162 



FIELD CROP PRODUCTION 



Great variation in the earliness of maturity, stiffness of 

 straw, resistance to rust, and abundance of yield are 

 to be found in almost all varieties. A great opportunity 

 for improving the crop is therefore within reach of each 

 grower if he will but take advantage of it. 



INSECT ENEMIES AND FUNGOUS DISEASES 



150. Insect enemies. There are no important insects which 

 confine their attacks to the oat plant. Several insects that 



are destructive to wheat are also 

 troublesome to oats, chief among 

 which are the chinch bugs, grass- 

 hoppers, and the army worms. 

 The most important of these in- 

 sects and the methods for their 

 control have been discussed in the 

 chapter on wheat, and as the same 

 methods may be employed to pre- 

 vent their ravages on oats, they 

 need not be discussed again. 



161. Fungous diseases. The 

 most destructive diseases that 

 attack the oat crop are the rusts 

 and smuts. There are two kinds 

 of rusts, the leaf rust and the 

 stem rust, so called because they 

 most commonly attack those 

 parts of the plant. The leaf rust 

 is more common than the stem 

 rust, and is identified by the red 

 spores on the leaves at harvest 

 time. In seasons favorable for 

 their development, the spores are 

 frequently so plentiful as to ad- 

 here to the harvesting machinery and the clothing of the har- 

 vesters. There are two kinds of smuts that attack the oat 

 plant. The loose smut is more common and far more destructive 

 than the covered smut. The loose smut may be recognized in 



FIG. 58. Covered and 

 smut of oats. 



loose 



