Summary of Observations
The following observations concerning shagbark hickory may be made from this study:
(1) The buds of shagbark fall into 2 classes based on bud shape, (1) globose-ovate and (2) elliptical, the latter being the largest bud as a rule.
(2) The buds of shagbark fall into 2 classes based upon the length of the attenuated apex of the outer bud scales. The elliptical form of bud consistently had the longest drawn out apex.
(3) Normal buds of shagbark occur singly on the twigs above the lobed leaf scar; however, 2, 3 or 4 superposed buds may occur on very fast grown sprouts or terminal shoots of vigorously growing trees.
(4) The twigs of shagbark are pubescent but range in degrees from almost none to densely pubescent. The fastest grown twigs are apt to be the least pubescent.
(5) Leaves are compound with 3-5 leaflets commonly found and 7 leaflets rarely found.
(6) Leaflet shapes varied from tree to tree being ovate, obovate or elliptical.
(7) Leaflet margins with one exception were more or less ciliate.
(8) Most female flowers of shagbark have 2 stigmatic lobes, however, 3 stigmatic lobes resulting in triangular nuts are not uncommon.
(9) The typical male ament is three branched but one and two branched aments have been observed.
(10) The husk of shagbark varies in thickness from 1/8 inch to 1/2 inch in thickness when dry. The usual husk is 4-parted but one tree bore 5-parted husks consistently.
The average husk thickness is around 1/4 inch.
(12) There are three general fruit shapes, (1) globose, (2) ovoid and (3) obovate.
(13) There are at least 5 general types of normal nut shapes for Onondaga County, N. Y. as listed in the text of this paper.
(14) Three abnormal nut types were also encountered growing concurrently with the normal types.
(15) Nutshell color varied from brownish to creamy white. The darker colors were generally associated with the elliptical, oval or obovate nut forms.
(16) Nutshell thickness varied between 1/2 and 2 millimeters; the more angled the nut, the thicker the shell.
(17) All of the hickory nuts tested had sweet, edible seeds. The seed coats varied from a light tan to a bronze in color.
Within the single species of nut tree called shagbark hickory, Carya ovata (Mill.) K. Koch., in central New York, there exists a great degree of diversity. However, in spite of these differences, the examined sample trees may be placed without a question in their proper genus and species and the author would venture the opinion that the advisability of placing variety names on portions of the species is a doubtful and hazardous procedure until much more is known concerning the species than is known at present.
MR. PAPE: This paper is the result of the fact that some of us down in Indiana are losing 75 to 95 per cent of our hickory crop each year by the curculio, and what we are trying to do is work up a little interest with this paper, so at the conclusion of this we can get a discussion started and learn the experiences of other people. Maybe you will be able to help us down in Indiana.
The Control of the Hickory Weevil (Curculio caryae)
EDWARD W. PAPE, Marion, Indiana
It is our thought that if some effort were made to bring to this assembly, a digest of what has been done to control the Hickory weevil, we might arouse enough interest to carry on some experiments.
If, at the conclusion of this paper, we can get enough discussion, we will be able to avail ourselves of the knowledge and experiences of others who have made attempts to control this pest, it would be to our advantage.
The Pecan weevil of the south and the Hickory weevil are identical and we learn the following from the experiments carried out by G. F. Moznette, Bureau of Entomology, U.S.D.A.
Pecan weevil damage is of two types—(1) that resulting from attack before the shell-hardening period in July and August and causing all affected nuts to drop, and (2) that resulting from attack after kernel formation and usually causing the shuck of infested nuts to stick tight to the shell instead of opening normally. Weevil-injured nuts of the second type contain grubs which destroy the kernels, or they contain holes about one-eighth inch in diameter which mature grubs have bored and through which they escaped after destroying the kernels. The first type of damage often passes unnoticed and is due to the feeding of early emerging weevils, which puncture the immature nuts with their long lancelike beaks to feed on the juices within. Since all nuts punctured in this way before the shell-hardening period drop to the ground, the entire crop may be lost if weevils are abundant and the crop is light. Such damage may be heavy even when a large crop is attacked. The second type of damage is generally noticeable at harvest-time in October and November, and in seasons when large numbers of weevils have been present practically the entire crop may be wormy at harvest.
Since the weevils do not feed very much on the outer surface of developing pecan nuts, stomach poisons applied to trees have been of little practical value in control. In 1944, however, laboratory tests showed that DDT could kill the adults, and that it was worthy of field trial.
Field tests were made at Fort Valley, Georgia, with DDT and the conclusions drawn from these tests show that the effectiveness of two applications of DDT at the rate of 6 pounds of a 50-percent wettable powder to 100 gallons of water in reducing harvest infestations to 1 percent gives rise to the hope that this treatment, applied for several seasons, will eliminate a pecan weevil infestation in an orchard, or will reduce it to such an extent that spraying every year will not be necessary.
The time of the first application of DDT cannot be based on the time of the first drop of nuts, because other pecan insects also cause the nuts to drop during July and August. However, pecan growers who wish to make the effort can time the first application accurately by spreading a sheet on the ground beneath an infested tree and lightly jarring the branches to dislodge the weevils. When the weevils are disturbed they fall and "play possum" and can be easily collected. When a minimum of six weevils can be taken by jarring the branches on any one tree, it is time to make the first application.
While the above will probably give an indication as to what can be done, using DDT to control the Hickory weevil, for those who have large plantings and can afford the expensive spraying equipment necessary, it will be necessary to look farther for control methods for the small orchard, where expensive equipment is not feasible.
The following is part of a letter from Dr. C. C. Compton, Entomologist for the Julius Hyman and Company.
"It is our thought that since DIELDRIN is so highly toxic to Curculionids it might be possible to take advantage of the habits of this insect and control it by spraying the soil surface. The larval stage of this insect leaves the nuts and enters the soil sometime in the fall. It is believed that the larvae penetrate the soil rather deeply, to a depth of perhaps a foot or more and remain in the soil over winter. In the spring or early summer the larvae transform to adults and emerge to lay their eggs. In some regions at least the adults do not emerge until the second year after the larvae enter the ground.
It is our thought that if DIELDRIN was applied to the surface of the soil that many of the larvae would be killed upon entering the soil or would be killed at some later time when the adults emerge.
Dr. C. L. Fluke at the University of Wisconsin has been working for the past several years with DIELDRIN applied as an orchard spray for the control of plum curculio. In Dr. Fluke's work he applied the DIELDRIN to the orchard floor or cover. He has had some very promising results. Dr. Fluke has used two application rates, namely, six pounds and three pounds of DIELDRIN per acre. Since he obtained a high degree of control at the three pound level, it would seem worthwhile to investigate the possibilities of applying even a lower rate, say one and a half pounds per acre. In Dr. Fluke's work he applied the DIELDRIN to the soil in the orchard using a DIELDRIN emulsifiable concentrate containing one and a half pounds per gallon.
DIELDRIN is now available impregnated on a 30-60 mesh attapulgus clay. Such formulations are now available containing 5%, 10%, and 15% DIELDRIN. The DIELDRIN granules would appear to have certain advantages over liquid sprays where the grove has considerable ground cover. A high percentage of the insecticide is retained by the cover and does not reach the soil. The 30-60 mesh granules have the advantage of penetrating even the densest cover and their application results in a maximum deposit of the insecticide on the soil surface.
Groves or orchards under cultivation can be sprayed or treated with the granules. In either case it is advisable to disc the insecticide into the soil following application.
The granules are free flowing and can be applied quite readily with any fertilizer or distributor.
Without any field experience to go by it would seem that a 5% 30-60 mesh DIELDRIN granule formulation would be most convenient to use. By using a 5% DIELDRIN granule material you would obtain a dosage of 1-1/2 pound of actual DIELDRIN per acre by applying 30 pounds of granules per acre. Likewise, 60 pounds of the granules per acre would give a dosage of 3 pound of DIELDRIN. On the basis of work done with DIELDRIN for the control of the Japanese beetle, 3 pounds of DIELDRIN per acre will control this insect for more than 5 years. While it is not safe to assume that we could expect the same results in the case of the Hickory weevil, it does give us something to go by."
It seems likely that the foregoing will create some interest and that by the time of the next annual meeting we should have the results from the use of DIELDRIN to control the Hickory weevil.
MR. PAPE: It is my thought now if we could get a little discussion here concerning what some of you have been doing to control this pest, we might get somewhere, or at least get enough suggestions or get enough parties interested to carry on some experiments in different parts of the country.
MR. SILVIS: What company makes Dieldrin?
MR. PAPE: Julius Hyman Company is the one that sent the most literature and Shell Corporation local agents handle it. Also in Indiana the Farm Bureau Cooperative store handles it. The cost in small quantities is two pounds for 85 cents.
MR. KYHL: Is Dieldrin poison?
MR. PAPE: It's poison like all of these modern sprays, but it isn't as dangerous as Parathion.
MR. STOKE: In Virginia I have had no experience with DDT, except with chestnut, and it takes three sprays at two-week intervals to control the pest.
DR. GRAVES: What time of the year?
MR. STOKE: Apply the last spray about two weeks before the nuts ripen. That means, with us, starting in late July. You have to figure it for your own region.
MR. GRAVATT: There is literature available from the Bureau of Entomology in Washington on spraying to control pecan and chestnut weevils. They have done quite a bit of research on it.
MR. STOKE: If this ground treatment is effective, I'd like to try it. It's a lot easier.
MR. PAPE: That would be very nice if you would repeat the work in Virginia. I know that the Pecan Growers will work on the problem in the South. If we could get work done in the Central States, it would be an advantage for all of us.
MR. STOKE: In my area the control of the pest is complicated by the presence of the chinquapin.
PRESIDENT BEST: We have a surprise feature this afternoon. Dr. Graves of the Connecticut Experiment station, who, as you know, is the father of a lot of this work on chestnuts, has consented to discuss with us certain new procedures that he used in grafting chestnuts.
DR. GRAVES: We have worked with this method of inarching blighted chestnuts so long and found it so successful that I felt it my duty to tell you people something about it. It's really a method of cure for the blight on Oriental chestnuts and their hybrids. I have not found it to work well on the American chestnut.
Now, suppose we have our tree, with a blighted area on the trunk. I am assuming that the blight starts near the base of the tree as it usually does.
When you see it, you cut it out with a sharp knife removing the bark to the wood. Blighted trees send up shoots from the base, below the blighted bark. So you take one of these shoots, sharpen it at the top and insert this sharpened tip under the healthy bark at the top of the blighted area. The shoot should be a little longer than the blighted area so that you can get a spring to the shoot as you push its tip in between the bark and the trunk. Even if it goes up above and breaks the bark a little bit, it doesn't matter. This inarched shoot renews the connection between the leaves and the roots across the blighted area.
You know the leaves make the food of the tree, which goes down in the bark to the roots. The reason blight kills these trees is that it begins to girdle and sometimes does girdle the tree and destroys the connection between the leaves and the roots, so the roots eventually die. But by this method of inarching you restore that connection between leaves and roots.
Now, you'd be surprised to see how well that's worked with us. We tried it first in 1937. We have been doing it now for 16 years. Every spring we take our trees that show the blight, our hybrids and Oriental chestnuts, and inarch, and the whole thing doesn't take more than a few minutes. Then after our shoot is inarched here, we tie it with old-fashioned string. The tips of the inarched grafts should be covered with grafting wax or paraffin.
The scion will probably send out shoots which should be removed. And another thing, cut the string when you know the graft has taken above.
If the blighted area is higher up in the tree, you can use bridge graft. This, you can see, is a kind of bridge grafting. But in bridge grafting, the scion must be anchored in the bark both above and below the lesion.
As I say, we have cured our hybrids. There doesn't need to be anybody losing a Chinese chestnut tree ever, using this method. No sense in it. You can usually do this grafting in the spring about April when the leaves and the buds are beginning to show their green.
MR. DAVIDSON: You say you paint the wood?
DR. GRAVES: Yes, with any ordinary paint. There is a tree wood paint, I know, that's better, but we use ordinary paint.
Meeting adjourned at 4:50 o'clock, p.m.
MONDAY EVENING SESSION
"What's Your Problem?"—Round Table Discussion
Moderator: J. W. McKay
Panel: J. C. McDaniel, D. C. Snyder, Jesse D. Diller, Stephen Bernath
DR. MCKAY: In these panel discussions the moderator usually lays a little background as an introduction to the subject of the evening. This title came from a conversation with Dr. Crane. We were talking about people asking questions about their problems, and decided to have a panel discussion. Right there we chose the title, "What's your problem?"
All of us have problems to deal with in every walk of life. We run up against difficulties, and usually much of our time is taken up in solving or coping with them. At Beltsville we answer a great many letters, and a great many people ask us about their problems. In answering problems, we push the industry forward, because we remove something that is holding it back.
Sometimes the answer to a problem is found by trying to analyze our successes. In growing nut trees we may have an unusually good crop on a particular variety or tree. The question is, why does that tree bear well that particular year, and very frequently it is difficult to understand why. It is very difficult, for example, in the case of one success, to repeat that success, because the second time you try to do it, something else comes in, and you probably have a failure and, well, you don't know why. It is frequently very difficult to analyze our successes. Another way of stating it is, of course, that our successes are often Nature's gift, and we do not know the factors and the forces that go into that gift.
I want to digress here just a little bit by quoting one thing that Mr. Best said. I wish, by the way, that we could incorporate some of his homey philosophy into some of our minutes so as to really benefit by some of his remarks. I was impressed this morning by his statement in dealing with a "fairyland of nuts," you remember that language he used, "no diseases, no insects, no failures."
DR. MACDANIEL: No squirrels.
DR. MCKAY: Wouldn't that be wonderful? I was impressed with another thing he said; I wrote it down here: "People are not going to break down with emotion when we talk about the old hollow tree down in the corner of the pasture where the 'possums were hatched." Language like that, to me, strikes a very harmonious note. I want to continue this digression a little to consider the fact that all of us, in a sense, are hobbyists in nut growing.
Hobbies in this day and age are coming to be more important all the time, because of the fast pace at which we live. We need to leave our regular duties once in a while and get out in the garden or the forest where we can observe nature and get away from some of the stresses and strains that modern living places upon us.
On this trip we were taking a hike along the north rim of Grand Canyon in an organized nature walk. The trees, bushes and flowers were all labelled right down the walk, and we came to this little poem on a regulation label. It goes like this:
"If you keep your nose to the grindstone rough, And you keep it there long enough, You will cease to hear the birds that sing, And the brooks that babble in early spring, And finally all that your world will compose, Will be the grindstone and your poor, old nose."
So that little poem strikes a real note about a person's hobby. You keep your nose to the grindstone, you will forget all these things. You need to get away from the grindstone once in a while. I don't mean to neglect your work, but I do mean to at least take a little time to go out and look at your trees and forget your troubles and relax and get away from the stresses and strains that modern living places on us.
Going back now to the subject; we asked you, through the Nutshell and through members of the Program Committee, to send in the biggest problem in connection with whatever nut species you grow.
The seventeen replies received included eight problems as follows: (1) brooming disease of walnut; (2) early vegetating particularly of Carpathian walnut and frost damage resulting therefrom; (3) delayed fruiting of chestnut seedlings; (4) season too short for ripening of fruit; (5) squirrels get the nuts; (6) failure of hicans to set fruit; (7) grafting problems under which are grouped all asexual propagation and cuttings; and, finally, (8) getting hickory trees established.
This is a rather low number, but I think out of those eight problems submitted you have a good representation of some of the things about which members of this Association talk when they come to meetings. I will first ask the audience if there is any one who would like to ask a particular question at this time.
MR. BECKER: At the Weber planting at Rockport, Indiana last year, we saw no nuts on the trees. I would like to know what is the cause for those trees not bearing.
DR. MACDANIEL: I would think that failure to bear was caused by a combination of things; lack of soil fertility, in the first place, soil physical conditions, probably insect damage and diseases like anthracnose keeping the trees from being vigorous, overcrowding now, with many of them, and perhaps to some extent genetic, some varieties that just naturally don't fruit very heavily.
DR. McKAY: Any others in the audience care to comment on that question?
MR. STOKE: Weather conditions, freezing may have caused it.
DR. MACDANIELS: My impression was that the trees were starving to death. Cutting down the competition with the weeds and feeding them nitrate would help.
DR. MCKAY: I think most members felt there that the trees were probably crowding each other.
MR. BECKER: They had never borne, had they?
MR. WILKINSON: I don't like to comment on it. My opinion is it's due to the undergrowth under the trees. Keeping the circulation of the air to the roots of the trees has an effect on its non-bearing. Up until they quit cultivating and pasturing the orchard, it bore, but after they quit, production stopped. There is a two- or three-year growth of grass and weeds, a mat on the ground, and I think it's a lack of air to the roots of the trees.
DR. MCKAY: Mr. Wilkinson, I heard the question raised as to whether the orchard had ever produced heavily or not. Can you answer that?
MR. WILKINSON: Yes, it certainly did for several years. As long as it was cared for, it was a heavy producer.
DR. MCKAY: How long ago was that, could you say?
MR. WILKINSON: That's been eight years and farther back. Nothing has been done for it in the past eight years.
MR. BEST: May I make a comment? Last year in our part of the country, which is a little bit west of the orchard we are talking about, we had almost zero weather in November before the leaves were off of the trees, and I felt that that took all the buds off our trees. We didn't have any nuts even on varieties that would bear every year. There are hardly any. And I think that cold freeze in the fall before the buds really got ready for it did a lot of damage.
DR. MACDANIEL: I believe that was a factor in the light walnut crop in that area last year, though some trees did bear.
DR. MCKAY: Of course, I think many of us fail to realize that a tree is a thing that's confined to one spot, and when it fills the ground with feeding roots and mines the soil of all nutrients near it, it's stymied, so to speak, until we give it some more food. Isn't that right, Dr. Crane.
DR. CRANE: That's right.
DR. MCKAY: And trees, when they reach out as far as they can and can't get any more food and no more leaves are allowed to fall on the ground, nature doesn't add any nutrients anymore, naturally, those trees are in a bad way and will continue to be until fertilizer is applied in some way.
A MEMBER: I'd like to trim my Persian walnuts so I can walk under the lowest limb. Does that have an adverse effect upon the bearing of the tree?
MR. BERNATH: I don't think that's good, to trim them too high. I think the lower the tree the better it handles all along. Take the fruit growers, they aim to have the trees as low as possible to make picking and spraying easy. If you prune a tree, especially the Persian walnut, too much, it will have a bad effect on the tree.
DR. McKAY: What about the effect on bearing?
MR. BERNATH: You won't have fruit for several years until the tree recovers what it has lost in foliage.
MR. KINTZEL: I have followed the orchards in California, and I have noticed they follow the practice of leaving the lower branches on the trees, and I have noticed that the lower branches have a lot of nuts on them, also. The branches are hanging down on the ground.
MR. KERR: In France and Germany, they are crazy to get wood, and so they cut off all the low limbs. I have a Persian walnut that is beside the walk, and they cut off the low limbs because they hit the sidewalk. This year I got a tremendous crop.
MR. SILVIS: I think this man has a tree that he wants to walk under. Under these circumstances he can cut off the low limbs. I agree with Mr. Bernath, however, that it will reduce the crop for two or three years.
MR. BERNATH: Yes, but he should start pruning when the tree is young. A tree is just like a child: you have to start to train them while they are young.
MR. STOKE: You must consider the tree at all ages. In the young tree Mr. Bernath is right, it will produce sooner if you leave all the leaves on. But we must consider the mature tree. The branches that are low to the ground have to have the sunlight and if they do not get it they become practically barren during later years. If the lower branches are cut back when they are young and the tree headed higher, the Persian walnut will have a trunk, say, 10 feet to 14 feet to the first limb, but these will produce walnuts ultimately. I think the gentleman is right in having the tree pruned high enough to walk under, and he will get more nuts in the long run than if he lets the lower limbs develop and then eventually cut them down.
DR. MACDANIEL: We had an example of that with that huge black walnut tree with black walnuts starting out 30 feet in the air arching down and touching the ground. But you wouldn't want to do that immediately with a young tree, take all the branches up so high.
A MEMBER: Do you have any control for the stink bug on filberts?
DR. MCKAY: We haven't worked with the control of stink bug, because it is what might be classed as one of our minor problems. The damage is not so great but what we can overlook it at the present time.
DR. CRANE: In pecan and almond growing in California the effective control measure for stink bug is the elimination of the host plants on which the stink bug breeds. Peach growers have the same problem. Stink bug will, if allowed to multiply in a peach orchard, ruin the peaches, making injuries very similar to that caused by the plum curculio. The only satisfactory method of control of stink bug injury is to eliminate the host plants on which they live, such as most legume plants, blackberry briars and other brambles. In an orchard, in a grass sod, stink bug is no problem, but where we have soy beans or cow peas or something like that growing in the orchard, or we have blackberry briars or wild raspberries nearby, stink bug is a bad problem.
DR. GRAVATT: I have filbert trees, and the stink bug gets practically all the nuts. The entomologists looked into the situation, and the condition that Dr. Crane mentioned was borne out. If there are blackberries around, it will be quite a problem to control the stink bugs.
DR. MCKAY: Now I am going to take up the problems that have been sent in by mail. The one dealing with early vegetating and frost damage to Persian walnuts was sent in by the most people.
Mr. Snyder lives in a fairly cold country. I am going to ask him to give us his ideas on this problem and what might be done with it.
MR. SNYDER: I am not qualified to discuss that problem, because we can't do anything much with Carpathian walnuts. We do have some grafted this year, and we will have one, in particular, Carpathian, No. 5—I don't know where it got that number—Crath No. 5, I believe it is, on a young grafted black walnut tree which is ripening up almost ahead of the black walnut, and both have made a remarkable growth. But so far as the spring is concerned, I don't know how they will come out.
DR. MCKAY: Mr. Bernath, what are your views? You live in a fairly cold area. You propagate Persian walnuts. What is your opinion of this problem?
MR. BERNATH: Well, there is a way to help that situation. After the ground freezes, keep that ground frozen. That will delay the growth of that tree, if you have the time and patience to keep the ground frozen.
MR. SNYDER: I don't believe it.
MR. BERNATH: Yes, it will.
DR. MCKAY: It seems to me we have a difference of opinion here between Mr. Snyder and Mr. Bernath. The question is this: During a warm spell in the spring will a tree with frozen roots grow up here in the air. That's the question.
(There was a chorus of "yes"es from the audience).
MR. STOKE: I would say that one good solution is to select late vegetating varieties. Mr. Oakes in a report to me on the blooming habits of Persian walnuts, stated that the variety Schaeffer did not start growth until the 29th of April. That is almost four weeks later than most other varieties. And I know from the tabulations that I have made that some varieties are weeks ahead of others. So let's select the late varieties that are good and worthwhile and plant those.
In my section our latest spring frost averages the 20th of April, and yet I have several varieties that do not bloom until after the first of May. That's the ideal condition.
DR. MCKAY: That's true, Mr. Stoke, but here is another point to consider. Persian walnuts have a short cold requirement, you know that. Hence, in February or early March or any time, even in January, when we have a warm spell of a week or ten days or even shorter, sap will rise in the trees, and they will start to grow.
MR. STOKE: Not all. In plants of some varieties new growth will hardly start.
DR. MCKAY: Perhaps you may have varieties that will not start, but the tendency is to start.
MR. STOKE: If you have one with that early tendency, cut it out.
DR. MCKAY: I'd like to get back to this opinion here on the question of frozen ground, dormant roots and the effect it has on the top of the tree. Now, how about our academicians over here, Dr. MacDaniels or Dr. Crane. Let's hear from one of you.
DR. MACDANIELS: It is my opinion that with a walnut tree of good size the frozen ground would have little or no effect on the buds starting growth. The twigs and the trunk would warm up to the temperature of the air, and when that happens growth occurs. Water is available from that in the trunk and the deeper roots. This would happen regardless of how the surface roots were treated.
DR. MACDANIEL: Or whether the tree had any roots on at the time.
DR. MACDANIELS: The best solution to the frost damage problem is to find trees which vegetate late enough to avoid the spring frosts. Somewhere on this terrestrial globe there must be some, because I remember years ago J. F. Jones sent out some Persian walnuts of Chinese origin. I planted three, and they did not start any growth until about the first of July, and they were still growing strong when frost hit them in the fall. Now, somewhere in between these extremes, somewhere in the climatic analogue of our region we will find Persian walnuts which will have a delayed vegetating period, and that will be the final answer. At least, I think so.
DR. MACDANIEL: I'd like to ask a question. In F-2 hybrid walnuts do you find much segregation of those for later initiation of vegetation?
DR. MCKAY: Yes, we find in those seedlings in some cases the tendency to vegetate very early and others very late. The most striking case that I know is an F-1 hybrid which is a very, very late starter in the spring. It is perfectly dormant when the other young walnuts are in practically full leaf. We do not have any offspring from that particular one yet, but it gives us some hope that from this hybrid we may get something later.
MR. BECKER: With us I don't think this early vegetation means anything. We are in Michigan. Dark, cold weather continues until about the middle of May, when frost ends, and then all of a sudden spring breaks loose, everything comes out, and we don't have any setback, as a rule, from then on. So early vegetation matters little, means nothing, the way I feel about it.
DR. CRANE: Mr. Moderator, you ought to point out that most of the United States isn't Michigan. If we had climatic conditions that Michigan has, we wouldn't have that problem, but this problem becomes much more acute, for example, as you go south.
The north knows nothing about cold injury, absolutely nothing. If you want to see cold injury, you go south. I told Dr. George Potter that twelve years ago. He was born and raised in Wisconsin and spent 17 years in the mountains of New Hampshire. I told him he never saw any winter injury, and he said, "Why, I never heard such a wild statement in my life." Well, that was because of the fact he had never seen it. He has been in the South now for 12 years, and he says, "You made a very truthful statement." He has seen the injury.
In Oregon in 1950 or '51 we had a fall freeze. The temperature was measured by the Experiment Station in Eastern Oregon, where they are trying to grow some fruit and nut trees so they will have something else to eat besides sage brush. They had extensive plantings of walnuts, Mayette, Franquette and all of those hardy varieties, and along with them they had some Carpathians. The temperature there in the fall dropped to 36 degrees below zero, and all of their walnuts of these other strains were killed to the ground, but the Carpathian came through uninjured. In the spring of the year however it warmed up, the Carpathians leafed out and were about ready to bloom when there was a sharp freeze, and the Carpathians sure got it in the neck. So what difference does it make whether you lose the trees in the winter or you lose them in the spring? You have lost them just the same. I think we ought to hear Spencer Chase cite the history of their big collection of Carpathians in Tennessee Valley Authority. I understand from him that they have never fruited any Carpathians down there at all. It's not winter hardiness, it's this early foliation. So we have got a lot of areas that are vastly different from that peninsula in Michigan which the Good Lord designed to make a favored country in a lot of respects.
DR. MCKAY: I recognize Mr. Devitt, who is here from Canada and is well qualified to discuss Reverend Crath's work there.
MR. DEVITT: It is interesting to me to hear of this early budding and late fruiting. Along the north shore of Lake Ontario and down through the Niagara Peninsula our climate is quite consistent. There was only one year when we had a late frost—it was on May 19th. That was in the year 1936. Every other year since they have bloomed every year.
MR. STOKE: I'd like to speak of a tree Mr. Crath sent me. The tree was bearing in Toronto 20 years ago. With me it winter kills sometime in the winter each year, I don't know when. In some years it has been killed back to 5-year-old wood, and this spring I found it was all dead. This tree comes out of dormancy as soon as the sun gets warm. It's hardy in Toronto but not hardy in Virginia.
DR. MCKAY: I think you can all see why this problem is one of the most acute ones we have to deal with today. This variation over the country in the behavior of this so-called hardy strain of walnut is of great interest now to people everywhere. People are believing that it can be grown, and there are still problems we have not solved. I would like to have just a brief statement from Spencer Chase on the performance of Carpathian varieties at Norris, Tennessee.
MR. CHASE: We reported this, I think, at our Beltsville meeting several years ago. Trees we had at Norris are Carpathian types secured from the Wisconsin Horticultural Society about 1940. After two years in the nursery they were planted, and last year, 1952, was the first year that they bore any nuts. But that was simply because we did not have a late frost last year. This year, they were all frosted again. So we have, in the South, from Virginia and Tennessee to a little farther southward, a problem of early vegetation of English walnuts. We should encourage everyone to watch for any late vegetating kinds for trial in the South.
MR. STOKE: Dr. Dunstan reported two walnut trees in North Carolina, where the season is about ten days earlier than at my place in Virginia that blossomed after the first of May. I am going to investigate these trees further.
DR. MCKAY: We have about five minutes that we might devote to some other problem. Nearly all of us do grafting work of one sort or another. Do I have a question from the floor on grafting?
MR. MACHOVINA: With cleft grafts or splice grafts held with grafting rubbers, do you have to cut the rubbers?
DR. MACDANIEL: If it's a chestnut and you have it waxed, I think the answer is yes.
MR. MACHOVINA: The wax is a hot wax and the rubber does not disintegrate very quickly.
DR. MACDANIEL: Probably you will have to cut it on species in which the growth bulges up between the turns of the rubber. This is true of chestnuts in particular, possibly persimmons, walnuts probably not quite so much trouble. Let's hear from one of the nurserymen.
MR. BERNATH: I think the best way is after the union is firm enough, to cut the rubber with a sharp knife.
MR. STOKE: I'd make one qualification. I said I didn't think you had to cut rubber. I think that's true with grafting above ground. Underneath ground, with moisture around it, it should be cut.
MR. BERNATH: If you leave the rubber on and bury it, that lasts for years. Even above ground you find it sometimes.
MR. PATAKY: If you get a fast-growing callus, you have to cut the rubber band, but if it is rather slow you don't. I do a lot of budding with roses. I don't cut the rubber bands off, because they will eventually drop off. If you graft a black walnut or Persian, you will have to cut it or it will girdle the graft.
MR. STOKE: It doesn't do it for me.
A MEMBER: Has anybody done work with polyethylene film in grafting?
MR. BECKER: I hesitate to tell you my experiment. I don't think much of it. I used polyethylene bags on chestnuts early in the season, and practically every one grew, but everything else that was out in the hot sun boiled. In the hot weather of June the grafts actually cook in the bags.
MR. MACHOVINA: Did you use a bag over the whole graft, or just a tube around it?
MR. BECKER: A bag over the whole thing. I have a few Carpathian grafts that grew well. I think I have better luck with hot wax than anything else.
DR. McKAY: Our time is up. I want to thank the panel, although we didn't work you too hard. The panel is adjourned.
PRESIDENT BEST: Dr. Gravatt will show a film entitled: "It Bringeth Forth Much Fruit."
* * * * *
DR. GRAVATT: Mr. President, ladies and gentlemen, you all are familiar with the fact that the chestnut blight is loose in Europe. It was reported in Italy in 1938, and it spread rather rapidly in Italy. It had been there many years before they found it. In spite of our numerous warnings to get them to watch for it, they let it get away. It has spread into Switzerland, caused a great deal of damage there with no hope of saving the larger chestnuts there or in Italy. It's spreading into Yugoslavia. They are making very energetic efforts to control the disease in Yugoslavia, trying to delay it as much as possible. It happens the forest pathologist who handles this work is a young lady, and she has got the forester and other people interested to try to hold it back as long as possible.
The threat of the chestnut blight to the entire chestnut growth in all of Southern Europe helped to bring about the organization of an International Chestnut Council and Congress. This is made-up of delegates from a number of the European countries, Spain, Portugal, France, Switzerland, Yugoslavia, Greece, Turkey, Japan and the United States. They have been meeting every other year, first for two years in succession, but the plan now is to meet every other year. They had a meeting in Spain and Portugal this past June, and the State Department paid my expenses over, and so forth, to attend as a delegate from the United States at this international meeting.
The meeting was very enjoyable. They have a very fine system there. They hire big buses to take you around over the country. Your hotel is all arranged for in advance, and you go sightseeing to the orchards and utilization plants. We have meetings just here and there along the way where we stop a half day or a day.
The next meeting will probably be held in about two years. They have decided now that the meetings will be more in the way of conferences, because the last three meetings have been partly sightseeing to observe chestnut orchards and laboratories.
The possibility of holding the meeting in the United States has been discussed by the delegates there. But it involves a lot of expense and the delegates were of the opinion that there would be a very small meeting in the United States, because the countries over there simply couldn't afford the expense of sending them over here.
The problem in Italy is very serious, because they have something over a million acres of grafted chestnut orchards, all of which they are probably going to lose, and something like a million acres of coppice growth that is going to be damaged but not such a severe loss. In connection with the work in Italy I suggested the production of a movie film that could be shown to the Italian people showing the chestnut industry and also the chestnut blight. This was to be shown in different parts of Italy to arouse more interest in watching out for the disease. They have more opportunity there of slowing up the disease if they will work hard at it, but they are not doing too much.
As some of you know when a lot of different people and agencies work on a movie film there must be all sorts of compromises. This was done by a temperamental Italian director, and other people had parts in it, so what you see is a compromise. They made 30 copies in Italian. H has been shown in many moving picture houses, and it is also on the loan basis to the United States. There are extensive film loan libraries, located in different parts of Italy, so any high school, college forestry group can borrow films showing different operations, many of them prepared in the United States and part of them in Italy.
DR. MACDANIEL: What about this so-called Korean chestnut? Is it actually a third species?
DR. GRAVATT: I don't think so, We had quite a bit of argument on this question, because in Spain where I found chestnut blight on chestnuts brought from Japan, we found the name Korean chestnut. Sometimes the Korean chestnut looks more like a Jap, sometimes it looks more like a Chinese, and usually it's sort of a blend between the two. We prefer to recognize these two species and call the Korean a natural hybrid. Both species are grown in pure form in Korea, and they intercross readily, and we do not regard it as a new species.
MR. WILSON: Are the Italian enough aware of their problem so that they will have developed an Asiatic chestnut in time to replace their present orchards, so that there will not be an interim?
DR. GRAVATT: There will be a big interim. That's an opportunity in this country to get the market before the Italians ever come back, I think.
(The film, "It Bringeth Forth Much Fruit" was shown.)
The International Chestnut Commission and the Chestnut Blight Problem in Europe, 1953
G. FLIPPO GRAVATT, Senior Pathologist, U. S. Plant Industry Station, Beltsville, Maryland
The International Chestnut Commission was organized under the auspices of the Food and Agriculture Organization of the United Nations. The aim of the Commission is to promote international cooperation in the study of all scientific, technical, and economic questions relating to chestnut growing. The main problem facing all chestnut culture in Europe is the rapid spread of the chestnut blight. France, Italy, Japan, Portugal, Spain, Switzerland, Turkey, United States and Yugoslavia are members of the organization. A representative from the F.A.O. in Rome serves as Secretary of the Commission. An international conference on chestnut problems was held in France in 1950, the first meeting of the Commission was held in Italy and Switzerland in 1951 and the second in Spain and Portugal, June 18-30, 1953. The average attendance at the meetings was 50 to 60 persons. I have attended all three conferences as the representative from the U.S. Departments of State and Agriculture.
The International Chestnut Commission meetings differ from the meetings of the Northern Nut Growers Association in many ways. Our Northern Nut Growers Association meets annually for 2-1/2 days while the meetings of the International Chestnut Commission last from 10 to 12 days but not every year. In Europe the members travel mostly in a large tourist bus, which carries the party for hundreds of miles, visiting nurseries, orchards, chestnut utilization plants and not neglecting the scenic parts of the route. All lodging and meals are carefully arranged for in advance. The group in Europe is made up quite largely of Federal and State professional workers, University professors, and representatives from the chestnut utilization industries.
Among the places which the delegates visited in Spain in 1953 was the Agricultural Experiment Station at La Coruna, where the Phytophthora ink disease of the chestnut has been studied extensively. They also visited the Experiment Station at Pontevedra, where new methods of propagating chestnuts are being studied. At Bilboa and at Villa Presente Nursery, Santander, we inspected plantings of Asiatic chestnuts; I found chestnut blight present on several trees at both locations and recommended immediate removal of the diseased trees. Fortunately, the Asiatic chestnuts are some distance from any native European chestnuts at each place and, according to the local foresters, the blight has not spread to the distant stands of native chestnut. Some years ago the Spanish authorities imported seed from Asia; chestnut blight probably was brought in on these nuts. All infected trees that are found are being destroyed, but a thorough inspection and eradication program is needed to control the disease before it spreads into the native European chestnut stands, from which the disease probably would spread into Portugal and southwestern France.
In Portugal we inspected many very fine chestnut orchards. These orchards are composed of grafted varieties, with only 3 or 4 varieties in each locality or region. Because of this there is a more standard nut product in most of Portugal than in the other European countries where mixtures of local varieties are frequently grown. A very large portion of the European chestnut orchards in Portugal are made up of seedling trees, topworked with local selections. In Portugal most of the orchards are located on the lower slopes and various crops are grown among the trees. In most other European countries the orchards are on rougher mountain land which is grazed.
In Portugal the State Road Department has established a number of roadside plantings of chestnut. These plantings are very productive. The State Road Department sells the nut crop to the highest bidder and uses the funds for additional roadside tree plantings.
In northern Portugal authorities have conducted a large-scale program to control the Phytophthora ink disease of chestnut by the following treatment: The soil is removed from the base of the tree and larger roots. The base and roots are sprayed with a sticker compound and then dusted with copper oxide and copper sulfate before the soil is replaced. Treatment is repeated every 5 to 7 years. Government officials secured the cooperation of owners of chestnut stands in treating practically all trees over large areas. Although this treatment for the Phytophthora ink disease was originally worked out by the Spanish pathologists at La Coruna, it has not been used extensively in Spain. The Phytophthora root disease is damaging chestnut orchards throughout southern Europe. In 1950 I noted that this disease was causing severe damage even in Asia Minor. In the southern part of the United States this same disease (here called Phytophthora root rot) caused heavy losses at lower elevations.
The 1953 Chestnut Commission meeting terminated on June 30 at the famous Palace Hotel at Bussaco, Portugal, where the Under Secretary of Agriculture gave the delegates an official farewell dinner. No definite plans were made for the next meeting of the Commission. It was the general opinion that a meeting in the United States would be poorly attended because of the expense of sending the delegates from Europe.
After the conclusion of the meeting, the U. S. Foreign Agriculture Services sponsored my trip to France, Italy, Switzerland, and Yugoslavia, to consult with Federal and local authorities on their chestnut blight problems. This disease was found in Genoa, Italy, in 1938; later it was determined that the disease was present at that time in other localities in Italy. The blight is spreading rapidly and is almost completely destroying the orchard and larger forest trees of European chestnut in Italy in localities where the disease has been present for some time. The blight occurs in many areas in northern Italy and as far south as Naples. The young chestnut coppice is not so seriously affected, but the losses caused by the blight will make growing coppice on a 10- to 20-year rotation basis less profitable than formerly.
The chestnut blight is abundantly present on the east slopes of the mountains along the French-Italian border; although it has not yet been found in France, its distribution in adjoining Italy makes it highly probable that advance spot infections are already present in France. The blight has spread into Tessin Province in southeastern Switzerland where it is destroying many of the orchards and forest trees. A large chestnut extract plant in this Province uses wood in making tannin for leather manufacturers. However, this plant, as well as some of the extract plants in northern Italy, is unable to utilize the chestnut wood as fast as the blight is killing chestnut trees.
In Yugoslavia, chestnut blight is spreading rapidly in the orchards and native growth along the Italian border. Authorities are actively cutting out all advance spot infections, to delay or possibly stop its spread across their country. In Yugoslavia, chestnut stands frequently are widely separated, a natural advantage in delaying the spread of the blight.
Chestnut blight has been controlled in western North America, where chestnut orchards and plantings are not numerous. Scattered infections have been found during the last 30 years in California, Oregon, Washington, and British Columbia; infected trees have been removed. Strict State Quarantine regulations have been enforced, to prevent chestnut blight from spreading to the West Coast.
The chestnut blight fungus is attacking three of the important oaks of Europe. The typical fanlike mycelial growth can be observed in the bark of infected oaks. In 1953 in Yugoslavia I observed vigorous young durmast oak (Quercus petraea) being killed by the blight. In Italy I found the disease killing pubescent oaks (Q. pubescens) and causing minor injury to the holly oak (Q. ilex). Before we can estimate the probable damage to these European oaks, we need more information on the effects of this disease on oaks of various ages and under various environmental conditions. In the United States the post oak (Quercus stellata) is the only oak species that has been seriously damaged by the blight.
Thus, the blight is threatening not only the native chestnut forest growth and orchards of Europe, but also the oaks. A steady extension of the blight throughout Italy can be expected. Advance infections in Yugoslavia are being cut out but how long the disease can be held back depends on future efforts along this line. Delay work in Yugoslavia also delays the time of loss of the chestnut and damage to the oak growth of Greece and Turkey. The inspection and eradication work being carried out in Spain may result in the elimination of this threat to the chestnuts and oaks in Spain, Portugal and southwest France. However, there is the possibility of the blight occurring anywhere in Europe. People working with chestnut should be on the alert to find and eradicate the first infections.
The film entitled "It Bringeth Forth Much Fruit", shown here today, was prepared at my suggestion by the U. S. Foreign Agricultural Services at Rome. It is being used to aid local authorities in Italy in attempts to delay the spread of the chestnut blight.
The Italian authorities, with assistance from the United States Foreign Agricultural Service, have purchased blight-resistant chestnuts in this country for planting in Italy. These resistant chestnuts are doing very well in Italy so far. However, the development of a new orchard industry with the Chinese chestnut and its hybrids in Italy will be a slow process. It is expected that shipments of chestnuts from Italy to this country, which is now going on at a rate of 15 to 18 million pounds per year, will gradually decrease.
DR. GRAVATT: I will talk on while they are fixing this next film.
Much of the trouble in Italy is that so many of the chestnut orchards are overgrazed, sadly overgrazed, and as these chestnut orchards are killed by the blight, the land is going back into this overgrazed condition, which leads to serious erosions. Italy needs all the water that can be saved. The mountains are eroded down to the rock in many areas and when you get to the rock, you can never bring the soil back. It's a serious problem to meet because of the tremendous over-population. Every little twig of wood is used. As these chestnut orchards are killed it's going to be a very difficult problem to plant them again because the land is overgrazed. Protecting the plantings against sheep and the goats is quite a problem.
(The film, "The Filbert Valleys," was shown.)
MR. STOKE: I noticed them grafting chestnut trees several feet from the ground. Why are they doing that?
DR. GRAVATT: They are doing it in order to develop a quick supply of scion wood. But the procedure is bad. It is much better to graft close to the ground, and mound it up with dirt. The blight gets in below the graft if the graft is high on the trunk. They have had success grafting below the ground level and find they may get a shoot six feet high the first year.
DR. MACDANIEL: How about the incompatibility in the graft? Does that show up much?
DR. GRAVATT: We don't know yet, because they always get a certain number of failures. I looked over quite a lot of grafting of Chinese chestnuts on Japanese-European hybrids, and they are thriving. After four years they are already regular trees with big crops on them.
TUESDAY MORNING SESSION
PRESIDENT BEST: Our first paper is "Rooting Chestnuts from Softwood Cuttings" by Roger W. Pease.
Rooting Chestnuts from Softwood Cuttings
ROGER W. PEASE, West Virginia Agricultural Experiment Station, Morgantown, W. Va.
Some 15 or 20 years ago the West Virginia Agricultural Experiment Station undertook to develop, if possible, blight resistant chestnuts from American chestnut stock. With the passage of time the approach to the problem has changed. During the early days little thought was given to procedures for propagation, but recently the emphasis has shifted toward methods for propagation when and if there are found hardy, timber-type, blight-immune chestnuts of any species.
The practicability of budding or grafting chestnuts is debatable. We are leaving budding and grafting to experienced workers throughout the country and are endeavoring to develop a method for rooting chestnuts from softwood cuttings. Results so far are encouraging, but the work is still in the experimental stage. We do not advise anyone to start rooting chestnuts on a commercial basis, but we hope that further experimental work will be done by interested agencies.
To give complete details of several years' work would take more time than is feasible here. Circular 87, Growing American Holly from Cuttings—Cold Frame Method, obtainable from the Mailing Room, West Virginia Agricultural Experiment Station, Morgantown, West Virginia, gives construction details of a suitable bottom-heated cold frame. However, with chestnuts, natural shade was not used and half of the sunlight was excluded. An article in the October issue of The National Horticultural Magazine—"Rooting Chestnuts from Cuttings"—outlines procedure and results through 1952.
In this paper I will present a resume of our experiences and observations. Our facilities were limited so that the number of cuttings set in each case was very small. Percentages of failure or success should be taken as indicative only.
In the propagation experiments, preliminary observations were made by placing softwood cuttings in a bottom-heated cold frame at intervals during the growing season. The soil medium was two thirds washed sand and one third peat moss. Daily watering was by a hand hose. The root-inducing substance was indole-butyric acid crystals in a talc based mixture, one to one hundred. The results were completely negative.
The next season a small cold room was constructed in which conditions thought to be desirable could be maintained. Air temperature was kept at approximately 65 deg. F., fog nozzles were operated continuously except for an occasional airing of the cold room, and about 200 foot candles of white fluorescent light were delivered upon the rooting surface. The rooting medium was white, washed, building sand placed over one half inch of sphagnum moss. The moss, in turn, had been laid in a rooting bench with a hardware cloth bottom exposed to the air. The interior air circulation was maintained by an electric fan operating day and night. The soil temperature was held at 70 deg. F.
Cuttings were taken at intervals throughout the season and their basal sections soaked in a water-based solution of indole-butyric acid crystals at concentrations varying around 60 parts per million. During a 70-day period roots were formed on cuttings taken in June, July, and August. Among the successful cases the poorest result was 66-2/3%, and the best was 100%.
The young plants were fed nutrient solution and later transplanted to a light, sandy soil within a bottom-heated cold frame. Some roots were dead at the time of transplanting, burned, perhaps, by the nutrient solution. The soil temperature within the cold frame was maintained at 70 deg. F. until late in the fall, and then the plants were hardened by reducing the water content of the soil medium and lowering the temperature. All of the plants were dead when they were inspected in March.
The next year a bottom-heated cold frame was equipped with fog nozzles. The soil medium was white, washed, building sand. Softwood cuttings, treated the same as the previous year, were inserted on August 20. Cuttings from juvenile American chestnut seedling trees, juvenile Chinese trees, and mature Chinese trees were used. Within a 70 day period heavy root systems were formed on 54-6/11% of the cuttings from the juvenile Chinese trees, 50% from mature Chinese trees, and 20% from juvenile American trees. No nutrient solution was applied, the young plants were transplanted to a sandy soil in another cold frame, were hardened as during the previous year, but the soil medium was not allowed to freeze during the winter. In April the plants showed well-formed terminal buds starting to swell and turn green. Some were transplanted into pots and placed in the greenhouse; others were transplanted into a light soil in a lath house. All died subsequent to transplanting. Inspection of the roots showed severe breakage. It was concluded that repeated transplanting had been fatal, and that in the future cuttings would be rooted in plant bands or pots and transplanted only once.
It is too early in the current season for accurate results to be recorded. However, modifications have been tried and observations made. These are presented here in outline.
Type of cutting:
a. Cuttings with soft, growing tips will apparently root more quickly than hardened shoots, but the leaves tend to turn brown and the plant dies. Conversely, cuttings from short, lateral growth, well-hardened, will retain their leaves better and eventually show a higher percentage of success.
b. Cuttings made from the basal and intermediary sections of long shoots show a greater death incidence than do well-hardened, terminal sections. Both types root satisfactorily.
c. Apparently sucker shoots and water sprouts are useless.
Time of taking cuttings:
a. Cuttings taken in late May, with soft growing tips, rooted quickly—some within two weeks. On the other hand, their foliage darkened quickly, and death followed. Short, lateral shoots, well-hardened, were not available in May.
b. As the season progressed, the percentage of rooted cuttings with healthy foliage apparently rose, at least through July, but roots were formed more slowly by the late season cuttings.
Condition of parent tree:
Apparently tree vigor as indicated by healthy, dark green foliage, is more important than vigor as indicated by the length of current season's growth. In Morgantown this has been one of the driest seasons on record. Cuttings from trees with pale or brown foliage, or with foliage tending to be brittle from lack of water soon lost their leaves. Whether this was caused by the condition of the parent tree or of the individual cutting is not apparent. It is too early to determine whether or not the drought will cause a general lowering of rooting percentages this year.
Cuttings may or may not callus. Roots seldom if ever spring from the extreme base of a cutting. Well above the base the stem enlarges, turns white, cracks, and sends out roots. Often the bottom inch of the cutting is black and dead, with a healthy and vigorous root system above the blackened portion.
Plant bands and pots:
Plant bands are apparently preferable to small pots. The slope of the pots tends to pack the soil medium and interfere with aeration. Bands or pots less than three inches in diameter tends to cramp the rapidly growing roots.
Cold room vs. cold frame:
Last year higher percentages of success were obtained in the cold room than in the bottom-heated cold frame. This year the cold frame was definitely superior. Because construction and operation of a suitable cold room is expensive, we do not plan to continue its use in chestnut work.
In the cold frame, fog nozzles operating during eight hours each day are apparently more effective than nozzles operating continuously.
No success has been attained with indole-butyric acid crystals in a talc-based powder or with untreated cuttings.
Formula for preparing auxin:
The auxin solution is prepared as recommended by G. H. Poesch in the Ohio Agricultural Experiment Station Bimonthly Bulletin, 191, April, 1938. One gram of indole-butyric acid crystals is dissolved in 125 cc. of 95% alcohol. Then 125 cc. of distilled water is added. This makes a stock solution of four thousand parts to a million in strength. The stock may be cut to the desired strength with distilled water. For late August cuttings, well-hardened, 80 parts per million is not too strong. For early June cuttings, forty parts per million appears to be adequate. The softer the cuttings, the weaker should be the solution.
In both the cold frame and the cold room the growth of algae is a problem. The sand medium becomes crusted, with subsequent interference with aeration. The algae sometimes creeps up the stems of cuttings, coats the leaves, and covers terminal buds. Starting each season with completely clean sand and equipment will not prevent the appearance of algae over a long season of continuous operation. On August 20 of this year the interior of the cold frame, including all of the plants, was well dusted with tri-basic copper sulphate, according to manufacturer's directions. To date no effect is noticeable either on the algae or on the plants.
The various observations reported here should be verified by further tests. They are offered merely as aids to anyone planning to experiment with rooting chestnuts. When sufficient data and experience have been gained, a complete Station circular will be published.
PRESIDENT BEST: If you have any questions, please save them until later. It's been suggested that we hear from Dr. Jesse D. Diller next, and that will give our good work horse, Dr. Crane, a chance to build up again for us, because we are going to work him mighty hard.
DR. DILLER: I'd like to have the title of my paper changed to, "Evaluating Chestnuts Grown Under Forest Conditions."
Evaluating Chestnuts Grown under Forest Conditions
JESSE D. DILLER, Pathologist, Division of Forest Pathology, Bureau of Plant Industry, Soils, and Agricultural Engineering, U. S. Department of Agriculture, Beltsville, Maryland
During the 49-year period since chestnut blight was first reported from New York City, the U. S. Department of Agriculture has made more than 500 importations of chestnut seeds and scions, including nearly every species of chestnut in the world, as well as some closely related chinkapins and Castanopsis species. As early as 1909 the Department initiated chestnut breeding work. It was known that few, if any, of the chestnut, or related species, possess the timber-type characteristics of our American chestnut. It was also known that, in general, the Asiatic species show great natural resistance to the blight. But little, or nothing, was known about their site requirements.
In 1927 the U. S. Division of Forest Pathology began breeding chestnuts to produce timber-type trees. The chestnut breeding work was expanded and has been carried on actively to date. From 1927 to 1930, the Division conducted an extensive exploration in search of orchard and timber-type chestnut in China, Korea, and Japan, and imported over 250 bushels of chestnut seed, representing four species.
During the early 1930's the Division of Forest Pathology distributed thousands of chestnut seedlings, grown from the imported chestnut seed. The planting stock was made available to interested Federal and State agencies, as well as to owners of farm woodlands, located in 32 Eastern States. The cooperators were asked to establish small experimental forest plantings with the trees furnished them. It was believed that such wide distribution of the many kinds would readily demonstrate which ones possess the desired timber-tree form, or possessed the ability to bear large crops of nuts suitable to wildlife; and would furnish valuable information on their site requirements.
As we now know, most of these early cooperative experimental forest plantings were doomed to failure because often the chestnut trees were planted on dry, grassy areas having infertile, shallow soil. Another serious contributing factor in poor establishment was the severe general droughts that occurred over most of the eastern half of the United States in the early thirties. But despite these heavy losses, a few plantations succeeded, in part, and from these limited areas, and from a few earlier plantations that succeeded, valuable information on their general site requirements was obtained; however, we still lacked information on specific differences in behavior between the progeny, as fast-growing forest trees or nut producers in the forest.
From these early plantings we learned that (1) Asiatic chestnuts and hybrids are more likely to develop into forest trees when planted on cool, moist, fertile situations; (2) in their silvicultural characteristics they are more nearly like our native yellow-poplar, northern red oak, and white ash, than like our American chestnut and native chinkapins; (3) with respect to tolerance of shade, they are much like our northern red oak; and (4) neither the Chinese nor the Japanese chestnut has quite the same forest-type growth as that of our native American chestnut.
With this background of experience, the U. S. Division of Forest Pathology from 1936 to 1939 established a series of 21 climatic test plots on above-average sites on Federal- and State-owned forest land in eight Eastern States. Fortunately, we still had available suitable planting stock of the many kinds of chestnut, chinkapins, and hybrids for conducting such an extensive test. At this point we should also mention that from 1947 to date, the Division of Forest Pathology, in cooperation with the Connecticut Agricultural Experiment Station, also established 11 hybrid test plots in Arkansas, Connecticut, Illinois, Michigan, Ohio, Pennsylvania, South Carolina, Tennessee, and West Virginia. In 1930 the Brooklyn Botanic Garden also began breeding blight-resistant chestnuts of timber type, and in 1947 transferred this project to the Connecticut Agricultural Experiment Station.
The 21 climatic test plots ranged from one to two acres each, and were planted with more than 20 progenies represented, as well as forest-tree chinkapin and some hybrids. Nearly all of the 21 climatic test plots were fenced against deer and domestic livestock. The 11 hybrid test plots, approximately 1/4 acre each, were planted with 100 hybrids (50 furnished by each of the two agencies), and 50 Chinese chestnuts—P.I. 58602, the most outstanding Chinese chestnut from the forestry standpoint, thus far discovered. The climatic test plots were established on freshly cleared forest sites, with trees randomized, and planted 8 feet apart. In the hybrid test plots, the seedlings were planted under forest growth and the overstory trees were girdled; the seedlings were randomized in these plots, with spacing of 10 by 10 feet.
The 1- to 6-year period of testing for the hybrid chestnut, and the 14- to 17-year period of testing of the chestnuts planted in the climatic test plots are too short for final judgment of performance; however, certain characteristics are appearing with reference to blight resistance, winter hardiness, timber-tree form, early fruiting, and rate of growth. The present paper does not attempt to summarize all of the data obtained from all these climatic plots but rather to point out some striking results obtained from several widely separated climatic plots. Results from the hybrid test plots are not included in this discussion.
A performance rating of 28 chestnuts, chestnut hybrids, and forest-tree chinkapins, tested in forest plantings for 12 to 13 years in Indiana, Iowa, North Carolina, and Pennsylvania showed that certain kinds always produce better trees than others. P.I. 58602 is the best Chinese chestnut tested thus far, as determined by performance in the above-mentioned test plots and in several plantations established in 1926. In the Middle Western States, all Japanese chestnuts, Henry (forest-tree) chinkapins, and the "ever-blooming" Sequin chestnuts have shown poor growth or have died. They do not appear to be winter hardy.
On the basis of these findings, the Division of Forest Pathology since 1946, has made available to Federal and State agencies only one introduction of Chinese chestnut—P.I. 58602—for planting as forest trees. They were distributed in lots of 50 trees, and used to establish 1/4-acre demonstration forest plots. All are located on public-owned land on favorable forest sites where Asiatic chestnuts would be expected to do well. The underplanting-and-girdling method was recommended in the establishment of all the plots.
Chinese chestnut P.I. 58602, because of its superiority in performance as a forest tree, is now also being used extensively at Beltsville, Maryland, in hybridizing work. Nearly all of the Japanese chestnut, Henry chinkapin, and Sequin chestnuts, as well as inferior hybrids in the climatic test plots during the past several years have died a natural death or have been destroyed. They have been replaced with Chinese chestnut (P.I. 58602) replants—thus gradually converting the climatic test plots into future Chinese chestnut "seed" plots of the very best Chinese chestnuts.
During the spring of 1953 several nurserymen members of the Northern Nut Growers' Association furnished the Division of Forest Pathology a total of 2,600 Chinese chestnut seedlings for tests to determine their suitability for forest planting. These and 600 seedlings of Chinese chestnut P.I. 58602 are now being tested for performance, in randomized plots, on favorable forest sites in North Carolina, Ohio, and Illinois.
Of 28 Asiatic chestnuts, forest-tree chinkapins, and hybrids grown in 21 climatic test plots in the eastern United States under forest conditions, only certain Chinese and hybrid chestnuts show promise of becoming satisfactory timber-type trees. The best Chinese chestnut discovered thus far is P.I. 58602—a seed importation made by the U. S. Department of Agriculture in 1924, from Nanking, China. Foresters, as well as farm woodland owners, interested in growing Asiatic chestnuts as timber trees, should accept only planting stock that, through performance under forest conditions, is known to develop into straight, single-stemmed trees.
PRESIDENT BEST: I think that Dr. Crane has his panel ready.
DR. CRANE: Mr. President, before I start, I have a few slides here to illustrate a couple of points before we call the panel to the rostrum. (Several slides were shown illustrating sunscald injury to the Southwest side of high headed Chinese chestnut tree trunks.)
DR. CRANE: On this panel, I want to get representatives from the various states. Mr. Wilson, from Georgia. Mr. Stoke from Virginia. Mr. Silvis from Ohio. Mr. Allaman from Pennsylvania. There is another good man down there who grows a lot of chestnuts, by the name of Gibbs.
Now, there seems to be a lot of disagreement in regard to the Chinese chestnut in two or three respects. One is the problem of named varieties versus seedlings. Another big problem is hardiness, how hardy they are, these Chinese chestnuts. Where can we grow them and where are they going to fail? A third question is the ability of the Chinese chestnut to compete with other vegetation as Dr. Diller has discussed. I think we ought to settle some of these questions for once and maybe for all, or at least for this meeting, through a discussion. Nurserymen and others have emphasized that chestnuts, to be successful in the United States and hardy, should come from North China, at the Great Wall or beyond. Others don't agree, claiming that chestnuts in China are grown from the extreme south to the extreme north and that we ought to do the same in this country also.
MR. STOKE: I haven't enough knowledge on it to express an opinion. I planted a good many seeds I got from the Yokahama Nursery Company, and the nuts were rather inferior as to size. They were healthy and hardy, but I don't know where they came from. I presume they came from Korea, but I am not sure. The size and productivity wasn't too high of that seedling stock I secured there.
DR. CRANE: What do you folks think? Anyone in the audience that has an idea?
MR. PATAKY: At our fall meeting in the Ohio group we had two bushels of chestnuts from Sterling Smith. As far as I know the seed is Korean chestnut, which is obviously a Chinese variety. He had three bushels last fall and they looked identically like the American chestnut. Mr. Stoke said the quality wasn't so good in what he had. That might be true, but I tested a lot of these chestnuts from Sterling Smith, and compared them with American chestnuts. They were just as good or better than the American.
MR. CALDWELL: I spent about a year in China travelling pretty well throughout the country. I believe you will find the better seed sources in the southern part. China is like Southern Florida or warmer for part of the year and yet in the other six months it would be colder than it is right here in Rochester.
They have timber trees, some as big as 50 or 60 feet high and two or three feet in diameter. In the warmer area you find better seed by far. What Dr. Diller describes as No. 58602 is not just one tree, but a whole collection of trees from a certain area where the trees have proven their resistance not only to cold but to frost injury in the spring or in the fall, which is even more important than the straight cold hardiness. Some people have mistaken ideas about the value of seed from trees in the northern part of China above the Great Wall. This area may have intense cold in the wintertime, but not in the spring or fall.
DR. GRAVES: Dr. Caldwell is right about No. 58602 being a mixture. Dr. Gravatt could tell you about that. It is a strain coming from several trees. It's evidently a very fine type, and I think we ought to know for the record just what 58602 is.
DR. GRAVATT: Professor Reisner's 58602 that Dr. Diller has been testing so widely is made up from a collection of seed from a number of isolated valleys of the Nanking area. It is rather southern in its native home, but Dr. Diller's tests and other tests have shown that it's hardy up north and it's hardy down south. As some of you have noticed, the nuts are very variable, with a number of different types mixed in together.
Dr. Diller and I have been discussing the question of hybrid vigor. It may be involved that each of these seedlings is a cross between different local strains. We must remember that the foresters have gone into this question of hardiness in great detail. You will find that you can't plant trees in Germany in a certain area unless the parent trees grew in a certain area, with comparable altitude and latitude. Minimum and maximum temperatures and other factors are also taken into consideration.
Pennsylvania started a program along the same line. They have divided their state into about five areas, and in each of those areas they are locating sources of seed that are going to be suited to those areas. They have evidence that many of these Chinese introductions coming from way down south are going to be hardy way up north, but in this matter of hardiness you sometimes have to wait for 50 or 100 years before you are sure of your conclusions.
DR. CRANE: That's right.
The next question I was going to ask these growers in the areas growing chestnuts is how much trouble they have had with hardiness or cold injury to chestnut trees that they have had. Has there been any?
MR. STOKE: I have had none.
MR. SILVIS: We have had none in Massillon.
DR. CRANE: Wilson, how about Georgia?
MR. WILSON: None.
MR. KEPLINGER: Dr. Meader sent me some stock from seed that he brought from near Seoul, Korea in 1947. They are very productive up there at Durham, New Hampshire. I have two trees from seed from these trees. They have much more narrow leaves, than any Chinese chestnuts I have seen so far.
DR. CRANE: Are you sure they are pure Chinese?
DR. MACDANIEL: I am sure they are not. I have seen pictures and had some correspondence with Dr. Meader on them. They seem to be the Japanese species, C. crenata type, or possibly hybrid, not strictly Japanese.
MR. PEASE: I want to throw in something a little bit aside. I think we kid ourselves and the public in assuming, tacitly, that Chinese chestnuts, no matter how narrow the strain, are going to breed true or anywhere near true. Any one lot of seedlings are likely to show great variation in hardiness, disease resistance and other characters. There is a great difference between resistance and immunity. I speak this way because I have seen plenty of people selling Chinese chestnuts who actually believe they are immune, and I have seen customers mad enough to shoot them when they have seen half of them die of blight.
MR. MILLER: When considering hardiness, climate is one thing and air drainage is another. In any climatic zone the exact location or site, particularly air drainage is important. I have my orchard on a southwest slope with perfect air drainage. I have 250-some trees that are six or seven years old growing very nicely, and I have not had any loss, even with English walnut, the Carpathian or any of the other trees. I think that many of us are overlooking the fact that air drainage and location of the orchard is one of the main things. I don't think this has anything to do with the particular seed or the varieties, but I think that is one thing that we must consider.
DR. CRANE: No question about that. Chinese chestnuts are like peaches, and they start pretty early in the spring.
MR. GIBBS: Chinese chestnuts are hardy from Maine to Florida. I think they winter kill because of unhealthy condition of the tree. The place that I did live, at McLean, Virginia, was low in a frosty place, and the first spring they killed back three times before they took off. Where I live now in the Blue Ridge Mountains, which is orchard country, the Chinese chestnut killed back in the spring, but there is nothing the matter with their winter hardiness. They stand winter cold as good as a walnut tree.
DR. GRAVES: I want to make the point that it is in part a question of age, to my mind, as to whether these trees get winter killed. I know we had some trees from the Department of Agriculture, Division of Forest Pathology, back in 1925, and in the very cold winter, 1933-34, they killed back almost to the ground. Again in the severe winter of 1943 Chinese chestnuts were killed. But I feel that when a tree is of good size with its roots down in the ground, it's not so liable to winter kill as are the small seedlings.
DR. CRANE: We have spent enough time on this matter. The question of growing seedlings as compared to grafted trees is up for discussion. Mr. Wilson is a big operator growing chestnuts in Georgia. I would like to have him tell what he thinks of this matter of seedlings versus varieties for nut production.
MR. WILSON: Dr. Crane, I am fully convinced if we ever make an industry out of this chestnut business it's going to have to be based on grafted trees of good varieties. I have one block of approximately 200 grafted trees of Meiling and Kuling. Those trees have a nice crop on this year. They have different age tops, but we have a nice crop of nuts on them. I have another block of some 260 seedlings that were planted in 1948. The crop on these trees, with the same fertilization and cultivation ranges from no nuts to a heavy crop of nuts. You can't have an industry on that kind of yield. There are probably only 30 trees out of 260 that have a paying crop of nuts. That won't go as a paying proposition. You have got to have nuts on all the trees, and I am fully convinced if we ever make an industry out of it, the grower has got to produce nuts. Trees are not enough, he can't sell the tree; he wants to keep his tree. He wants nuts to sell, and you can't get them on the seedling trees. I am fully convinced you can't do it.
DR. MACDANIEL: Have any of your grafts gone bad?
MR. WILSON: I have had no incompatibility, except on one tree. My oldest grafts are four and five years old, top grafted in place on two and three year old seedlings.
DR. CRANE: Mr. Stoke, what is your experience?
MR. STOKE: I have two trees in my yard at home. Dr. Reed gave me credit for doing the first grafting of Mollissima in this country. I don't know whether it's true or not. Those were grafted in '31. They made perfect union, and they are perfect today, and they will be perfect when I am dead and gone. I find no incompatibility between Mollissima and Mollissima. One acre of good, select varieties, grafted, will produce as many nuts as three or four acres of seedlings.
DR. CRANE: Mr. Bernath, how about the situation up in the Hudson Valley?
MR. BERNATH: My trees are of small size. We have some in bearing, but as far as having any difficulty with them or freezing back, we have none.
DR. CRANE: Mr. Snyder, how about the situation out in Iowa?
MR. SNYDER: I am not trying to grow Chinese chestnuts anymore. We have had two different lots from U.S.D.A. and both of them have gone out in the winters sooner or later. We have had nice seedling rows, and Dr. Colby sent over a collection of scions, enough to graft each one. Every one grew. This winter they are all gone. We can grow American chestnuts, but we can't grow the Chinese.