90 



ELEMENTS OF FARM PRACTICE 



possible without freezing it, and where it is dry. It is a 

 good plan to keep seed potatoes in baskets or slatted boxes 

 piled up in a cool cellar so that the air can circulate freely 

 about them. 



Scab. — The rough blotches on the surface of potatoes 

 are called scab. The disease is caused by certain spores or 

 seeds, just the same as diphtheria or other contagious dis- 

 eases are caused by germs. To prevent scab the spores of 

 the disease must be destroyed. The spores may live over 

 winter in the soil on which scabby potatoes were grown the 

 year before. They may get into the soil with manure from 

 animals that have been fed scabby potatoes, or they may 



Figure 38. — A manure spreader. 



be on the seed planted. The latter is the most common 

 way of spreading the disease, and, as the seed is very easily 

 treated to prevent scab, there is very little excuse for getting 

 scabby potatoes in this way. Formalin is a liquid which 

 may be purchased at any drug store for from twenty-five 

 to fifty cents per pint. A pint mixed with thirty-five gal- 

 lons of water makes a solution which will destroy the scab 

 spores on seed potatoes, if they are soaked in it for two 

 hours. Treat for scab before cutting the potatoes. If cut 

 first, some of the pieces may stick together and the spores 

 in between will not be reached by the solution. 



