EXERCISE 46. TREATMENT OF SEED POTATOES FOR 



SCAB 



Equipment: A supply of seed potatoes, one ounce of 

 formalin (forty per cent) and a clean three-gallon bucket. 



Method : Mix the ounce of formalin with two gallons of 

 water.* This will make sufficient solution to treat a bushel 

 of seed or more, since the solution can be used repeatedly. 

 Soak the seed in this formalin solution for about two hours 

 just before planting. A convenient method of treatment 

 consists in putting the formalin solution in a barrel or tub, 

 the potatoes in a basket or bag, and immersing them in the 

 barrel or tub of solution. 



Discussion : The scab is a fungous growth upon the sur- 

 face of the potato and greatly diminishes the market value 

 of the crop. When scabby potatoes are planted, the spores 

 of the disease are carried over to the next crop and the result 

 is a large number of undesirable, scabby tubers. Since this 

 disease is known to live over in the soil for several years, 

 a change of soil is sometimes necessary. However, it. is 

 not difficult to keep the disease in check if proper precau- 

 tions are taken regarding the treatment of the seed and rota- 

 tion of the crop. 



* One pint of corrosive sublimate in t hirty gallons of water will be 

 quite as satisfactory as the formalin solution, if the latter is more con- 

 venient to obtain. 



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