PEAR BLIGHT. 



313 



terwards the tree was blighted entirely 

 around the body, and for some distance 

 above and below where this bud had started. 

 Was this frozen sap ? 



I should explain to you that the bark is 

 now discolored by a composition of nitre, 

 copperas and potash, that we applied to it. 

 One morning a small spur on the north side 

 of, and on the trunk of a Madeleine tree, 

 about the same size as this Doyenne, was 

 discovered to be blighted. In the after- 

 noon the blight had extended about three 

 inches above and below this spur. The 

 next day it progressed about as much far- 

 ther ; it was several days before it extended 

 around the tree, so as to reach the south 

 side. The top is not yet affected, except 

 by loss of sap from this girdling. A Juli- 

 enne was afffected precisely in the same way. 

 Were these caused by frozen sap ? If yes, 

 why should it all be deposited in a diminu- 

 tive spur, while a vigorous top escapes ? 



Among other dwarf trees, planted in the 

 spring of 1847, was one White Doyenn^, 

 with so few roots that it needed to be 

 staked to keep from falling down by its own 

 weight. With much care it barely lived, 

 but it did not make the least wood. This 

 year it bore three beautiful pears ; and after 

 they were picked, it blighted dead, — per- 

 haps from grief, certainly not from frozen 

 sap in young wood. I would furnish you 

 many more cases, but it makes me feel too 

 sad when I think about them. Mr. Hovey 

 said he should put on mourning if his stand- 

 ards thus died. 



All these trees stood upon a knoll of 

 sandy loam, with like subsoil, in some 

 places rich, in others not; in some places 

 specially manured, in others not. Through- 

 out the whole, both soil and subsoil are 

 well drained, and no pear root was ever 

 suspected of penetrating as deep as it is 

 necessary to dig there to find water. 



I do not believe that frozen sap has spoiled 

 any of our trees ; neither do I adopt any 

 other theory. 



The wash mentioned as having been ap- 

 plied to trees, sometimes had a good effect. 

 It always stopped the must)-, vinegar smell, 

 and generally arrested the blight — some- 

 times only for a short time ; in other cases 

 the trees would die in spite of all our doses. 

 The idea of applying it was suggested by 

 the fact that the disease appeared to be 

 located between the epidermis and liber, 

 and not in the cambium. It was often 

 stopped by shaving off the outer bark as far 

 as any discolored matter could be seen ; and 

 this discoloring could always be traced far- 

 ther in the outer bark than the inner. In 

 other cases, this shaving produced no effect. 



We keep a journal of all such matters; 

 and I hope, next season, to send you the 

 result of several experiments connected with 

 this and other subjects. J. W. Bissell. 



Rochester, Nov., 1848. 



Remarks. — We thank Mr. Bissell for 

 these interesting facts, which he has laid 

 before us. 



His observations would seem to prove 

 that the disease, as known upon his grounds, 

 did not arise from frozen sap. 



Our readers who have pursued this sub- 

 ject, as treated in this magazine, will have 

 noticed that we are convinced that the two 

 most disastrous forms of pear blight arise 

 from frost in winter, (frozen sap,) and from 

 the sudden effects of the sun's rays in sum- 

 mer, after a shower, (sun-blight.) 



We have satisfied ourselves, we repeat, 

 that malignant pear tree blight originates 

 in these two modes ; but, as Mr. Bissell, 

 Dr. Wendell, and other correspondents 

 have shown, they are not sufficient to ac- 

 count for the rapid and singular mortality, 

 which sometimes occurs in pear plantations 

 affected by this disease. 



