2 BULLETIN 872, U. S. DEPARTMENT OF AGRICULTURE. 



power, if he is the owner of a well-constructed mill, so to control pests 

 that he can state, with honesty, that the product he places upon the 

 market is reasonably free from insects, including their eggs, and 

 that if infestation develops soon after his product has been ware- 

 housed or otherwise disposed of, the infestation is due to one or more 

 of several known conditions for which he is in no way responsible. 



There has persisted among many millers, as well as consumers, the 

 belief that the egg or " germ " of insects is within the grain at the 

 time it enters the mill and that it goes uninjured through the milling- 

 process to lie dormant in the finished product until such time as con- 

 ditions of warmth and moisture favor its development. This belief 

 rests upon a false foundation. The ordinary destructive insects that 

 infest grain or flour or any cereal product lay eggs large enough to 

 be readily seen by an experienced eye once they are separated from 

 the host material. They are all so large that they can not pass 

 through the meshes of No. 10 XX silk bolting cloth. Since this is 

 true, even badly infested flour can be reprocessed and rendered ab- 

 solutely free from pests if bolted through a No. 10 XX or finer cloth. 



It is possible to produce flour entirely free from infestation as it 

 comes from the bolting machines. If it is sacked in containers upon 

 which no eggs have been laid or in which no larvae are present, and is 

 stored in a warehouse in which there is no infestation, it will leave the 

 mill free of infestation. If such a product shows infestation by the 

 time it reaches its destination, it has become infested while en route. 

 To guarantee a product leaving the mill establishment as free from in- 

 festation is so entirely within the bounds of reason that one wonders 

 whether certain millers should be permitted to ignore insect infesta- 

 tions and put upon the market supplies that are invariably infested. 



MEDITERRANEAN FLOUR MOTH. 1 



MEDITERRANEAN FLOUR MOTH MOST SERIOUS MILL PEST. 



While there are many insects that may become troublesome in flour 

 mills, it is the Mediterranean flour moth alone that seriously affects; 

 the operation of the mill and has brought with its advent from 

 Europe into the mills of the United States losses that have forced 

 millers to consider insect suppression. The weevils and other gran- 

 ary pests which are brought into mills with grain, and the flour 

 beetles or "bran bugs" which become established in practically all 

 mills sooner or later, will not be discussed in this bulletin, though 

 they must be taken into consideration by millers. The remedial 

 measures advocated for the suppression of the Mediterranean flour 

 moth, with cleanliness will hold these nonwebbing insects in check. 



' Ephestia kuehniella Zell. 



