APPLE LEAVES, PLANT-LOUSE — REMEDIES, ITS INSECT ENEMIES. 59 



else it too would be liable to be destroyed. This utterly exter- 

 minates the aphis from the shrub, every insect being suffocated 

 and dropping frota the plant, so that 



" unnumbered corses etrew the fatal plain." 



One measure more, and this the mostimportantof all, whereby 

 to subdue these insects, remains to be stated A person wl^o is 

 acquainted with the aphides, and the several kinds of other in- 

 sects which prey upon and destroy them in different ways, will 

 never permit a valuable tree or plant to suffer injury from them. 

 He will at once repair to the hedges and borders of the forests in 

 his vicinity, and with a beatijpg net, such as is used by entomolo- 

 gists for gatliering insects, or an opened inverted umbrella, or some 

 other implement convenient for this purpose, he will >oon collect 

 from the foliage a few scores of these natural enemies of the plant- 

 lice, and conveying them alive in small boxes and vials, will set 

 them free upon the tree or shrub that is infested. Most of these 

 being in their larva state, and without wings, will not leave their 

 new situation so long as any food for them remains there. This 

 is said to be the remedy to which all the more intelligent French 

 and German gardeners are accustomed to resort in an emergency 

 of this kind. The rapidity with which these natural enemies of 

 the aphides not only suppress but utterly exterminate them, in 

 instances where they are so multiplied and excessively numerous 

 as to seem unconquerable, is truly surprising. "At one time the 

 present season (1855) the cherry trees in my grounds became 

 overrun with the Cherry plant-louse — to be considered hereafter-^- 

 to such an extent that the under surface of the more young and 

 tender leaves, and the succulent ends of the limbs and twigs, 

 were all covered and black with them. If not checked it was 

 evident that every tree would soon perish. I was about to im- 

 port from the neighboring fields and forests a stock of the natural 

 destroyers of these pests, when I found on examination that nature 

 had already scattered numbers of these every where among the 

 aphides. AH apprehensions as to the result were hereupon at 

 once allayed. A week afterwards, upon a careful inspection, 

 not a single aphis could ahy where be found upon these trees. 

 Of the teeming millions which wei-e revelling there so recently, a 



