348 OHIO EXPERIMENT STATION: BULLETIN 175. 



Seeds brown, small, somewhat the shape of a quarter of an apple. 1-32 of 

 an inch long. Frequent in flax seed. A case of serious damage occurred near 

 Wooster in 1896. It is evident that the only way to prevent flax dodder is to 

 sow no dodder seeds with the flax. The seeds are smaller and may be separated, 

 but it is yet necessary to reject the seed from fields in which the dodder occurs, 

 if one wishes to be wholly safe. 



240 Clover Dodder (A) *Cuscuta Epithymum Murr. Clover dodder is oc- 

 curring- with greatly increasing frequency in Ohio 

 clover and alfalfa fields . It has the same tawny 

 stems, twining about the clover and uniting the stalks 

 above, but robbing and destroying the clover wherever 

 the dodder grows upon it. One correspondent des- 

 cribed these spots as resembling the work of fire in 

 clover. It has been sent to this office from many 

 scattered localities, thus indicating the need of very 

 much closer scrutiny of the clover seed sown. The 

 samples of clover and alfalfa seeds examined show 

 a marked percentage of dodder seeds therein. The 

 small cut, Fig. 45, will give some idea of the appear- 

 ance of a clover stalk with the dodder upon it. Dod- 

 der in clover means that the dodder seed has been 

 sown with the clover seed, and further, that no clover 

 seed should be saved from a dodder infested field. Fig. 45. Clover Dodder. 



. Seeds small, rusty to brown, 1-32 of an inch long, W" Millspaugk.) 



rounded on back and with roughened surface, occurring in clover and alfalfa 

 seeds. Clover dodder, like flax dodder, can be prevented only by sowing clean 

 seed. When it is found that the clover is attacked by the dodder the field may 

 be plowed at once and cultivated to make sure of controlling the pest; in case 

 the field is left, no seed should be -saved from the infested field. In practice, 

 the dodders on clover are a less serious problem than on alfalfa, since the life 

 of the seeding is so much shorter. Hillman finds the yet smaller seeds of a 

 native dodder in American alfalfa seed. 



241 Field Dodder, Alfalfa Dodder (A) *Cuscuta arvensis Beyr. This species 

 and the preceding both occur freely upon alfalfa and clover and especially in 

 commercial alfalfa seed; the seeds of field dodder are distinguished from clover 

 dodder by their double size. The vegetative characters of the species are scarcely 

 distinguishable to the ordinary observer. Dodder seeds are so liable to occur in 

 alfalfa seed which has not been recleaned, that is wiser to insist upon recleaned 

 seed when purchasing. Unfortunately, moreover, recleaning does not insure 

 the removal of all the large seeds of this dodder; some will usually remain in 

 badly infested samples of seed. The dodder problem in alfalfa growing requires 

 care and close examination of seeds purchased and of newly seeded areas. 



Seeds the largest of our clover infesting dodders, rusty-yellowish to brown, 

 roughened, irregularly spherical, about 1-16 inch long, occurring in seeds of 

 clover and alfalfa. See seed cuts. The still larger seeds of a native dodder 

 come in western alfalfa seed. 



In dealing with dodder patches in either clover or alfalfa, it is best to take 

 the areas as early as possible, dig up thoroughly all plants in them, to slightly 

 beyond limits, and to burn, in situ, the dried remains in order to destroy the 

 dodder seeds. Sometime may elapse before reseeding, which will be desired in 

 alfalfa fields. By surrounding the infested area with a shallow furrow, some 

 im flammable material may be spread after which the torch may be applied for 

 the destruction of the dodder seeds. This method may still not succeed unless 

 the plants have been killed and permitted to dry. The digging method has 

 been tested and found effective. 



