88 ENTOMOLOGICAL SOCIETY OF ONTARIO. 



INSECT FOES OF AMERICAN CEREAL GRAINS, WITH MEASURES FOR 

 THEIR PREVENTION OR DESTRUCTION. 



By F. M. Webster, Wooster, Ohio. 



The three principal cereal grains of America north of Mexico, viz., maize, wheat and 

 oats, cover an approximate area of from 140,000,000 to 150,000,000 acres. In other 

 ■words, the natural flora over this vast territory, comprising a great variety of species, has 

 been largely exterminated, and, instead, but three have been substituted, all of which are 

 annuals with a capacity for reproducing each year from twenty to two thousand fold. As 

 nature is said to abhor a vacuum, so does she resent a monopoly, except it be in cases 

 where but few species can exist, and the increase of the individuals of these are ultimately 

 restricted by other influences, such as a rigorous climate or a barren soil. Our grain 

 fields include neither the barren desert, the frozen mountain tops nor the ice-clad regions 

 of the far north, but the fertile prairies and valleys over which vegetation naturally grows 

 in great luxuriance and profusion, each species, if left to itself, being kept in its proper 

 numerical sphere by natural laws. The agriculturist, however, comes upon the scene 

 and incites an insurrection, causing the three species bsfore mentioned to not only rebel, 

 but overrun and take possession of these broad acres, putting the original inhabitants to 

 death and establishing themselves in nearly or quite full power. If the contest were 

 wholly a natural one, the interlopers would soon be forced into their proper places, and 

 exist only in proportion as they could resist the returning encroachments of the natural 

 flora. But the plow and the hoe again interpose, and the victors still hold the field. 

 Nature then does what is naught but good generalship, brings up her reserves in the 

 animal and vegetable enemies of the three usurping species and precipitates them upon 

 the foe. It is hei'e that the hand of the husbandman seems to lose its cunning. He can 

 fight the forests, the weeds and the grasses, but when it comes to warring upon the in- 

 sects and fungoid enemies of his grains he seems to lose heart. His reserve force is, or at 

 least should be, in his superior knowledge ; but too often this virtue seems to be either 

 sadly aborted or entirely wanting. He does not study ways to destroy or circumvent 

 these enemies of his crops, but, on the whole, allows them to go their way, patiently 

 taking what they leave and hoping for better luck another year. 



It is here that I wish to take up my subject and show how many of the insect foes 

 may be either destroyed or prevented from inflicting serious injury. The field of applied 

 entomology is not the science of killing insects, alone, but includes also the warding off of 

 their attacks. For my own part I would reverse these terms, as it seems to me that the 

 evasion of an attack is ordinarily the most important. I would put it in this way : 

 Warding off the attacks of injurious species by preventing their breeding, and, in case 

 this is not practical, destroying them either before or after the attack had begun. And 

 I may be allowed to here make use of an oft-quoted adage, " An ounce of prevention is 

 better than a pound of cure." 



There are upwards of 140 species of insects affecting these three grain crops, and 

 maize alone has over 100 insect foes, a number of course depredating alike upon all three. 

 Of these, such as infest the stored grain excepted, there are very few whose attacks can 

 not be far more easily warded oS" than remedied after they have begun. I know of no 

 better insecticide than good farming. After eight years of study of the Hessian-fly 

 (Gecidomyia destructor) I am satisfied that four-fifths of its injuries may be prevented 

 by a better system of agriculture. For years I have seen wheat grown on one side of a 

 division fence without the loss of a bushel by attack of this pest, while on the other side 

 the crop was almost invariably more or less injured. No effect of climate, meteorological 

 conditions, or natural enemies could have brought about such a contrast of results. The 

 whole secret was in the management of the soil and the seeding. In fact, the question of 

 success in evading the pest, in the one case, did not appear to be an entomological one at 

 all ; and I am fully convinced that the Hessian-fly problem, so far as it relates to agri- 

 culture, throughout that portion of the country lying between the Alleghany Mountains 

 and the Mississippi River, and between the Ohio River and the Great Lakes, may be 

 considered practically solved. 



