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.
E. W. Leavenworth had found the fast growing sorts of the pear, and those stimulated with high manuring, much more liable to blight than those with short, compact wood; and that the disaster usually occurred during the prevalence of the hottest weather; which was in accordance with the observations of several others.
W. Ashley. We cannot give you any newer light as to the theory of this disease than you will find in our former pages. There is, doubtless, more speculation than wisdom in the books on this subject. There can be but little dispute, however, that one way or other pears trees (at least the improved sorts,) are more susceptible to great atmospheric changes than other hardy fruits. The remedy is to shield the most vulnerable points from excessive heat or cold. Mulch the ground, and sheath the stems - whenever they are not sheltered by the leaves, with straw. This - so far as we have observed - works well in preserving the trees in sound health.