OATS — HARVESTING, MARKETING, ENEMIES 301 



Purified Oats 



"All oats that have been chemically treated or purified shall be 

 classed as purified oats, and inspectors shall give the test weight on 

 each car or parcel that may be so inspected." 



INSECT ENEMIES 



367. The oat plant is generally exceptionally free from 

 insect injury. In occasional seasons, chinch-bugs, grass- 

 hoppers, or green-bugs {Toxoptera graminum) do consider- 

 able damage. Methods of exterminating chinch-bugs are 

 outlined in the chapter on insect enemies of corn. 



Green-bugs 'are small green 'colored lice that suck the 

 juices from the young plants. They are most serious in 

 the western and southwestern sections of the country. 

 Green-bugs are usually kept in check by their natural 

 enemies among which is a species of lady bug. 



FUNGOUS DISEASES 



The two diseases of paranjiount importance affecting 

 oats are rust and smut. 



368. Oat rust. -^ There are two distinct kinds of oat 

 rust. One of these {Pucelnia coronata) occurs chiefly on 

 the leaves and is known as the "crown" rust owing to the 

 fact that the spores at their upper parts have the form of 

 a crown. The other kind of rust (P. graminis avence) 

 occurs on the stems and is known as "black-stem" rust. 

 Each of'these rusts has twd stages, the red-rust stage, 

 appearing first, followed by the black-rust stage. For 

 this reason they are often confused by farmers. Both 

 "crown" and "black-stem" rust have been found to be 

 coextensive with the oat crop, usually occurring together 

 and being much more prevalent in humid than in arid 

 sections. The black-stem rust is of extreme importance in 



