DISEASES AND ENEMIES 



395 



alfalfa is used. However, where the pasture is about half alfalfa 

 and half grass, little difficulty is experienced. 



The principal .precaution in pasturing alfalfa is not to graze 

 it too closely. It is generally thought best to have enough stock on 

 to keep it only partly eaten down, and make at least two light cut- 

 tings of hay during the season 

 Close grazing for one season 

 will usually destroy alfalfa, 

 while it may be grazed for a 

 number of years, with proper 

 care. 



Conditions seem to be some- 

 what different in dry regions. 

 In very dry climates it can be 

 pastured without much danger 

 from bloat and is usually not 

 easily destroyed even by rather 

 close grazing. The reasons for 

 this are not very apparent, but 

 usually in dry soil the crowns 

 of the plant are very much 

 deeper set into the ground. 



Diseases and Enemies. 

 While there are a number of 

 diseases found on the alfalfa 

 plant, only one or two are im- 

 portant. 



Dodder, or love vine, is a 

 parasitic weed found on both 

 alfalfa and clover (Figs. 170 L. 

 and 171). Dodder is a leaf- 

 less vine which attaches itself to the plant and lives by absorbing 

 nourishment. It is propagated by small seeds. The seeds ger- 

 minate in the spring, but as soon as the young plant has attached 

 itself to alfalfa, the roots die. It usually spreads rather rapidly. If 

 only a few small areas are found in a field, these can be destroyed by 

 cutting the alfalfa plants very low and burning all the material. 



FIG. 171. Alfalfa dodder. 



