134 INSECTS INJURIOUS TO STAPLE CROPS. 



not It^iy her eggs upon plowed land, if the land he plowed 

 early she will he driven to other fields; hut the exact time 

 of oviposition varies for different latitudes. 



Generous fertilization Avill aid the plants in overcoming 

 injury very considerahly. Dr. J. B. Smith advises "the 

 application of all the necessary potash in the form of 

 kainit, put on as a top-dressing after the field is prepared 

 for planting," and sa3"s: "Fall plowing and kainit as a 

 top-dressing in spring will, I feel convinced, destroy by 

 all odds the greater proportion of the web worms that in- 

 fest the sod, and would also destroy or lessen many other 

 pests which trouble corn during the early part of its life.'' 



The Corn Root-louse (Aphis maidiiuaUcis Forbes). 



Description. — Where joatches of corn become dwarfed, 

 the leaves becoming yellow and red, with a general lack 

 of vigor, one may well be suspicious of the work of the 

 Corn Root-louse. Though such an appearance may be 

 due to the Root-blight or the Grass Root-louse [Schizo- 

 neura panicola Thos.), the cause of the trouble may 

 usually be ascertained by an examination of the roots. If 

 due to root-lice, they will be readily seen gathered 

 together in large masses. The Root-louse may be recog- 

 nized by being of a blnish-green color, with a white, waxy 

 bloom, of an oval form, with two short, slender tubes 

 projecting from the posterior part of the abdomen. These 

 have open ends and were formerly supposed to excrete the 

 sweet liquid " honey-dew '' upon which the ants feed, and 

 were therefore called " honey-tubes. '^ If the Grass-louse 

 be the depredator, however, it may be recognized by its 

 white color, its blackish head and markings, and the 

 absence of the honey-tubes, their position being indicated 



