THE OLIVE 



127 



when diluted with water, are nevertheless too much weakened for 

 effective use against scale insects. 



The reason that high fire test kerosene is recommended as an in- 

 secticide is, that the lighter oils with which it is associated in a 

 crude state, have been eliminated by the refining process, these be- 

 ing exceedingly deadly to vegetation, leaving the refined kerosene 

 which should always be used for this purpose. The heat of the 

 sun increases to an injurious extent the action of kerosene, and 

 stronger solutions than that above given if used at all, should be 

 applied on cloudy days or in the evening. 



Experiments with different grades of refined oil, the Elaine 

 amongst the number, show that they all emulsify equally well if 

 the alkali contained in the soap is of sufficient strength. But the 

 Elaine separates the soonest. 



The kerosene wash should be applied in a fine spray from the 

 center of the trees, and not the least of its recommendations will be 

 its very great economy. 



In addition to insect pests and vegetable parasites, the olive tree 

 numbers among its enemies the blackbird, the robin, the starling, 

 the jay, and the crow, as they are all eager clevourers of its fruit, 

 but it is aided and greatly assisted by the nightingale, the titmouse 

 or tomtit, and the woodpecker, as they never touch the berries, and 

 are insect eaters only, and should therefore be encouraged in the 

 orchard. The predatory birds should be fired at in the air, so as 

 not to wound the trees with the shot. The pugnacious English 

 sparrow, by driving away all other birds, especially the little tomtit, 

 is an enemy particularly to be marked for destruction. 



