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DESTRUCTIVE INSECTS OF VICTORIA 



of chemicals and water, will be found suitable for districts 

 in the interior or beyond 10 miles in a direct line from 

 the sea-coast : — 



" One would suppose that an orange tree having a dense 

 foliage would fill up the space within the tent, and require 

 less gas to be effective. But the cold surface of the leaves 

 condenses the gas, and fumigators find that a slightly 

 heavier charge of chemicals is necessary for such a tree, 

 and where the foliage is scant a less amount than is given 

 in the table will answer. Some orchardists and fumi- 

 gators consider that the work has not been effective un- 

 less some of the leaves or tender twigs have been injured. 

 This is not necessary, for in our early experiments we 

 have treated trees and killed the scale without even in- 

 juring the most tender twig or blossom. As the trees 

 recover very quickly, even when seriously scorched, a 

 slight burning is no detriment, and is evidence that the 

 work has been effective, except in the case of ' black 

 scale ' (^Lecanium oiece)^ during the early summer, when 

 the eggs are under the females. The proper time to 

 fumigate for this scale is during the fall or early winter, 

 when they are in the larval state. 



