16 The Blight in Pear Trees. 



smelling as I have described above. It is said in paragraphs 

 which float through the newspapers, that the scolytus pyri 

 works under the bark, and girdles the limb, and kills it If 

 the ringing thus made by the scolytus should be much more 

 than an inch in width, the limb would probably die^ and the 

 leaves turn black ; but, if the ring should be of less width, 

 death would not ensue, but, on the contrary, an accelerated 

 growth, and greater fruitfulness, as in common ringing with 

 the knife. 



"I offer no theories, but I suggest that diligent observation 

 shall be directed to the state of the branches in early spring, 

 when the juices are in active circulation, and the limbs have 

 been subjected to the alternate action of sharp frost and hot 

 sun. The first thing is to ascertain in what the disease con- 

 sists. If it is a fermentation of the sap destroying the vital 

 connection between the bark and the alburnum, making, in 

 eflfect, an extensive girdling of the tree, or of the body of the 

 limbs, we may then search for the cause. I begin to fear that 

 the cause is beyond cure. The pear tree shows its foliage 

 early ; and the most thrifty and succulent kinds are apt to be 

 attacked with the blight. The early activity of the fluids, 

 and the redundancy of them, may be greater in some years 

 than in others, and if, at such times, unusual and severe altern- 

 ations of heat and cold supervene, the efl'ect may be to produce 

 death in the larger limbs, and even in the upper part of the 

 trunks of young trees, vitiating the sap, and causing it to de- 

 cay. Persons at all familiar wilh the process of deadening 

 trees in clearing forest lands, know that, even when entirely 

 girdled, (cut round with an axe,) some kinds will continue 

 to grow and maintain their verdure the whole season ; and 

 some will even put forth leaves the second year, and then die. 

 In the same way, the branches of the pear tree will expand 

 their foliage, and make thrifty shoots, being a mere devel- 

 opment of the buds by means of the juices laid up in the 

 branches ; and, when that supply is exhausted, they become 

 blighted at the extremity, and so proceed downward until the 

 marks of death extend to the lowest point of disease, just as 

 the green trunks of young trees, driven into the ground as 

 stakes, will throw out shoots which grow for several months, 

 and then wither and dry up as if by blight." 



