46 



favorable to their growth were to all appearances 

 perfect. These trees were treated with organic 

 nitrogenous manures applied in liquid form, from 

 one to three applications being given, and within a 

 year from the first application the mottled leaf had 

 disappeared and the trees were making strong, 

 healthy growth. 



ORANGE SCALE. 



Red Scale is a small circular insect of a reddish 

 brown color, which increases very rapidly under 

 circumstances favoring its growth, which are moist 

 and muggy atmospheric conditions. The only effec- 

 tive way of getting rid of it is by fumigating the 

 trees with hydrocyanic acid gas, which is generated 

 by treating potassium cyanide with a diluted solu- 

 tion of sulphuric acid. Fumigation is done in the 

 night time, the gas being liberated under a tent, 

 which covers the tree. For 100 to 150 cubic feet of 

 tent space the amount of ingredients generally used 

 are 1 oz. potassium cyanide, 1 oz. sulphuric acid, and 

 3 ozs. of water. 



The red scale, which is the most harmful of all 

 insect pests to the orange tree, has up to the present 

 time not made its appearance among the orange 

 groves of the South Australian portion of the Upper 

 Murray Valley. 



Brown Scale. This variety of the genus of Leca- 

 nium, or unarmored scales, is fairly well known to 

 the citrus growers of the Murray Valley. The full- 

 grown insect is about one-eighth of an inch long, 

 broadly oval, convex upon the disc, surrounded by 

 a thin flat margin, and of a brownish color. The 

 scale thrives upon the bark and leaves of the branches 

 of the tree by sucking out the sap, and is generally 

 found in the greatest numbers in situations not 

 directly exposed to the sun. 



