BUREAU OF ENTOMOLOGY. 245 



amperage in the lubes, (3) distance of treated material from the 

 focal support of the tul)e, and (4) length of treatment necessary to 

 destroy insect life. The experiments w\\\ be closed when the cost per 

 volume of treated material has been determined for the various 

 species of stored-product insects examined. This will enable manu- 

 facturers to calculate easily the expense of X-ray sterilization and to 

 determine whether it is practical for their purposes. The value of 

 this form of treatment of stored-product insects lies in the fact that 

 it is possible to sterilize sealed cartons and thus guard against 

 infestation. 



A general investigation of the different ways of storing grain was 

 made by agents in the field that the possibilities or probabilities of 

 infestation, the degree of cleanliness, and the practicability of fumi- 

 gation in each case might be determined. 



A new enemy of rice and other stored products has been investi- 

 gated and the work is nearly completed. The rice weevil was found 

 in piles of straw thrashed in each of the years 1913, 1914, and 1915, 

 and in shocked corn in the field. Much advice has been given in 

 regard to the weevils injuriously affecting beans, peas, cowpeas, and 

 other edible legumes. Nearly a dozen species of these weevils are 

 under consideration, and new facts have been learned in regard to 

 their life history and the effect of cold as a remedy. Observations 

 were made o«ti the successful heating of a flour mill at Dodge City, 

 Kans., to destroy the Mediterranean flour moth. 



For several years no one has been able to explain why the Angou- 

 mois grain moth has been very injurious in portions of Pennsylvania 

 and not so injurious in adjoining States. Investigations by this 

 bureau in April, 1917, showed that the wheat growers in the vicinity 

 of York and other'sections of Per.nsylvania have a custom of cutting 

 the crop with a self-binder from the latter part of June to the first 

 of July, after which it remains in shock three or four days and is 

 then carried directly into the barn for " curing," provided the 

 weather permits. Grain and straw are stored in bundles in the 

 large, well-built barn mows in Pennsylvania and thrashed out at any 

 time convenient to the grower. On April 30 it was ascertained that 

 many farmers had not thrashed their grain, and others had just 

 finished. The barns in which the grain is stored are ordinarily of 

 stone, extremely well constructed, and, being warm, are especially 

 conducive to injury by the Angoumois grain moth, as in the dark 

 portions of such barns this insect can develop throughout the winter. 

 In Maryland and Virginia the grain crops are thrashed as soon after 

 harA'esting as possible, and the grain is stored in cool repositories. 

 The farmers of Pennsplvania have been advised to thrash their grain 

 by the middle of August and to store it in tight Osnaburg sacks as 

 a preventive of injury. The barns, of course, must be fumigated 

 thoroughly with carbon disulphid or hydrocyanic-acid gas and be 

 cleaned well before storage. A loss of from 16 to 25 per cent of the 

 wheat is common in the State, and one cleaner is known to have 

 cleaned as much as 25 pounds of infested grain from one bushel of 

 wheat sent to his mill. With a total change of practice, including 

 earl}^ thrashing, cold storage, the employment of fumigants. and 

 careful cleaning up of infested barns, the State soon should be rid 

 of this pest. 



