368 



PEAR BLIGHT ON THE MISSISSIPPI. 



end of the summer. The effect upon trees 

 so injured is distressing. It is always fatal 

 to the pear tree. Young ones die the first 

 season so attacked, while aged trees perish 

 within two or three years after by degrees ; 

 but die they must. 



Now for the result of my own orchard : 

 All my pear trees, but five, are now dead. 

 The quince trees are dying. Of the apple 

 trees, a dozen dead, and the balance bad- 

 ly injured; but these will likely recover. 

 Wherever trees are thus attacked, they 

 appear to be poisoned, — the sap oozing out 

 gluey and vitiated ; the bark shrivels, be- 

 comes dry and black, as, also, the wood, 

 until it spreads down to the root, when the 

 whole tree is overcome. The injured parts 

 emit a bad, offensive odor ; in fine, morti- 

 fication takes place, with precisely the same 

 symptoms as in animal bodies. The least 

 sting of the insect introduces rank poison ; 

 especially upon the pear tree, constitution- 

 ally more tender than the apple, and being 

 carried, in a short time, Avith the descend- 

 ing sap into the vitality of the plant, it per- 

 ished like the animal, bit by a venomous 

 snake. I am not positive that the described 

 bug is the very insect to whom I impute 

 the mischief; but it is more than probable. 

 During last spring and summer, while the 

 injury was doing, those trees were covered 

 with that bug ; and late in the fall I found 

 about 50 of them in mummy state, fixed 

 with their backs, and put up in a regular 

 circle, upon a ripe pear, and a fine and close 

 web spun over them. 



A singular feature of this disease is also 

 the fact, clearly established by Captain 

 Lewis Bissell, before the Horticultural 

 Society of St. Louis, last siimmer, that it is 

 communicated to healthy trees by contact, 

 by using a knife upon them, drawn previ- 

 ously through an affected limb, which pro- 

 duced the same disease within two weeks 



after application, — starting from the in- 

 cised spot, and showing the great virulence 

 of the poison. The same gentleman has 

 an old pear orchard in this vicinity of 25 

 years standing, which stood for about 20 

 years all theories of frozen-sap-blight, and 

 the hot western sun, in practice, without 

 injury, until about six years ago, the de- 

 scribed insect made its first appearance in 

 these parts, wttence it also attacked this 

 orchard in the same manner — with the 

 same result. Previous to that time, the 

 disease was almost unknown here, although 

 we heard of it occasionally from the more 

 eastern states. An old gentleman from 

 Kentucky, who was 90 years old, told me 

 often, that in the interior of that state there 

 were the finest pear orchards, 50 years ago, 

 where now not a tree would be found in a 

 circuit of 50 miles ; they were in modern 

 times killed by blight, and his description 

 of which corresponded exactly with our 

 insect-blight. It is certainly migratory. It 

 has come from the east, and is going west- 

 ward. It formerly could not exist here, be- 

 fore there were those fruit trees raised ; 

 for it does not feed upon oak and maple. 

 Our low and narrow gorges and valleys, 

 along cold spring water courses, and be- 

 tween hills, are measurably exempt from 

 this plague, — showing that the insect is 

 averse to cold, and will hardly go far north 

 of this. Is it on this account that our 

 New-England friends, and those in the vi- 

 cinity of the lakes, raise such varieties of 

 fine pears with impunity ? 



The theory of the sun-blight is, probably, 

 in effect, nothing else but the above disease. 

 Although the branches wither in the sun, 

 the sun is not the cause ; for every plant, 

 as well as animal, has a temperature of its 

 own, which is nearly alike in summer a,' 

 winter. The foliage of plants are theil 

 lungs, which regulate the heat of the at- 



