SCIENCE AND INDUSTRY. 
Wheat, Weevils and Bulk-Handling. 
" . By PROFESSOR W. A. HASWELL. 
INGE the Federal and State Governments have decided on the 
adoption of the method of bulk-handling in relation to wheat, 
the problem of dealing with destructive insects in the stored 
grain has assumed a new aspect. 
In the period 1916 to 1919, the problem which had to be dealt with 
was how best to combat the attacks of weevils on the vast stocks of 
bagged wheat destined, owing to war conditions, to remain stored in this 
country for a long period until sufficient shipping could be provided to 
relieve the congestion. 
When the conditions prevailing in the wheat stacks and storage sheds 
were examined, and the published results of various investigators of the 
wheat weevils and their life-history were studied, it became evident 
that, in order to get at the root of the evil, what had chiefly to be aimed 
at was the protection of the wheat from the access of moisture from any 
source during transit and storage. 
/ 
Weevils are incapable of attacking wheat of a ¢ertain standard of 
dryness.) The hardness which is involved in the presence of a scanty 
percentage of moisture in the substance of the grain, bafiles the mature 
female weevil in its endeavour to pierce it in order to provide lodgment 
and food for its eggs and larvwe; and no active multiplication of the 
pest can take place under such conditions. The percentage of moisture 
in the grain necessary for the rapid increase of the weevils is a relatively 
high one—about 10 per cent. of water is necessary. Freshly harvested 
wheat rarely contains nearly as much moisture as this, ‘and before the 
conditions necessary for the active multiplication of weevils in it can 
be established, the additional water must reach it in some way at some 
stage during its transport or storage. This may be’ brought about by 
the carriage in open waggons or railway trucks without tarpaulins 
during rainy weather; or the wetting may result from defects in the 
method of storage. To the latter set of causes was due a large part of 
the damage done by insect agency to the New South Wales wheat of 
1915-16, stored at Darling Harbour and White Bay; and that of 1916-17 
stored later at’ Enfield. The stacks were rodfed over with sheets of 
galvanized iron, supported on battens which rested directly on the built- 
up stack of wheat bags. In consequence of the direct dependence of 
the roof on the stack, when any subsidence of the latter occurred owing 
io the depredations of mice, or any other’ agency, the roof collapsed to 
a greater or less extent, and in the event of rain falling, the wheat 
might get a thorough wetting. Moreover, the slope of the roof was 
often insufficient, and the overlap of the galvanized-iron sheets inade- 
quate; while the hessian walls in close proximity to the sides of the 
stack, did not provide sufficient protection against heavy rains accom- 
panied by high winds. 
(1) This applies to the grain weevils proper (Calandra granaria and Q. oryzee), which in Australia 
are by far the most destructive insects occurring in stored grain, The grain-borer (Rhizopertha 
dominica) flourishes in dry grain. 
304. 
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