Northern Nut Growers Association, Report of the Proceedings at the Fourth Annual Meeting / Washington D.C. November 18 and 19, 1913

by Unknown

I presume that all of you who have any interest at all in the chestnut know considerable about the blight which has been killing these trees in the northeastern part of the country, so I will say nothing whatever about the general features of the disease but confine my talk to those points which have assumed, within a year, some special importance from the point of view of fighting the blight, or related topics.

Perhaps the first thing that I can allude to is the discovery of a certain disease in China which, at the time, was supposed to be identical with the chestnut disease in the northeastern part of this country. I say "supposed" because we had no positive knowledge at the time that it was the disease. Specimens were sent to this country by the agricultural expert, Mr. Meyer of the Department of Agriculture, for examination. Cultures and inoculations were made by the pathologists in the Bureau of Plant Industry and all of the tests that could be applied showed it to be identical with our American disease.

Mr. Meyer's report upon this disease, as he found it in China, has some points which may be of interest to you. He said the disease apparently had been there for many years, as the lesions of the disease showed if they were examined carefully. The fact that it has been there for many years is, I think, questioned by no one at the present time. Its growth in China seems to be somewhat different, in fact in many cases quite different, from the growth on the American and the European chestnut trees. It is rather of the type that we are familiar with on the resistant Japanese trees. More-over, it appears on some of the trees as shown in the photographs which I will pass around. The appearance of the disease more closely resembles, in some ways, what we are familiar with in the European apple canker as it appears on the apple trees. I think those who are familiar with the apple canker will notice the resemblance, in at least one or two of these photographs. Now, I don't mean by that that it is the same as the apple canker, but I do want to call your attention to its appearance in these photographs, and at the same time, to tell you something that Mr. Meyer wrote about this disease as it appeared in China. He said he found no trees that were absolutely killed by the disease. This may mean, and probably does, that the Chinese tree is resistant, to a certain extent, to this disease; that is, it shows a certain amount of resistance, much in the same way that the Japanese chestnut tree does to the disease in this country.

For some years (as some of you will remember, I think) there have been two different views as to the origin of this disease. One is that it is a native fungus which, for some reason, has assumed a parasitic form; the other that it is an imported disease. The principal reasons for the latter view are that it spreads in this country on the American chestnut in much the same manner that other imported diseases have spread on other plants. The fact is that this disease (so far as we can find absolutely identical with the American form) has been found in China; about this point there is no doubt at all, and I think we can safely say, although we cannot absolutely prove it at this time, that the disease in this country was imported from the Orient. What bearing this will have on the question of control of the disease in this country remains to be seen.

Have we any chestnuts which show immunity to this disease? The American chestnut is subject to it in its most virulent form. There are of course a number of varieties of the American chestnut which have been cultivated. Of these the two which I have seen most of are the Hathaway and the Spineless. Both of these are subject to the disease in the ordinary form. The American varieties which have been originated within a few years, the Boone and the Rochester, I am not prepared to say anything about at the present time. The resistance or immunity of these varieties has not been determined so far as my own work is concerned. Of the European varieties we have a great many and they produce, as a rule, the large chestnuts of the market and are known under various names. Some are scions of named varieties and I will mention some of the more prominent. The first and best known, perhaps, is the Paragon chestnut. This is susceptible to the disease and takes it in almost as violent a form as does the American, and so it is with the Ridgely, a nut which originated near Dover, Delaware. The Dager and the Scott also take the disease, and so do many of the so-called French varieties—the Marron, the Marron Combale, the Early Marron and others—so far as I have been able to ascertain. I have not seen very many Numbo trees, but of those which I have seen, some have been diseased. Two varieties, which I have seen have not had any disease upon them. One of these I saw only once or twice and was unable to make a thorough examination. This is the Darlington chestnut which grows near West Chester, Pa. I have no reason to think this is immune in any way to the disease; all I can say is that I have not yet seen the disease on this variety. Another variety which I have heard a great deal about from the point of view of resisting the disease is the Hannum. I don't know anything about this. I have been unable to locate any trees which I could examine. Now these are all the varieties of the European or American sorts that I care to speak about, and we can say that they are all, so far as we know, with the possible exception of the one or two last mentioned, subject to the disease.

Now let me turn for a moment to two other types of chestnut. First the chinquapin, a small dwarf chestnut which grows in the southern Atlantic states but reaches as far north as New Jersey and perhaps farther for all I know. The chinquapin in the past has been regarded as a rather resistant species and my own observations seem to bear out this supposition. I have seen very few chinquapins which had the disease. It may be due partly to the fact that they are not so subject to the attacks of insects and injuries through which the blight might gain entrance, or it may be due to the resistance in the species—I cannot say about that. I had an opportunity this fall to see the Rush chinquapin. I examined these trees—there are two of them—and I think there is no question but that they are hybrids between the chinquapin and the American chestnut. One of these trees was diseased, the other had no disease upon it.

The Japanese chestnuts have been known for a long time to be highly resistant to the inroads of this disease. Some may be immune, if we use the word immune in a very loose sense. It has been regarded as of rather coarse quality and some varieties as entirely unfit for human food. This is true of many of the Japanese chestnuts, but I have recently seen some which, so far as I could tell, were nearly as sweet as the American chestnut and Paragon chestnut which I tested at the same time and which were growing side by side. I could detect very little difference between them. The Japanese nuts were very large, considerably larger than the Paragon. Whether these will retain their sweetness in drying I cannot say. These Japanese chestnuts are seedlings, and are known as the Delaware, the Felton, the Kent and the Henlopen. Like all of the Japanese chestnuts they are highly resistant to the blight.

I wish to call your attention to a few of the standard Japanese varieties upon which I have made observations. These were all grafted trees, that is the Japanese variety was grafted on American stock. The McFarland is a rather well-known variety. Of five trees which I have had under observation, all of them became diseased below the graft but none above the graft, showing the resistance of the Japanese scion on American stock. I think this is given out as a Burbank variety. The Hale is another one which has the same record exactly. On the Coe I have seen two cases of the disease on the Japanese part and several cases where the trees are diseased below the graft. The Alpha, one of the Parry varieties holds about the same record as the Coe—two cases of disease on the Japanese part and several below the graft. The Parry Giant has been considered one of the largest nuts; in four trees observed there was one case of the disease on the Japanese part and two below the graft. The Superb had the disease below the graft but not above; the Reliance just the same way. Then along with these plots were one variety of European, the Scott, which was quite as susceptible to the disease as any other European, and another variety, the origin of which I do not know. This last appears to be something of a hybrid with some chinquapin blood in it—whether this is so or not I cannot definitely say—I can say this, however, that it takes the disease not as readily as the European but more readily than the Japanese.

Just a few words now in regard to the present distribution of the chestnut disease, or at least its extended distribution. The disease is now known to occur in Maine, New Hampshire, Vermont, New York east of the Catskills and as far north as Lake George, and generally as far south as northern Virginia. Farther south there are some scattered infections, one nursery having been found in North Carolina which had the disease. The western distribution of the disease, if you take isolated cases, is now carried to the Pacific coast. We know of an orchard in Agassiz, British Columbia, in which the disease has been found. Nobody knows how this was transmitted, but the chestnut trees upon which the disease occurs were supposed to have been sent to the owner from the Orient. They apparently are not of the usual Japanese type, however; that is all I can say about them now.

The chestnut blight has been found on all parts of the branches, twigs, trunk and the exposed roots. Last year we found the disease on the nuts themselves and on their burs and we were able to isolate the disease from the shell of the nut and we were also able to produce the disease on the bark of a chestnut tree through inoculation from the nut itself. So that the disease can occur on almost any part of the chestnut tree.