ON THE BLIGHTS OF THE PEAR TREE 



365 



shoots are chosen ; one of these is nailed on 

 the ground work, a line or layer of the moss 

 closely laid upon it, and one end rammed 

 beneath it, the other projecting out beyond 

 it ; then another rod is nailed down above 

 this, and again a layer of moss. This is 

 repeated till the surface to be covered is 

 completed. The whole appears thickly tuft- 

 ed with moss, which is shorn to an even 



surface, and 'being held in its place by the 

 rods, it makes a very pretty and unique 

 drapery for the walls. 



In a country with the long winters of the 

 Northern States, there are frequently leisure 

 hours, when rustic work may form an agree- 

 able occupation and amusement for the gar- 

 dener; and we leave the subject, with these 

 few hints, in his own hands. 



ON THE BLIGHTS OF THE PEAR TREE. 



BY T. W. HARRIS, CAMBRIDGE, MASS. 



It seems to have been taken for granted, 

 by many persons, that the pear tree is sub- 

 ject only to one kind of blight. Hence 

 have arisen the conflicting theories and 

 speculations that have been published on 

 this subject. Having no theory to main- 

 tain, and no speculations to offer, but such 

 as are founded on facts. I propose to show 

 that insect-blight is a disease distinct from 

 fire'hlight oxidi frozen sap-blight. 



By the term visect-hlight , as here used, 

 must be understood the sudden withering 

 of the leaves, and the death of the limbs of 

 the pear tree in summer, occasioned by the 

 internal attacks of one or more of the in- 

 sects, called Scolytus Pyri by Professor 

 Peck. This kind of blight is common in 

 New-England ; but it does not appear to 

 exist, or to have been observed, in the 

 western states, where, however, blights of 

 the pear tree, somewhat similar in pro- 

 gress, and equally fatal in termination, pre- 

 vail more or less every year. Blights, 

 which are not the result of insect attacks, 

 inasmuch as insects have never been de- 

 tected in the blighted limbs, occasionally 

 affect pear trees in New-England. Some 

 of my own trees have been thereby de- 

 stroyed ; and the most careful examination 



has failed to disclose any trace of insect 

 depredation in them. On the other hand, 

 numerous opportunities for seeing the ef- 

 fects of insect blight, and of dissecting spe- 

 cimens of Scolytus Pyri from the blighted 

 limbs, enable me to declare confidently that 

 the diseases are specifically distinct from 

 each other ; as much so as small-pox and 

 measles. It is not my purpose to discuss 

 the question, whether fire-blight and frozen 

 sap-blight, or winter-blight, be identical; 

 the contrast between them and insect-blight 

 being what is now to be attempted. 



The effects of insect-blight begin to ap- 

 pear in June, and continue through July; 

 but the foundation of the disease may be 

 traced to the operations of the parent insect 

 during the previous summer. If all the 

 limbs that were killed by insect-blight in 

 the summer of 1847, could have been exa- 

 mined during the latter part of the summer 

 of 1846, there would have been found in- 

 sects in them, in the larva or grub state, 

 eating their way from the buds, where the 

 eggs were deposited, inwards, through the 

 bark and sap wood. These insects continu- 

 ed the work of destruction till the following 

 spring, when they were transformed to bee- 

 tles, and finally came forth from their bur- 



