Aside from grafting, the hybridizing of nut trees, like that of cereal grain plants, has become a scientific sport appealing to the play instinct of man. When work becomes play in any field of human activity progress goes by leaps and bounds. The recent advance in tree grafting has amounted almost to a revolution rather than an evolution process. Application of a few new grafting principles of great consequence is now the order of the day. Old established grafting methods frequently ran into failures when dealing with all but a few trees like the common fruit bearing kinds.
The two chief obstacles to successful grafting were desiccation of the graft and fungous or bacterial parasites which entered the land of milk and honey where sap collected in graft wounds. Both of these dangers have now been practically eliminated and it remains for us to extend the season of grafting, carrying it away from a hurried procedure in busy spring weeks.
The chief obstacle to this extension of the grafting season has been the difficulty in finding the right sort of grafting wax or protective material for covering the graft, buds and all, as well as the wound of the stock. For covering the entire graft in order to avoid desiccation grafting waxes had to be applied in melted form with a brush. They had to be applied in melted form for filling interstices of wounds in which sap might collect and ferment. These waxes had the effect of not retaining their quality under greatly varying conditions of heat, cold and moisture. The paraffin waxes which the author has preferred were inclined to crack and to become separated from the graft and stock in cold weather. Furthermore they would remelt and become useless in the very hot sun of southern latitudes.
Experimentation for several seasons has resulted in the finding that raw pine gum is miscible with the paraffins in almost all proportions because of physical or chemical affinity. This gives to the wax an elasticity and adhesiveness of such degree that we may now graft trees in cold weather. Cohesiveness of molecules of the mixture is such that remelting in the hot sun may not destroy the effectiveness of this protective coating in hot weather.
Since the author has depended upon this mixture he has grafted peaches, apples, hazels and hickories successfully in midwinter as well as in midsummer. Many other kinds of trees have been grafted successfully out of the so-called grafting season but these four kinds which represent two of the "easiest grafters" and two of the "hardest grafters" will suffice for purposes of illustration.
According to old-established idea trees may be grafted successfully only from scions that have been cut when dormant and stored in proper receptacles. This is what we may term "mediate grafting," a considerable length of time intervening between cutting the scions and inserting the grafts. On the other hand what we may call "immediate grafting" is the taking of a scion from one tree and grafting it at once in a tree that is to receive it. Mediate or immediate grafting may both be done at almost any time of the year, winter or summer, spring or autumn.
When preparing the scion for immediate grafting in the spring or early summer it is best to cut off all the leaves and herbaceous growth of the year. We then depend upon latent buds situated in the older wood of the scion. The latter may be one year or several years of age.
In midsummer when top buds have formed we may remove only the leaves, allowing the growth of the year to remain and to serve for grafting material.
In experiments with the apple for example it was found that mediate grafts inserted on July 10th in the latitude of Stamford, Conn., began to burst their buds five or six days later. Immediate grafts inserted at the same time began to burst their buds about fifteen days later from buds of the year and about twenty days later from latent buds in older scion wood.
New shoots from these mediate apple grafts continued to grow as they do in Spring grafting. Immediate apple grafts on the other hand put out about six leaves from each bud and then came to a state of rest with the formation of a new top bud. After about ten days of resting these new top buds again burst forth and grew shoots like those of the mediate grafts.
The philosophy of these phenomena would seem to include the idea that the mediate summer grafts had contained a full supply of pabulum stored up in the cambium layer. The immediate summer grafts, on the other hand, had contained only a partial supply of pabulum, enough to allow them to make six leaves and a top bud. After a few days of resting these shoots with meager larder could then go forward with new food furnished by the whole tree.
Mediate and immediate winter grafts were alike in their method of growth in the spring. This would seem to confirm the idea that character of new growth is dependent upon the relative quality of stored pabulum in the cambium layer.
In experimental work it was noted that both mediate and immediate winter grafts make a slower start in the spring than do the grafts inserted in springtime. This is perhaps due to the formation of a protective corky cell layer over wound surfaces. New granulation tissue would then find some degree of mechanical obstacle in the presence of a corky cell layer at first.
Herbaceous plants allow of grafting. We are familiar with the example of the tomato plant grafted upon the potato plant, furnishing a crop of tomatoes above and potatoes below.
It seemed to the author that the herbaceous growth of trees should be grafted quite as readily. This seems to be not the case. A number of experiments conducted with grafting of the herbaceous growth of trees in advance of lignification has resulted wholly in failure with both soft wood and hard wood trees.
The walnuts carried herbaceous bud grafts and scion grafts for a long time however. These grafts sometimes remained quite green and promising for a period of a month but lignification progressed in the stock without extending to the scion. Speculation would introduce the idea that lignification relates to a hormone influence proceeding from the leaves of a tree and that the leafless scion does not send forth hormones for stimulating the cells of the scion to the point of furnishing enzymes for wood building.
Perhaps the most interesting part of new tree work relates to experiments which are failures. Negative testimony is like the minor key in music. There are many men who care to do only things that "cannot be done." These are the ones who have made our progress in almost every field of human activity.
STOCKS FOR HICKORIES
Willard G. Bixby, Long Island
MR. BIXBY: The sheets which I am distributing to you contain tables to which I shall refer during this talk. But first I will give a little foreword regarding the trees. The trees enumerated in the tables shown were nearly all given me by Mr. Henry Hicks of Isaac Hicks & Son, Westbury, Long Island, and were taken to Baldwin and set out in the fall, practically the entire roots being saved and later the trees severely cut back. They were transplanted without loss except in the case of the shagbark, and those lost were all undersized trees. All of the hickories were of one age, but those lost were ones which had not made normal growth and had they been discarded in the beginning there would have been no loss whatever in the transplanting of 300 or 400 trees. Later, in the spring of 1924, I found some loose bark pignut (Carya ovalis) seedlings on a farm not far away from my place, and these were also transplanted; but they were too small to graft this year. These experiments in grafting, made during 1923 and 1924, have shown us some new things. With some of the walnuts we had 100 per cent success. With the hickories there was not 100 per cent success, but that was due to the fact that we were putting scions on stocks that were not congenial in many instances. You will notice the results as shown on the tables.
G—Grafts Set C—Successful Catches ————————————————————————————————————————— Shagbark Mockernut Pignut Pecan Bitternut Total G C G C G C G C G C G C % Barnes 6 6 3 3 3 3 3 3 3 3 18 18 100.0% Brooks 5 0 4 2 5 1 5 2 19 5 21.0% Clark 5 1 5 0 5 2 5 1 5 2 25 6 24.0% Fairbanks 27 17 27 17 59.3% Gobble 1 O 1 1 1 1 1 1 1 1 5 4 80.0% Griffin 1 1 1 1 1 0 1 0 1 1 5 3 60.0% Hales 5 3 4 1 5 4 5 5 19 13 52.5% Kentucky 5 4 3 1 5 4 5 4 5 1 23 14 61.0% Kirtland 3 1 3 2 3 2 3 2 12 7 58.4% Laney 6 4 6 4 66.7% Long Beach 4 3 3 2 4 1 4 2 3 1 18 9 50.0% Manahan 5 1 5 1 6 2 5 1 5 1 26 6 24.2% Siers 5 5 5 5 100.0% Stanley 3 3 3 2 3 3 9 8 89.0% Taylor 4 3 3 3 4 3 4 3 15 12 80.0% Vest 5 1 5 0 5 1 5 2 5 1 25 5 20.0% Weiker 5 1 5 2 5 1 15 4 26.8% — — — — — — — — — — —- —- 32 17 51 20 52 26 46 24 91 53 272 140 53.1% 29.2% 50.0% 47.0% 59.3% 51.5%
An inspection of the 1923 grafts made August 21, 1924 showed the following number growing: on shagbark 14, on mockernut 6, on pignut 26, on pecan 24, and on bitternut 16, the only place where there was any material difference being in the case of the mockernut where nearly three-quarters of the number of grafts growing last summer failed to grow this spring, in fact all varieties failed to grow excepting three, the Barnes, Gobble and Long Beach, all three of which I suspect from other evidence, have mockernut parentage. In the ease of those on pignut and pecan stocks there was no loss from 1923 and in some instances at least of those on shagbark and bitternut stocks the loss was due to outside causes, such as being broken off.
G—Grafts Set C—Successful Catches ———————————————————————————————————————— Shagbark Mockernut Pignut Pecan Bitternut Total G C G C G C G C G C G C % Barnes 8 7 10 4 18 11 61.0% Beaver 5 1 5 1 20.0% Brooks 11 8 10 5 21 13 61.9% Clark 6 0 8 0 5 0 5 1 24 1 4.6% Fairbanks 5 3 5 3 60.0% Greenbay 5 0 5 0 0.0% Hales 5 1 5 1 20.0% Kentucky 5 2 4 2 9 4 44.5% Kirtland 5 5 4 3 9 8 88.8% Laney 5 3 5 2 10 5 50.0% Manahan 6 2 6 2 33.3% Mosnat No. 5. 7 1 7 1 14.7% Mosnat No. 6. 10 6 10 6 60.0% Siers 5 4 5 4 80.0% Stanley 12 1 12 1 8.3% Vest 10 3 15 5 16 5 10 3 12 3 63 19 34.2% Weiker 5 3 5 3 60.0% — — —- — — — — — — — —- — 16 3 122 52 54 21 15 4 12 3 219 83 18.7% 42.6% 38.9% 26.7% 25.0% 37.9%
In 1923, it was very evident that the Barnes was the only variety showing 100 per cent success on every stock. That was not repeated in 1924, but it still showed a high percentage of success.
From the comparatively modest percentage of catches, 51.5% on the average in 1923 and 37.9% in 1924, one might hastily conclude that the grafting was not skillfully done or that the grafts did not have proper attention afterward, but as noted above the grafting was done by Dr. Deming, whom I regard as one of the most skillful men that we have, and as the work on walnuts done at the same time showed 100% success with a number of varieties, I think any question as to the skill with which the work was done and the care the grafted trees had afterwards can be dismissed.
It is to be regretted that the number of scions at hand was not sufficient to repeat exactly the experiments of 1923 as well as to follow out the points suggested by the 1923 work, but as there was not enough for both, the latter was done.
The 100% success of catches of the Barnes in 1923 was not repeated in 1924; but the high per cent of catches on the mockernut, (7 out of 8 in 1924), is gratifying in view of the few varieties that we have that have shown adaptability to that stock. As the Barnes is one of our good varieties and there is such a wide section of the country where the mockernut is the prevailing hickory, it is believed this behavior of the Barnes will prove a valuable addition to our knowledge in top-working the hickory.
No variety as strikingly adapted for use on the pignut has appeared, but there are a number that have shown fair adaptability.
The varieties most desirable for top-working various species of hickories as suggested by this work supplemented by other observations of the writer, would be as follows:
Shagbark—Most varieties. Mockernut—Barnes. Pignut—Brooks, Kentucky, Taylor, Kirtland. Bitternut—Beaver, Fairbanks, Laney, Siers.
It is useful to know that the Barnes is the only one especially successful on the Mockernut. By the spring of 1924, all grafts on mockernut had died except the Barnes, the Gobble and the Long Beach, and each of these is thought to have mockernut parentage.
In the cases of the pignut and the pecan stocks, all of the grafts successful in 1923 were still living in 1924. With the shagbark and bitternut most lived. As to pecans there is not much to be said; pecan varieties would usually be used for the topworking here.
The results of a few grafts set in 1924 on Carya ovalis and on shellbark seedlings which were 100% failures, are not noted, as the shellbarks were, in the judgment of the writer, too small for the purpose, and the Carya ovalis had been set out in the spring of 1924 but a few weeks before the grafting was done. In other words the latter had not become sufficiently established to make good stocks, and the former were not large enough. In each case there was not sufficient vitality available to expect success.
This brings out one point which has impressed me strongly; that is the need of having vigorous stocks if they are to be grafted or transplanted successfully. I feel that this point cannot be too strongly emphasized. If a stock either from youthfulness or inherent lack of vigor is not rapid growing it is almost useless to try to graft it or transplant it until it does show the needed vigor.
As to stocks to grow in the nursery with the idea of grafting them later, the two commonly used, the bitternut for the bitternut hybrids and the pecan for others, there is little further to be recommended at this time, although for some varieties, notably the Vest, a stock better adapted to it than any we now have is earnestly to be desired.
* * * * *
THE PRESIDENT: Are there any questions on these three papers on hickory grafting?
MR. REED: There are two points in regard to propagation which I believe should be mentioned; one is that these various methods that have been discussed make it possible to propagate successfully during a great portion of the year. By beginning early in spring with the dormant graft, and continuing throughout the summer, these methods can be made to follow one another so that if one fails still another can be used. These methods greatly prolong the season, and when it is not convenient to propagate at one period by the method proper to use at that time another can be employed at a different season.
The other point is that we are constantly learning more in regard to the influence of stock upon scions. For example, hickories on pecans seem satisfactory while the reverse is at least doubtful. Mr. Jones finds that sieboldiana is not a good stock for regia. We all find nigra apparently satisfactory as a stock for any species of Juglans. These conspicuous differences of influence of various species upon scions suggest the possibility of less, but perhaps quite as important, difference of varieties. It is one of the newer phases of study and experimentation which should be considered by all and reported upon to this association.
THE SECRETARY: At my place the Vest, used in top-working large shagbark hickories, has been very successful. I do not know any that have been more successful or that grow more rapidly than it does on the shagbark hickory.
DR. MORRIS: The Marquardt is successful at my place.
MR. O'CONNOR: I do not know why we have not had success with paraffine in a single instance. In grafting fruit trees I had excellent results. I thought that if this could be done on fruit trees why not on nut trees? But I am going to try with the hickory again. I am going to be more careful in selecting good, strong stock for that purpose, and I think in that way we should have better success.
DR. MORRIS: Did you not perhaps cover the buds of your hickory grafts too thickly with melted grafting wax? Might not that account for your failure? Hickory buds will burst their way through almost any thickness of grafting wax, but when the paraffines are used without pine gum admixture the paraffine over the buds is particularly apt to crack and to allow the graft to dry out.
MR. O'CONNOR: I did not cover the hickory grafts with melted grafting wax at all; I simply put them in like apple grafts with ordinary grafting wax.
DR. MORRIS: Practically all hickory grafts will fail under such circumstances, but practically all hickory grafts will catch if they are covered with melted grafting wax of the right sort, provided that the scions and stock are also of the right sort.
THE SECRETARY: May we now have the President's address?
THE PRESIDENT: Before I begin I wish to call to your attention this pamphlet regarding the fifth Mid-West Horticultural Exposition, to be held in the Hippodrome, Waterloo, Iowa, November 11 to 16, 1924. It will be under the auspices of the Iowa State Horticultural Society, co-operating with its afflicted societies and the Greater Waterloo Association. The exposition will cover the Mid-West territory, from Pittsburgh to Denver. I wish especially to mention the printed list of premiums on page 27. Mr. S. W. Snyder, Center Point, is superintendent of this department. Cash premiums in Department b-Nuts, amount to $289. In addition there will be a grand sweepstakes, a trophy cup, donated by a member of the Northern Nut Growers' Association, for the exhibitor winning the greatest number of points. Anyone interested could write to the secretary, Mr. R. S. Herrick, State House, Des Moines, for a printed premium list. If any members of our Association have pet nuts of a variety which they would like pushed to the front now is the chance. Snyder Brothers are offering special premiums for new nuts unnamed and unpropagated.
The object of this association, as defined in its constitution, is "the promotion of interest in nut-bearing plants, their products and their culture," and as its name implies, in the northern part of this country. Without going into detail it seems to me that we have achieved the object of our association, at least to the extent of making practical use of our accumulated knowledge. Public interest has been aroused, which may become stale. Articles have appeared in magazines and newspapers from time to time on subjects relating to nut culture. We are also on a continual lookout for new varieties, and those of our members skilled in the art are constantly improving and working out new methods of grafting and budding, particularly as evidenced by Dr. Morris' work entitled "Nut Growing." We know approximately how soon a grafted nut tree, especially the black walnut, will begin to bear. At Mr. Jones' Nursery, Lancaster, Pa., an Ohio black walnut tree in the nursery row bore a cluster of seven nuts 17 months after the graft was placed. Mr. J. W. Wilkinson, of Rockport, Ind., has demonstrated that grafted northern pecan trees bear early and abundantly for their size.
We have given advice conservatively in reply to all inquiries relative to nut-bearing plants, perhaps too much so. Much honor and credit is due to certain members of our association for their untiring work and efforts in its behalf. It is not necessary to mention names as I am sure most of you present know to whom I refer. Our annual reports testify to their splendid work.
From this time forward I believe we should adopt the policy of boldly advocating the planting of orchards of nut trees. The intending planter will decide for himself what variety he will plant, and as a guide he should judge from the wild varieties growing in his vicinity. By so doing he cannot go very far astray in what will be to him a new venture. Of course certain varieties will be restricted to certain limited areas. This applies particularly to the introduced varieties, as distinguished from the native nut-bearing trees.
The black walnut has a wider range than any of the other nut trees. Travel wheresoever you will about the country and you will observe wild black walnut trees growing almost on every farm. The planting of the Persian, or English walnut, as it is more generally known, has had more of a popular appeal, perhaps from the fact that we are accustomed to seeing clean, smooth nuts of uniform size of that variety in almost every grocery store, the kernels of which may be extracted without great effort. The black walnut, on the other hand, has been tolerated as a sort of poor relation, and has been given no particular attention, because we have been used to seeing it around. It has not been made to do its share of contributing towards its keep. Our earliest recollections of it bring to mind bruised fingers as a result of our endeavors to crack the nuts and the tedious work of manipulating a darning needle to extract the kernels, which we usually picked to pieces in the process. We now know that we simply did not have the right kind of black walnuts. We should put our accumulated knowledge to practical use to urge on every occasion the planting of nut orchards, especially of approved varieties of the black walnut. This I understand is what the United States Department of Agriculture is advocating, and we should co-operate all we can with the department in that recommendation.
It will, no doubt, be urged that sufficient grafted black walnut trees are not available for orchard planting on a large scale. This, no doubt, is true, but on many farms there are wild black walnut trees of a size suitable for grafting or top-working. Grafting wood may be obtained in larger quantities than the grafted trees. Those of our members skilled in the art have not been selfish in imparting their knowledge to others and are always ready and willing to instruct others in the art. Most owners of these trees would only be too glad to substitute profitable tops for their trees in lieu of their unprofitable ones.
I believe that at all our meetings we should have practical demonstrations in budding and grafting, as this will tend to arouse the interest of the uninitiated and will spur the initiated to greater perfection.
During the past year there has been a discussion relative to the calling of the black walnut by some other name. Personally I believe we should not attempt the change. The public will not understand and it will take them a long time to become educated to the change. Valuable time will be consumed in picking out a new name. Let us take the name as we find it. Properly handled, after the husks are removed, the walnuts will not be as black as they are painted, and besides, we do not eat the shell anyhow. The quality of the kernel will make its appeal. The trouble with all of us has been that too much attention has been given to the looks, rather than the quality, of our food stuffs. Quality has been sacrificed for looks. Various illustrations of this come to mind with all of us.
I believe success will attend the planting of black walnut orchards. This will encourage others to follow with orchards of other nut-bearing trees. Orchards of all kinds of fruit trees are being planted each year and the planters are content to wait until the trees are large enough in order to reap the benefits thereof. But somehow the impression prevails in the minds of many people that a nut tree should show results and yield profits soon after it is planted. In recommending to a lady of means that she should plant, as shade trees, northern pecans she promptly wanted to know how many bushels of nuts she would get off of the trees the next year.
Perhaps we place too much importance on selecting just the right spot and soil in which to plant a nut tree and thus cause the intending planter to be too timid in making a start. Those who know anything about trees know pretty well where it is not advisable to plant trees, especially those with a long tap-root. They can judge fairly well from the wild trees of the same variety growing round about.
As evidence of what a nut tree will do, those of you who have visited Devil's Den in Gettysburg Battle Field, have perhaps noticed a butternut tree, now quite old, growing out of the top of the cleft in a huge rock, having sent its roots down to the adjoining soil for nourishment. This tree has borne nuts even in its adverse situation.
For the benefit of those interested in the northern pecan, I wish to record the fact that a seedling pecan tree is growing in Clermont County, Ohio, on upland, not far from the eastern boundary line of Hamilton County, about five miles north of the Ohio River. The nut from which the tree grew was brought from Rockport, Indiana, and planted about forty-one years ago. The tree is quite large and bears nuts comparable with the wild seedling nuts that may be obtained from the Rockport district. If a seedling does this, you may readily see what a grafted tree will do.
THE PRESIDENT: We will now ask Prof. Collins for his address.
THE SEARCH FOR BLIGHT-RESISTING CHESTNUT SPROUTS[A]
Prof. J. Franklin Collins, Rhode Island
The chestnut blight has now been with us for more than twenty years and has destroyed practically all the chestnut trees of the northeastern part of the country. It has spread in all directions from its original center in the immediate vicinity of New York City until it has reached the limits of the native chestnut growth in the northeast and north, and is steadily approaching its limits in the west and south. The disease, a native of China and apparently imported into this country on some Japanese or other oriental chestnut, found a more susceptible host in our native chestnut and so became a virulent parasite on this new host. It was not until 1904 that general attention was attracted to the disease. By that time it had obtained a strong foothold on the chestnuts of southeastern New York (particularly the western end of Long Island), in southwestern Connecticut, and in northern New Jersey.
All of you are more or less familiar with the efforts made in Pennsylvania, New York, and elsewhere in the northeast, in co-operation with the federal government, to control the disease. These efforts are now an old story to most of you and there is no need of repeating it at this time.
Early in the fight against the blight the attention of many of us was directed to locating possible immune or resistant species, varieties, or individuals. The search for resistant native individuals and the accompanying experiments in crossing and grafting various species and varieties has been kept up ever since. Foreign explorers have constantly been on the lookout, with more or less success, for chestnuts in other countries that might be resistant to the blight. It has long been known that most forms of the Japanese chestnut (C. crenata) were in general highly resistant to the blight. Later it was found that the more recently introduced Chinese chestnut (C. mollissima) was also quite resistant, although both the Japanese and the Chinese were far from being immune. Quite recently Mr. Rock, explorer for the U. S. Department of Agriculture, has brought a new chestnut from southern China for experimental purposes. Notwithstanding newspaper reports to the contrary the possibilities of this chestnut in this country apparently are unknown at the present time. Nobody seems to know if it will stand our climate, resist the blight, produce worthwhile timber or fruit; nor is its name known, according to late advices that have reached me.
Some years ago the late Dr. Van Fleet made numerous crosses between the Japanese and the American chestnuts, the Chinquapin, and other species and varieties. Personally, I have not been in very close touch with Dr. Van Fleet's experiments. Doubtless some of you know more about them than I do. Regarding these I will only say at this time that the work begun by Dr. Van Fleet is being continued by the Federal Bureau of Plant Industry, with Mr. G. F. Gravatt in direct charge of the work so far as the Office of Investigations in Forest Pathology is concerned. Mr. Gravatt is also testing out the value of scions taken from seemingly resistant native trees when grafted on resistant stocks.
Some years after the blight had destroyed most of the chestnut trees in the northeastern states we kept getting reports from various localities to the effect that the blight was apparently dying out. Many of these reports came from sources that made us doubt their value, but others came from more reliable sources. We have had opportunity to investigate a number of these reports and have usually found that the statement that the blight was dying out was, in a sense, strictly true, the reason being that the chestnut trees were entirely dead, except for sprouts. This fact naturally prevented the disease from showing us as much as in former years.
Some twelve years ago I noticed in Pennsylvania a sprout of an American chestnut about an inch in diameter which had a typical hypertrophy of the disease, apparently completely girdling the sprout at its base; also a girdling lesion farther up on the stem. The hypertrophy was such a pronounced one and in other respects such a typical example of the disease that I photographed it. A few years later I was surprised to observe that this sprout had increased to more than three times its former diameter and that the two diseased areas just mentioned apparently had disappeared—at least they were no longer in evidence except as rough-barked areas. To make a long story short this sprout is still alive and has increased in size and height each year. Although now (1924) it is considerably branched and makes a small bushy tree it is badly diseased in numerous places and is only partially alive, but the dead portions have not resulted from some half dozen of the original disease lesions (apparently girdles), but from later infections. The very fact that a sprout should have lived for more than twelve years in the center of one of the most badly diseased areas known to the writer seems at least to suggest the possibility that future chestnut sprouts may yet grow in spite of the disease and persist—at least in a shrubbery form if not as a tree.
The sprout to which I have just called attention is not an isolated case, but merely one of the most pronounced that I know about. In a careful survey in July (1924) of the region immediately surrounding the sprout just mentioned two or three other notable, but less pronounced, cases of a similar sort were discovered. In two cases fine looking branched sprouts some twenty feet high with healthy-looking foliage were noted. Both were diseased but the disease seemed not to be very conspicuous or virulent. In a recent survey of woodland in Rhode Island (July, 1924) much healthy foliage was observed and several large sprouts were found on which the disease (although present) seemed to be doing little damage when compared with its former virulence in the same general region.
I call attention to these cases primarily to acquaint you with the results of our latest observations on what seems to me to be cases of gradually developing resistance in some of the remaining sprouts. In all my intensive work on the blight between 1907 and 1913 I cannot now recall a single instance where a chestnut sprout in a disease-ridden area ever reached a diameter of an inch or thereabouts before its existence was cut short by the blight; and yet today—a dozen years later—we are finding quite a number of living sprouts over two inches in diameter, and a few that are three, four, and even up to seven inches in diameter. Last Friday, August 29, I heard of a small chestnut tree in New Jersey that bore a few burs last year and which has a dozen or more this year. If the nuts mature we hope to get some of them to propagate. Last Sunday, August 31, I saw a three inch sprout in Connecticut that had had a few burs on it. I would be glad to learn of any cases of this sort that may come to your attention.
You are all thinking men and women and all of you have had experiences with diseased trees of some sort, many of you with very serious diseases, and some of you I know have had a wide experience with the chestnut blight, so you can draw your own conclusions as to the significance of the facts that I have stated.
As to the state laws for transporting material from one state to another I am not posted, but I believe that we can be advised by writing to the government at Washington.
DR. MORRIS: We do not know whether the Washington government will sterilize those scions and send them out for us, but there should be some way of sending from one state to another.[B]
It seems to me that in all probability, the vital energy of the protoplasm of the endothia is diminishing. Quality, flavor, or anything you please, is bound up with certain vitality, and that diminishes and finally will cease. That is the reason for the endothia growing less now.
PROF. COLLINS: My point was perhaps not exactly that. I meant that the result is that, with the average cases, we are now getting chestnuts not so quickly destroyed. The explanation may be exactly what you have stated.
DR. MORRIS: There are two factors to be considered. First, the running down of the vital energy of the protoplasm; and second, in the factors which affect the vital energy of the plant.
PROF. COLLINS: In the paper I have just read there was mentioned the apparent number of trees in various parts of the country which are very slowly dying from the blight, and some which have resisted it entirely, so far; but that was not the point I desired to emphasize. There are some around New York City which are still growing, and Dr. Graves could tell us of this.
MR. O'CONNOR: Would it be desirable to take out an old tree where there are new sprouts? One tree on Mr. Littlepage's place in Maryland has a number of sprouts coming up. I suggested that if we could get people together and clean the woods up we could dig up the old trees and only leave the blight-resistant ones.
PROF. COLLINS: That is near Bell Station where we do our experimental work. We found one place infected. I cleaned it out and we have not seen anything of the disease since.
MR. BIXBY: Some five or six years ago I sent a number of chestnuts to Warren, New Hampshire, which is outside of the blight district. I did not know then much about the blight. They grew for several years and it was not until one year ago that the trees were found with blight. I got the party to cut them down. How long must I wait before it is safe to send other trees there? I believe they will grow there and bear, but we do not want to get them affected with the blight.
PROF. COLLINS: I do not know that anybody could answer that. Apparently we have waited 20 years and are still unsafe. It is a case of experimentation.
MR. KAINS: As to the hybrids of Dr. Van Fleet and Dr. Morris, in the spring of 1923 I planted 10 and there are only four alive now. They were affected by blight and killed. They were rather large trees when planted, and I think for that reason more susceptible. We had the idea from the nursery that they would be more likely to withstand the disease than would the American sweet chestnut. Have you any reports as to the way these hybrids behave?
MR. REED: As to Dr. Van Fleet's hybrids, so far as we know they are all going with the blight. The collection in Washington is practically gone. We are still caring for them and doing what we can but the prospect is not at all good. We get reports of these distributed around the country, but in no case have we had a report indicating that the Van Fleet hybrids were at all resistant.
[Footnote A: Note—"Blight-resisting" as used in this paper should be interpreted as a slower death of the host than in former years, whether or not the result of increased resistance to the parasite on the part of the host, or to decreased virulence of the parasite, or to both factors combined.]
[Footnote B: Decision From the U. S. Department of Agriculture. Washington, D. C.
In a letter of later date, addressed to Mr. C. A. Reed, Dr. B. T. Galloway, of the U. S. Dept. of Agr., wrote regarding the matter of distributing Merribrooke chestnut scions, as follows:
"I have talked with Mr. Stevenson, of the Federal Horticultural Board, regarding this matter, and he says that, while there is no federal quarantine covering the chestnuts, as a matter of policy we have not been letting any chestnuts or scions go through our hands into the non-blight regions. Mr. Stevenson says that Dr. Morris himself might be able to carry out the plan he suggests by dealing direct with some of the state institutions in non-blight regions, selecting states that have no quarantine against chestnuts."]
PROF. COLLINS: I will now read my paper on
PROTECTION OF WOUNDS IN NUT TREES
I have been asked to discuss briefly the handling of wood decay in top-worked nut trees. I am not sure that I know very much about the latest methods employed in this type of work. Personally I have had no practical experience with it. I understand, however, that nut trees are top-worked by cutting off limbs and inserting one or more scions. I am informed that limbs as large as six inches or more in diameter have been cut for this purpose, particularly on pecan trees in the South, and that decay has started at the top of these stubs after the scions have become established, resulting in a pocket of decay. I assume that it is about such places as these that you want me to say something. Such conditions, whatever their origin, call for straight tree surgery methods. My work on tree surgery has been almost entirely with shade trees and chestnuts, and only to a very limited extent on other nut trees.
The general methods of handling decay are essentially the same on all trees, as also are the fundamental principles underlying the same, whether on nut or shade trees. I must admit I do not know just what methods are being employed by nut growers at the present time to counteract such decay in top-worked trees, so my suggestions may include nothing with which you are unfamiliar. Again, they may include some methods that you have already tried and found wanting so far as nut trees are concerned.
As a prevention of decay my suggestions, based on my own shade tree experience, would be:
(1) Avoid cutting large limbs when smaller ones are available and will serve the purpose just as well or better.
(2) Keep the scars thoroughly and continuously covered with some good waterproof and antiseptic material so as to prevent infection of any part of the cut surfaces.
(3) Always make the cut somewhat slanting so that rain water will readily run off, and insert the scions preferably at the upper extremity of the cut. Such an oblique cut normally heals quicker and better on shade trees than a transverse cut, particularly if a vigorous young sprout is left at the peak of the cut. I am quite certain the same statement will hold true with scions of nut trees placed at the peak of the oblique cut.
After decay has started, I would suggest—
(1) Cut out all the decayed woody matter, preferably from one side, so that a free and easy drainage of the wound may result. If necessary, when several scions have been placed around the stub, sacrifice one of the grafts and make a rather long oblique cut or groove from which all decayed matter has been removed. Use shellac, liquid grafting wax or melted paraffine over the cut bark, cambium and adjoining sapwood immediately after the final cut is made.
(2) Cover the entire wound with some good preparation to keep out disease germs and water. Preferably use for a covering such materials as will be more or less permanent and which have been found by practical experience to be least injurious and most effective on the particular nut tree that you are treating.
(3) Keep the wound thoroughly painted or covered at all times until it is completely sealed over by a new growth of callus.
(4) If the top-working was originally done in such a manner that the removal of all the decay results in a cavity that cannot be properly drained, it is advisable to fill the cavity with some waterproofing and antiseptic material in order to prevent it holding water and also to assist the cambium in covering the wound. The cavity must first be treated in accordance with approved tree surgery practices. In shade tree work, quite a variety of substances have been used to fill cavities with more or less success; e. g., wood blocks and strips, asphalt and sawdust, asphalt and sand, clear coal tar, clear asphalt, elastic cement, magnesian cement, Roman (or Portland) cement, etc. Of these only two—wooden blocks and Portland cement, have been in general use more than a few years. Blocks of wood were used in France to fill cavities more than 60 years ago, and in this country to some extent about 50 years ago. Later, Portland cement was used in preference to wood for fillings, probably mainly because it was more easily handled. To us of the present generation, Portland cement in combination with sand is the one material that seems to have been in general use sufficiently long to allow us to draw any seemingly reliable conclusion as to its real merits.
For the personal use of the average orchardist, Portland cement is one of the last in the list mentioned above that I would recommend. According to a few reports that have reached me, wooden blocks and tar proved to be fairly satisfactory half a century ago, and strips of wood embedded in some flexible and antiseptic material, are proving very satisfactory today. An excellent preparation to use between the strips of wood, containing asphalt and asbestos, can be readily bought on the market, and it has the advantage of being mixed ready for use. For cavities with horizontal openings that will hold semi-fluid substances, clear asphalt or gas-house (coal) tar may answer all purposes. For cavities with oblique or vertical openings, or for those on the underside of a limb, probably some of the magnesian cements, which readily adhere to wood, will be found more satisfactory when properly mixed and applied.
Although I have said more about filling cavities than of other phases of the work, I do not wish the impression to go forth that I recommend such work except as a last resort, so to speak. The one thing that I do most emphatically recommend above all others is the prevention of decay so far as possible by practices that are less likely to allow decay-producing organisms to gain entrance in the first place, or at any other time.
THE PRESIDENT: Does anyone care to discuss this paper?
MR. KAINS: Mr. President: During the last five years, I have planted several hundred nut trees, including the English walnut, black walnut, the heartnut, pecan (northern ones) and some hybrid hickories. I have noticed that in this nursery stock there has been a good deal of dying-out of the original stock where the trees had been grafted, and where the scion had not covered over. In some of those cases decay has set in, and the trees have died before they could be attended to or have been broken down by the wind. The point is, I think it a mistake for nurserymen to use as large stocks as they have been using in many of these cases, because the stump of the stock is too large for the slowly growing scions to cover over quickly enough. My experience in the planting of fruit trees has been uniformly successful with smaller stocks (that is, trees smaller than I have been able to buy for nut trees) with peaches one year from the bud and with apples not more than two years; with berries and stone fruits, not more than two years. In every case, with the fruit trees, one year stocks have given me better results. First, because they healed over more quickly, and second, because I could cut to better advantage in the trees. In no case have I been able to get nut trees as small as I can apples and peaches. I believe that with the smaller trees amateurs will have better success. I bring this matter to the attention of those men who are devoting their lives to the propagation of nut trees.
THE SECRETARY: The subject of transplanting nut trees was treated fully by Mr. Bixby in his paper this morning and will be treated by Mr. Hicks this afternoon in his address on the subject. Mr. Hicks will give a lecture, illustrated with slides, showing how the larger nut trees may be successfully transplanted.
DR. MORRIS: Mr. Kains' thought was that there was a good deal of difficulty from using stocks that were too large. Paraffine will keep them safe from microbes.
MR. KAINS: We had difficulty from the drying of the scions.
DR. MORRIS: I find that if raw pine gum is put in it prevents the paraffine from cracking.
MR. O'CONNOR: In regard to wounds on the trees I find that creosote makes a very good antiseptic. I use coal tar and creosote, mixed to a consistency of cream. I have used Portland cement but I treated with creosote first. In some cases I used bichloride of mercury.
MR. REED: It seems to be the experience in the South that, so far as the amateur is concerned, he gets better results with the pecans by planting trees of from three to five feet. Trees smaller than that are regarded as dwarfed; but the man who is in a position to exercise greater care could get quicker results from buying the large-sized trees. Yet it requires more care in transplanting, more fertilizer, and more attention.
MR. REED: I wish to make the motion that the chair name a nominating committee at this time.
THE PRESIDENT: Is that agreed? All right; then I name Mr. O'Connor for chairman, Mr. Reed, Mr. Olcott, Mr. Bartlett and Mr. Hershey on the committee. Are those names acceptable? (Vote shows unanimous acceptance).
THE PRESIDENT: The convention will adjourn until two o'clock.
FIRST DAY—AFTERNOON SESSION
Meeting called to order by the President.
THE SECRETARY: I will read a communication from Mr. Snyder, of Center Point, Iowa. But first I would like to explain that when the President in mentioning the Horticultural Exposition at Waterloo, spoke of a sweepstakes cup from a member of the N. N. G. A. for the greatest number of points won in the nut exhibition of which Mr. Snyder has charge he did not state that he himself was the member who gave the cup.
A HARANGUE ON THE NUT SITUATION IN IOWA
By S. W. Snyder, Iowa
Previous to the organization of the Mid-West Horticultural Exposition the Iowa State Horticultural Society had given but little attention to the nut question. But along with the exposition came a demand for a nut department, which resulted in the writer being appointed superintendent and given authority to prepare a limited premium list.
This resulted in bringing out a number of new and unnamed varieties of nuts and created some enthusiasm. When it came time to prepare for the second exposition, authority was given to greatly increase the premium list, which resulted in bringing out more new varieties and created a wonderful lot of enthusiasm.
When it came time to prepare for the third exposition a list was adopted calling for $138.00 in cash premiums, which resulted in bringing out such a large exhibit of choice nuts that when we came to make preparation for the fourth exposition the premium list was increased to a total of $181.50. This brought out so many fine nuts that it became a common thing to hear the remark, among the visitors that it was the most important department in the exposition.
For the coming exposition, to be held next November, the premium list as adopted calls for $280.00 in cash premiums, and while I am no prophet I am going to predict that it will result in bringing together the largest nut exhibit ever collected under one roof in the United States.
At our last exposition held in Council Bluffs, some of the directors of our state fair observed that the nut department was attracting much attention and was bringing a good many visitors to the exposition. They decided that they must have a nut premium list for the state fair and requested me to make up a list covering the nut subject as strictly applied to the State of Iowa. This I did and am attaching the list hereto. Although our state fair comes off in the month of August, and no nuts are available for exhibit, except such as happen to be kept over from the previous year's crop, yet it brought out at our 1923 fair the largest and best exhibit of nuts that has ever been shown within this state, not excepting the exhibits of the exposition. The board of directors were so well pleased with the interest manifested in the nut department that they are continuing the list for this year's fair and doubtless it will become a permanent feature of future fairs of this state.
So much publicity and attention has been given the nut question within our state that it has resulted in bringing to light several new varieties that we think should be propagated before the original trees may have been destroyed.
The horticultural department of our Iowa State Agricultural College is now taking an active interest in the nut question and has assigned one of the professors to the job of collecting information about and taking pictures of, the best known nut trees within the state.
If they follow up the nut subject with as much vim and energy as they have other phases of horticulture we may look for something in the nut line in the next few years that will be worth while.
The native nut situation might well be summed up by saying that we have so many good walnuts, butternuts, hazels, pecans, hickories, and hybrids of the two last named species, that we could banish all foreigners and still have plenty left to supply every need.
The crop of nuts for this season is fairly good; some trees have none, others a light crop, and some varieties are carrying a heavy load.
Of introduced nuts some are proving to be hardy and fruitful, but in my judgment they are all lacking in eating quality as compared with our own native nuts, unless I should except the filbert which has not yet proven that it will bear profitable crops in this climate.
In closing I want to give just one instance of the great interest that has been aroused for nut growing within this state.
A certain little city of less than two thousand inhabitants happens to own thirty acres of land that is suitable for the growth of timber. The citizens propose to plant the entire tract to nut bearing trees and bushes, and eventually make it a free park in which the children of the village may be turned loose to gather the nuts.
Just imagine, if you can, how the enthusiasm of the boys who may be fortunate enough to live in that little city, will more than bubble over as the nut gathering season approaches. I hope to be able to assist those people in their laudible enterprise and wish I may live to see it develop into the greatest thing of its kind in the United States.
THE PRESIDENT: Dr. Brooks, will you kindly give the Vice-President's report from West Virginia, preceding your paper?
DR. BROOKS: I have no special report to give as Vice-President of the association from West Virginia. I might say, perhaps, that the West Virginia station is in a land of hills and dales. Our latitude is from 200 to 5,000 feet above the level of the sea, and our average elevation is 1,500 feet. From our excellent position we can look down 600 feet or so upon the Ohio. Our land contains many species of trees, including nut trees. Among these there is one species of beech, two of hazel, two of chestnut, six of hickory, two of walnuts and fifteen of oaks. Fortunately, the chestnut blight has not swept the entire state. The chestnut has been in the past and is still our most popular tree. There are areas where tons of chestnuts are still put on the market every year. The people are still thinking more and more of some plant that might take its place; they are considering the shagbark hickory and the black walnut. I predict that in the future there will be more planting of hazel nuts, black walnuts and shagbark hickories in this state. The prospect there is promising.
SOME OF THE MORE IMPORTANT INSECTS ATTACKING NORTHERN NUTS
By Fred E. Brooks
Associate Entomologist U. S. Department of Agriculture
The prevalence of insect pests need not be regarded as an alarming obstacle to nut growing in the North, and yet there are numerous species of insects which are capable of destroying our nut crops. On the whole I presume there are fewer insects that attack nuts in this country than commonly attack apples, but apple growers are not limited in planting nor prevented from making profits on account of insect depredations. Neither should the probability of more or less insect injury discourage the would-be planter of nut trees.
The presence of an insect in any locality may mean, among other considerations, that the soil, and climatic conditions of that locality are favorable to the plant upon which the insect feeds. We may be sure that wherever the Baltimore butterfly is abundant, nearby is a congenial spot where the turtle's-head, the food plant of the butterfly, flourishes. Just so, in localities where there are many chestnut weevils we may expect to find chestnut trees thriving and fruiting generously. The same is true of the associations of many other insects and plants.
Theoretically speaking, one would not care to risk the expenditure of much time or money in propagating a plant in a region that was destitute of insects that might attack that plant. The absence of such insects would possibly indicate a lack of natural conditions favoring the growth of the plant in question. Thus the presence in any locality of insects that feed on nuts may mean that nuts thrive naturally in that locality and that insects are there because of the abundance of a favorite food.
May I hasten to add, however, that this fact should not lead to an under-estimation of the possibilities of insect destructiveness, nor encourage lax methods in dealing with injurious species. In the beginning of any nut-growing enterprise we should anticipate the coming of insect pests and be ready to meet them. The planting of pure stands of native nut trees sets up a condition under which insects coming from the forest may increase more safely and rapidly than under the more hazardous environment of a scattered forest growth. This applies to cultivated plants generally. It is true of an orange grove, a cornfield or a potato patch. The mass planting of any crop is quite sure to call sooner or later for measures to offset the stimulus which such plantings offer to insect increase.
Reference may be made to a familiar nut plantation which illustrates a natural result of neglecting one of the insect factors. This plantation is the government's chestnut orchard at Bell, Maryland, which was planted for scientific purpose some years ago by Dr. Van Fleet. This orchard of around one thousand trees contains numerous species and varieties of chestnut, some of which bear fruit every year. The various scientific projects carried on in this orchard in the past have all been of such a nature that they called for no consideration of weevil increase. Many nuts have been allowed to lie under the trees until the weevil larvae issued and entered the soil. This has resulted in a constant increase of weevils until infestation of the nuts became practically one-hundred per cent. All nuts of the crop of 1922 were so wormy that when planted they failed to germinate. Injury to the crop of 1923 seemed somewhat less severe, but its extent may be indicated by the fact that 3080 nuts from this orchard which were kept by the speaker in rearing jars yielded 11,085 worms. In the woods adjacent to the orchard the native chestnut trees are disappearing on account of the blight, and presumably weevils are on the decrease. Within the small area of the orchard, however, the increase has been abnormal, due, as has been indicated, to the peculiarly favorable and man-made conditions. If, from the time the trees of the orchard began to bear, the investigations being carried on had called for close gathering of the nuts at maturity and the destruction of all the worms that issued from them, there is little doubt that infestation would have been kept within reasonable bounds. At present, after two years of attention to the collection of ripening nuts, there is an apparent decrease in the number of weevils. Strong emphasis should be placed upon the importance of gathering chestnuts as soon as they are ripe and prevention of the worms from reaching the soil. This is especially true of districts where woods surrounding chestnut orchards do not contain bearing native chestnut trees.
The Nut Weevils
Now that the subject of nut weevils has been introduced, let us consider in more detail these grotesque, long-snouted insects whose larvae, or grubs, play havoc with so many of our nuts. Most of us have had the experience of gathering in autumn rich stores of our delicious native chestnuts. But how often our anticipations of boiled and roasted feasts have been blighted. We have found that the chestnuts were like the manna which fed the children of Israel in the wilderness, "When we left of them until the morning they bred worms and became foul." There are numerous cases in this country where chestnuts in shipment have been seized and condemned under the provisions of the Food and Drugs Act. Usually the phraseology of the libel has been "because the shipment consisted in part of filthy animal substances, to wit, worms, worm excreta, worm-eaten chestnuts and decayed chestnuts." Altogether the loss to chestnuts from weevil injury is beyond computation.
The beetles which are the parents of the familiar worms in chestnuts are not commonly seen, or, if observed, they are not associated with the disgusting inhabitants of the nut kernels. These beetles represent in their structure a very interesting adaptation to a special end. The mouth is located at the tip of an enormously long snout, or proboscis, and the drill-like instrument is used for puncturing the thick covering of various kinds of nuts so as to admit the egg into the kernel upon which the young will feed. In some cases the mouth is situated at a greater distance from the eyes and other head appendages than is the anal extremity of the insect. There are in the northern part of this country two species which attack chestnuts, one which attacks hickory-nuts, one which attacks hazel-nuts and about a dozen which attack acorns. And here may be mentioned an interesting peculiarity of the feeding habit which is decidedly to the advantage of the nut-grower. Each species adheres closely to its own food plant. The hickory-nut weevil does not attack hazel-nuts nor the hazel-nut weevil hickory-nuts. None of the acorn-infesting species will seek for food in the nuts of chestnut, hickory or hazel. Once the chestnut weevils are absent in a locality, there is no chance that oak trees will serve as a means of spreading the weevils back into the locality. So closely confined are these weevils to their particular food plants that many of them distinguish between the different species of oak and will oviposit only in certain kinds of acorns.
All the different species resemble one another in both the adult and larval stages. There is also a general similarity in their behavior. I have recently discovered, however, a marked difference in the life cycles of certain species. For example, the larger chestnut weevil and the smaller chestnut weevil look alike, but they are decidedly unlike in their development. The grubs of the larger weevil begin to leave the nuts at about the time the nuts drop. They enter the soil to a depth of several inches and fashion smooth-walled cells in which they remain unchanged until the following summer. During June and July they transform to pupae, and soon afterward to adults. In August they issue from the ground and seek the trees where they collect around the burs and begin to deposit eggs soon after the nut kernels start to form. This life cycle is continued year after year. To forestall starvation of the race in case of entire failure for a year of the chestnut crop, a few individuals carry over the second winter in the ground and then issue as beetles along with the one-year-old specimens. It is probable that a small per cent of the insects may remain in the soil over three winters. Thus does nature by unique arrangements safeguard the lives of even the very small creatures.
The life cycle of the lesser weevil is quite different. The larvae of this species leave the nuts somewhat later in the autumn than do those of the larger weevil. Like them, they enter the ground and pass the first winter unchanged. The grub stage is continued throughout the summer, but late in autumn, after the beetles of the larger species have been on the trees for some weeks and deposited most of their eggs, the larvae of the smaller species transform to adults. Instead of coming from the ground, however, they remain in their earthen cells throughout the winter. The next spring, prior to the blooming of the chestnut-trees, they emerge from the ground and soon thereafter collect in large numbers on the male catkins of the chestnuts. At this time very little feeding is done and the sex instinct does not manifest itself. As the time approaches for the nuts to mature, however, the beetles begin to feed and pair and soon thereafter to lay their eggs in the ripening nuts. Most of the eggs are deposited directly into the nuts after the burs begin to open. In the case of the larger weevils the beetles are present only about three months of the year. Those of the lesser species, however, are perpetually present, those of the younger generation reaching the adult stage in the ground before those of the previous generation have finished laying their eggs in the ripening nuts. As with the larger species, a few of the smaller weevils carry as larvae for several years to tide over possible failures of the chestnut crop. The life cycle of the hickory-nut weevil is similar to that of the larger chestnut-weevil, and that of the hazel-nut weevil is like that of the lesser chestnut weevil. Both cycles are represented among the acorn-infesting species.
Any intelligent warfare against the nut weevils calls for a knowledge of these distinctive life histories. Thus, an abundance of maturing larvae of the larger species this autumn will insure an abundance of beetles to deposit eggs in the nuts next autumn. With the lesser weevil, however, maturing larvae this autumn will not affect the number of beetles on the trees the succeeding autumn but will provide beetles for the crop two years hence. Large numbers of beetles of the lesser species may be destroyed by collecting them from the blossoms of chestnut, but, at that season of the year there are no beetles of the larger species abroad.
These weevils are to be made the subject of a bulletin by the Bureau of Entomology in the near future, in which it is hoped to go more fully into a discussion of control measures.
Walnut Husk Maggot
Although none of the weevils of the group just discussed attacks walnuts, the fruit of this tree has a serious enemy in the walnut husk maggot. This insect is most familiar in the form of multitudes of dirty-white maggots inhabiting the blackened, slimy husk of ripening walnuts. Originally, the black walnut furnished the favorite food of this insect, although the husk of butternuts was sometimes attacked. More recently the pest has turned its attention to the Persian walnuts which are fruiting in many places in the east. The watery, dark-colored pulp into which the husk of the nut is converted when the maggots begin to feed penetrates the shell of the nut and injures the kernel by staining it and imparting a strong flavor. The operation of hulling is also made doubly disagreeable, the nut coming out of the husk discolored and dirty.
These maggots hatch from eggs inserted into the husk of nuts by a light-colored fly about the size of our common housefly. Although easily overlooked, these flies may be seen on the nuts at almost any time in August and September. They have strong ovipositors with which they puncture the surface of nuts and insert into the openings masses of white eggs from which the maggots hatch.
As to the control of this pest, the speaker obtained very promising results in spraying Persian walnut trees belonging to our friend, J. G. Rush, at West Willow, Pa., with a solution of 1-1/2 pounds of lead arsenate to 50 gallons of water with 10 pounds of glucose sugar added to impart a sweet taste. The flies were observed feeding on the sweet coating given to the leaves and the nuts that ripened later were comparatively free from maggots. It was obvious that the flies died from the poison before depositing many eggs in the nuts.
During the past two seasons the speaker has made special studies of several species of beetles which cut or girdle young hickory trees, or the branches of larger trees, causing the severed part to break off or die. Not fewer than four distinct species of beetles in the east have this habit. Three of the insects do their damage in the larval stage. One of these, Elaphidion villosum, has been called the twig-pruner. It is a well known species and its work in pruning the branches of hickory and various other trees has often been referred to. The other two species which sever the wood in their larval stage are Pseudobidion unicolor and Agrilus arcuatus. Thus far, these two have no common names. In certain localities they are proving to be very troublesome to both young and bearing trees. In one block of a nursery in Virginia I estimated that the Agrilus larvae had ruined one-hundred dollars worth of young hickory trees. Fortunately, the adult of this species feeds freely on hickory foliage and can be killed readily under nursery conditions by spraying with arsenical poisons.
The fourth girdler referred to is our familiar hickory twig-girdler, Oncideres cingulatus. In this case the adult insect cuts a ring-like furrow around the wood and the portion above dies. The purpose of the girdle is to provide dead wood in which the young may feed. After the girdle is made, a process which occupies several hours, and, sometimes several days, the eggs are laid in the bark above. In central West Virginia and northward the grubs which hatch from these eggs require two years in which to reach maturity. In the vicinity of Richmond and southward, however, the larvae mature in one year. This more rapid development in the south probably accounts in part for the recent serious outbreak of this insect in Virginia and the Carolinas.
Each female beetle is capable of girdling several twigs. One female of about a dozen kept in confinement last autumn made eleven girdles and deposited 55 eggs. Several of the beetles continued their interesting operations until after several snows and severe frosts had occurred.
The twig girdler in the beetle stage feeds rather freely on the bark of twigs. Enough of the surface is eaten to justify the belief that the beetles may be killed by spraying with arsenical poisons. This treatment is being tested at the present time. In the cases of all these insects which sever the branches the wood is killed for the safety and comfort of the insect as it undergoes further development above the severed point. There is a period of at least several weeks in each case after the twig dies during which the insect in one stage or another remains in it to complete its growth. This affords an opportunity to gather the twigs and burn them with the assurance that the insects are being destroyed thereby.
At least some progress has been made in discovering the habits and the methods of controlling these and various other insects that may be expected to give nut growers in the north more or less trouble. The remedies that can be offered at the present time are not in all cases entirely satisfactory. There is much yet to be learned, but there are control measures within the reach of most of the nut growers which are well worth consideration and adoption.
THE SECRETARY: Dr. Zimmerman, will you read to us now?
DR. ZIMMERMAN: Perhaps some of the members will not be so glad to hear what I have to say, but I feel that there is a need for something along the line I will refer to.
DEVELOPING A NUT INDUSTRY IN THE NORTHEAST
BY DR. G. A. ZIMMERMAN, PENNSYLVANIA
We have all heard of the pecan. No doubt most of us have traveled through the South at some time or other and have entertained a wish for a pecan grove. A personal friend of mine, a minister, told me recently that the only time he was ever tempted to invest in a commercial proposition was when a real estate agent laid a picture of a pecan grove before him. I had entertained the thought that some day I might possess an orchard. Therefore, a couple of winters ago, when I found it necessary to go south for my health, I silently hoped I could kill two birds with one stone, by getting some undeveloped land and starting a pecan grove, which at the same time would keep me in the open air and give me exercise. Consequently, my eyes were always open and I was on the constant lookout for pecans. After miles of travel they appeared. They were very interesting and I went into the subject pretty thoroughly. I was informed that no cheap land was available any more that was desirable for pecans. I am not so sure of that. I was also informed that most of the people who had planted groves had made a mistake, that the pecan business was just beginning under new ideas, and that most of the work would have to be done over. From the amount of trees that are being top-worked I am inclined to believe this is true.
But I didn't kill the two birds with one stone. I did not attempt to build up a pecan grove, but instead I came back with the idea firmly impressed that we have a better proposition for the future right here, that we have right here in the North the building material in the shagbark hickory and the black walnut for a nut industry that will rival or even surpass the enviable position the pecan holds today. Was I correct or was I wrong? A second trip last winter has served only to imbed that idea into a firm conviction.
What ground have I for drawing this conclusion? Some of you, my friends, may disagree with me in some of my remarks, and no doubt insist that I am uninformed. Perhaps I am, but I am giving my convictions nevertheless, and I ask you to withhold judgment for twenty years before deciding against me.
Why has the pecan forged to the front as it has? Because the pecan is a good food, easily available, of pleasant taste and presents a fine appearance. From a commercial standpoint, after 20 years or more on the pecan, there is only one really desirable variety available, namely the Schley, and the fact that it readily sold last fall for 80 cents per pound wholesale, while the choice of the other varieties brought 60 and 65 cents per pound, bears me out in this. I am not referring to the greater productivity and other qualities of some of the other varieties. Many of them are tolerated for various reasons.
How about the shagbark in the North? It is my belief that we do not have at present a shagbark that will anything like meet the pecan of the South, yet the consensus of opinion of the people I know who have eaten both, decides in favor of the shagbark. The quality of a very ordinary shagbark is better than the best of pecans. What then, is lacking? Size, shape, thinness of shell, cracking qualities, color, everything but flavor is lacking in most shagbarks. Don't misunderstand me. I am not condemning what we have, for I believe that if as many years are spent by as many people in finding or developing a shagbark, we will have one that will surpass the pecan. But as the matter stands I am constrained to say that I do not know of a really good nut today that will stand the test of building an industry that will compete with the pecan. We must find or develop a couple of really good nuts that will compete, nuts that are large, smooth, shell thin enough to crack with the fingers, a white kernel that is plump and easily extracted. I do not believe that any thick shell nut will ever meet the favor it should or become extremely popular. The Weiker, one of our best, is of good size, looks fairly well, but the shell is thick and it is poorly filled. It will never fill the place for a real industry, and yet they sell for a good money-making price today.
If we build our groves after this standard we will be in the same place in a few years that many of the pecan growers are now, namely, with a lot of trees on hand that must be top-worked later on. But they are the best we have and, like the old adage that it is better to love and lose than not to love at all, it is better to go ahead with these than not to go at all.
How about the black walnut? This nut will come to the front and be popular for baking purposes and candy-making, for it is the only one that holds its flavor after heating. But its competition will be against the thin-shelled English walnut. It will not be extremely popular until we get one with a shell equally thin. At present we do not have one.
How then can we anticipate a great future industry after meting out this doleful outlook? Are we going to discard everything we have and start again? By no means. The price of nuts, even of the ordinary class, is sufficient even now to well repay any man for his effort, if producing them on a large scale, and what must be done is to encourage more people to become interested.
If we could arrange to have nice exhibits of named varieties of nuts at the various county fairs, and have someone there to explain them, a good deal of interest could be created. I frequently see native nuts displayed, but not named varieties.
I shall not refer to the hazel, chestnut, pecan nor butternut, all of which I believe can be developed into a more or less successful industry but only repeat in closing that I am convinced, after pretty thorough investigation, that the shagbark hickory and the black walnut can be developed into an industry in the Northeast in a much shorter time than it has taken to develop the pecan, to a point that will equal or surpass the enviable position that nut holds today. But, and let me impress this point, we must develop a few new and better nuts to do it. On account of the colder climate, which goes for the developing of fine flavor in all products, I do not believe the pecan will ever equal the shagbark in quality. This is our great natural advantage.
DR. MORRIS: I accept all of the statements by Dr. Zimmerman with one exception. The pecan is tremendously prolific and so productive that there are records of 30 bushels to a tree. I do not know that any of the shagbarks or shellbark hybrids ever will rival that in production. From the marketman's point of view production is of prime importance. In this the pecan out-rivals the black walnut.
TRANSPLANTING NUT TREES
Willard G. Bixby, Baldwin, N. Y.
When I set out the first nut trees which now are growing at my place at Baldwin, I was very particular to follow the best advice obtainable. What this was is to be found in Bulletin No. 5, published by the association, pages 8 and 9, under Planting Directions. I will not take time here to read them but will refer those interested to that publication.
Much that is to be found there is unquestionably the best practice that we know today. The importance of preventing the roots from drying out, digging holes of sufficient size and filling with good top soil, firming the soil well about the roots, severely cutting back after planting and staking newly set trees if they are of appreciable size above ground, are of the utmost importance and should be emphasized, but others of these directions have been modified in my practice and I will relate the unfortunate experiences which caused these changes to be made.
From the start there has been trouble in transplanting hickories, difficulties with other trees being small in comparison. Out of a number of fine looking little grafted hickories set out in the fall or spring some would be sure to die. They mostly came from Mr. Jones, who, as a rule, has furnished the finest looking hickories that I have received, and were finely packed and seemingly ought to have lived, but only part of them did. After losing a number out of one lot, I watched the lot purchased next year with particular care. Three out of a lot of six, which had put out leaves well in the spring, by the middle of July began to show signs of distress, the edges of the leaves beginning to turn brown which the year previous had been the beginning of the end. I knew what had happened the year previous, felt that the trees would die if something was not done, and did something. That something was to dig about six quarts of chicken manure and two trowels of nitrate of soda around the three trees that looked sick and saw that they were watered plentifully till a heavy rain came. At first nothing was noticed, but after a while the brown disappeared on the leaves that were only slightly brown, while in other cases new leaves put out and finally a second growth of shoots, very small to be sure, but the trees had been saved. This was diametrically opposed to previous practice of putting no manure or strong fertilizer in holes when planting the trees, but the result was so satisfactory that I have continued to dig in about 1/4 of a wheelbarrow of well rotted stable manure around each tree when planting and two trowels of nitrate of soda in May when the growth should start in the spring.
The above treatment seemed almost entirely to solve the difficulties of transplanting and for about two years practically no hickories were lost. Twenty-four Hales trees, 10 years from grafting brought here from Monticello, Florida, all lived through the first year and 23 of them through the second and now seemingly have a long life ahead of them. Inasmuch as Mr. Jones expressed his doubts as to how successful this experiment would be I regarded it as somewhat of a triumph. On the other hand out of the finest looking lot of young Iowa hickories grafted a year ago this spring and shipped in the fall and set out just as carefully as I knew how, with well rotted stable manure in the holes and seemingly having every prospect of a long life before them, all have died now, excepting four, two of which I am making desperate efforts to save.
The reason for this failure has not yet been proved, but I have an idea what it is. With two exceptions the stocks were not large, unusually small in fact, and the growth of the grafts was small, but, except for their small size of stock and graft they were fine looking little hickories as one often sees. The two that are in good condition today were bitternuts on bitternut stocks and both the stocks and grafts were notably larger than others. One of these bitternuts by the way, is bearing this year. Evidently there was not as much vitality stored in the smaller trees as in the larger ones. I am inclined to believe that the real trouble was because the grafts, excepting the bitternuts, had not become sufficiently established before having to stand the shock of digging, shipping and transplanting. I have noticed in experiments made to determine the adaptability of a number of species of hickory as stocks that it was not unusual to find that a graft would do reasonably well the first summer and die the second. If this happens occasionally when hickories have not been transplanted it is undoubtedly very much more likely to happen when they are transplanted. I have had practically no losses in transplanting hickories when the graft had grown two seasons before being transplanted. The safe plan, then, would seem to be to let a graft grow two seasons before transplanting. Unfortunately this will add to the cost of grafted hickories which even now are so expensive to produce that almost no nurserymen grow them.
Another one of the commonly accepted principles that I do not now follow is that of not planting trees any deeper than they grew in the nursery. I prefer to plant them a little deeper, say two inches or so. I do not recall losing any trees seemingly from this slightly deeper planting, while I did lose a considerable number of seedlings last year that were inadvertently planted two inches or so too shallow.
Outside of the hickory I have had little trouble in transplanting any trees excepting some of the hazels. Unless hazels, particularly American hazels, are very well rooted, they will need more care the first year than most nut trees, particularly protection from the hot sun and drought. If I get poorly rooted hazels I now plant them in a shady place for a year or two if they have not grown well the first year, and then move them where they are to stay.
THE PRESIDENT: Mr. Snyder of Center Point advocates planting trees two to four inches deeper.
DR. MORRIS: In Dr. Brooks' paper he spoke of some of the twig girdlers in the beetle stage which feed upon the bark of twigs before ovipositing, and he said that gives a weak point where we may attack them. On my place at Stamford, where there are forests, that would be impossible. I have had a good many hazels partially destroyed this year by girdlers. A great many of the branches have the larvae in them. I find also a large number of small hazels on which the leaves and branches are dying, though there is no apparent injury to the bark. Suddenly, however, a little twig will drop off and yet, in cutting into them, I did not find any larvae.
DR. BROOKS: That happens to be the work of an insect which I am just beginning to study, one of the flat-headed borers, and the reason you have not seen the larva is that it is very small. It is not half an inch long. In the second year it comes out as an adult. I judge that control measures should be used in the spring, when I think without doubt that it would feed on the poisoned spray.
DR. MORRIS: I find a great many larvae in dead twigs on the ground. If we are going to get this pest out of the way, we should not only look at the twigs on the tree, but at those on the ground as well.
DR. BROOKS: That is true of all of these curculios. Dr. Morris' statement is true. The ground should be gone over and the dead and dying branches and twigs of the trees should be collected. The insects mature in them.
DR. COLLINS: Would you advocate pruning often?
DR. BROOKS: No.
Adjournment to lecture hall. Mr. Henry Hicks of Westbury, Long Island, gave a talk on the transplanting of large trees by his methods, illustrated with lantern slides. This was followed by a talk with lantern slides, on
HEREDITY IN TREES AND PLANTS
By Dr. A. F. Blakeslee, New York
Dr. Blakeslee said in part:
One of the first things we notice as we go out into the open is diversity in the habits of trees and plants. It is through the details thus presented that we are able to distinguish one species from another. You can see this diversity the year round in nut trees, and in the nuts.
If you arrange nuts, or any other objects for that matter, in a curve according to size, you will find that the most numerous of them are of about the average size. This is equally true when applied to mankind. What is the reason?
There are a number of factors affecting this, but, in general, there are two main causes—environment and heredity. We do not know which is the more important but both are absolutely necessary.
In the picture being shown we see the influence of the black walnut upon plants around it. It creates an environment which influences the ability of other plants to grow near the roots.
It must be remembered, however, that what the animate plant transmits is not the actual character in question, but the ability of the animate plant to develop characteristics. By placing the plant near a black walnut tree we do not affect anything but the capacity of the plant to develop in certain directions.
I have shown here a diagram to illustrate a certain stock fertilization. Here we have the plant with its stamen and pistils, the egg cells and the pollen. There are two types of pollenization, one where the pistil is fertilized by insects carrying sticky pollen; the other by movement of the wind carrying the pollen. If I should believe my records, in attempts to cross trees, I might have a cross between a birch and an alder, in which the pollen is carried by the wind. I tried once to hybridize pines. I put some pitch pine pollen on the female flower of another species and seed resulted. I did this the second year and again I got seed. The third year I put bags on the female flowers before I could see them developing. Then I got no seeds. I believe that the pollen which had caused the seed to set in the preceding instances had come from the south for perhaps hundreds of miles.
There are times when the pollen of the staminate plant is all shed before the pistillate gets ready. Sometimes we have a plant that is self sterile. I have experimented with pollen from several different nut trees and also with the Norway spruce. Then again, there are abnormal cases; sometimes there is parthenogenesis. The jimson weed is the first plant which has ever been reproduced by parthenogenesis. Since that was discovered, an investigator in California has found a similar case in fruit developed without pollination.
One of the most important conceptions in heredity is its effect upon characters and factors. Take the Japanese bean here shown for example, one dark bean and one mottled. In the next hybrid generation we find three mottled and one dark. That is the familiar "three to one" ratio of Mendel's law. We believe now, that all, or at least a very large proportion of the heredity characters in plants of all kinds may be due to a series of factors; but the habit of growth of the plant is due to a single factor. We have the case here of a second generation of the weeping mulberry that I crossed with the white mulberry. As a result there was an average of three erects to one weeping one. Certain characteristics may be made up of the inter-action of a large number of factors. This will give a little idea as to the complexity of Mendel's law.
How do we get new characters in nature? New types are due to the rearrangement of previously existing characters, just as with the old-fashioned kaleidoscope, where you turn the crank and get new pictures. Another way is by the sudden appearance of new factors.
I wish to speak about one effect of hybridization, which is really connected with heredity factors, the vigor which occurs when we cross different varieties, species, or even races. In my experience certain types that have been naturally contrasted finally lose vigor, and after two or three generations the plant disappears. Then again I could show you cases where yields are greatly increased due to hybridity. These are established facts, not only as regards species of plants and trees but also as regards the human race. Hemy, in Dublin, who has done the best work in this line of endeavor, believes that many of our more rapid-growing trees are rapid-growing because they are hybrids.
To summarize, I have tried to point out the fact that diversity which we see in nature is real, and that it is brought about by two causes, namely, environment, and heredity. And that heredity is brought about by factors in the bodies of the chromosomes which are shuffled around like cards in a pack; they reappear in the same way that the cards will reappear. We have no means, as yet, of controlling the appearance of the factors, but we have two methods of getting new factors, as follows:
One—The finding of new things in nature; that, probably, is the very best method that can be used. The work of the theoretically planned project points out the tremendous importance of the exceptional individual.
Two—By taking the exceptional individuals, and by crossing them, you can recombine, although the results may be very complex, and obtain characters that are very desirable.
As ministers sometimes say to clinch the moral, I would say, "Seek earnestly that which is best and hold fast to that which is good."
THE PRESIDENT: Has anyone a question he would like to ask?
DR. MORRIS: In attempting to make crosses between juglans and carya we find often that the pollen of carya will excite the cell of the juglans but without making a fusion. What is the element of the male cell of the hickory which starts the female cell of the walnut into action?
THE SECRETARY: I would like to ask Dr. Blakeslee one thing; he showed the influence of the black walnut on the growth of the hedge, and he showed that something other than the effect from the black walnut had caused these plants to be dwarfed. Is that understood to be a fact?
DR. BLAKESLEE: No; some of the effect was due to the black walnut.
MR. HICKS: In some cases the trees get sick and die. I have observed many plants and trees growing close to walnuts and I can point out peach trees and other fruits planted close to black walnut trees which have been injured. I should like to see the question determined.