Year: 1874
Type: article
Abstract: Wutte it has been known to botanists for more than twenty-five years that the potato rot is caused by the growth of a minute fungus, called by Montagne, who first described it, Botrytis, by later writers Peronospora infestans, there are certain points in the life history of this fungus which have not yet been cleared up,-points which, if answered, might suggest to the farmer a means of avoiding, to some extent, the occurrence in its worst forms of this unfortunately too common epidemic.The object of the present paper is to give to the agriculturalist a statement of the condition of our knowledge of the habits of the Peronospora infestans, its germination, growth, propagation, &c., to state the questions which science has still to answer, and the direction in which investigations will have to be made in the future, and, finally, as far as is possible, to apply the knowledge which a microscopic study of the Peronospora has given us to a consideration of the means of avoiding or diminishing the rot.It might, perhaps, seem superfluous to recount the symptoms by which the disease, the rot, manifests itself, so familiar are they to the persons into whose hands this paper is likely to fall.It makes its appearance in midsummer in our latitude, usually about the first of August, sometimes earlier, oftener a little later.At times its advent is so sudden that, within a few hours, the potato fields change from green to brown and black, and the plants which, in the morning, gave promise of an abundant crop, before night present a mass of decaying vegetation, in which are involved not only the leaves and stems, but, also, the tubers.'The disease occurred in this violent form in 1842, and again in 1845, and spread over a good part of the United States and the British Provinces, and also destroyed the crop in Great Britain, Ireland, Belgium, and parts of Germany and France.The greatest injury was done 'in Nova Scotia, New Brunswick, and Ireland, owing to the fact that, in these countries, the potato was the principal crop.Since 1845, the disease has recurred, but never with such violence, although during the last year, 1874, the damage was considerable.Although public attention was first called to the . BULLETIN OF THE BUSSEY INSTITUTION.rot in 1842, it is not at all likely that it then appeared for the first time, but we must suppose that some of the vaguely described epidemies of the last century were of the same nature.It is with such sudden and violent outbreaks as those of 1842 and 1845, that in the public mind the potato rot is associated.Asa rule, however, the disease is of a milder type.Instead of a sudden destruction of the crop, there appear on the leaves and stem brown spots, which gradually extend.After a while, certain plants are found to be rotting, and this process may keep on until a whole field is involved.This case, as far as the farmer is concerned, is very different from the other, inasmuch as, having seen that some plants are rotting, he can then, by harvesting the rest, save a portion of the crop.In whichever form the rot occurs, it makes its appearance always about the same time, as before mentioned, about the first of August, and always in damp weather.There is no case reported as occurring in a dry season, and a moist condition of the atmosphere is absolutely necessary to its production to any decided extent.Damp, muggy weather is, however, quite as favorable to its development as heavy rains.As was just remarked, the disease is first recognized by the brown spots appearing on the leaves.What is the structure of these brown Farlow, W.
DOI: 10.5962/p.355230
Author: W. G. Farlow
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: hybrid
OpenAlex ID: W4378231279