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.
5. In a few cases the points of the shoots , and at other times the side and base leaves, were found diseased with the curl in mid-summer. In all such cases there was a clear connection between these diseased manifestations and the state of the weather.
6. Each one of my trees, (I have five or six hundred,) so far as I have observed, has a definite proportional liability to the catted leaf) that Is, the tree that suffered severely, slightly, or not at all last year, suffered similarly this year.
7. I think also, (although my attention has not been so definitely directed to that point as to some others,) that those trees that are most liable to be heated in a calm warm day, and subsequently to be severely chilled by cold wind, are also most liable to be affected by curl. All this is consistent with another fact, that half hardy trees, of which the peach is one, do undoubtedly succeed best when their position, on the whole, is a cool one; and as little exposed as possible to changes of weather.
S. So also, sickly trees are found in succeeding years, to be particularly exposed to the curl. This results obviously from the fact that its whole vigor is reduced.
9. When first beginning to curl, the whole leaf, but particularly the fort stalks, ribs, and glands, exhibit a high degree of transparency, and usually a redness. This, on examination with the microscope, exhibits no insect, egg, puncture, or other irregularity, often not even the curl, in the very young state of the leaf. Its growth, also, for a few days, seems nominally rapid. What strikes the observer is the transparency which seems to reveal almost the whole interior circulation of the leaf; the wax-like smoothness of the surface of the young leaves; the reddish tinge; the early disposition to curl. This last disposition is sometimes seen in the tendency of the two opposite halves of the leaf to adhere to each other, and at others, in the edges of the leaf to corrugate, just as in that form of the potato disease that is caused by chills at a later period in the summer. The progressive enlargement of the leaf, its endless contortions, its changes to various colors, but especially the studding of its surface with delicate velvety blotches, of a most beautiful texture and coloring, are all very noticeable facts. These velvety blotches are undoubtedly a fungus formation, not however, I think, of a parasitic character.
Soon these progressive manifestations are finished, as the leaf blackens, dies and falls.
May we not derive some illustration of the mode of atmospheric influence in this case, from the condition of leaves generally, in autumn. Then, when the light and heat are no longer such as to satisfy the normal requirements of vegetation, when especially the downward progress of vegetation has been hastened by severe and sudden frost, wo see the same discoloration and death. In the autumn, however, the deposition of woody matter in the leaf is complete. Hence, when those atmospheric changes come that paralyze the circulation, and give to chemical law the mastery over vital energies, and the sap becomes acid, the leaf is not transparent, as in the spring, when the tissues were thin and imperfect, and the whole leaf was little more than an aggregation of thin vessels filled with watery juices.
So of the curled leaf m the spring. The sap was excited at an untimely period, and then, instead of being permitted to perform its proper office, that of expanding the dowers, leaves, and shoots, it was held in check thirty-six days this year, (though less than that period in 1850,) and followed in the ease of last year, by severe frost and snow. The condition of the sap became necessarily morbid, as naturally and truly as in the parallel case of a* animal overheated and subsequently chilled. In the latter case feebleness, and it may be fever or sores, follow as the natural proof of dimmished vital energy, or morbid condition. In the case of the peach this year, when the circulation revived, or at least was greatly accelerated, on the 8th of May, the depraved state of the sap was seen in the feeble flower and the sickly leaf, to say nothing of the buds which fell off, and the branches that died without developing flowers and leaves at all, - buds, flowers, and branches, which, before the untimely excitement of the circulation in March, were as promising as any other.
It is quite too early to recommend a remedy with confidence. A longer and more accurate acquaintance with the progress and modifications of disease, may be needy ful. Yet I would with some assurance suggest.
This would be to permit the earth around the tree to freeze deeply and then cover it deeply wish waste rubbish, so as to retain the tree-in a dormant state as long as possible, at least until the Circulation may be permitted to advance without fear of a check. I am aware that a large amount of fluid is stored up in the tree in autumn, and that many of the roots penetrate below the ordinary reach of the frosts. Hence it may be impossible perfectly to check the circulation. Bat I think the mode suggested would in ordinary cases prove sufficient. Potato vines, buckwheat straw, but especially evergreen boughs, would all be found useful. These might be placed near the trees after the ground had begun to freeze, (before that it would invite mice.) The application should be made when the frost and snow have most accumulated. They should be renewed in this climate, (central New-York,) about the first of May. When the summer heat has well set in, and the earth is thoroughly warmed, it might be restored as a means of defence against excestive heat and sudden changes.
This would be to plant only the hardiest stones, such as come from northern fruit. These would make hardier stocks than southern stones. In? case of cultivating seedlings, it would he well to plant forgery, and then, about the fourth and fifth years, to reject all such as show themselves liable to the curled leaf. Had I proceeded in this manner in the selection of my stocks, I should now be much better able than I now am, to judge of this whole subject.
With such stocks as I have, the following results have been arrived.at;
1. The Teton de Venus, George the Fourth, and Late Yellow Rareripe, (all glanded varieties, ) are nearly a failure, usually, and almost entirely, from the winter's cold, and equally from the effects of the curled leaf.
2. The Early Tillotson, True Early York, Red Rareripe, and Morris'Red Rareripe, (all glandless except the last,) are a little better in regard to the winter's cold, and very much better in respect to the curled leaf.
3. My other budded sorts are yet too young to be judged of with certainty. I hope, however, the White Imperial will resist the curled leaf, especially where planted in moist soil, as has been recommended for this sort.
4. 1 have four seedlings that bid fair perfectly to resist the curled leaf, as well as the winter's cold. Two of them are glanded and very late; the one a fair fruit for the table, the other fit only for cooking. The other two are glandless; the one early and fine, the other very late, fit only for cooking.
With the foregoing precautions, I think the evils of the curled leaf will be remedied in part, and in part avoided; and that by the latter remedy peach trees may be produced whose buds will retain their vitality through the cold of all ordinary winters.
Such trees as set their fruit safety in May, and ripen in good season in the autumn, are almost sure to tad summer heat enough to mature rich and luscious fruit. By these means 1 hope to see fair and tolerably constant crops of good peaches yet produced, in seasons ordinarily favorable, even in Oneida county. C.E.G.
Viea, Die. 23, 1851.