GRASS AND HAY 55 



Dakota. This section is characterized each season by periods of rel- 

 ative drought, which are in accordance with the needs of alfalfa for 

 seed production. 



Weeds. Over a considerable portion of the country weeds con- 

 stitute the worst enemy of alfalfa. This is especially true in the 

 humid sections and in those parts of the West and Southwest where 

 the bulk of the rainfall comes during the comparatively mild win- 

 ters. 



In the irrigated sections of the West, especially in those sec- 

 tions characterized by rainfall during the comparatively mild win- 

 ters, the growth of the wild barleys (Hordeum spp.) is a decided 

 drawback to the successful production of alfalfa. 



Since alfalfa is not usualy a clean-cultivated crop the problem 

 of weed destruction is a serious one. Disking is usually the most 

 effective remedy for weeds, as the alfalfa is generally benefited by 

 the operation, while the weeds are greatly injured owing to their 

 different root systems. In sections where the wild barleys are trou- 

 blesome it is sometimes thought necessary to burn the first crop of 

 hay. Another method is to cut the first crop while the wild barley 

 is still immature and feed the mixture of alfalfa and grass hay. 

 The objection to this method is that it necessitates the cutting of the 

 alfalfa when too young. A heavy growth of crab-grass is sometimes 

 burned in the early spring. 



Dodder is one of the very worst weeds. It germinates in the 

 ground and the young plants soon attach themselves to the alfalfa 

 seedlings. As soon as the threadlike stem is firmly attached to the 

 alfalfa plant the stem connecting it with the ground withers away. 

 Thenceforth the dodder lives entirely on the alfalfa. It is very dif- 

 ficult to eradicate when once established, and for this reason great 

 care should be taken to avoid introducing it with the alfalfa seed 

 at seeding time. Grazing close with sheep has been recommended 

 as being effective in holding dodder in check. If dodder appears in 

 isolateof spots through the field, it is advisable to cut the affected al- 

 falfa plants very low and remove them. Destroying the dodder by 

 burning with different inflammable materials has occasionally 

 proved successful, but it is apt to be more expensive than the re- 

 moval of the affected portions of the plants. If the stand of alfalfa 

 is badly affected with dodder, the alfalfa should be plowed up before 

 the dodder goes to seed and the land kept in cultivated crops for 

 two or more years. 



Rodent Pests. The worst animal pests are gophers, ground 

 squirrels, prairie dogs, and mice. These are especially troublesome 

 in the western half of the country, where they injure the alfalfa by 

 eating the roots as well as the foliage. The mounds of gophers are 

 very annoying, as they interfere with mowing. These pests are less 

 troublesome where irn gating water is available with which to drown 

 them out. The burrows, however, cause the waste of much water 

 when irrigating. Poisoning and destruction by traps and cats are 

 the best means of holding the pests in check. 



Insect Pests. Grasshoppers are at present the worst insect ene- 



