18 The Blight in Pear Trees. 



I therefore regard the blight in pear trees as the result of 

 cold at some unfavorable period during the season of rest, not 

 yet clearly ascertained, but ascertained with sufficient cer- 

 tainty to be termed winter blight, the name given it by Mr. 

 Beechcr, and which I prefer to Mr. Downing's name of fro- 

 zen sap blight. It is commonly called a disease, but a dis- 

 ease it is not, for a tree may lose a part of its head, and yet 

 remain in full vigor. Cutting out the limbs does not promote 

 restoration, and is only needful to remove a deformity, in 

 case the tree has sufficient vitality remaining to spring anew. 

 I have a neglected tree now on my farm, with its deadened 

 head intermingled with the new branches which have sprung 

 through it, and the old limbs are gradually falling without aid 

 from man. Where the tree has this power of restoration 

 from sufficient vitality remaining, any remedy applied to it 

 will, for a considerable time, receive credit for making the 

 cure. In this way, the hanging of old iron hoops on trees 

 has been deemed very efficacious, on some theory of electric 

 action, because the persons who practised had no fire blight. 



A belief quite different from this is generally diffused now, 

 by the wide circulation of Mr. Downing's popular treatise on 

 Fruit Trees, the general excellence of which I am happy to 

 admit. I will proceed to examine what he says, and give 

 some of my reasons for not confiding in his conclusions. 



Mr. Downing says, that careful observation for several 

 years, and repeated comparison of facts with accurate ob- 

 servers in various parts of the country, have led him to the 

 following conclusions : — 1st. That what is popularly called 

 the pear blight is, in fact, two distinct diseases. 2d. That 

 one of these is caused by an insect, and the other by sudden 

 freezing and thawing of the sap in unfavorable autumns. 

 The first, he therefore calls the insect blight^ and the second 

 the frozen sap blight. 



His description of insect blight, and all he says in regard 

 to it, is so literally copied from Mr. Lowell's letter, that I 

 cannot regard him as writing from his own observations, I 

 will therefore quote from Mr. Lowell, to whose authority you 

 have referred as settling the question. That letter was writ- 

 ten to ]Mr. T. G. Fessenden, who had sent to Mr. Lowell 

 some branches of blighted pear tree, and also of quince, which 



