THIRTEENTH ANNUAL YEAR BOOK— PART XII 709 



or threshing machine when the crop is thoroughly dry, it is best to stack, 

 as it is sure to be injured by rain if left in the field any length of time. 

 In hauling, cover the wagon rack with heavy sheeting or canvas, so that 

 the seed which is threshed out may be saved. The alfalfa should be cut 

 for seed when from two-thirds to three-fourths of the pods have turned 

 brown. 



Alfalfa may be threshed in either a clover huller or in an ordinary 

 threshing machine by proper adjustment of concaves and by using special 

 alfalfa seives. 



There is harvested annually in the United States about 16,000,000 

 pounds of alfalfa seed, half of which comes from Utah and western 

 Kansas and Nebraska. Arizona, Oklahoma, California, and Montana also 

 produce considerable quantities. Some 3,000,000 pounds of seed are 

 annually imported from Europe and South America. 



PESTS THAT AFFLICT ALFALFA. 



While alfalfa is not subject to more pests than most agricultural plants, 

 there are a few especially troublesome. These may be divided into three 

 classes: (1) Weeds; (2) Plant Diseases; (3) Insects and Animal Pests. 



WEEDS. 



Weeds give more trouble in growing alfalfa than any other one thing. 

 As already emphasized, thorough preparation of the seed bed is of the 

 utmost importance, because the young alfalfa plant does not fight weeds 

 well. In the early alfalfa growths, quick growing annuals, such as the 

 yellow and green foxtails and pigweed, present the greatest difficulty, 

 but these are weeds which a thorough cultivation of the seed bed be- 

 fore planting will eradicate. 



Blue Grass. — Without question the ordinary Kentucky blue grass is the 

 worst weed commonly found in the alfalfa field. This is especially true 

 if the field is pastured. Even when cut regularly blue grass is likely to 

 crowd in after two or three seasons, and by the third or fourth year 

 often has such a firm hold that the vigor of the alfalfa plants is greatly 

 reduced. 



Blue grass can be easily controlled or entirely driven out by culti- 

 vating the alfalfa, as discussed in other portions of this bulletin. 



Dodder. — In alfalfa seed imported from European and South Ameri- 

 can countries are a number of weeds the worst of which is the dodder. 

 Other troublesome weeds often so introduced are English plantain or 

 buckthorn, wild carrot and dock. 



Dodder is undoubtedly the worst weed to be found in alfalfa fields, 

 but fortunately it is not as yet very common. As soon as the seed ger- 

 minates the shoot of this parasitic plant begins its search for a host, 

 for it can live but a very few days from its own strength. Coming in 

 contact with the alfalfa plant, it entwines itself about it, sending many of 

 its suckers deep into the walls of that plant, and taking the food ma- 

 terials from the alfalfa for its own use and growth. The dodder grows 



