This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
Several nurserymen in Geneva, New York, are now using salt freely in their Pear Nurseries, at from 200 to 400 lbs. per acre yearly, and say that it has a wholesome tendency to correct the disposition to blight, as also to prevent it for the future. Certain it is that where used there have been less indications of its prevalence than in other parts where it was not used. We believe that salt is yet to play a very important part in our agriculture and horticulture as a top dressing or for mixture with concentrated manure. It is now, together with lime, the very best of all applications to mix with muck and reduce it to a friable condition. Iron shavings, copperas in solution have also been used, as also Potash manure, and been found of special efficacy in restoring the trees to full health and renewed vigor. An instance in point is just related by a correspondent of the Rural Messenger:
" I had a very fine pear tree (Flemish Beauty) that became affected, first by blight in one limb, which I removed, and then another and another was affected in the same way, until I had removed a considerable portion of the top of the tree. Early next spring I resolved to try the application of scrap iron to the roots. I procured my iron, removed the soil from the roots carefully, deposited the iron between them, and replaced the earth. There was no further progress in the blight, the tree continued to grow that season, and the next leaves and blossoms came out vigorously, no black spots appeared on the leaves and the tree bore finely, and no appearance of the disease was in the tree afterward. In subsequent conversation with friends I found that some of them had become informed on the same subject, and had tried the same remedy with perfect success. Some told me that they had procured turning and drilling chips from the machine shops and had used them, as they thought, with much advantage to their trees.