JOHNSON GRASS 381 



Canada Thistle is one of the worst weeds known. It is found 

 chiefly in the Northern states and Canada, and is found in all 

 kinds of fields. Many special methods for its eradication have 

 been tried and recommended. None of these is entirely success- 

 ful in all cases. 



A small patch of weeds may be smothered by placing over 

 the patch a straw stack, or a hay stack. A pile of manure is some- 

 times used to smother the area. Even builders' paper or tar paper 

 is sometimes tried. Anything will weaken the plants which will 

 prevent the growth of new leaves. This will tend to starve the 

 underground root stalks and thus .allow them gradually to decay, 

 but they will live underground without decay for more than a 

 year. 



If the surface of the ground be kept well tilled, the leaves will 

 gather very little nourishment for the rootstalks. 



Some have been successful in controlling small patches by the 

 use of pigs or chickens penned closely on the small area. 



A plan which may be followed for a large field infested with 

 Canada thistle is to spray the field with copper sulfate solution, 

 using fifteen pounds of the sulfate to fifty gallons of water. This 

 amount should be enough for one acre. Spray when the weeds 

 have formed their flower stalks, but have not yet developed any 

 seed. Of course this is best done before the grain crop is forming 

 its heads. The spraying kills only the part above ground and new 

 growth is certain to follow, but this will be so short when the grain 

 harvest is on that most of the thistles will be kept out of the bundles 

 of grain. After harvest is over the ground should be plowed and 

 then kept harrowed every week or so for the remainder of the sum- 

 mer. This will reduce the leaf surface sufficiently to weaken the 

 rootstalks by the time winter comes on. The next year the field 

 should be put into a cultivated crop such as corn or potatoes, and 

 this should be so thoroughly tilled as to prevent any leaf growth 

 of the weeds. 



Johnson Grass. This weed is a southern grass and is one of 

 the worst, having an abundance of rootstalk surface. The grass 

 becomes very tall, and smothering it by the growth of money 

 crops is practically impossible. Several of the methods above 

 mentioned for Canada thistle may be applied effectively in con- 

 trolling Johnson grass. Hogs required to pasture on the field will 

 eat the rootstalks and destroy the weeds. 



When fields are only partially infested with Johnson grass 



