U. S. D. A., B. E. Bui. 85, Part VI. C. F. I. I., July 12, 1910. 



PAPERS ON CEREAL AND FORAGE INSECTS. 



CONTRIBUTIONS TO A KNOWLEDGE OF THE CORN 



ROOT-APHIS. 



{Aphis maidi-radicis Forbes.) 



By R. A. Vickery, 

 Agent and Expert. 



INTRODUCTION. 



The corn root-aphis {Aphis maidi-radicis Forbes) is one of the 

 many insects infesting the corn plant in this country. It has cer- 

 tainly been known as an enemy of corn for nearby a century, and per- 

 haps much longer. Besides corn it attacks sorghum and broom corn, 

 but does little damage to these plants. Within the last three years it 

 has attracted considerable attention as an enemy of cotton in the Car- 

 olinas, where it feeds on the roots of young cotton and is called the 

 " root louse " or " blue bug." Among its other recently ascertained 

 food plants are pumpkin, squash, strawberries, cultivated asters, and 

 perhaps dahlia and French artichoke. 



Ever since this insect was first noted by Walsh in 1862 it has re- 

 ceived considerable attention from economic entomologists. Its life 

 history and habits in Illinois have been very thoroughly studied by 

 Dr. S. A. Forbes, state entomologist, and his assistants; and during 

 the past three years it has been studied, under the direction of Prof. 

 F. M. Webster, by the assistants in Cereal and Forage Insect Investi- 

 gations, Bureau of Entomology. These studies have been made over 

 a large extent of country, as follows : In the Northwestern States dur- 

 ing the season of 1908 by Mr. E. O. G. Kelly; in Indiana by Mr. W. 

 J. Phillips ; in South Carolina during the seasons of 1908 and 1909 by 

 Mr. G. G. Ainslie ; a in Florida and eastern North Carolina, as a cot- 

 ton insect, by Mr. H. F. Wilson under the direction of Mr. W. D. 

 Hunter, during the season of 1909; and in the Piedmont section of 

 North Carolina by the writer, also during the season of 1909. 



a These investigations were carried on by Mr. Ainslie as a part of cooperative 

 work by the Bureau of Entomology and the South Carolina experiment station 

 of the Clemson Agricultural College, and the results of his work were published 

 by Prof. A. F. Conradi in the twenty-second annual report of that institution, 

 for the year ending June 30, 1909, pages 51 to 65. 



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