^58 



MISSOURI AGRICULTURAL REPORT. 



put upon the roots in order to survive. It is a fact, then, that if we can 

 do away with the two species of common red ants, the corn-root-aphis 

 would practically disappear. Hence, in suggesting remedies or pre- 

 ventive measures for these aphis, it becomes necessary to take into ac- 

 count first of all the ants. 



It is a very rare thing, indeed, that a corn field becomes badly in- 

 fested with the corn-root-aphis the first year following some other crop. 

 It is, as a rule, old corn fields that have been continually in corn, or that 

 have been in corn for at least three years, that suffer from these insects. 



Therefore, by a judicious rota- 

 tion of the corn crop, one can very 

 easily escape any serious trouble 

 from these pests. 



The corn-root-aphis depends 

 upon the corn, smart-weed, fox- 

 tail or pigeon grass, or purslane, 

 and will not survive to any con- 

 siderable extent upon any other 

 plant. Hence the raising of a crop 

 which will prevent the growth of 

 these plants will starve out the 

 corn-root-aphis in spite of the at- 

 tendance it must receive from the 



Fig. 17.— Corn-Root-Aphis, Aphis maidir- nunierous small red ants that may 



adicis, oviparous female ; enlarged fourteen ^ . . . r 



diameters; a, hind tibia. be ill the field. Fertilization OI 



the field so as to help the plants to become thrifty and outgrow the at- 

 tacks of tiiese insects and to withstand drought better than otherwise, 

 will also help them to escape the injury from these insects. 



Next to rotation, however, thorough plowing and harrowing early 

 in the spring of the field intended for corn and the disk harrowing of 

 such a field at frequent intervals until the corn is planted, which corn 

 may be delayed for sometime for this purpose, will prevent the 

 growth of their food plants and will also practically clear a field from 

 any injury from these insects. This is accomplished by plowing 

 about eight inches in depth and then harrowing at frequent intervals 

 thereafter, so as to throw up and disturb and scatter the ants nests, in 

 the burrows and chambers of which are the little red ants and the eggs 

 of the aphids. By throwing these eggs about through the soil and scatter- 

 ings the eggs and ants, the eggs or aphids will, of course, perish unless 

 the ants find them, and the ants are so demoralized and the eggs so scat- 

 tered by this continued harrowing, that they are not able to find but a 



