204 EXPERIMENTAL FARMS 



5-6 EDWARD VII., A- 1906 



No. 1. No. 3. 

 Unattacked. Very seriously 



Water-free material — affected. 



Protein 18-49 17-19 



Fat or oil 2-51 3-41 



Carbo-hydrates 40-35 47-35 



Fibre 29-50 24-55 



Ash 9-15 7-50 



100 -00 100 -00 



Presuming that the stage of growth of the alfalfa is practically the same in both 

 cases, a comparison of the data should enable us to learn what eiTect or influence, if 

 any, the dodder has had upon the host plant — alfalfa. 



In respect to the most important nutrient, protein, the unattacked alfalfa is some- 

 what the richer; but the difference is by no means a marked one. The fat, or rather 

 ether extract, includes a certain amount of chlorophyll, so that the slightly higher 

 percentage in the affected alfalfa can scarcely be construed as indicating any superior- 

 ity. The percentages of fibre and ash are slightly lower in the dodder-aifected alfalfa. 



It might scarcely be warrantable to draw any conclusion from so fewi data as to 

 the physiological effect of the dodder; but I think we may safely infer that no great 

 difference in feeding value exists between the dodder-free and dodder-affected alfalfa. 



Frank T. Shutt, 



Chemist, Dom. Exp. Farms. 



Eradication. — The chief safeguard against dodder injuring a crop of clover or 

 alfalfa, is to examine carefully all seed purchased and clean out thoroughly all weed 

 eeeds before sowing. The dodder seed, when once known, can easily be recognized by 

 its dull surface and triangular shape. When dodder plants are found to be growing 

 in a field the patches should be cut at once and the ground hood so that no low-growing 

 plants may ripen seed. Burning small areas by putting straw or coal oil over them is 

 said to be effective, but would be less convenient than hoeing out the infested plants. 

 Where a whole field has been thoroughly infested, it should be put under a short 

 rotation in which clover for hay is omitted for at least two rotations, as it is claimed 

 that tlie seeds will remain in the soil for five j'ears without decaying; therefore, st)me 

 of the seeds of the original sowing, particularly if these were rather dry, might be 

 delayed in germinating for that time. As stated above, it is only quite recently that 

 dodder has occurred in Canada in sufficient quantity in crops to do extensive harm; 

 but, with the increasing cultivation of alfalfa, it is 'of course possible that it may 

 become a more frequent enemy of farmers. It is therefore important that its habits 

 and appearance should be known as soon as possible. 



