THE MUSTARD FAMILY 93 



directly after harvest will induce the seed of this and other 

 annuals to germinate; the plants make good feed for sheep or 

 may be destroyed by cultivation or frost. A rotation of crops 

 such as recommended for Wild Radish will suppress this pest. 

 On lands where the production of spring cereal grains predomin- 

 ates, two or more applications of the weeder or harrow, pref- 

 erably a tilting harrow, once when the grain begins to show 

 above ground and once or twice when the crop is between three 

 and six inches high, will destroy the seedling mustard plants 

 and prevent them from choking out the grain. Some claim 

 that this practice of harrowing spring crops slightly delays 

 maturity, but this can be obviated by thicker seeding. Applica- 

 tions of clover and grass seed may be made directly in advance 

 of the harrow when last applied. When the soil is too wet to use 

 the harrow, as it frequently is during the early^ growing season, 

 in the eastern provinces, the growth of Wild Mustard may be 

 checked and most of the plants killed by spraying with a solution 

 of two pounds of bluestone in ten gallons of water, applied at the 

 rate of about fifty gallons per acre in a fine spray. The seeds 

 are longer-lived than most others of the Mustard family. Recent 

 research work showed that they do not retain their vitality 

 beyond fifteen years. 



ALLIED SPECIES : Indian Mustard (Brassica juncea (L.) 

 Cosson) differs from Wild Mustard in being smooth, nearly hairless, 

 somewhat covered with a fine bloom. The upper leaves are 

 narrower, the lower ones pinnatifid with a large terminal lobe. 

 The pods are slightly shorter on spreading footstalks. This 

 weed has been detected in a few places in Manitoba and Ontario. 



Black Mustard (Brassica nigra (L.) Koch). Although 

 found occasionally in all the provinces, the true Black Mustard 

 does not seem to be a troublesome weed in Canada. It may 

 be at once known by its long spreading branches, covered with 

 short square pods only half an inch long, which are erect and 

 closely appressed to the stem. 



Bird or German Rape, Rutabaga (Brassica campestris L.) 

 including Turnip (Brassica Rapa L.) and Rape (Brassica Napus L.) 



