PROCEEDINGS FOR 1917 XV 



Canadian Conditions as Affecting Losses. 



In view of the occurrence in Canada of a number of grain-infesting insects, 

 which are responsible every year for considerable losses to certain classes of stored 

 grain and grain products, it might be assumed, in view of the enormous amount of 

 grain produced in Canada and stored for shipment, that the losses from grain in- 

 festing insects might be serious, as is not infrequently the case in other parts of the 

 world. Fortunately, however, there exist two factors which are operative in Canada 

 in an economically favourable direction, namely, short storage and climate. 



The greater portion of the grain, such as wheat, oats, barley, etc., produced in 

 Canada is stored in the grain elevators and other places of storage for a comparatively 

 short time; the period depending largely upon the conditions of the world's grain 

 markets. The statistics respecting the Canadian wheat crop of 1915, which are the 

 latest complete figures available, illustrate this fact clearly. In the "Census and Sta- 

 tistics Monthly" (Department of Trade and Commerce), Vol. 9, January 1916 

 it is stated that the balanceof the 1915 crop available for export amounted to 264,- 

 173,200 bushels. In the Weekly Bulletin (Department of Trade and Commerce) 

 Vol. 15, No. 671, December 4th, 1916, the total quantity of wheat stored at terminal 

 elevators, interior elevators and public elevators in the East for the week ending 

 November 24th, 1916, was stated to be 20,991,108 bushels. These figures show how 

 comparatively quickly the grain crop moved and how little, if any, is stored in the 

 elevators for a sufficient length of time to permit damage by insects affecting stored 

 grain. 



The extremely low winter temperatures that prevail in the districts where grain 

 is stored would have a controlling effect on insects infesting grain stored in unheated 

 buildings. 



On account of the aforementioned facts, and especially the rapid movement of 

 the grain crop, serious losses to stored grain are not experienced in the elevators 

 where the main portion of Canadian grain is stored. Our experience is confirmed by 

 reports submitted to me by the Board of Grain Commissioners of Canada; one of 

 their oldest inspectors reported that during an experience of over thirty years manag- 

 ing terminal and storage elevators he had never met a single instance of deterioration 

 or injury to grain caused by insects while in store. 



Insects Affecting Stored Grain in Canada. 



Where grain is stored for two or more years in warehouses or other buildings, 

 particularly if they are heated, losses are liable to occur in Canada through infestions 

 of a number of species of insects that attack grain and stored products. The com- 

 monest of these are the grain weevil Calandra granaris L., and the rice weevil C. 

 oryzae L., both of which are introduced insects. There are a number of species of 

 insects which we have found attacking stored products such as (lour and meal and 

 which will readily' breed in grain stored in the neighbourhood of such products. 

 Among these may be mentioned the flour beetles Triboliiim conftisum Duval, and 

 T. jerrugineus Fab., the saw-toothed grain beetle Silvanus surinamensis L., the ca- 

 delle Tenebrioides 7naiiritanica L., and the flour and meal moths Ephestia kuehntella 

 Zell., Plodia inter punctella Hbn., and Pyralis Farinalis L. Occasionally the An- 

 goumois grain moth Sitotroga cercalella Oliv., and Tinea granella L., are found 

 causing damage to stored grain. 



Control Measures. 



Carbon bisulphide: Fumigation with carbon bisulphide has been successfully 

 used for many years in Canada for the destruction of insects affecting grain and other 

 stored products. Experiments have shown that it is inadvisable to attempt to fumi- 

 gate at a temperature of 60 degrees F. or lower. At a temperature of 70 degrees F. 

 and higher the use of four pounds of carbon bisulphide to every thousand cubic feet 

 of space is recommended and the fumigation should last for thirty-six hours; if the 

 grain is not to be used for seed an exposure of forty-eight hours to the fumes may be 

 allowed with good results. 



Hydrocyanic Acid Gas: This common mode of fumigation has not been found 

 entirely satisfactory for these insects as the gas does not appear to have sufficient 

 power of penetration under ordinary conditions to kill the insects in every stage. 



