CHAPTER rV 



METHODS OF TREATING SICK SOIUS 



i_ Damping off, whether induced by Pythium, Khi- 

 zoctonia, or any other parasitic organism, is usually 

 confined to seedlings in the seed bed, under cover or 

 in the open. The loss of seedlings not only means a 

 waste of seeds, but it also results in late crops. 

 Growers are usually in the habit of using the same 

 soil in^^the seed bed, year in and year out. This prac- 

 tice cannot be encouraged, since contamination of 

 the seed-bed soil is bound to take place. The dis- 

 ease-produdng organisms are usually brought in 

 with the manure. A number of truckers make it a 

 practiceto empty their beds and fill them with fresh 

 soil. TTiis, unfortunately, is not always a safe 

 method, 'for the reason that the new soil too may 

 be contaminated, or that it may become infected 

 as soon as it is placed in the bed previously con- 

 taminated. Sick seed-bed soils may be freed from 

 damping off in various ways. 



Formaldehyde. When steam sterilization is not 

 feasible because of the absence of a steam boiler, the 

 formaldehyde treatmrait is the next best. With this 

 treatment we may control Fusarium, Rhizoctonia, 



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