154 THE BOOK OF WHEAT 



infest the same area. The Canada thistle is a native of Europe 

 and Asia. In Great Britain it is called corn or creeping thistle. 

 Its growth is rather slender, and from one to two feet in height. 

 Its deep-laid, extensively-creeping and sprouting rootstock make 

 it one of the very worst of weeds. Both of these plants are 

 constantly invading new territory, especially such as is con- 

 tinually cropped in wheat. The areas infested become useless 

 for growing small grain. Intensive cultivation with a certain 

 amount of hand work is the best remedy. 



General Remedies. While experiments in killing certain weeds 

 by spraying with chemical solutions have been made, the most 

 practical method is to prevent as far as possible the spread of 

 their seeds. This is accomplished by sowing clean seed wheat, 

 and by killing the weeds when they do succeed in starting. Con- 

 ditions most favorable to the growth of wheat place the weeds 

 at the greatest disadvantage. Intensive farming always finds 

 effectual methods of dealing with them. 



Losses. The wheat growers lose millions of dollars annually 

 on account of weeds. They are the largest factor in elevator 

 dockage. In North Dakota 1 47 samples of wheat were found to 

 have an average real dockage of .64 pounds per bushel. This 

 varies each year, and the average dockage for the 1906 crop of 

 wheat was about 2 pounds in the Minneapolis market. If 500,- 

 000,000 bushels of wheat are grown in the United States an- 

 nually, and the dockage averages only half of one pound per 

 bushel, then over 4,000,000 bushels are not only waste, but they 

 also injure the commercial value of the real wheat. Where 

 large quantities of wheat are cleaned, the cost is about one- 

 fourth of a cent per bushel. 



Birds. In the United States 29 species and subspecies repre- 

 sent the family Icterida3, a group of birds including those com- 

 monly known as bobolinks, meadowlarks, orioles, blackbirds, 

 grackles and cowbirds. Rating the blackbirds in the order of their 

 grain-eating propensities revealed by stomach examinations, 

 and putting first those that eat least, the list reads : Bobolink, 

 redwing, cowbird, rusty blackbird, yellowhead, crow blackbird, 

 boat-tailed grackle, Brewer's blackbird and California red- 

 wing. Since the first two are the ones most complained of, 

 the amount of grain actually eaten would not seem to be the 

 1 N. D. An. Report (1904), p. 45. 



