12 FAKMEES BULLETIN 891. 



individual farmer may protect his crop from early injury by the 

 corn root-aphis by cultivation or rotation, hut if neighboring heavily 

 infested fields are left untreated and the insect is permitted to live and 

 multiply undisturbed the migrating winged ajjhids may infest fields 

 previously free from them. This is especially likely to be the case 

 in 3^ears when the spring Aveather is of such a character that it per- 

 mits the root aphis to multiply but serves to delay corn planting. 

 It is therefore important that every farmer rotate his crops and culti- 

 vate his old cornfields so as to destroy the root-aphis and the attend- 

 ant ant colonies, whether he plans to replant them to corn or not. If 

 this be done by entire communities, this pest will soon be classed 

 among the corn insects of minor importance or among those known to 

 be only occasionally injurious. 



PUBLICATIONS OF UNITED STATES DEPARTMENT OF AGRICUL- 

 TURE RELATING TO INSECTS INJURIOUS TO CEREAL AND 

 FORAGE CROPS, AVAILABLE FOR FREE DISTRIBUTION BY THE 

 DEPARTMENT. 



Common White Grubs. (Farmers' Bulletin 543.) 



Larger Corn Stalk-borer. (Farmers' Bulletin 634.) 



Chalcis-fly Alfalfa Seed. (Farmers' Bulletin 636.) 



Grasshopper Problem and Alfalfa Culture. (Farmers' Buletin 637.) 



Hessian Fly. (Farmers' Bulletin 640.) 



Alfalfa Attacked by Clover-root Curculio. (Farmers' Bulletin 649.) 



Chinch Bug. (Farmers' Bulletin 657.) 



Wireworms Destructive to Cereal and Forage Crops. (Farmers' Bulletin 725.) 



True Army Worm and its Control. (Farmers' Bulletin 731.) 



Corn and Cotton Wireworm in its Relation to Cereal and Forage Crops, with 

 Control Measures. (Farmers' Bulletin 733.) 



Clover Leafhopper and its Control in eutral States. (Farmers 'Bulletin 737.) 



Cutworms and their Control in Corn and other Cereal Crops. (Farmers' Bulle- 

 tin 739. ) 



Alfalfa Weevil and Methods of ontrolling It. (Farmers 'Bulletin 741.) 



Grasshopper Control in Relation to Cereal and Forage Crops. (Farmers' Bul- 

 letin 747.) 



Fall Army Worm, or " Grass Worm," and its Control. (Farmers' Bulletin 752.) 



How to Detect Outbreaks of Insects and Save the Grain Crops. (Farmers' Bul- 

 letin 835.) 



Bollworm or Corn Earworm. (Farmers' Bulletin 872.) 



Rough-headed Corn Stalk-beetle in Southern States and its Control. (Farmers' 

 Bulletin 875.) 



Corn Root-aphids and Methods of Controlling It. (Farmers' Bulletin 891.) 



Western Corn Rootworm. (Department Bulletin 8.) 



Oat Aphis. (Department Bulletin 112.) 



Alfalfa Caterpillar. (Department Bulletin 124.) 



Wireworms Attacking Cereal and Forage Crops. (Department Bulletin 156.) 



Sharp-headed Grain Leafhopper. (Department Bulletin 254.) 



Desert Corn Flea-beetle. (Department Bulletin 436.) 



New Mexico Range Caterpillar and its Control. (Department Bulletin 443.) 



Two Destructive Texas Ants. (Entomologj- Circular 148.) 



WASHINGTO.V : GOVEBNMEXT PRINTING OFFICE ; 1917 



