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blight. In the midst of the luxuriant growth 

 of summer, a limb affected by this disease 

 suddenly turns brown and dies. If the disor- 

 der is not arrested the entire tree is usually 

 destroyed by it. There is no half-way reme- 

 dy ; the malady extends downward from the 

 point of its external appearance, and it is 

 necessary to cut off the affected limb imme- 

 diately, at least a foot below all symptoms of 

 the disease. 



Winter Blight, called by Downing, Frozen 

 sap Blight. This disorder manifests itself by 

 the extremities of the limbs shrivelling, turn- 

 ing black and dying. Downing attributes the 

 cause of this to the action of frost in winter ; 

 others think it is owing to the strong penetra- 

 ting rays of the sun in summer. Trees that 

 grow luxuriantly in moist soils in the nursery, 

 are the most subject to it. We have rarely 

 seen a large tree in this vicinity affected with 

 the disorder, although we understand, that it 

 is almost confined to large trees in some sec- 

 tions of the country. There probably may 

 not be less than three sources of the pear 

 blight; an insect causing the Insect- Blight ; 

 the changes of winter weather, causing the 

 Winter-Blight ; the rays of the sun causing 

 what might be called Sun-Blight. 



