COMMON GUM SCALE. 93 



undergrowth of gum saplings, killing out all badly -infested 

 plants, together with the scale attacking them. Large 

 trees of Messmate, Stringybark, and Peppermint, on account 

 of the loose stringy nature of their bark, suffer severely ; 

 but generally those of the smooth bark kinds, such as the 

 Blue Gum and the Giant Gum, escape with a severe 

 scorching, and in most cases will be but little the worse 

 for the fiery ordeal through which they have passed. This 

 is shown by the enormous size of some of our monarchs of 

 the forest, which, if they had been greatly affected by the 

 periodical fires of many years, would have long since 

 jperished. 



Where plantations are contemplated, a sharp watch 

 should be kept for the first indications of the presence of 

 this scale, as it increases with an almost incredible 

 rapidity. In small places, a few sprayings with a strong 

 kerosene emulsion will usually be effective ; but where the 

 scale has obtained a good footing and densely encloses the 

 branches, it will be found that the usual chemical treat- 

 ment will be of very little use. All seedlings before being 

 planted should be examined by an expert who has an eye 

 trained for the work, and any plant showing the least sign 

 of being affected should be rejected and burnt. 



In New Zealand, Mr. Kirk says that, since the initial 

 distribution of the Rhizobius beetle, the work accomplished 

 by this insect is little short of marvellous, and through its 

 means Eriococcus has been relegated to a position of 

 insignificance in the gum plantations of the south. In all 

 parts of the affected area the scale is being rapidly eaten 

 out, and around Timaru, the original centre of infection, 

 it has entirely disappeared, the rapidity with which Rhizo- 

 bius has multiplied being almost incredible. In January 

 of 1908, his assistant collected over 1,300 scales on ten 

 gum trees at Eolleston in a little over three hours. Thus 

 the numbers in a large plantation are almost beyond the 

 imagination. " In Australia, the balance of power is even 



