720 Grasses and Leguminous Crops in New York 



It seems rather doubtful if the alfalfa dodder produces seed 

 in this state, but it has another equally efficient means of over- 

 wintering. As the steins twine about the alfalfa crowns close to 

 the ground, they escape cutting, and are able to persist throughout 

 the winter in a dormant vegetative condition. 



The control of this disease may be protection or eradication. 

 If alfalfa is to be planted, a sample of the seed to be used should 

 be sent to the Geneva Experiment Station to be tested for impuri- 

 ties ; and, if dodder is reported, the seed should be thoroughly 

 sifted in the following manner : 



The frame of the sieve to be used should be 12 inches square by 

 3 inches deep. The screening must be of 20 x 20-mesh wire cloth 

 made with No. .34 steel wire or No. 33 copper wire (Old English 

 gauge) . This can be obtained from Dorchester and Rose, Geneva, 

 N. Y. Next, secure a cup that will hold not more than one-half 

 pound of seed. Pour a quarter to one-half pound of seed into the 

 sieve and shake thoroughly for 30 seconds. In this way all the 

 dodder seed, a small amount of small alfalfa seed, and many of the 

 weed seeds will be removed. The loss of the small alfalfa seed is 

 not serious, be<!ause the plants produced would probably not be 

 vigorous. A man should be able to sift three to seven bushels a 

 day. 



Dodder and clover seed are almost impossible to separate, and 

 contaminated clover seed should be refused. 



If dodder is present in the field, it may be killed by cutting 

 the clover or afalfa close to the ground for at least a yard about 

 the dead area. Do not remove the plants, but pile in the dead 

 area. After the plants are dry, put more straw on the area, 

 sprinkle with oil, and burn over thoroughly. The object of the 

 oil is to draw the fire down to the ground and kill all the dodder 

 stems which may have not been cut. 



downy mildew 

 Downy mildew fungus, Peronospora trifoliorum De By, causes 

 a yellowing of the affected leaves, accompanied always with a 

 downy, violaceous growth on the lower surface of the diseased 

 areas. The disease is not especially serious, except on the first 

 growth. No control measures are known and are probably 

 unnecessary. 



