THE POTATO 187 



like blotches which sometimes are so numerous as 

 nearly to cover the whole potato. Only the sur- 

 face may be affected or the fungus may have pene- 

 trated and broken down the tissues almost to the 

 centre. While probably not wholly preventable, 

 yet it is the potato disease that is most readily held 

 in check. With clean or properly disinfected seed, 

 if one puts it into clean ground (free from the 

 fungus) the crop should and will be essentially 

 clean. It is well known that once the fungus gets 

 into the soil it will live over winter and infect the 

 next crop more completely than the former. Just 

 how many years may be necessary to completely 

 rid the soil of the fungus is not definitely known, but 

 it is certain that another crop of potatoes should 

 not follow scabby potatoes for two or three years 

 and probably better not for four or five. Other 

 crops on this land are not attacked, which points 

 anew the safety and desirability of a scheme of 

 crop rotation extending over several years. 



"Having decided upon the variety to be planted 

 — and this choice must rest upon many characteris- 

 tics, such as quality, shape, period of ripening, 

 resistance to disease, marketableness, etc., — then 

 select those that are the freest from scab of any 

 that you can find. It is well to remember that the 

 absence of the characteristic surface markings is 

 not conclusive evidence that the potatoes are free 

 from the fungus. They may have been in contact 

 in the bin with scabby specimens, as a result of 

 which they are infected abundantly with the scab 

 spores. Unless you are sure of the condition of 

 the seed it will pay as a precautionary measure 

 to treat (disinfect) the seed. 



"The old method is quite largely in use in the 

 state and must still be regarded with much favor. 



