202 DISEASES OF THE PEAR TREE. 



structive in the warm and fertile valleys of southern Ohio, 

 where vegetation continues late, is more succulent in 

 its texture, and where the frosts are sudden and sharp, than 

 in the dryer and cooler climate of New England. But this 

 same reason is also adduced in support of the original fire- 

 blight theory, and indeed it applies with strength to both. 



But after admitting that the different theories may be in 

 part correct, and that the blight may be caused by a combi- 

 nation in a greater or less degree of each assigned cause, 

 we are driven to the conclusion, from a large number of 

 observations, of which these limits wholly preclude even a 

 brief recital, that the cause of the blight, like that of the po- 

 tato disease, remains hi:! in a large number of instances from 

 our knowledge. And that, whether the latent tendency to 

 disease is only increased and developed by changes of the 

 Weather, or whether those changes actually produce them, 

 is yet enveloped in doubt. 



Happily, however, the remedy is not obscured in uncer- 

 tainty. For whether by an insect, or by the poisonous in- 

 fluence of the descending juices, its progress must be ar- 

 rested by an immediate excision of the dead branches. And, 

 as the poison passes downwards some time before its effects 

 are visible externally, the amputation must be made two or 

 three feet below the affected part, if the poison as well as 

 the dead part, is to be removed. Equally necessary is it, 

 that the infection of the diseased limbs be removed as speedi- 

 ly as possible out of the way, by burning. 



This remedy cannot be effectual, unless very promptly 

 and fearlessly applied. Many cultivators, in fear of mutila- 

 ting their trees, do not cut low enough, and leave the seeds 

 of death remaining in the tree. Others delay the applica- 

 tion of the remedy for a number of days, till cure is hope- 

 less. In extensive and malignant cases, the disaster may 

 be difficult to subdue even by the most prompt measures ; 

 but in ordinary instances entire success will follow. In any 

 event, it will be better to cut away and burn by successive 

 portions a whole tree, than to lose it entire by this disease, 

 a result equally certain, with the added evil of spreading 

 the malady. 



Two contiguous neighbors had each a large pear orchard ; 

 one of them neglectei all attention, the other spent ten 



