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.