156 FIELD CROPS 



met with veiy promising results. Other helpful measures are 

 drainage, the use of early maturing varieties, and the erad- 

 ication of weeds. 



A helpful method of prevention of black stem rust is the 

 eradication of the common barberry, which is cultivated for 



ornamental purposes and 

 which acts as a host by har- 

 boring the spring spores of 

 this disease. It is estima- 

 ted that in the three spring 

 wheat states alone the loss 

 from black rust amounted 

 in 1916 to nearly $180,000, 

 000. A single plant or hedge 

 in a city may give off spores 



Figure 61. — Common barberry on the loft, j.i,„4. „,:n j.„„„„i u_. , 



and Japanese on the right. that Will travel Dy mOaUS 



of grasses to fields at a dis- 

 tance. The common barberry, however, should be distin- 

 guished from the Japanese variety which does not harbor 

 or propagate the disease. The common barberry is an up- 

 right shrub, 4 to 8 feet high, with grey bark, branched thorns, 

 leaves with spiny margins, and berries, borne in* clusters hke 

 currants. The Japanese is a low, spreading shrub, 2 to 4 

 feet high, with reddish brown bark, single thorns, smaller 

 leaves with smooth edges, and with only one to three ber- 

 ries in a place. A concerted campaign is being carried on 

 from Washington and by several states and public safety 

 commissions that is destined to remove the plant entirely 

 and prevent the great economic losses caused by it. 



(c). Smut. Smut is a fungous disease which attacks 

 the wheat crop and causes very heavy loss. The smut plant 

 grows within the wheat plant and produces masses of spores 

 in the head where the kernels of grain should be produced. 

 The whole head is generally attacked, and usually all the 

 heads of a plant, which latter fact is a strong indication that 



