202 INSECTS AFFECTING FIELD CROPS 



The Corn Root Aphis. These are bluish-green lice (Aphis 

 maidi radicis Forbes) found on the roots of corn, from which they 

 suck the sap. 



Description and Life History. The species is dependent upon 

 colonies of small brown ants, Lasius niger americanus Em. The 

 ants carry the eggs into their nests, bringing them into the sun- 

 light on warm days and carrying them below the frost line in cold 

 weather. The young are carried by the ants to suitable weeds 

 until the corn gets up, when the ants transfer them to the corn. 

 The lice multiply very rapidly, living young being produced by 

 the females. There may be a dozen generations during the season. 



C 



Fio. 217. The corn leaf-aphis, winged and wingless females and nymph. (After Forbes.) 



In some broods winged individals occur, and these migrate to 

 new fields. Corn is not the only plant damaged, for squash, 

 pumpkin, strawberries, cotton, etc., may be attacked and become 

 stunted and lack color in consequence. 



Control. Plow and harrow in the fall to break up nests of 

 ants. Keep fields clear of weeds to deprive lice of food in the spring. 

 Rotation of crops should be practiced. Thorough cultivation and 

 proper fertilization are desirable to induce vigorous growth. 



The Sugar-cane Beetle. This is a robust black beetle (Ligy- 

 rus rugiceps Lee.) about one-half of an inch long, with stout, 

 coarsely spined legs. Eggs are laid in the ground on weakened 

 or decaying roots. The grub burrows in the stalks of corn and 

 sugar cane (Fig. 218). The corn is usually killed. Injury occurs 

 early in the growing season. The grub pupates in the fall, the 



