20 



FARMERS BULLETIN 835. 



1 



)nth |- 



within the main corn belt of the country, but also in the South 

 Atlantic States. Since it passes almost its entire life underground, 

 its presence frequently is not suspected. It is a small, stout, soft- 



FiG. 12. — The corn root-aphis (Aphifi tnaidi-radicis) : Wiuged, viviparous female. Greatly 



(■iil;irg(>(l. 



bodied, Avhitish-looking insect and may be discovered in infested 

 fields by pulling up the unhealthy corn plant and closely examining 

 the roots and surrounding soil. This kind of aphis depends entirely 

 upon the services of a small brown ant, sometimes called the corn- 

 field ant, in order to secure its food and the means of surviving the 

 winter, and the presence of an unusual num- 

 ber of brown ants in cornfields may indicate 

 an infestation of the corn root-aphis. The 

 eggs of the insect are laid by a wingless female 

 „_ aphis (fig. 13) which develops only in the 



/y.-^^^&fA\ fall of the year. The ants carry the aphis 

 I'T. ^mB\ ^ eggs into their nests, caring for them all win- 

 ter long, and in the spring when the eggs 

 hatch the young aphids are carried out and 

 placed in contact with the roots of certain 

 wild plants such as smartweed. If corn is 

 then planted in such infested places, the ants 

 transfer the aphids to the roots of the corn 

 plants, where they ccmtinue to live upon the sap, thereby robbing 

 the corn of its nourishment and often causing a heavy loss to the crop. 



CULTURAL PRACTICES FOR THE CORN-ROOT APHIS. 



Stir the soil thoroughly previous to planting. The object of this 

 procedure is to disturb the ant colonies and scatter and kill the aphids 

 so as to enable the plants to make a substantial growth before the ant 



Viv.. 13. — The coru root 

 aphis : Egg - laying fo 

 male. 



