CH. VI 



TOBACCO 149 



virgin soil, , and the necessary plant growth for the 

 fire, and frequently because of a superstitious belief 

 that mountain -grown plants are better than those 

 grown in the lowlands. However, it is not necessary 

 to use the above antique and crude methods to protect 

 the seed beds from this disease. The soil can be 

 thoroughly sterilized by the use of hot water, formalin, 

 or Bordeaux. Of course it must be remembered that 

 the beds are always subject to reinfection by sticks 

 and other vegetable matter remaining in the soil, which 

 may contain and protect the organism, and also by 

 the foreign material which may be carried in by wind 

 and insects, or the workmen's tools, shoes, etc. 



The hot-water method consists in first preparing 

 the beds as for sowing, and then thoroughly soaking 

 them with boiling water. The water should be boiling 

 hot and used in considerable quantity. 



The formalin method consists in mixing two pounds 

 of formalin in fifty gallons of water, and applying to 

 the seed beds at the rate of fifty gallons to each forty- 

 eight square feet of surface. If possible, the soil 

 should then be covered with burlap, or some similar 

 material for forty-eight hours in order to prevent rapid 

 evaporation. It should then be thoroughly aired for 

 several days before sowing. 



The Bordeaux mixture method consists in treating 

 both beds and plants with the mixture, whenever the 

 trouble appears. Always give the treatment as soon as 

 there is the least sign of the disease, and thus prevent 

 its getting well started. Enough Bordeaux should be 

 used to thoroughly wet the plants and surface of the 

 soil. Care should be taken to use an excess of lime 

 or the plants will be killed by the mixture. Plants 

 treated by this mixture are easily injured by drying, 

 and therefore should be well watered while under treat- 

 ment (Fig. 62). 



Root Rot. A root rot which attacks tobacco, violets, 

 peas, and many other plants has been reported from 

 Western Europe, extending from England to Italy, 



