THE PEAR. 



861 



form of biight can be prevented by the application of lime- 

 wash, soft soap, or soda lye. But these will hardly ac- 

 count for all the forms of blight in the pear. Sometimes 

 in fine growing weather, nearly the whole tree is suddenly 

 killed by this insidious disease. Perhaps, when the shoots 

 are very tender, succulent, and full of sap, they are unable 

 to endure a high degree of heat. Again, trees that are 

 growing in very rich ground, sometimes do not ripen their 

 wood perfectly, when a sudden frost, followed by a hot 

 sun-shine, bursts the tissues of the shoots, and corrupts the 

 sap, causing the shoots to perish, and if not timely arrested 

 by severe pruning, totally destroys the tree. This disease 

 is quite frequent in cold climates. Whatever may be the 

 causes of blight, it is certain that those varieties making 

 rapid growth, are most affected by it. The Seckel pear 

 growing slowly, is free of it. Again with us, if old trees 

 are headed down severly in order to graft on, they are 

 almost sure to be blighted, the ensuing summer, in the 

 vigorous young shoots. 



Mr. Van Buren, one of our best pomologists, thinks the 

 disease caused by an insect, which punctures the bark on 

 the trunk, and large limbs at those points, where it is 

 changing from the smooth to the rough state. It first ap- 

 pears as a dark spot, as if a little powder had been burned 

 there. The spot enlarges, the bark sinks down to the 

 wood, and at length becomes surrounded with a crack or 

 seam, separating it from the healthy part. Soon as the 

 spot occupies a considerable portion of the trunk or limb, 

 the leaves at the end of the twig turn black and die ; as 

 does also more or less of the diseased limb itself. The 

 leaves die on the same side of the tree that is diseased 

 below. Hence, when the leaves begin to die, or even 

 refuse to grow, you will generally find the bark belovv 

 Bomewhere diseased. When not larger than a pea, they 

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