58 On the Aphis Lanigera, or American Blight. 



the whole, we did not think, that the advantages gained were 

 commensurate with the trouble of the operation, and we de- 

 termined to resort to some more effectual and less tedious 

 process. 



When the smallest quantity of oil was dropped, from the 

 point of a pin, upon a single Aphis, I perceived that it caused 

 instant death ; this encouraged me to repeat the experiment 

 on a larger scale. With a painter's brush, we applied train 

 oil to those parts of the tree, which were infested by the 

 Aphides, and the result of such application exceeded our 

 most sanguine expectations. It not only effected their 

 destruction at the moment, but we had the satisfaction of 

 observing that every place, which we had besmeared with oil, 

 during the last summer, had been cautiously avoided by the 

 insects, during the present, although they were still visible on 

 other parts of the same tree. The only doubt, which sug- 

 gested itself to my mind, was, whether the oil might not be 

 injurious to the tree ; but the very reverse appeared to be the 

 fact : for wherever the tree had been deprived of its bark, 

 this application had preserved the albumen from the effects 

 of the weather, and the young bark was gradually closing 

 over the wounds. Perhaps, had the whole of the outer bark 

 of the tree been smeared with oil, it might have proved 

 injurious, by obstructing the pores, and preventing them 

 from imbibing moisture from the atmosphere (as we know 

 that the oiliness of the wool of sheep is often prejudicial to 

 the trees against which they rub themselves) ; but no mischief 

 can occur, from its application being confined to such parts 

 only, as are attacked by insects. From the comparative cheap- 



