SOME PROBLEMS IN THE TREATMENT OF DISEASED CHESTNUT TREES

By Roy G. Pierce

Tree Surgeon, Pennsylvania Chestnut Tree Blight Commission

The problems that present themselves to the growers of chestnut trees concerning the present disease may be summed up under three heads: first, what the disease is, how it is caused, and how it may be recognized; second, what is to be done with diseased trees to bring them to health or to prevent them from infecting other healthy trees nearby; third, what means in the future can be undertaken to keep a tree healthy, that is, to prevent reinfection.

First, what the disease is, how it is caused, and how it may be recognized. The disease known as the chestnut tree blight is caused by the fungus, Diaporthe parasitica, which usually finds entrance to the tree through wounds in the bark. The mycelium or mass of fungous filaments gradually spreads through the bark in much the same manner as mold spreads over and through a piece of bread, even penetrating the wood to a depth of sometimes five annual rings. The spread of the fungus, resulting in the cutting off of the sap flow, is the immediate cause of the wilting and dying of the leaves and branch above the point of girdling. This wilting of the leaves, followed later by the death of one branch after another as the fungus spreads, has given rise to the term "blight" of the chestnut trees.

The danger signals which the chestnut tree displays when diseased are not a few. In summer, when the tree is first affected, the leaves turn yellow-green and wilt, later turning brown. Small burs and withered leaves retained in winter are some signs of the diseased condition of the tree. At the base of the blighted part a lesion, or reddish brown canker, is usually found. This lesion may be a sunken area or, as is frequently the case, a greatly enlarged swelling, known as a hypertrophy. After a branch has become completely girdled sprouts or suckers are very apt to be found below the point of girdling. In old furrowed bark on the main trunk of the tree the presence of the disease is seen in the reddish brown spore-bearing pustules in the fissures. In determining the presence of the fungus in the furrowed bark of old trees, one must learn to recognize the difference between the light brown color characteristic of fissures in healthy growing bark, and the reddish brown color of the fungus. When the disease has been present several years the bark completely rots and shrinks away from the wood, and when the bark is struck with an axe a hollow sound is produced.

Many of the owners of chestnut trees throughout Pennsylvania do not acknowledge that a fungus is causing the death of the trees. They state that since they have found white grubs or the larvae of beetles in nearly every tree that dies, that it has been the larvae that killed the tree. It is acknowledged that generally white grubs are found in dying chestnut trees, and that in nearly all of the large cankers or lesions these grubs are present. However, if one will take the pains to examine the small twigs and branches or the new shoots rising from the stumps, that are diseased, he will not find the grubs present.

Second, what is to be done with diseased trees to bring them back to health or to prevent them from infecting other healthy trees nearby. To bring the trees back to health implies that the disease can be cured. This is not always true for the tree may be already nearly girdled, when the disease is first noticed. A tree taken in time, however, may have its life prolonged indefinitely though it may have the blight in some portion of it every year. More particularly does this apply to valuable ornamental and orchard trees.

Prof. J. Franklin Collins, Forest Pathologist in the Department of Agriculture in Farmer's Bulletin No. 467 on "The Control of the Chestnut Bark Disease" gives the following: "The essentials for the work are a gouge, a mallet, a pruning knife, a pot of coal tar, and a paint brush. In the case of a tall tree a ladder or rope, or both may be necessary but under no circumstances should tree climbers be used, as they cause wounds which are very favorable places for infection. Sometimes an axe, a saw, and a long-handled tree pruner are convenient auxiliary instruments, though practically all the cutting recommended can be done with a gouge with a cutting edge of 1 or 1½ inches. All cutting instruments should be kept very sharp, so that a clean smooth cut may be made at all times."

All of the discolored diseased areas in the tree should be removed. Small branches or twigs nearly girdled are best cut off. Cankers in the main trunk or on limbs should be gouged out. Carefulness is the prime requisite in this work. If the disease has completely killed the cambium, the bark should be entirely removed as well as several layers of wood beneath the canker. By frequent examination, however, diseased spots may be found on the tree where the mycelium of the fungus is still in the upper layers of the bark. It is not necessary then to cut clear to the wood, but the discolored outer bark may be removed and a layer of healthy inner bark left beneath the cut. The sap may still flow through this layer. The border of the diseased area is quite distinct, but cutting should not stop here but should be continued beyond the discolored portion into healthy bark, at least an inch. The tools should be thoroughly sterilized by immersion in a solution of 1.1000 bichloride of mercury, or 5 per cent solution of formaldehyde, before cutting into the bark outside of the diseased area. Experiments have shown that a gouge or knife may carry the spores into healthy bark and new infection take place. Experiments are being carried on in the laboratory to determine the length of time which spores will live in solutions of different strengths of fungicides.

It has been shown that a cut made pointed at the top and bottom heals much faster than one rounded. The edges of the cut should be made with care so as not to injure the cambium. The chips of diseased bark and wood should not be allowed to fall on the ground then to be forgotten. A bag fastened just below the canker will collect most of this material as it is gouged out and prevent possible reinfection, which might take place if the material were allowed to scatter down the bark. Canvas or burlap spread around under a small orchard tree might be sufficient to catch all of the diseased chips of bark and wood cut out of the lower infections. This diseased material should be burned together with blighted branches. After completely cutting out all of the diseased parts the cut surfaces should be either sterilized or covered with a waterproofing which combines a fungicide with a covering. Among these might be mentioned coal tar and creosote, or a mixture of pine tar, linseed oil, lamp black and creosote.

The trees which have been killed by blight, or nearly girdled, have been overlooked. These should be cut off close to the ground, the stump peeled and the bark and unused portions of the tree burned over the stump. The merchantable parts of the trees should be removed from the woods promptly, as all dead unbarked wood furnishes an excellent breeding place for the blight fungus.

Third, what means in the future can be undertaken to keep a tree healthy, that is, to prevent reinfection. The spores may be carried by so many agents that it is difficult to prevent reinfection. However it is clear that the farther infected products or trees are removed from healthy trees the less liable they are to have spores carried to them. Cooperation with nearby owners of diseased trees will help solve this problem.

Spraying on a large scale has only been carried on, so far as I know, on the estate of Pierre DuPont, Jr., at Kennett Square, Pennsylvania. At this place there are many large chestnut trees ranging from sixty to ninety feet in height, many of which were planted some sixty-five years ago. Mr. R. E. Wheeler started the work of cutting out diseased limbs and cankers in October 1911, and began spraying with Bordeaux mixture in April 1912. The formula 5-5-50, five pounds of copper sulphate and five pounds of lime in 50 gallons of water was found to be injurious to the foliage in the Spring. This was changed therefore, to 4-5-50, which had one pound less of copper sulphate. This did not seem to injure the foliage.

About 70 trees were sprayed twenty times during the season. Nearly all of these were gone over four times to remove diseased branches and cankers, once in October 1911, then in early summer and again in September and November 1912. As an example take tree No. 6 which was studied, December 14, 1912. It is 39 inches in diameter at breast height, and approximately 70 feet in height. On this one tree six diseased limbs were removed, and sixteen cankers were cut out. Of these sixteen, two infections continued, that is, were not completely cut out, and had spread; three had infections below old limbs which had been removed, and eleven were healing over. This tree was about 1000 feet away from other badly infected trees, though but 25 feet away from other chestnut trees in the same row. The experiment of Mr. DuPont in spraying shows what can be done on valuable lawn trees. On the whole, these trees look well and healthy. Trees which were not sprayed over three times and were within 50-100 feet from badly blighted trees, became infected in so many different places that it will be necessary to remove them.

One of the problems to be solved next year will be that of the least number of sprayings which will be effective in preventing new infection.

The Chairman: The question of the chestnut blight is now open for discussion.

Mr. Littlepage: I should like to ask these gentlemen how far west they have heard of chestnut blight—that is, heard of it with any degree of authenticity, and also whether or not they care to express an opinion as to what the prospects are in the middle west, say out in Indiana, Illinois and Ohio?

Mr. Pierce: In answer to that question, I will say that in Pennsylvania we have found infections in Wayne County and also in Fayette County, both near the western extreme of the state, but those have been attended to, very largely, and the boundaries closely determined. In Ohio there have been several reports of the blight being found, but I don't think either of the reports have been proven. There has been a fungus that I have spoken of as the Connellsville fungus, that has been all around in that neighborhood, south-western Pennsylvania and eastern Ohio.

The Chairman: Is the Connellsville fungus also diaporthe parasitica?

Mr. Pierce: Yes, sir. It was placed by Mr. Anderson, who did the work on that, in the same genus as diaporthe, but he preferred the name endothia parasitica.

The Chairman: The question is of changing the generic name, from diaporthe, on the basis of the previously established species?

Mr. Pierce: Yes, sir, previously established species of endothia. It is only a suggestion of Mr. Anderson; it was made by him. This was very similar to the true blight fungus and when our men first went out into the western part of the State, they reported these various cases that came up there as chestnut blight, and none of the pathologists of our force then were competent to determine the difference, except that the fact was noted even then that it was not growing as a parasite in the sense that the true blight fungus has been growing in the east.

The Chairman: That may be due to varietal differences, though, rather than specific?

Mr. Pierce: Yes, although Mr. Anderson seemed to think it was specific.

The Chairman: Is there any further discussion? The subject is worthy of a good deal of comment.

Mr. Pomeroy: I want to ask the speaker what the approximate cost would be for one spraying of a tree about that size, 70 feet in height?

Mr. Pierce: We have photographs on the table there showing our eight hundred dollar spraying machine, the same kind used in Massachusetts in gypsy moth work. With this two men can spray about ten such trees in a day. I haven't got it down in black and white but I figured that, on those chestnuts at DuPont's, they sprayed about 600 gallons a day. Ten trees a day would make it, say, with a $2.50 man, not very high for a tree. I think it costs in all something like four dollars a tree during the whole season, but that is a very rough estimate and the materials are not included.

The Chairman: The cost will have to be calculated on a sentimental basis for the ornamental trees, and on a commercial basis for the commercial trees. The actual value of the spraying has not yet been determined. This spraying cannot reach the mycelium in the cambium layer; if the disease has been carried in by a beetle or woodpecker your spraying would be ineffective.

Mr. Pierce: Yes indeed, that was just the thought Mr. Galena had, notwithstanding the fact that they cut out all visible infections and the trees were so blue with spray that you could see them for half a mile.

The Chairman: But, later on, cracks and squirrel scratches and all sorts of injuries would allow new spores to be carried in?

Mr. Pierce: Yes, sir.

Mr. Reed: The future of the chestnut depends so largely on the conquering of this disease that no other horticultural problem of this nut is, just at present, imperative. So far as we know, all of the European and American varieties are highly subject to this disease, so much so that there is no inducement to plant them, and we are waiting for Dr. Morris and a few other hybridizers to find some hybrids, or straight Japanese varieties, that are of sufficient merit, and of sufficient degree of resistance to this disease, for us to have a basis for building up the future industry. On the tables there are quite a number of exhibits from Mr. Riehl and Mr. Endicott of Illinois. Most of them are hybrids between the American and the Japanese species, but, so far as we know, they have not been tried in communities where the disease prevails. We don't know whether they are resistant or not, as they are being grown in a section entirely outside of the area where the blight exists. I think I am right in that, am I not, Mr. Pierce? Is there any chestnut blight in southern Illinois?

Mr. Pierce: There has been none reported.

Mr. Reed: I think that the varieties that these men in Indiana have originated are the most promising we know of. I think that in examining these specimens you will agree that they are of fairly high quality and good size, and if they prove to be resistant to the disease much may be expected from them.

Mr. Hutt: I have not seen the chestnut blight at all. I hope that it isn't in our section. I have heard it was brought in from some point but I do not know whether it was identified exactly as the chestnut blight.

Mr. Pierce: I saw a specimen sent from North Carolina and it proved to be the Collinsville fungus.

Mr. Corsan: If you remember reading Fuller's book on nuts, he reported that the chestnut blight extended through the Carolinas but said that chestnuts were still coming from that direction in great abundance. Up in Canada we haven't the chestnut blight. The chestnut tree runs from the Ohio River to the Niagara River but it doesn't cross into Michigan, except along the Michigan Southern and Lake Shore Railroad where some enterprising gentlemen have planted the chestnut with the tamarack alternately all the way from Cleveland to Chicago. I examined the state of Indiana across and from top to bottom several times in the summer and I never saw any chestnuts there, but I have seen some newly planted places in Michigan; near Battle Creek I saw a farm of about fifty acres. We are having up in Ontario, beyond Toronto, a blight that has attacked the Lombardy poplar and that looks similar to the chestnut blight. I have been watching it for the last ten years and the tree seems to have at last outlived it. It dies down and then a little sprout comes out from the carcass.

The Chairman: Isn't that the poplar tree borer that always attacks the Lombardy?

Mr. Corsan: Oh no, it's very similar to the chestnut tree blight. We can grow chestnut trees all we like but no one has brains enough to grow them. The farmers grow pigs and things but don't bother with chestnut trees; consequently the chestnut blight does not exist there.

Mr. Pierce: I didn't answer a portion of Mr. Littlepage's question. Mr. Littlepage asked whether or not the blight might be expected in the Middle West. That depends, more or less, upon the results of the work Pennsylvania is now carrying on. If we can keep the disease from extending through the territory in which we are working, there is a very good chance to keep it out of the West. If we are not successful, it may be expected to develop, in time, over the whole chestnut range.

There seems to be a very good opportunity for growing the chestnut commercially beyond its present range; that is, where it is so infrequent as not to be in danger from infected growths nearby.

In the eastern part of the state different people have reported that the blight seemed to them to be dying out and, a number of these reports coming from a certain locality, the Commission decided to investigate one which seemed to be better reported than the others. It was found, after a very extensive investigation, that this dying out was true only in the sense that it was not spreading, perhaps, as fast as it had been spreading before. The mycelium and the spores were healthy and were affecting the new trees in quite the same manner as the year before and as in other parts of the state.

The Chairman: The question of controlling blight after it has appeared is of very great consequence. Concerning any commercial proposition with chestnuts the people are wide awake to the seriousness of the blight. They are afraid to go into growing chestnut orchards; they have had so many fake propositions in the past in pecan promotions that they are afraid of chestnuts and everything else. Any proposition for bringing forward chestnuts commercially must be a plain, simple, straightforward statement of the truth, the whole truth and nothing but the truth. We are ready, all through the North and East, to raise hundreds of acres of chestnuts, such as Mr. Reed has spoken about, ones which resist the blight, or ones which resist the blight comparatively well.

Let us consider comparative immunity for a moment. We know how expensive it is to manage an apple orchard, and yet, with the present high prices, the profits on apple orchards, well managed, are great. May we not have chestnut orchards managed with the same degree of relative expense and the same degree of relative profit? I would like very much to hear from some of the men who have actually raised chestnuts in orchards concerning the relative care of the chestnut compared with the apple, and the relative profit. I see Col. Sober here; can't you tell us about your experience in managing the blight? Can it be managed successfully in proportion as apple tree parasites are managed?

Col. Sober: My experience has been this; I have four hundred acres of chestnuts in bearing. They range from five years to fifteen years old. I find that I can control the blight easier than I can control the scale on apple trees. If anyone doesn't believe this I invite him and all to come to my place and see for themselves. I think I have nearly one million seedling and grafted paragon trees. I don't think you will find fifty affected trees on the whole place today. I have men going in every grove at the present time who have inspected thousands of trees and found seven that had blight on the limbs, so I know what I am speaking about.

The Chairman: What is your method?

Col. Sober: Cutting out, cutting off anything I see; if it is really necessary, cut the tree down; but we don't often find that necessary because just as quick as we see any affected, or any limb dying or dead, we cut it off. I had my groves laid out in sections of a hundred feet wide and numbered; and I had charts made so that they can be inspected section by section. In that manner, every tree is inspected. One individual will inspect the trunk and another one the top. In each section I can show you as far as we have gone. I can show you how many trees are in each section and how many affected trees there are in that section, or whether there are any or not. I say I can control it easier than I can control scale and with less expense and I want that to go on record. There is no question about it. It can be seen at my place. I go over my groves about four times a year and have been doing it all the time, and I don't doubt but that I discovered this disease the first of anybody in the state, perhaps, in 1902. I was looking around to cut scions and I saw one tree whose center was dead and around it were the finest shoots almost that I had ever seen for grafting purposes. I went to it and saw the center was dead. I cut some scions and today that is one of the finest trees I've got on my place. From what I know now that was a blighted tree.

A member: Did you paint over the scars?

Col. Sober: No sir, but we are doing it now, using white lead.

A member: How much blight is there around you?

Col. Sober: I am surrounded with it on all sides. Right up against my groves about 17 per cent of the trees are affected. That is the report coming from the parties inspecting now for the Blight Commission. I shipped Mr. Mayo about four or five thousand trees this fall. I don't suppose there were a dozen that were thrown out, thinking they were blighted or diseased. We have records of all that up at my place. There are some trees right here now that came from my nursery. I wish you gentlemen could just see for yourselves; come out and see.

The Chairman: In advancing this chestnut on a commercial basis it had better be stated that it does not blight as badly as the American chestnut and that when blighted it can be cared for with less cost than the apple tree. I would suggest that some such notice be sent out with commercial stock. That would put it on the right basis so that the chestnut would find its position, which it is not finding now because the people are full of the blight; and if a frank, full statement of this sort were made I believe it would be extremely important.

Mr. Rockey: I went through practically the whole extent of Mr. Sober's orchard recently and found one infected tree. I can vouch for the statement that he has made that he is almost surrounded by blight.

The Chairman: I have given attention to only a few of my own trees that were blighted because I have too much else to do and too large a place, a couple of hundred acres engaged in a small and large way,—a variety of ways—with nut trees; and the few I have cared to save after blight has begun I have saved by cutting it out very thoroughly and using either white paint or grafting wax. I used also pine tar and some gas tar. I killed some good trees that I wanted particularly to save by putting on gas tar.

The matter of compelling the removal of infected trees is a very important one, but it must rest with the authorities. In the vicinity of New York we have so much hard wood that you cannot sell it unless you are in some sort of a trade combination. Fine oak, fine hickory, fine chestnut, you can't dispose of in New York City, because we have such a lot of it. We have wild deer within fifteen miles of New York City on three sides of us on account of the forests. You have got to find some special way for disposing of this blighted chestnut timber. Telephone and telegraph poles and ties all go for nothing, unless you happen to be so situated that you can manage the matter commercially, and a way should be found by the state so that people can dispose of their blighted timber, which is just as good as any other.

It is very important to note that the boy scouts are interested, and we ought to encourage their interest. It is a splendid thing, getting the interest of boys engaged. You know how active a boy is in getting a snake from under a rock and he will do the same thing with the chestnut blight. It is his natural tendency to hustle when he gets after anything. This chestnut blight belongs to the microbe group and the microbe is the great enemy of mankind. In wars the microbe kills about eight men for every one killed by missiles. If we can encourage the interest of boy scouts in fighting the greatest of all human enemies, the microbe, including this little fungus, we shall have a splendid working force.

In regard to the injection of poisons and medicines into trees, it seems to me that a very firm stand ought to be taken by all responsible men who know anything about plant pathology. We know that a poison injected into a tree must either act injuriously right there upon the cells of the tree, or else must undergo metabolic changes. A tree cannot use anything that is thrown into it, poison or food or anything else, until it has undergone a metabolic change; you must have a distinct, definite chemical process taking place and we ought to state that most of the substances which are alleged to be of value, when injected into a tree, are either absolutely worthless or injurious. One man tried to persuade me that his medication if applied to the cambium layer would be absorbed, and said that if I would only use it on a few of my trees I could see for myself. He said it would drive off even the aphides. I tried it on four trees affected with aphides and found that he told me the truth. It drove them off, because the trees died and the aphides left. One tree lived a year before being killed; it was a most insidious sort of death, but the aphides left that tree. (Laughter.)

Some of the Asiatic chestnuts resist the blight very well. Curiously enough when grafted upon some of the American chestnuts they then become vulnerable. Two years ago, from a lot of about one thousand Corean chestnuts in which there had been up to that time no blight, I grafted scions on American stump sprouts and about 50 per cent of those grafts blighted in the next year, showing that the American chestnut sap offers a pabulum attractive to the Diaporthe, and that is a fact of collateral value in getting our negative testimony upon the point.

Concerning the question of carrying blight fifty miles, there's no telling how far birds will fly carrying the spores of Diaporthe upon their feet. The spores are viscid and adhere to the feet of beetles, or migratory birds which sometimes make long lateral flights following food, rather than direct flights north and south. It is quite easy to imagine birds carrying this Diaporthe over an interval of possibly fifty miles, making that distance in one night perhaps. Someone may have carried chestnuts in his pocket to give to his granddaughter fifty miles away, and in that way carried the blight. If any grafted trees have been carried fifty miles, or any railroad ties, with a little bark on, carried fifty miles and then thrown off, it might blight the chestnuts in that vicinity. One can have as much range of imagination as he pleases as Longfellow says, There is no limit to the imagination in connection with questions of spreading the blight of Diaporthe.

Some of the Japanese and Corean chestnuts and some of the Chinese chestnuts resist blight fairly well. Among my chinkapins, I have the common pumila and the Missouri variety of pumila, which grows in tree form forty or fifty feet high. I have the alder-leaf chestnut, which keeps green leaves till Christmas, sometimes till March when the snow buries them, and those comparatively young trees have shown no blight; but one hybrid, between the chinkapin and the American chestnut, about twelve years of age, has blighted several times. I have cut off the branches and kept it going, but this year I shall cut it down. It will start at the root and sprout up again. I thought I'd give up that hybrid, but having heard Col. Sober's report I will begin at the root and look after some of the sprouts. That hybrid is the only one of my chinkapin group that has blighted at all.

In regard to the use of bichloride of mercury or formaldehyde, it seems to me that formaldehyde will be a better germicide than bichloride of mercury, because bichloride of mercury coagulates the albuminous part of the plasm and may destroy the cell structure, whereas the formaldehyde will be more penetrating and less injurious. One would need to know how strong a formaldehyde solution can be used safely. I presume the most vulnerable part of the tree would be at the bud axils. Spraying must require considerable experience at the present time and is of doubtful efficiency for timber chestnuts I am sure. We would like very much to hear any further comment upon this subject.

Prof. Smith: Mr. Sober's orchard is so unusually large that evidently it does not apply to average cases. The average man is buying chestnut trees for the garden or yard or lane. Prof. Collins has an acre on the top of a hill at Atlantic Forge and there he has fought diligently with the skill of a highly trained man, and the blight is gradually driving him back. I think that in a short time the trees on Prof. Collins' acre will be gone. I believe we need much more information before we can offer any hope that chestnut trees from a nursery will be safe against blight. I should like to ask the Blight Commission if they are at the present time planning to breed immune strains of chestnuts, and if not, I wish to suggest that it is a piece of work well worthy of their consideration. They might try grafting on American stocks, or on their own seedlings, some of the Korean chestnuts, on any variety that promises resistance, and also hybridizing, with the hope of getting a good nut that will resist the blight.

The Chairman: That is a very important matter, no doubt. In regard to the few chestnuts bought for lanes and gardens, I know a good many men who have bought a few grafted chestnuts with the idea of setting out a number of acres if those few did well, being men of a conservative sort. Men of that sort are the ones we want to have in our Association. We want to have men who will buy four trees, and if they do well, set out four hundred acres. That is what a great many men have had in mind in buying two, four or six trees of any one kind; they want to try them out. That is the wise way, the conservative way, the truly progressive way. If we are going to have very large numbers of any one kind of chestnut set out, we must make a statement of the dangers, so that men may be forewarned. If they set them out without warning and are disappointed, they drop the entire subject and go to raising corn and hogs; and then, to save trouble, turn these hogs into the corn and get to doing things in the easiest way, rather than carry on the complicated methods of agriculture that belong to the spirit of the present time. I would like to know if many efforts are being made toward breeding immune kinds. I am at work on that myself.

Mr. Pierce: Our Commission has recently gotten, I think, about fifty pounds of Chinese chestnuts of several kinds, which they expect to plant for experiment. Besides that they have made some other arrangements of which I know very little. This investigation will take years. The Commission has been compelled to devote itself to so many lines of work that I am afraid this question has not been given the attention it might have had. I think in the future there will be a good deal done along that line.

Two of us have been given the title of tree surgeons, and we work, or make arrangements to have someone else work, sometimes the scout, in the orchards throughout the state. I have a list of two hundred owners of cultivated chestnut trees that I got in the last month from various sources. Anyone in Pennsylvania who has a cultivated chestnut tree, can send a postal card, get one of us out to examine the tree and see whether it is blighted, and we will demonstrate what can be done in the way of treating it. I have done that right along in the last two months. If it is only a single tree I cut out all I can myself.

The Chairman: There are two distinct questions; first, the chestnut as a food tree, and second, as a timber tree. Your work has been chiefly with the chestnut as a timber tree?

Mr. Pierce: No, mine has been mostly on the lawn, so that it is for nuts.

Experiments made on one or two species of Japanese chestnuts show about 9 per cent of tannin; the tannin in the American chestnut runs only 6 per cent and in the small American, runs less. We know that the Japanese is somewhat more immune than the American. We have already found that it has 50 per cent more tannin. I believe one of us wrote you about experiments to find out the percentage of tannin in Corean, North Japanese, South Japanese and Chinese chestnuts. The investigation will be carried on for the next two or three months.

Mr. Corsan: May I ask if there is any soil food that would increase the amount of tannin? Trees protect themselves. We have watched the black walnut and seen him fight all sorts of enemies. The tree has poisons everywhere and the nut a thick shell to boot and doesn't coax enemies to get at him or to eat him until he is ripe.

A Member: Have you found that fertilizing a tree increased the percentage of tannin?

Mr. Rockey: That hasn't been determined yet but it will be studied.

The Chairman: It is a question if the tendency would not be for tannin to go over to sugar and cellulose under cultivation. I don't remember the chemistry on that. Aren't there any expert chemists here who can tell us? The natural tendency of the tree under high cultivation would be to change tannin over into sugar and starch.

Mr. Corsan: This talk of the chestnut blight reminds me of a remark made by a gentleman at a peach growing convention. He said the best thing that ever happened to this country was to get that San Jose scale because it stopped lazy men from growing peaches. He said, "I don't mind it a bit and can make more money than when peaches were nothing a basket." Probably nature will help us some way.

The Chairman: We have to consider what nature wants to do.

Mr. Mayo: If I am in order, I would like to know whether this fungus trouble is likely in the future to attack or has at any time attacked, the apple, pear or quince?

The Chairman: I think it has been pretty well decided that they are not in danger. I will, however, ask Mr. Rockey and Mr. Pierce to answer that question.

Mr. Rockey: Up to the present time there has been no indication that the blight will get into them. This might be a good occasion for me to mention the Connellsville fungus again. It was found on some of the oaks and other trees in this section of the country, and for a time it looked as though the blight was getting into other species, but since that fungus has been identified there has been no indication that the blight will extend beyond the chestnut group as a parasite, although you can inoculate oaks and other trees with the fungus and it will live in them, but only on the dead portion of the tree and not as the parasite lives on the chestnut.

Prof. Smith: I should like to ask Mr. Sober if he has found any evidence that the paragon chestnut differs from the native chestnut in resistance to the blight, and if his paragons are different from other paragons?

Col. Sober: I cannot say whether my chestnuts are different from the other paragon chestnuts or not, or whether they are as resistant to the blight. I know it is a very sweet chestnut. In regard to keeping my groves clean—from 1901 to 1910, we had three broods of locusts and two hailstorms that opened the bark in almost every tree and branch. The limbs were stung by the locusts thousands of times, so that I didn't have a crop of chestnuts. Professor Davis was cutting off limbs for a couple of months so you see my trees were open, if any ever were, to receive the blight. The hailstorms destroyed the leaves and I didn't have any chestnuts that year in one part of my grove and with all that—you people come and see how clean it is, that's all there is to it. I know what I've done and what I can do.

The Chairman: The next paper in order is that of Professor Smith.