236 BLIGHT. 



a very feeble insect. We call it, from habit, or from 

 some unassigned cause, the "American blight" (aphis 

 lanata);*this noxious creature being known in some 

 orchards by the more significant name of" white blight.'' 

 In the spring of the year a slight hoariness is observed 

 upon the branches of certain species of our orchard 

 fruit. As the season advances this hoariness increases, 

 it becomes cottony, and toward the middle or the end 

 of summer the under sides of some of the branches 

 are invested with a thick, downy substance, so long as 

 at times to be sensibly agitated by the air. Upon ex- 

 amining this substance we find, that it conceals a multi- 

 tude of small wingless creatures, which are busily em- 

 ployed in preying upon the limb of the tree beneath. 

 This they are well enabled to do, by means of a beak 

 terminating in a fine bristle : this, being insinuated 

 through the bark, and the sappy part of the wood, 

 enables the creature to extract, as with a syringe, the 

 sweet, vital liquor that circulates in the plant. This 

 terminating bristle is not observed in every individual : 

 in those that possess it, it is of different lengths, and is 

 usually, when not in use, so closely concealed under 

 the breast of the animal, as to be invisible. In the 

 younger insects it is often manifested by protruding 

 like a fine termination to the anus; but as their bodies 

 become lengthened the bristle is not in this way observ- 

 able. The alburnum, or sap wood, being thus wounded, 

 rises up in excrescences and nodes all over the branch, 

 and deforms it; the limb, deprived of its nutriment, 

 grows sickly ; the leaves turn yellow, and the part 

 perishes. Branch after branch is thus assailed until they 

 all become leafless, and the tree dies. 



Aphides in general attack the young and softer parts 

 of plants ; but this insect seems easily to wound the 

 harder bark of the apple, and by no means makes choice 

 of the most tender part of the branch. They give a 

 preference to certain sorts, but not always the most rich 

 fruits ; as cider apples, and wildings, are greatly infest- 

 ed by them, and from some unknown cause other varie 

 ties seem to be exempted from their depredations. The 

 Wheeler's russet, and Crofton pippin, I have never ob 



* See note FF, appendix. 



