148 



Insefts and Diseases. 



the trees by sucking the juices. They may be destroyed by a solu- 

 tion of whale oil soap, or even by common soap-suds. It may be 

 applied with a syringe ; or young trees in the nursery, and their 

 branches, may be bent over and immersed in the liquid contained in 

 a large pail. It should be repeated as often as they reappear, and 



Fig. 180. 



the evening is the best time to apply it. If too strong, it may injure 

 the leaves, and a previous trial on a single tree as a precaution is 

 best, till the right degree of strength is ascertained. 



The Woolly Aphis (Aphis lanigera*}, a European insect, falsely 

 termed American blight, is a species of aphis or plant-louse, covered 

 with long, white, cottony hair. In England it has proved very 

 destructive ; and on young trees in this country it has done some 

 injury. It is destroyed by whale-oil soap, and by lime-wash. 



The apple-root aphis (Pemphigus pyri) penetrates the roots and 

 causes knobby excrescences, which, when numerous, check and 

 injure the tree. To destroy it, scrape the earth away, and wash with 

 strong soap-suds. 



The Apple Bark-louse (Aspidiotus conchiformis) is thus described 

 by Dr. Fitch : " It makes its appearance as a little brown scale, 

 one-eighth of an inch long, the shape of an oyster shell, fixed to the 

 smooth bark, resembling a little blister. This scale is the dried 

 remains of the body of the female, covering and protecting her eggs, 



* Eriosoma lattigera, of later naturalists. 



