BLIGHT IN THE PEAR TREE. 



59 



There is only one drawback to the ex- 

 tensive cultivation of the pear tree — but this 

 is an important one ; we mean, of course, 



THE BLIGHT. 



To see a fine healthy tree, apparently in 

 the condition of the utmost vigor, suddenly 

 — sometimes in a single day — turning black 

 in its branches, and dying as if struck by 

 lightning ; this is indeed discouraging to 

 the cultivator. 



We have, in our work on Fruit Trees, 

 given our views, at considerable length, on 

 the nature of this disease, popularly known 

 as the fire blight, or fire blast. We will only, 

 therefore, here repeat, that there are two 

 distinct maladies known by this name, and 

 often confounded tog-ether. One is the in- 

 sect blight ; the other the frozen-sap blight. 



The insect blight we do not consider a 

 malady of a very serious nature. As it be- 

 gins at the extremity of the tree, at or near 

 the ends of the branches, and as its spread- 

 ing depends entirely upon the care or care- 

 lessness of the cultivator, it is his own fault 

 if it ever destroys many trees. Experience 

 and observation have convinced us that the 

 pruning knife, vigorously applied the mo- 

 ment the insect first commences his attack 

 in June,* and faithfully persisted in, will 

 soon rid one's garden or orchard of this mi- 

 nute but most poisonous Scolytits. 



But the frozen-sa'p blight is quite another 

 and a much more alarming disease. Some 

 parts of the country are most severely visit- 

 ed by it ; and where it is common, its effects 

 are so disastrous, that unless some remedy 

 can be offered, the extensive culture of this 

 fine fruit must be abandoned there. 



It is, to our own mind, thoroughly es- 

 tablished, that this form of blight arises from 

 the sudden freezing and thawing of the 



* Speedily known by the appearance of the shoot, which 

 turns black, leaf and branch, almost immediately. It should 

 always be amputated a foot below where '.here are any marks 

 of discoloratioa. 



sap vessels in winter. Just in proportion, 

 therefore, as the system of a tree is filled 

 with sap, or unelaborated juices, at the close 

 of the growing season, such will be its lia- 

 bility to be affected by this form of blight. 

 Hence,trees growing on dry and high ground, 

 where the growth is completed early in sum- 

 mer, will usually entirely escape this form 

 of blight ; while those growing on low and 

 moist soil, where vegetation continues to a 

 late period, will always be more subject to 

 it. Hence also, the comparative rarity of 

 the frozen-sap blight in the drier and poorer 

 soil of the Atlantic states, and its great pre- 

 valence in the deep deposits of vegetable 

 matter which make up a large part of the 

 best soils of the west. 



If any one will carefully examine a tree 

 affected by the frozen-sap blight, he will 

 notice spots on the bark of the trunk or 

 principal branches, which have a dead or 

 withered appearance. The bark there is 

 contracted, blackish, and is shrunk below 

 the level of the surrounding healthy por- 

 tions. This is often observable very early in 

 the spring. As the season opens, the tree 

 starts into leaf, and grows luxuriantly : sud- 

 denly, about the middle of June, sometimes 

 a little earlier or later, a terminal shoot, a 

 branch, or the whole tree, droops and dies. 



If we pursue the examination a little 

 further with the knife, we shall find the in- 

 ner portion of the bark, next the wood — in 

 short, that part where the downward current 

 of sap takes its course — has assumed a 

 blackish hue. This taint is not confined to 

 that part of the tree, viz., the limb or branch 

 where the external symptoms of the blight 

 are shown, but extends, more or less rapid- 

 ly, from that point through the whole of the 

 rest of the tree, unless it is arrested by am- 

 putation in a very early stage. 



The death of pear trees by this form of 

 blight has been supposed to be a mecha- 



