INSECT ENEMIES OF WHEAT 185 



a ton and a half of sulphuric acid were used. Only two living 

 Avorms and one moth were found, after the operation. It will 

 perhaps require years for the mill again to become so infested as 

 to need another treatment. 



There is no weevil-proof wheat, but the small, hard-grained 

 varieties are little troubled by insects. Advantageous prac- 

 tices for prevention are prompt threshing, inspecting, quaran- 

 tining and disinfecting grain and everything connected with it; 

 scrupulous cleanliness; construction of warehouses and mills to 

 exclude insects; use of improved machinery in mills; and stor- 

 age in large bulk in a cool, dry, well-ventilated repository. 1 



General Needs and Results. With a better and increasing 

 knowledge of farm management, of cultural system, and of the 

 natural destroyers of wheat, it should require less than a gen- 

 eration of time to double the yield of wheat per acre. Thirty 

 per cent is certainly a very reasonable figure to represent the 

 average annual loss to wheat from attacks by natural agencies 

 of destruction. One of the greatest immediate needs is to im- 

 press the wheat grower with the fact of this loss, for it is often 

 little realized, especially when it results from invisible or un- 

 perceived instrumentalities of disease that secretly tread their 

 way through field and plant over great areas of the wheat 

 regions. 



To minimize the effects of this great host of natural de- 

 stroyers of wheat is a task that is profitable, certain of re- 

 ward, and most imperative in its demands for attention. Since 

 wheat is raised the world around in temperate zone climates, 

 there is little danger of a world famine in wheat on account of 

 their combined effects, for there is always a great probability 

 that large areas will meet with normal conditions. An unusual 

 coincidence of abnormal conditions over wide regions in differ- 

 ent parts of the world may, however, raise the price of wheat 

 and greatly change the magnitude and direction of the com- 

 mercial streams of wheat over the entire world. Such a 

 coincidence occurred in 1897, when the world's wheat crop was 

 greatly reduced by drought in India and Australia, by whole- 

 sale destruction from insect pests in Argentina, by a wet har- 

 vest in France, and by inundation of the wheat fields of Aus- 

 tria-Hungary. 



1 Chittenden, Some Insects Injurious to Stored Grain. 



