The Indian Wheat and Rice Weevil. 



He writes : — 

 " The only cheap and perfect application for the prevention of the attack of weevil 

 upon corn and grain consists in the employment of bisulphide of carbon. The quantity 

 required, provided the grain is kept in closed vessels, is very minute, not more than IJlbs. 

 to each ton of grain, so that 8d. is the cost of preserving a ton of wheat.' The bisulphide 

 leaves no disagreeable taste or smell behind, but the quality of the grain remains unimpaired. 

 When bags are used instead of the iron cylinders, specially prepared for use in the bisul- 

 phide process, the protective influence of this chemical soon ceases, and a fresh application 

 of the bisulphide must be made. In either case this liquid is applied as follows : a ball of 

 tow is tied to a stick of such a length that it can be just plunged into the middle of the 

 vessel containing the grain. The tow receives the charge of bisulphide like a sponge, and 

 is then at once plunged into the sack or cylinder and left there, the mouth being tightly 

 closed. When necessary the stick may be withdrawn and the charge (of 1 oz. of bisul- 

 phide to 100 lbs. of corn) may be renewed." 



Mr. L. O. Howard, of the Uuited States Department of Agriculture, 

 Division of Entomology, writes in a letter which will be found in full 

 in the appendix : — 



" It is, however, considered a very good idea here Jin America to establish a large 

 ' quarantine ' bin into which all grain is put after receipt and disinfected by means of 

 a little bisulphide of carbon. It is then removed and stowed away. The bin in question 

 must be made as tight as is possible, and the method of using the bisulphide is to place 

 a pound or so in a shallow vessel on top of the grain. The vapour of this rapidly volatiliz- 

 ing substance is heavier than air and sinks through the mass destroying all contained 

 insects. Care should be taken in its use on account of its extreme inflammabilitj'. 

 The airing which the grain will get in removing it from the bin will probably be sufficient 

 to rid it of the odour." 



Mr. F. W. Cahaniss recommends the use of naphthaline powder, 

 which he says will drive out some of the weevils and kill the rest, 

 without injuring the grain for germinating or for the market, as the 

 odour leaves it in a short time, the powder evaporating completely and 

 hence not affecting the grain for food purposes. Further investigations 

 on the subject would, however, appear to be desirable. 



Mr. Cabaniss writes : — 

 " It is best to pliice the naphthaline powder at the bottom of 'the bin or bulk of 

 grain. To accomplish this, take a bamboo about \k inches in diameter and long enough 

 to reach from the top to the bottom of the bulk of grain. Punch the joints out of the 

 bamboo so as to be able to pass a stick through from one end of the bamboo to the other. 

 Have the stick made to fit the cavity in the bamboo. Pass the bamboo with the stick 

 in it down through the bulk of grain from the top to the bottom. Withdraw the stick 

 and drop into the top of the bamboo about half a tenspoonful of naphthaline powder. 

 The bamboo can then be drawn out as the naphthaline is safe at the bottom of the bulk 

 of grain. If the bulk is large this should be done one to every 10 feet square of the 

 bulk. Repeat the application every 15 or 20 days as the powder evaporates." 



Of all the remedies which have been suggested, the most effective 

 is, no doubt, to grind up the grain, or to heat it in an oven, to kill the 

 insects, but this will probably, in the majority of ca;es, be impracticable; 



' Bisulphide of carbon can now be bought at about tw ,lve annas per pound in 

 Calcutta. 



