168 



bottles stowed that the weevils died in a fortnight. A tube that 

 had been sealed for 5 days showed a content of 15 per cent, carbon 

 dioxide and this was sufficient to kill the weevils. These experiments 

 indicate the possibility of enclosing stacks with a covering of malthoid, 

 making them as airtight as possible and then pumping in carbon 

 dioxide. An experiment on these lines was carried out with 8,500 bags 

 of heavily infested wheat. Inside the malthoid 10 to 15 per cent, 

 of carbon dioxide was maintained continuously. Gas was generated 

 by passing air over a bed of hot coke in a furnace, with the object 

 of obtaining a mixture containing as nearly as possible 80 per cent, 

 nitrogen and 20 per cent, carbon dioxide with no free oxygen. The 

 purpose was to displace all the oxygen and thus render the oxygen 

 content too low to support life. The experiment was highly successful, 

 no living weevils being found in the stack though there were millions 

 of dead ones. It is evident that weevils can be destroyed by this 

 means without handling the wheat. Though it is impossible to make 

 the malthoid enclosure absolutely air-tight, the continuous passing 

 in of nitrogen and carbon dioxide enables the asphyxiating atmosphere 

 to be maintained. Larvae and pupae as well as adults were destroyed 

 by this process, but it is not yet known whether the eggs can survive 

 it. It was pointed out that a malthoid covering is an absolute 

 protection, neither insects nor mice being able to penetrate it. "With 

 regard to the salt-water treatment that has been recommended for 

 old bags, etc., on the seaboard, it has been found that the weevils 

 can live for nine days in sea-water and can also survive five hours in 

 methylated spirit. 



The meeting expressed satisfaction with the work carried out by 

 the South Australian WeevU Committee and recommended that the 

 investigations should be continued. These should deal with the 

 examination of insect-infested grain from all parts of the Common- 

 wealth ; investigations into the life-history of the insects causing 

 the damage, and a study of such factors as temperature, moisture 

 and aeration ; an estimation of the water content of such wheat in 

 various conditions ; recording of the changes in the water content 

 during maturation and dormancy af the grain and co-ordination of 

 these changes with atmospheric conditions and experiments on the 

 degree and rate of absorption of water in atmospheres artificially 

 charged with moisture. The South Australian Committee should 

 also continue their experiments on the effect of hermetically sealing 

 wheat and its influence on vitality, with investigations on heat 

 treatment and its effects on the vitality of wheat and its keeping 

 and milling properties. It was also suggested that the effect of lime 

 should be further investigated. 



Brittain (W. H.). Practical Results in Spraying a Commercial Orchard 

 for the Green Apple Bug. — Canadian Entomologist, London, Out., 1, 

 no. 12, December 1918, pp. 393-397. 



Operations demonstrating the control of the Capsid, Lygus communis 

 var. novascotiensis, Knight (green apple bug), in an apple orchard 

 taken over for that purpose during 1917, prove the advantage of 

 prompt and thorough spraying for this pest as soon as infestation 

 is observed, the benefit being evident even when only a single year 



