INSECTS INJURIOUS TO CEREALS 



263 



effective method of dealing with the grain weevils is by 

 the use of carbon bisulfide. It has been shown, by 

 recent experiments, that this liquid should be used at 

 the rate of 2 or 3 pounds to every 1000 cubic feet of 

 space. 



One of the best methods of keeping seed corn, seed peas, 

 beans, popcorn, and other seeds, is to store them in tight 

 dry goods boxes. The boxes should be filled within 3 or 

 4 inches of the top. When infested with 

 the weevils, the required amount of the 

 carbon bisulfide may be poured into a 

 shallow tin basin or pan and set on top 

 of the grain. The top of the box should 

 then be covered with two or three heavy 

 blankets to keep in the fumes. The 

 liquid will readily evaporate and the 

 heavy gas will settle down through the 

 grain killing everything in it. 



The precaution should be taken of 

 not going near the boxes with a lighted Fig. 83 

 lantern or fire of any kind until after 

 the blankets have been removed and the 

 gas has dissipated itself in the surrounding atmosphere. 



Of course, where a cereal or box of crackers is found to 

 have become infested by the weevils it may be necessary 

 to throw them away entirely. An infested pantry or 

 storeroom should be carefully cleaned and all the rem- 

 nants of material that may be attractive to the weevils 

 thrown away. If a storeroom is so situated that a 

 continuous heat of 130 degrees can be maintained for 

 several hours, the weevils in all of their stages may be 

 killed. 



Pupa of 

 the rice weevil. 

 (X 10.) 



