Abstract
THE POTATO DISEASE.—It will be remembered by those of our readers interested in the potato disease, that Lord Cathcart offered a prize in 1873 for the best essay on the “Potato Disease and its Prevention;” and it will also, be fresh in their memories that of the ninety-four essays sent in, not one was considered by the judges to deserve the prize. This circumstance, and Prof. Dyer's summary of the history of what was known of the disease, delivered before the Horticultural Society last year, gave rise to some correspondence in this and other journals. Few subjects, probably, have been so fertile a source of wild theories and speculations. Mr. Eccles Haigh, one of the competitors for Lord Cathcart's prize, now comes before the public on his own responsibility, with a theory which at least has the merit of ingenuity, and is based upon a cleverly worked out idea. But it seems to us that the writer has taken up a wholly untenable position. In a pamphlet of forty-four pages, small octavo, the writer traces the causes not only of the murrain, in which Peronospora infestans is so destructive, but also of the “curl,” a disease very prevalent just before the appearance of the present scourge; and, to his own satisfaction, explains how these diseases are to be prevented. To be brief, gardeners are credited with having induced by their mode of cultivation the “curl,” and afterwards, in getting rid of that, brought on the present far more formidable scourge. Mr. Haigh endeavours to show that during the “curl” period the potato bore enormous crops of berries, whilst since the prevalence of the murrain it has almost ceased flowering and fruiting; and in these facts (?) lies the whole gist of the matter. The production of fruit in profusion is regarded as an exhausting process so far as the tubers are concerned, and this is so far a very philosophic assumption, inasmuch as fruit-bearing is one of two ways to ensure the propagation of the plant. But here it becomes necessary to give the author's view respecting the “Functions of Nitrogenous Matter.” It is in substance that the iormation of fruit draws the nitrogenous matter from the plant and tubers, and when excessive crops of fruit are borne, the tubers are left without sufficient of this vital principle to continue the existence of the plant. On the other hand, when little or no fruit is produced, the tubers are left overcharged with this nitrogenous matter, which here becomes a source of decomposition, in proof whereof we are gravely told that the decay of manure is due to the presence of nitrogenous matter. It has long been admitted that excessive luxuriance predisposes in favour of disease; but this assumed presence of nitrogenous matter in the wrong place will hardly be accepted as an adequate explanation of the phenomena presented by the curl and the murrain. It is assumed that the potato left off bearing berries just about the time of the appearance of the murrain, and this we are told was brought about by the use of artificial manures containing a large percentage of nitrogenous matter. The “curl”was cured or rather prevented by using sets (tubers) from plants which had not been allowed to ripen seed. We have not space to examine the writer's arguments in support of this theory, but we may give his remedy.
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Our Botanical Column . Nature 12, 196–197 (1875). https://doi.org/10.1038/012196a0
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DOI: https://doi.org/10.1038/012196a0