UNITED STATES DEPARTMENT OF AGRICULTURE 



| BULLETIN No. 872 { 



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Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



Washington, D. C. 



November 11, 1920 



INSECT CONTROL IN FLOUR MILLS. 



By E. A. Back, 

 Entomologist in charge of Storcd-Product Insect Investigations. 



CONTENTS. 



Page. 



Mill insect conditions bettered 1 



Incentive leading to insect sanita- 

 tion i 1 



Mediterranean flour moth 2 



Page. 



Methods of control 7 



Preventive measures 7 



Natural control by parasites 11 



Artificial control measures ._ 11 



Conclusion 39 



MILL INSECT CONDITIONS BETTERED. 



The control of insect pests in flour and cereal mills has become a 

 very important feature of food conservation and of mill construction 

 and operation. The cleanliness of many of the well-lighted, concrete 

 mills, such as are being built more frequently now than ever before, 

 and their comparative freedom from pests, are emphasized by the 

 conditions that exist in old-type structures. These latter offer insects 

 every advantage in their fight against the miller. It is true that many 

 of these older mills are established in rambling, loosely constructed 

 buildings that can be neither properly cleaned, from the standpoint of 

 insect destruction, nor made tight for the application of successful 

 control measures. Fortunately the losses caused by insects to the mill 

 owners and the advantages of modern construction are working hand 

 in hand to bring about a constant change for the better. With modern 

 equipment installed in buildings erected with a view to suppressing 

 insects, more millers are joining the ranks of those who know that 

 they can control insects and offer the public a product reasonably free 

 from infestation. 



INCENTIVE LEADING TO INSECT SANITATION. 



Owners of flour mills are frequently blamed by brokers, retail 

 grocers, and the public at large for insect infestations found in their 

 products when these appear on the market or in the home. Sometimes 

 the miller is to blame ; often he is not. It is, however, within his 



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