The first exercise upon the programme this afternoon is a paper entitled "The Rusts and Smuts of Wheat, their Life, History and Preven tion," by Prof. W. A. Kellerman, of Columbus, Ohio.

Prof. Kellerman then delivered to the Convention an address upon the subject above announced, which was as follows:

THE RUSTS AND SMUTS OF WHEAT.

[By W. A Kellerman, Ph., D., Professor of Botany, Ohio State University.]

[Abstract.]

Botanical science has made rapid strides in the past few years. This advance, though not so publicly conspicious as in case of some of the physical sciences-for example, that portion that deals with the application of electricity-is yet none the less real and important. Assiduous investigators have, within our own memory, placed vegetable physiology on a sound and scientific basis; others have been as patiently and successfully devoting their time and energies to the elucidation of the life histories of vegetable organisms. We know fairly well the cycle of development not only of the common higher plants but also of many of the lower and microscopic species. Among the latter are many forms directly or indirectly inimical to the farmer, some of them-the so called Bacteria-invade at times, his own organism and cause more or less dreaded diseases, indirectly they do him harm by attacking his crops and reducing his harvest. In this last category are found the two classes of vegetable parasites assigned as the subject of my lecture-namely: Rusts and Smuts of Wheat.

These two kinds of plants are fungi, that is to say, they belong to that lower group which is characterized not only by comparative simplicity in structure, but also by the more important physiological character of being dependent on organic matter for their food. Our common plants can in the presence of the green coloring matter, or chlorophyll and sunlight, convert the mineral matter which they absorb from the soil and the air into organic matter, which then contributes to the building up of the vegetable fabric. But the fungi have no chlorophyll and are therefore compelled to live on matter which is assimilated by our common plants-in short, their parasitic mode of life is ▲ necessity.

Let me observe that notwithstanding their low place in the scale of organic struotere and their inability to convert inorganic into organic matter, they yet have a cycle of development as definite and invariable as the common higher plants. The life history of many of the species has already been made out and among these some of the Ruste and Smuts find a place.

If with lens in hand we make a careful examination of the affected blade of wheat, we will find that the red material, or so called red-rust, consists of minute globular bodies which when placed under suitable conditions germinate by sending out a slender tube-like body. These are therefore the reproductive bodies of the parasitic plant-or Deeds, we may call them, spores more properly speaking; they penetrate the host plant soon after germination-the slender thread or tube passing into the stomata or breathing рого of the leaf. This tube continues to grow and branch abundantly, penetrating perhaps the active plant and drawing its nourishment from the surrounding tissue-thereby Weakening the host plant and reducing the yield of grain. After a short period-say eight or ten days of such development of the vegetative portion of the parasite, the reproductive bodies or spores are formed in clusters immediately below the epidermis, rupturing the latter so as to expose the mass of red spores. The countless millions of them germinate rapidly if favorable atmospheric conditions obtain and the disease spreads over the field; or to use the farmer's expression the wheat is "struck" with the

!

But the life history of this rust has not all been told. In the same cluster with the red spores a few black ones may make their app arance, and a few days or weeks later black spores alone are found. Yet they are connected with those same vegetative threads that produced the red-rust or red-spores; the fact is then demonstrated that this parasite produces two kinds of fruit, or as we may say has at least two stages. The red-spores (seeds) are delicate globular bodies, quickly killed by exposure, are called the summer spores; the black reproductive bodies are oblong or pointed, have thick coverings, do not germinate at once but lie dormant through the winter-hence called winter-spores. When they begin to grow in the spring they do not penetrate the wheat-plant, but some one of our common shrubs or herbaceous weeds. And strange as it may seem they do not produce the red or black rust, but instead a form of the fungus known by the common name of "yellow cluster cups," and by the technical name of "Ecidium." The yellow spots so commonly noticed on violet leaves in the spring, or on barberry or other plants, are examples of this stage of the parasite. This should be called the first of the three stages of this fungus.

The case of our rust of wheat is still more complicated by the fact that there are at least three distinct kind, or species-readily separable by peculiarities of the spores which are easily recognized by the aid of the microscope; also, further by the fact that the first or acidial stage of one (Puccinia graminis) occurs on the Barberry; of the second (Puccinia coronate) on Buckthorn, or Rhamnus; and of the third (Puccina rubigorera on a Gorrage-wort.

From this life history, too briefly traced, it would seem that if the first or cedial stage be destroyed by promptly cutting down and burning all of the host plants affected by it, no red or black rust could afterward appear. The experiment, however, while in some cases undoubtedly checking the later stages somewhat, is from a scientific point of view a total failure. Red rust in abundance may be seen from year to year, even when the first stage is destroyed. The apparent mystery is solved when I state that it has been repeatedly found that the vegetative stage which produces the red rust spores in many cases lives through the winter. Whether true of all species of rusts affecting wheat I can not say, but I have proof from my own observation and the testimony of others that it is true of some of them.

There is no known method of destroying the rust or preventing its ravages, which does not at the same time destroy the wheat plant also. Experiments however are in progress. Let me relate briefly my own work completed at the Kansas State Agricultural College just before coming to the Ohio State University this year.

I sprayed plots of wheat (also of barley and oats) with the recognized and in many cases certainly efficient fungcides, as follows: Bordeax mixture, tinct. of sulphur, iron chloride; and on other plots applied flowers of sulphur. I used spring wheat in the experiment, and sprayed the plats first when the plants were an inch or two high, and thereafter weekly until harvest. At this time the treated plats were compared with the adjacent untreated ones in respect to the rust visible. All were alike, or in other words I failed utterly to prevent or even in the slightest degree to check the disease. It is to be hoped that other experimenters will discover other means of preventing this terrible pest.

The smuts of wheat most fertile were briefly disposed of. Their cycle of development is less complex. The smut itself as shown by microscopic examination consists of extremely minute globular reproductive bodies, denominated spores-less correctly speaking seeds. When these germinate they infect the seedling wheat plant while it is yet very young and delicate. In this host they grow concealed until approaching maturity; the smut fungus enters the head of wheat in the earliest stage of development of the latter. There are two kinds or species of wheat smut and their characteristics at this stage of development diverge, the one-stinking smut-enters the growing grain only, consumes the nourishment which should have been stored up in the latter, but not changing its external shape materially. The ruptured grains at threshing time will show the black mass

within. This smut has a peculiar penetrating disagreeable odor, hence the name. flour is perceptibly damaged if the wheat is much affected, and both are unsalable.

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The other fungus (loose smut) penetrates both grains and chaff, and the whole head is presently converted into a powdery black mass more or less weathered away when harvest time arrives. Some of the shriveled remains of the head will yet retain enough of the black spores to make plain the nature of the affection.

It would be a long story to relate the experiments in detail which have resulted in the discovery for the stinking smut of cheap and efficient fungicides; that is to say, modes of treatment of the seed grain (which may have spores adhering to them), that entirely suppresses the disease. I know of no experiments touching the prevention of loose smut except those carried on by my former assistant (W. T. Swingle) and myself, but unfortunately they were not successful and need not be further discussed.

Of numerous fungicides (twenty-four in all) that were used in the experiments to prevent stinking smut one is especially to be recommended, namely, hot water, temperture 132°F. The immersion of the seed in water kept at this temperature should be continued fifteen minutes, when the seed (which should be in a basket or frame lined with wire netting, say twelve meshes to the inch) is first dropped into the hot water the temperature will suddenly fall so low that the spores of the smut that may be present will not be killed, even with prolonged immersion. It is therefore necessary to add at once sufficient hot water to bring up the temperature to about 132°F-never above 135°, and better never below 130°. Observing this, and also the further precaution to shake, lift and plunge the basket of seed so as to insure the contact of the hot water with every grain of the wheat, the smut will surely be killed, and the seed thus freed from adhering spores will produce a clean crop. The seed may be treated days or weeks before seed-time, or it may be sowed immediately after treatment and before the grains are completely dried.

Numerous experiments with oats showed in every case that there was an increased yield of grain, due, apparently, to the effect of immersion in the hot water, aside from the mere killing of the smut. Thus, when there was seven to ten per cent. of smut in the crop, the yield from the treated seed was augmented not only by an amount equivalent to that of the prevented smut, but by at least twice that amount. It is very probable that a similar result would be found in case of wheat treated in the manner described above. At any rate the stinking smut can be effectually prevented if a proper fungicide be used. The expense in treating the seed is very trifling, and if it is badly infected great financial profit must necessarily follow.

The Chair: A few minutes will be devoted to the discussion of this subject by the Convention. Any member of the Convention who has any questions to ask Prof. Kellerman, they may now ask them, and I have no doubt he will be pleased to answer.

Secretary Bonham: I would like to ask the Professor whether in his experiments he found that he was able to successfully check the black rust that appears on the head of oats and wheat in the spring. I didn't understand from your remarks whether you had been able to successfully check that or not.

Professor Kellerman : No, sir, we have succeeded in no case in checking the rust. All that we have succeeded in doing is in preventing the smut, and we have not succeeded in preventing all forms of smut. It is only the loose smut of oats and the loose smut of barley and the stinking smut of wheat that we have yet prevented. The loose smut of oats,

which does so much damage, especially in the southern part of this State, as I have been informed, we have not been able to check at all.

Secretary Bonham: That loose black smut that appears on our wheat in the spring was excessive this last spring. We have seen in southern Ohio nothing like it, and I think in some fields in southern Ohio one head out of every five was blighted, and in others one head out of every ten was blighted. Old farmers have often told me that that is a sure sign of a good wheat crop. What is the relation between that and a good wheat crop, Professor? Is there any relation between the two?

Prof. Kellerman: Well, Mr. Chairman, I am glad to talk as long as you will endure it. I thought when I began that I better explain in making what remarks I had to make, that it was a question of endurance; not of endurance on your part to-day, but on my part, because I didn't feel very well prepared to talk. I got along, however, better than I expected, and if you want to endure a little more of it, just go ahead and ask me questions and I will talk all day, if you give me a chance.

I think there is a relation between the two. I don't laugh at a farmor and say "it is all nonsense," when he tells me that the weather has caused this disease or that disease. The fact is the conditions—and I only mentioned it incidentally-the conditions which are favorable to the ordinary average growth, are as a rule favorable to the parasitic growth of this plant. If we have damp days and warm days, a vigorous growth of vegetation, in general, would be very likely to produce a vigorous growth of these parasites; for the simple reason if no other, that these spores germinate very rapidly, and so in the plant the disease is multiplied. There is a relation and a close relation of course; but all I meant to say was that you must not have all these conditions as primary causes. When an acorn germinates, you might say that the moisture in the soil caused the germination. That is right; but if you would say that the moisture in the soil caused the oak tree, I don't know that that would be stating it correctly. At any rate, you never think of any thing else than that the oak tree has developed out of the acorn. Therefore I warn you to think that the smut and rusts are only developed out of the seeds which are planted along with the grain that you sow, or they may, of course, be self-planted, like the most of our weeds, and be in the soil ready to germinate. There is a close relation; and the observation of farmers is of more value to the scientific man than any observations he can make; for the very reason that he has a broader scope and a better opportunity to make these observations. Now, I say to this extent I may agree with the farmer, not that we have thought the farmer was just right when he said damp weather caused it, but we knew from his statement, that he had observed there was a close connection between the two; but further

than that, in the manner I have indicated, I know of no connection. At least that is a general statement that will hold true.

Secretary Bonham: Has there not been some means discovered of preventing this black rust?

Prof. Kellerman: No, sir, not that I know of; nothing that we could consider as scientifically established.

Secretary Bonham: Has not Prof. Bessey stated that by the use of blue vitriol, it will be checked?

Prof. Kellerman: That is the very point at question. I have as a matter of fact, floating in my mind, the impression there has been some such statement made by Prof. Bessey, or some others. I will state what I know-I don't know much about the subject; but itis not intended as any comment upon what Prof Bessey has said.

Prof. Bessey does say just what has been indicated. I know he does say this, that if you burn smut in your corn fields, you will lessen the smut; that is, you take it out of your field. Last season, I took the trouble to collect a large amount of corn smut and I planted several rows of oorn, but before planting it, I put, with my fingers, a large quantity of corn smut in the hill where I was going to put the corn, and then I came along or had a boy come along and drop the corn in and I helped him cover it. Then, to be sure I was going to succeed in this matter, I had a pail of water brought to the field and I dumped the grains of corn into that pail of water so that they would be wet, and then I poured in a mass of smut. Let me tell you that I didn't go out in the fall and gather the smut and keep it through the winter in my laboratory, but I went to the field to a shock of corn at the time I planted the corn and got my smut. Surely it ought to have germinated, because other smut, exposed in this way seems to germinate. I then poured this smut on the wet corn so that the grains of corn were literally black with smut, and in a third case I poured smut on top of the corn after I put it in. There were three dif ferent cases. Well, I was, I am glad to say, called to this University before the corn was ripe.

Secretary Bonham: Have you heard from that corn yet?

Prof. Kellerman: Yes sir, I have; my faithful and truthful assist ant has reported to me and we have a list. We counted every stalk of corn clear through. We had of course several rows. We counted every stalk of corn and counted the smutty corn, and we had two rows adjoining those which were not so treated, and we found just as much smut and no more smut, on the untreated as on the treated corn, and to make it still more convincing, I treated the corn as I treated the wheat-with hot water and with potassium sulphide, which I do know killed the spores in the case of stinking smut of wheat, as I mentioned a while agos