INSECT ENEMIES OF WHEAT 181 



foods, but the insect thrives on the other cereals also, and on 

 orchard grass. Late sowing is a preventive measure. 



Other Insect Enemies. The most important of these are the 

 wheat straw-worms, the wheat bulb worm, the cut-worms, the 

 joint worm, several species of sawflies, and the army worms. 

 The damage caused is local and not great. Most of them can 

 be more or less controlled. 



The total loss from insect enemies of growing wheat is es- 

 timated to average at least 20 per cent of the crop. That is, 

 in the absence of attacks from these pests, the wheat crop 

 would have a value approximately $100,000,000 greater than it 

 now has. 



General Remedies. Cultivation upsets the equilibrium es- 

 tablished by nature. The resulting environment may be so 

 favorable for the development of an insect as to enable it to 

 multiply beyond all previous proportions. The most obvious 

 remedy is to render the conditions unnatural for the insect 

 concerned. Intelligent control presupposes a working knowl- 

 edge of the insects to be controlled, and frequently the first 

 step to be taken by the American wheat grower is the gaining 

 of this knowledge. Entomological difficulties must be forecast 

 and forestalled. The state agricultural experiment station or 

 the Department of Agriculture can always aid in this, for there 

 is a fairly effective remedy known for every insect of great 

 importance. 



Where such large areas are involved as in wheat raising, 

 remedies must be largely preventive and general. Summer fal- 

 lowing and crop rotation are the most effective. These re- 

 sult fatally for many insects which are not equipped for en- 

 countering the sudden destruction of vegetation, or the abrupt 

 displacing of one kind by another. Even if insects are able to 

 migrate from one field to another, disaster from adverse winds, 

 storms, heat or cold may result to the migrants, especially if 

 they are such frail insects as the Hessian fly or the wheat 

 midge. Good seed should always be sown, and in well prepared 

 soil, for a vigorous crop can best withstand attacks. 



Insect Enemies of Stored Wheat. Several species of insects, 

 popularly known as weevils, cause extensive injury to stored 

 wheat. Commerce has distributed them to all quarters of the 

 globe. In warm climates these insects live an outdoor life, 



