On wheat mildew (Puccinia graminis, Pers.) and its connection with the barberry aecidium (Ae. berberidis, Gmel.) / by Charles B. Plowright.

  • Plowright, Charles Bagge, 1849-1910.
Date:
1882
Catalogue details

Licence: Public Domain Mark

Credit: On wheat mildew (Puccinia graminis, Pers.) and its connection with the barberry aecidium (Ae. berberidis, Gmel.) / by Charles B. Plowright. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    3/16
    ON WHEAT MILDEW CHAPTER I. ON THE CONNECTION OF THE WHEAT MILDEW WITH THE BARBERRY, Has the Barberry really anything to do with the mildew in Wheat ? This question is one of great prac- tical importance to the agriculturist and through him to all classes of the community. It is by no means a novel one, and cannot be shelved as a new-fangled notion too crude to be worth investigation ; for it is just a century ago, this present year, that the first re- corded experiment bearing upon the question was per- formed, in the same county in which these lines are penned. Seventeen years ago the connection was proved to the satisfaction of Continental botanists, but many of us in this country and in America either de- nied it altogether or accepted it in a half-hearted sort of way. The magnitude of the interest at stake, as well as the great importance of the subject from a scientific point of view, demand that we should take the trouble to decide one way or the other. If the experiments upon which the assertion of this connection is based will not bear repeating, let us cast the vaunted theory to the winds and have done with it. But if, upon the other hand, these experiments prove the connection, let us accept it although it does uproot our prejudices and entails the acceptance of a great deal which at present we regard as too wonderful to be true, for Puccinia graminis is by no means the only case of the kind. It was in the hope of being able to arrive at a definite conclusion one way or the other, that the writer in the summer of 1881 performed a series of ex- periments* * * * § by infecting a number of Wheat plants with ripe spores of the Barberry fungus, with this re- sult, that while 76 per cent, of the infected plants took the disease, no less than 70 per cent, of similar Wheat plants, which were kept as check plants, be- came spontaneously affected with mildew. The natural conclusion arrived at was, that 6 per cent, was not conclusive evidence. It is obvious that mildew is a highly infectious disease, and the necessity for a less rough method of experiment is demanded if unequivocal results are to be obtained. In the spring of this year (1882) another series of experiments was instituted, in which not only was the Barberry fungus sown upon Wheat, under circum- stances which should, as far as possible, preclude the agency of accidental infection, but conversely the Wheat mildew was sown upon Barberry plants— with the result, it may be premised, of once again demonstrating that the Barberry fungus and the Wheat mildew are two states of one and the same fungus. Lest it should be thought I have jumped too eagerly to this conclusion it may here be said * Plowright, Grevillen, vol. x., p. 33—41. that when I began these experiments this year it was with a mind biased against the theory of “ heteroe- cism ” (that is, the occurrence of the same fungus in different phases of its growth on totally different plants), that the experiments now amount to more than a hundred, and that they have embraced many other species of Uredines besides the one which forms the subject of this paper. Had we given our forefathers more credit for the faculty of observation it would not have taken us a hundred years to arrive at our present position ; nor will the time be wasted if we glance in detail at some of their writings on this subject. History of the Subject. The mildew of Wheat has, as a blight, probably been known from remote antiquity. The Romans held a festival on April 25—the Robigalia, or Rubigalia— with the object of protecting their fields from mildew. The sacrifices offered on this occasion consisted of the entrails of a dog and a sheep, accompanied with frankincense and wine.* The fungoid nature of the mildew was not known until the latter half of the last century, for Tull,f writing in 1733, attributes it to the attacks of small insects “ brought (some think) by the east wind,” which feed upon the Wheat, leaving their excreta as black spots upon the straw, “ as is shown by the microscope!” Felice Fontana,* some thirty years later, published an account of the fungus with figures. Persoon,§ in 1797, gave it the name it still bears (Puccinia graminis), and also figured it, as did Sowerby,|| in 1799, under the name of Uredo frumenti. The first mention of the subject immediately under consideration is by Marshall, who, writing in 1781, says :— “It has long been considered as one of the first of vulgar errors among husbandmen that the Barberry plant has a pernicious quality (or rather a mysterious power) of blighting the Wheat which grows near it. “This idea, whether it be erroneous or founded on fact, is nowhere more strongly rooted than among the Norfolk farmers ; one of whom mentioning, with a serious countenance, an instance of this malady, I very fashionably laughed at him. He, however, stood firm, * Smith, Smaller Dictionary of Greek and Roman Anti- quities. 5th edit., 1863, p. 322. t Jethro Tull, Horse Howeing Husbandry, 3d edit., 1751, p. I51*2- X Felice Fontana, Osservazioni sopra la Rttggine del Grano, Lucca, 1767. § Persoon, Tentamen Dispos. Method. Fungomim, 1797, p. 39, t. iii., f. 3. I! Sowerby, English Fungi, vol. ii., 1799, t. 140. Marshall, Rural Economy of Norfolk. 2d edition, London, 1795, vol, ii., p. 19.