Alfalfa for New York 



15S1 



course of a few days it attaches to the alfalfa plant. The dodder plant 

 does not develop a root system of its own, but lives on food extracted 

 from the alfalfa plant. 

 The infested plants die in 

 time. 



The dodder plant, being 

 a twining vine, spreads 

 from one alfalfa plant to 

 another. It seldom seeds 

 in New York State, but 

 the original infestation 

 comes from dodder seed in 

 the original alfalfa sowing. 



The dodder plants also 

 live over winter, on the 

 crowns of alfalfa plants, 

 and in this way spread 

 rapidly from year to year. 



If the field is thoroughly 

 infested, about the only 

 recourse is to break it up 

 and put it to some other 

 kind of crop for at least 

 two years. Where the 

 dodder occurs only in 

 small spots it can be con- 

 trolled, and sometimes 

 eradicated, by mowing 

 those spots very close as 

 soon as they appear, 

 drying the material, and 

 burning it on the land. 

 The burning will injure the alfalfa plants only slightly and may kill any 

 dodder still adhering to the crowns. 



Fig. 245. — Alfalfa dodder plant, as it grows on alfalfa 



plants 



Root rot 



In old alfalfa fields many of the large roots are likely to begin to rot 

 at the crown. The root decays slowly and dies in one or two seasons. 

 There is no remedy for this. The rot is usually favored on rather wet 

 lands and is increased when the crowns are injured by machinery. Culti- 

 vating the fields with a disk harrow stimulates growth, but usually it 

 increases root rot by injuring many of the plants. 



