270 



THE BOOK OF CORN 



root louse has been found on the plant as early as 

 May 9, only four days after the field was planted. 



The dwarfing- of the plant, especially in patches 

 here and there, with a yellowing or reddening of the 

 leaves, beginning with the lowest ones, and a general 

 apparent lack of thrift and vigor, are sufficient to cause 

 suspicion of injury by this louse. This will be con- 

 firmed in part if numerous burrows of ants are seen 

 in or near the hills. The presence of ants in the field 



Fig 74— Winged Viviparous Female of Corn Root Aphis 

 Greatly enlarged (after Forbes) • 



may be overlooked after the ground has been recently 

 cultivated, but can scarcely escape attention shortly 

 after rain, when these little insects actively open up 

 their burrows, heaping up the little pellets of earth 

 about the openings of their nests. The root aphis of 

 the corn is of a bluish-green color, slightly whitened 

 by a waxy bloom. The form of the body is usually 

 oval, with two short, slender, but conspicuous tubes on 

 the hinder part. These stand erect or project slightly 

 backward, and have open ends externally. They are 

 called "honey tubes," it having been formerly supposed 



