2i8 Weeds. 



again when it is about three inches high, 

 will kill cockle and many other weeds. This 

 method is less effective on winter grains, as 

 the cockle starts in the fall with the grain 

 and many of the plants are too firmly estab- 

 lished by spring to be removed by the 

 harrow. Harrowing winter grains as soon 

 as growth starts in the spring does kill 

 many small weeds, however. 



Observations. While this weed is easy 

 to eradicate if proper attention is given to 

 the methods just outlined, it will be found 

 to be quite persistent where wheat is the 

 main crop and no rotation is followed, on 

 account of the difficulty of removing the 

 seeds of cockle from the seed grain, hence 

 the necessity for exercising care in pre- 

 venting its introduction through seed grain 

 wherever possible. 



(6) WHEAT-THIEF. 



Wheat-thief (Lithospenniim arvense) is 

 sometimes known as gromwell, pigeon 

 weed, and redroot. It usually grows from 

 eight to sixteen inches high, but sometimes 

 in rich soils it becomes considerably taller. 

 It is more or less branched in its habits of 

 growth. Its leaves are narrow and about 



