3o6 



THE CEREALS IN AMERICA 



time, has no covering attachment, but simply opens a small furrow and sows the 

 seed. The result is the plants come up one and a half to two inches below the gen- 

 eral surface, and the ' crown ' of each plant is formed and established say two to 

 two and a half inches below the general surface. The winter rains, light freezes 

 and thaws gradually but only partly fill in the open furrow, and the more vital and 

 sensitive parts of the plants are left at the original depth, below the reach of even 

 very severe freezes." 1 



IV. WEEDS, FUNGOUS DISEASES AND INSECT ENEMIES. 



Homemade spraying apparatus for killing wild 

 mustard; also used for spraying potatoes 



414. Weeds. — The oat, like all other spring 

 sown cereals, is apt to be infested with any weeds 

 whose seeds happen to be present in the soil. 

 Weeds are frequently a hindrance to the proper 

 curing of the crop. In the Northern States the 

 most conspicuous weed in the oat crop is the wild 

 mustard, which may be eradicated by spraying 

 the oats with a three per cent solution of copper 

 sulphate at the rate of fifty gallons of the solution 

 per acre. (144) 



415. Fungous Diseases. — The oat plant is 

 generally exceptionally free from insect enemies 

 and fungous diseases. Besides the two species 

 of rust occurring upon wheat (146) there occurs 

 also on oats crowTl rust (^Pnccinia coronata Cda.), 

 so called from the horn-like projections on the 

 teleutospores. No remedy is known. There are two forms of smut, namely, loose 

 smut ( Ustilago avenae (Pers.) Jens.) and covered smut ( Ustilago avefiae laevis (Jens.) 

 Kell. and Swing.). The first form, which is most common, converts the entire 

 spikelet into smut spores, while in the second only the kernel is so affected. Both 

 are successfully prevented by treating with hot water or formalin. (149) A bac- 



Loose smut on oats. Glumes more 

 fully destroyed in specimen on the 

 right. 



I Ga. Bui. 44(1889), p. 1] 



