90 DISEASES OF GINSENG. 



any worms to the stratifying beds.) They could easily be carried 

 by means of tools or perhaps on the shoes of a person walking 

 from an affected garden, especially in wet weather. 



Stone and Smith state that a temperature of freezing or of 

 140 degrees F. is necessary to kill both eggs and worms in the 

 soil, but for practical purposes in sterilizing the soil should be 

 heated to 180 to 212 degrees. . Treating the soil with chemicals 

 was of no practical value. The eggs are well protected and hard 

 to kill. It is a difficult matter to kill all the worms, distributed as 

 they are through the soil. Shoveling up the soil and allowing to 

 dry is an excellent method as the worms perish on drying. Put- 

 ting the soil in a condition so it will freeze is a good plan. Per- 

 haps the best method is to steam sterilize the soil. It is worth 

 while to suggest, also, that the mulch be witiiheld long enough to 

 allow the ground to freeze thoroughly, if it can be done without 

 injury to the plants." 



