attacks of this fungus. 



