Insect Killers. 339 



been used with more or less success. Among those applications 

 which have been recommended for the destruction of insects in- 

 jurious to the roots of fruit trees and vines, hot water and bisul- 

 phide of carbon are deserving of notice. Applied to the root 

 louse of the apple tree it is claimed that hot water has proved 

 efficient, but a very little consideration will sufhce to convince 

 every nurseryman that there are great difiiculties in the way of 

 the successful use of this remedy. Were the operations of the 

 insect confined to the collar of the tree, or the superficial roots 

 only, one might hope that by removing the surface earth and ap- 

 plying the hot water freely, to exterminate the pest; but those of 

 you who have suffered from it know too well that this insidious 

 foe establishes itself as well on the small outlying rootlets, and 

 also on those which penetrate the soil to a considerable depth. 

 Hot water applied to the surface of the soil cools rapidly as it 

 passes through, and the heat thus abstracted soon reduces the tem- 

 perature below the killing point ; it is difficult and laborious also 

 to transport a sufficient quantity of hot water where this evil is 

 wide spread. 



Nature comes to man's aid in this extremity. We have a para- 

 site known as the root louse, Piir'aa radicum Riley, which feeds, 

 in the larval state, on this insect with avidity. The parent fly, 

 which is two-winged, and measures, when its wings are expanded, 

 nearly half an inch across, lays its eggs among tlie colonies of lice 

 nearer the surface, and from thence the footless maggots seek out 

 and devour the lice wherever they can find them, 



Bisulphi<le of carbon is used as a remedy for the phylloxera on 

 the vine, and is also equally applicable to other insects feeding 

 on roots. Its use was suggested by French experimenters, and it 

 has been extensively tried. It is a very volatile substance of an 

 intensely disagreeable odor, inflammable, and, under some cir- 

 cumstances, explosive. It is recommended to make one or more 

 holes in the soil, near the affected vine, to the depth of from one 

 to two feet, and into each hole pour one or two ounces of the liq- 

 uid, then close the orifice with earth and tramp it lightly down. 

 The volatile fluid gradually vaporizes, and the poisonous elUuvia 

 arising from it permeates the porous soil and destroys the insect 



