Februar}', '21] flixt: chixch-bcg resisting corns 83 



President Wilmon Newell: The next paper on the program is 

 entitled "Chinch -bug Resistance Shown by Certain \^arieties of Corn," 

 byW. P. FHnt. 



CHINCH-BUG RESISTANCE SHOWN BY CERTAIN VARIETIES 



OF CORN 



By \V. P. Flint, Urbana, III. 



In locaHties where chinch-bugs have been abundant for a number of 

 years, one will frequently hear statements from farmers that certain 

 varieties of com are not greatly damaged by them. Investigations of 

 these statements have shown in most cases that some other factor than 

 varietal resistance has been responsible for lessening the chinch-bug 

 injury. 



In the summer of 1917, Mr. J. J. Doerschuk, then county agent in 

 Randolph county, Illinois, called the WTiter's attention to the fact that 

 a variety of corn known locally as White Democrat seemed to be showing 

 marked resistance to chinch-bug attack. 



In the spring of 1918, under the supervision of Mr. Doerschuk, seven 

 varieties of corn were planted in four-row^ strips in a field in a locality 

 where chinch-bugs were extremely abundant. These varieties included 

 White Democrat. Iowa ^Silver Mine, Boone Countv White, vSutton's 

 Favorite, St. Charles County White, Yellow Ninety Day, and Reid's 

 Yellow Dent. There were but few chinch -bugs in this field up to the 

 time of their summer flight, which occurred when the corn was about 

 three feet high. A general heavy infestation of the field resulted. 

 The second brood of bugs was very abundant in this field. Early in 

 October the stalks and ears from ten hills of corn of the White Democrat, 

 Iowa Silver Mine, and Reid's Yellow Dent were carefully weighed, the 

 weights being 53, 17, and 11 pounds, respectively. None of the other 

 varieties were as good as the Reid's Yellow Dent. 



In 1919, White Democrat and a local strain of Reid's Yellow Dent 

 were sown in alternate strips of two rows each in fields of fifteen to twenty 

 acres in two widely separated localities where chinch-bugs were abund- 

 ant. By the first of September one could easily distinguish the varieties 

 from a distance, at least <S0 per cent, of the White Democrat stalks were 

 standing, while the stalks of Reid's Yellow Dent had nearly all fallen 

 from the effect of the chinch-bug injury. The corn was harvested in 

 October, in one of the fields Reid's Yellow Dent yielding 21 >2 bushels 

 and White Democrat 'S0}4 bushels per acre; in the other 15^ and 19^ 

 bushels per acre, respectively. The difference in the com was very 

 marked, the White Democrat being well matured and in good condi- 



