544 FIELD AND GARDEN PRODUCTS 



Dodder (Cuscuta). The term "dodder" is the common name 

 applied to the several species of a genus of parasitic plants repre- 

 sented in all parts of the world. The species of dodder infesting 

 various plants, but especially alfalfa, are mostly natives of this 

 country, though a few have been introduced from Europe. They 

 are flowering annual plants, having slender, leafless stems about the 

 size of small wrapping twine. The general color of the dodder stem 

 is from that of straw to orange, or reddish yellow. The green color 

 common to most herbs is never seen in the stem of the dodder, 

 owing to the fact that the plant produces no chlorophyll, to which 

 is due in most plants not only their green color, but also their 

 power to transform the crude materials taken from the soil into vege- 

 table tissues. The dodder has no such power ; hence the peculiarity 

 of the life-history of these plants. (Ney. Bui. 15.) 



Thus the dodder is unable to provide for itself, and so is de- 

 pendent upon some other plant for its maintenance. During the 

 first stages of germination the young plantlet is self-supporting, 

 wholly dependent, however, upon the store of nourishment con- 

 tained within its seed. This consists of starch. When this nourish- 

 ment is exhausted the young plantlet has attained a height suffi- 

 cient to permit it to grasp and twine its stem about some plant that 

 may be sufficiently near. This occurs providing the plant be one 

 for which the dodder has a natural affinity. When these conditions 

 obtain, minute haustoria (suckers) are thrown out by the parasitic 

 dodder at points where its stem comes in close contact with that of 

 the plant to which it clings. One species of dodder, Cuscuta epithy- 

 mitm, Murr., is found extensively in 'alfalfa fields. Stems slender, 

 twining, leafless, light but never green in color, bearing suckers at 

 points of contact with the host plant, dying away at base soon after 

 germination and continuing to live from plant adhered to; flowers 

 small, less than one-eight inch long, general color white, usually 

 densely clustered, blooming late in the season ; seeds minute, almost 

 spherical, rough, one to four from each flower; embryo slender, 

 coiled spirally, destitute of cotyledons. 



As the dodder is apt to spread rapidly when once established 

 in a field, some effective remedy alone can prevent this, and at the 

 same time eradicate the pest. Probably the most effective remedy, 

 and one easily suggested, is that of burning the infested area. If 

 this is done in late Autumn the best results will doubtless follow, 

 as at this time the seeds of the dodder have but recently reached 

 maturity and are either still in the seed capsules or simply resting 

 on the surface of the ground. In either case a quick, hot fire, 

 burning closely to the ground, will suffice; and, if such, will prob- 

 ably do no injury to future crops of alfalfa from the same roots. 

 The standing alfalfa mowed and allowed to dry for a day of two 

 probably would furnish sufficient heat, and this, too, at the right 

 place. Sulphate of iron (green vitriol) if sprinkled upon the dod- 

 der is said to kill it without injury to the alfalfa. (Grasses of 

 North America.) 



Better than any remedy, however, is a means of prevention. 



