DODDER AND ITS ERADICATION. 51 



drawn from bulk and weighing one kilogram (two and one-fifth 

 pounds) is free from dodder then a certificate to the effect that that 

 sample is t3chnically dodder-free may be given. Conceivably, a 

 seed or two of dodder may be yet present in the bulk, but the 

 chances are over 476,000 t ) 1 against it, as that is the average 

 number of lucerne seeds in a kilogram. 



Besides the lurking danger in the seed used, dodder, as stated, 

 occurs on many wild plants in the veld, and is liable to be spread 

 thence to cultivated lands by means of animals, blown seed, or the 

 current of streams. But experience has shown that accidental or 

 natural introduction is much less common than artificial infection, 

 either through seed or from implements brought from foul to clean 

 land through unintentional human agency, irrigation water and 

 the like. 



I 



M 



& 



Lucerne and Dodder Seed. Actual size. (.1) Fair sample of Lucerne, imported. 

 (b) Ctisciita ai'vtuisis, foreign origin, (c) Cuscuta trifolii, foreign origin. 

 (;) C:is:uta ap/>e:tdiculata, mdi-jjuous. 



When small spjts of dodder are found either on lucerne or on 

 wild plants they should be taken in hand at once, if possible before 

 Howe ring. An effective method is to cut the lucerne close to the 

 ground, clearing up the surface and drawing everything from a 

 yard beyond th? edge of the attested patch to the centre, and there 

 burn it. If moist or otherwise incombustible, the heap may first 

 be sprinkle:! with pirafin. Under no circumstances should the 

 cut siu.? be carried away, as in so doing, fragments are sure to fall, 

 and so disseminate the disease. If in flower there is danger of ripe 

 seed n >t being burnt. After a week the spots should be carefully 

 <'.\aminecl lest a fragment has escaped destruction and be spreading 

 again. 



Another system i* to spray the patches after they have been 

 cut and allowed to wither somewhat, with a 10 per cent, solution, 

 1 Ib. to 1 gallon of wat->r, of sulphite of copper (blue vitriol, blue- 



