366 DISEASES AND IKSECTS. 



are easily destroyed, they would present an obstacle almost 

 insuperable in the propagation and culture of trees. 



There are many ways of accomplishing their destruc- 

 tion. Our plan is to prepare a barrel of tobacco juice, 

 by steeping stems for several days until the juice is a 

 dark brown, like strong beer ; we then mix this with a 

 solution of soft soap or soap suds. A pail is filled with 

 this, and the ends of the shoots where the insects are 

 assembled are brought down and dipped into the liquid. 

 One dip is enough. Such parts as cannot be dipped are 

 sprinkled liberally. It is applied to the heads of large 

 trees by means of a hand or garden syringe. It should 

 be done in the evening. The liquid may be so strong as 

 to injure the foliage, hence it will be well for persons 

 using it the first time to test it on one or two subjects 

 before applying it extensively. This application must be 

 repeated as often as any of the aphides make their appear- 

 ance. The dry weather of midsummer is generally the 

 time most favorable for their appearance. 



2. The Woolly Aphis or American Blight. — This is a 

 small insect, covered with a white woolly substance that 

 conceals its body. They infest the a23ple tree in particu- 

 lar, both roots and branches, living upon the sap of the 

 bark, and producing small warts or granulations on it by 

 the punctures. They are more particularly troublesome 

 on old rough-barked trees, as they lodge in the crevices, 

 and are difiicult to reach. The wind carries them from 

 one place to another by the light down in which they are 

 enveloped, and thus they spread quickly from one end of 

 a plantation to the other. Not a moment should be lost 

 in destroying the first one that makes its appearance. 

 Where the bark is rough it should be scraped smooth, if 

 the roots be aftected the earth should be removed, and 

 every part washed, and every crevice filled with the fol- 

 lowing preparation, recommended in Harris's Treatise : 



