86 



INJURIOUS INSECTS AND FaNQI. 



[Juno 1895. 



All granaries and corn stores should be well ventilated and 

 kept as airy and cool as possible. Floors and beams, wooden 

 partitions, bins, and panellings, should be thoroughly scrubbed 

 and washed with thick soft soap solutions. Walls and ceilings 

 should be plastered so as to have smooth surfaces, which should 

 bo limewashed from time to time. 



- As the Sitophilus or^/m^ requires considerable heat, the fre- 

 quent moving of stored grain, the aeration of granaries and 

 stores and the admission of cold air will stay, or materially check, 

 the actions and multiplication of this species. The same pre- 

 cautions will be to some extent effective against the Sitophihis 

 granaria, but unless great care is taken there may be a large 

 and rapid increase in the numbers of this species, and consequent 

 nnportant damage to grain. The fumes of bisulphide of carbon 

 have been proved to be destructive to these weevils, but there 

 is some difficulty in concentrating and applying them, and this 

 could only be done by putting infested grain into receptacles 

 made as air-tight as possible — large galvanized iron tanks, for 

 instance- — and placing an open vessel containing bisulphide of 

 carbon on the top of the grain within the tank. As is well 

 Imown, the fumes of bisulphide of carbon are heavier than air, 

 and will, therefore, soon sink down into, and thoroughly per- 

 meate, the whole mass of grain within the receptacle, and destro}^ 

 all insects therein. From to 2 lbs. of bisulphide will be re- 

 quired for each ton of grain according to the air-proof qualities of 

 the tank. No harm is caused to the grain, but great care must 

 be taken in handling and dealing with the bisulphide as it 

 is most inffammable. Bisulphide of carbon can be used in bins 

 and other receptacles that are not wholly air-tight, but in such 

 circumstances much more of the substance would be required, 

 and the results are necessarily less satisfactory. 



On account of tlie almost certain introduction of weevils into 

 all granaries and corn stores in imported wheat, it is essential 

 that measures should be taken to prevent British grain from 

 being infested by keeping foreign grain separate, if possible 

 and by thoroughly cleansing and aerating places that are 

 infested. Foreign grain is infested in the dirty granaries in 

 which it is placed before being shipped. Some infestation 

 occurs in the holds of the vessels. This has been somewhat 

 diminished in recent years as the duration of the voyages has 

 been so much lessened, and far greater attention is now paid to 

 cleansing and purifying the holds after grain cargoes have been 

 unloaded. It need hardly be said that it is most important 

 that every effort should be made to keep ships' holds free from 

 these and other pests of similar habits, in order that grain which 

 is put on board clean and free from infestation may not run 

 any chances of becoming infested and damaged during transit. 



