844 THE AMERICAN FARMER, 



Blight. This is one of the most formidable diseases with which the frait-grower has 

 to contend, and is generally regarded as incurable. It attacks the pear, apple, and quince, 

 but proves the most destructive to the pear. The disease is characterized by the withering 

 and turning black of the leaves of some of the most thrifty branches, this condition some 

 times extending over the entire tree, causing the leaves to wither and fall, even in midsum 

 mer. The disease is quite liable to extend to the branches, the wood becomes shriveled and 

 hard, and in a short time turns black, and if allowed to remain on the tree, will be liable to 

 extend to the trunk. There are two distinct diseases known as the blight, the IXSECT 

 BLIGHT, supposed to be caused by a minute insect, the larva of which bores into the wood, 

 perforating it; the other, a blight supposed by many to be caused by the freezing of the sap 

 in the wood, the theory being that when the trees have not fully matured their growth of 

 wood, or, after having dropped their foliage permanently, a few warm days cause the sap to 

 ascend the branches again; the sap is afterwards frozen during the severe winter, and thus 

 produces the diseased qondition. 



This opinion was formerly entertained by some of our best authorities on fruit growing, 

 and prevails at the present time to a considerable extent. It is the opinion of Prof. Caldwell of 

 Cornell University, Prof. Burrill, and some others, that the blight is caused by bacteria, 

 which are small microscopic organisms not over 1 -8000th of an inch in length, nor of 

 l-16000th of an inch in breadth. It has not been fully decided whether they are animal or 

 vegetable, but are generally thought to be vegetable growths, and increase with prodigious 

 rapidity under favorable circumstances. A pruning knife, used on a diseased tree, may con 

 vey the disease to a healthy one, it being easily conveyed from one to another by such means, 

 as well as by various other methods. The best remedy for the difficulty is to cut off the 

 portion of the trees which are infested, but the work must be done in the early stages, as 

 well as thoroughly done, for the bacteria may have passed three or four feet from the portions 

 of the tree which show visible signs of having perished. As soon, therefore, as the disease 

 makes its appearance, the affected branches should be cut considerably back of the discolored 

 wood, and be immediately burned, as the disease may be communicated to others by means 

 of the fungus growth in the sap, which may be easily perpetuated. 



If the affected branches are not cut off considerably below the point to which the disease 

 extends, the evil will not be entirely removed, as the diseased sap remaining will extend it to 

 other parts of the tree. The pruning must be severe and be kept up until the disease is 

 entirely checked. When the entire tree seems to be involved, the better way is to cut it down 

 and burn it, root and branch, to prevent the spread of the disease. A prominent agricultural 

 journal gives the following on the pear blight: 



&quot; It has been shown by careful microscopic examination, in its earliest stages, that this 

 disease is caused by a minute fungus which develops in the bark and penetrates inwardly, 

 destroying the cell structure as it proceeds. The fungus is so small that the distinguished 

 investigator, J. Gibbons Hunt, under a powerful microscope, could not distinguish the species, 

 but this is of no consequence. This being the cause of the disease, the preventive is obvious. 

 Any one who is in a neighborhood liable to blight can have immunity by washing his trees 

 anmJally with pure linseed oil, sulphur wash, or other things that will kill a fungoid spore 

 without injury to the bark. Of course many get into a crevice where the washes cannot reach, 

 and hence there may be some cases where, even though the trees be washed, there will be 

 disease. The cause of the disease has been so clearly demonstrated, and the remedy so 

 patent, that cases of fire blight only prove ignorance or neglect. 



Since the above was written, the writer has seen a beautiful row of Dwarf Duchesse 

 d AngouMme pears on the grounds of Mr. Hiram Sibley at Rochester, one of which was badly 

 stricken by fire-blight, though he was told the trees were sulphur and lime washed every 



