DISEASES OF OATS 201 



These figures show that there is ordinarily little profit in 

 growing oats where low or average yields are obtained, par- 

 ticularly when the value of the straw is not taken into con- 

 sideration. It is probable that crops of oats of less than 25 

 bushels to the acre are usually produced at a loss, though in 

 the South the high value per bushel sometimes returns a 

 profit from yields of 20 bushels or even less. 



INSECTS AND DISEASES 



243. Insect Enemies. Several of the insects which are 

 troublesome in wheat are also destructive to oats, though this 

 crop is seldom seriously injured by insect pests. Among the 

 more troublesome insects in oats are the army worm, chinch 

 bug, green bug or grain aphis, and the grasshopper. Except 

 in years of specially heavy damage, it is usually not profitable 

 to attempt to destroy insects in oat fields, for the expense 

 of killing them is greater than the damage they do. The 

 means of combating chinch bugs which are given under 

 wheat (Sec. 208) are equally applicable for oats and other 

 crops. The most destructive insects in stored grains are 

 the Angoumois grain moth and the various grain weevils. 

 Oats, because of the protection given by the hull, are less 

 frequently damaged by these insects than wheat, rye, or 

 barley. Placing the grain in tight bins and fumigating with 

 carbon bisulfid or hydrocyanic acid gas is recommended 

 where these pests are common. 



244. Diseases. The most common and destructive 

 diseases which attack the oat crop are the rusts and smuts. 

 The rusts are of two kinds, usually known as the leaf rust 

 and the stem rust, from the portions of the plant which they 

 most commonly attack. The leaf rust of oats is well known 

 to everyone, because of the abundance of its brick-red 

 spores on the leaves and stems at harvest time in years 



