ODD 



existed in the bags or storehouses used, that adults Hying from other 

 centres of infestation work their way into the bags, that infested 

 material may be used to protect wheat stacks, or that infested wheat 

 may be brought into contact with, or stacked near sound grain. 

 Treatment by poisonous gases is not considered practicable for bagged 

 grain, as the cost is prohibitive. Carbon bisulphide was found to 

 be expensive in use, while hydrocyanic acid gas used under similar 

 conditions, i.e.. with a temperature of 70°F., was found urLsatisfactory 

 even after 48 hours' fmnigation. Carbon dioxide was considered the 

 most effective for fumigation, 14'35 cubic ft. of gas being forced in 

 at the bottom of an air-tight silo containing 1 ton of grain. Drying 

 the wheat artificially or in the sun and then storing in air-tight 

 bins is considered sufficient to prevent weevil attack. Excessive 

 moisture, or a temperatiu-e of 80° F. without moisture, is fatal to the 

 weevils. 



Since fmnigation in the case of bagged wheat is so costly, obvious 

 precautionary measures are to prevent the weevil from gaining access 

 to the grain, by avoiding the possibilities of infection detailed above ; 

 such precautions however are difficult to carry out in practice. Tem- 

 perature and moisture are the primary considerations ; 10 per cent, 

 of moisture is essential to enable the weevils to breed and when the 

 wheat is put into bags it does not, imder ordinary circumstances, 

 contain nearly this amount of moisture, so that unless moisture is 

 added from without the grain will remain weevil proof. If stored 

 in a dr}- chmate therefore and kept completely protected from weather 

 and fi'om the absorption of moisture from the soil, the grain can be 

 stored indefinitely without danger from weevils. The prevailing 

 methods of transport and storage in Australia are apparently very 

 defective, especially as regards grain stored on the seaboard, where 

 the natural moistening of the grain by the damp air penetrating the 

 mass of bags is greatly accelerated by the methods of storage, as 

 these do not by any means afford complete protection from heavy 

 rains. 



Reports of Bureau Meetings. — Jl. Dept. Agric, S. Australia, Adelaide, 

 XX, no. 12, July 1917, pp. 1009-lOU. [Received 16th October 

 1917.] 



The most serious insect "pest of citrus trees in Pompoota,'^S. AustraUa, 

 is the red scale of the orange, Chrysomphnlus {Aspidiolus) aurantii. 

 Fumigation with hydrocyanic acid gas under gas-tight tents during 

 the winter months when the scale is dormant has proved the 

 most successful treatment. The quantity recommended is 1 oz. 

 cyanide of potassiiun 98 per cent., loz. sulphurio acid and 3 oz. soft 

 water, to 150 cubic ft, 45 minutes being allowed for the process. 

 Spraying with red oil emulsion has been used on some plantations 

 with success, and should further experiments prove that this method 

 is efficacious, the work of combating the pest will be light and easy. 

 Saissetia [Lecanium) oleae (black scale) is effectively dealt with by red 

 oil emulsion, the foliage being thinned before spraying. The weevil, 

 Otiorrkynchus cribricoUis, does considerable damage to young trees of 

 all kinds. As the adults hide during the day, generally just under 

 the surface of the soil, a bandage placed^round^the stem of the tree 



(C423) b2 



