Although the chestnut blight has destroyed the native Castanea dentata trees, it is hoped that breeding programs may produce a blight resistant, hardy tree, of a size that will lend itself to orchard planting and cultural practices, and which will be regularly productive of high quality nuts.

* * * * *

President Davidson: Thank you, Mr. Moore.

The next thing on the program is the talk by Mr. G. S. Jones of Phenix City, Alabama, on Growing Chestnuts in Lee County, Alabama.



Growing Chinese Chestnuts in Lee County, Alabama

G. S. JONES, R.F.D. 1, Phenix City, Alabama

Ever since childhood, chestnuts have held a fascination for me. How well I remember the delightful Sunday afternoon trips we used to make in the fall up on Earkett's Hill to gather a few small nuts from some native trees which often had been burned by woods fires. I occasionally revisit this area to see these trees, which are in better condition now than then. Native chestnuts were never, to my knowledge, very abundant in our area and are now indeed scarce, but I still hear of a few living trees, some of which grow as far south as North Florida.

I first became interested in Chinese chestnuts from an article I read in the early '30's in a Department of Agriculture yearbook which I think had been written by Mr. Gravatt. This article told about these trees being introduced into this country because of their high resistance to blight. Until this time I had heard little about chestnut blight. In order to find out more about these trees I wrote Mr. Gravatt, who in reply said seedling trees were available for distribution on an experimental basis. I applied for some of these, more, I must admit, to get them to grow on our place just to have some chestnuts than with any thought of disease resistance. When these trees came in the spring of 1934 I even had some trouble in getting permission to set them in an open field near the house, for chestnuts were considered as a tree of minor importance, to be grown in some out of the way place.

These trees were set in sandy loam soil with a porous yellow subsoil in a field of medium elevation which has excellent air drainage so I have had little damage from cold injury. The soil is of fair fertility for the Upper Costal Plain area. Of the trees sent me, fourteen of the ML selection, originating, I am informed by Mr. Gravatt, from seed obtained in Anhwei Province of China, and 10 MO selection originating in Chekiang Province were set in my orchard. Only two of these failed to survive, leaving a total of twenty-two. These were cultivated with the field crops, mostly cotton and corn, and I must admit didn't have much individual attention for several years. I even left the side branches to minimize injury from the mule and plow used in cultivation. Some leaves and trash were put around them at times and they received some benefit from the fertilizer of the row crops. I mention this to show that my chestnuts grew quite well though only moderately fertilized, but receiving good cultivation while young. I might mention that I set two trees in stiff Piedmont clay soil a few miles above here, to try them under woodland conditions. These have never done well, although one had burs but I found no nuts. Other trees which I observe have not been given cultivation grow very slowly, although I have not seen any tried on what I would consider good woodland areas.

My trees, spaced about 40 x 40 ft., have grown quite rapidly so that now some of the limbs are almost touching. Tree ML No. 2, which is about average size, measured last fall in diameter 12-1/2 inches, in height 24 feet, with a limb spread of 30 feet. By 1943 the trees were getting so large that cultivation was discontinued. An attempt is made to keep all litter possible in the orchard, which, with the shade of the trees, has caused much of the soil to become loose and mellow. Since our sandy soil is very low in calcium I applied limestone one time at the rate of about 1500 lbs. per acre. This I hoped would improve the texture of the soil and make better conditions for growing bur clover between the trees. Basic slag which contains about 10% phosphate was applied at the rate of about 600 lbs. per acre in the early '40's. For the last four or five years I applied about 200 lbs. of guano (4-10-7 usually) and 200 lbs of basic slag annually. Since 1944 I have been adding about 50 lbs. of minor mineral elements to the above mixture. Whether it is a coincidence or not I cannot say, but the next year after applying these elements my yields increased from 430 lbs. the previous year to 961 lbs. and have remained high ever since. Minor mineral elements show beneficial results on our garden crops, and I am inclined to believe they are needed, since our soil is so sandy and porous, and especially the soil that has been cultivated so long. Since my trees have produced so well with this moderate fertilization, I have made no check against higher rates of application. In fact I am against the use of large amounts of mineral guanos since I know certain tender shrubs and plants are injured by their use and some soil bacteria and animal life are also harmfully affected, according to reports I have read.

Three of my trees bore a few nuts at four years. No record of yields was kept until the seventh year or 1942, in which I gathered about 328 lbs. of nuts. After that my records show for 1943, 554 lbs., 1944—430 lbs; 1945—961 lbs; 1946—1722 lbs; 1947—1554 lbs. No individual tree records were kept except in a few cases. I kept a rough record by looking at the burs at the end of the season, and classed trees as excellent, good, or poor producers, along with other characteristics of the trees. However, I know several of my trees produced over 100 lbs. each in 1946 and one tree, ML No. 2, of which I kept a record by weight, in 1947 produced a little over 150 lbs. of nuts.

[A note from Mr. Jones early in 1949 reports a crop of 1,836 pounds of chestnuts harvested from his 21 trees in 1948, the largest yield to date. His ML No. 2 tree produced 165 pounds.]

Nuts on a few of my trees begin ripening the latter part of August, but September is the heavy month, with some extending to the middle of October. Their early ripening period while the weather is usually hot and dry, I think tends to cause damage to nuts from the effects of the hot sun and rapid drying. Damage to the nuts and consequent spoilage can be kept at a minimum if they are gathered promptly, which should be daily.

Preparing Chestnuts for Market

Here is how I generally handle my crop. As soon as the nuts are gathered I put them in a container with water and remove the nuts that float. This eliminates practically all spoiled nuts and those beginning to spoil. Those that sink are then placed in coarse mesh burlap bags (about 25 lbs. to the bag) which are tied near the top. These bags are laid on a slatted platform under a shade tree and pressed out flat, so nuts will not be thicker than 2 or 3 inches. These bags are thoroughly wet with water once or twice daily, depending on the weather, until I can carry them to cold storage and store at 30 deg.F., or they are marketed fresh, advising buyer of the perishable nature of these nuts. Last year my nuts kept excellently in cold storage, and after remaining there about six weeks had dried sufficiently to keep much better after taking out than when they were fresh.

Nuts for planting purposes can be kept in excellent condition for several weeks by spreading them thinly between layers of damp sphagnum moss and storing in a cool place. This cannot be allowed to get very wet or sprouting will begin. While holding the nuts out of cold storage I attempt to keep sufficient moisture available so the nuts are not allowed to dry much, and yet have plenty of ventilation to keep them from heating or souring. Until I began using this method, a large percentage of my nuts began spoiling soon after gathering, which caused me much discouragement, as I did not want to offer such a product for sale. Since then my losses still run around 12%, but this could be reduced still further by more prompt gathering and by the elimination of several trees which retain nuts in the burs to a large extent.

I have been able to dispose of my nuts quite easily in near-by Columbus, Ga. and for the last few years have had quite a demand for nuts to use in planting.

My orchard as a whole has been very healthy, showing no blight signs that I can detect, although there is little chance of exposure to blight in my section. One tree is slowly dying, which may be due to cold injury, as it comes into leaf early and also ripens very early. So far I have noticed no damage from chestnut weevils. As my trees are seedlings, there is quite a bit of variation in size of nuts and production of individual trees.

Undesirable Traits in Seedling Trees

I might mention some undesirable traits which I notice in my trees. First, I would place retention of nuts in the burs as the worst trouble. This is quite bad in five or six of my trees. Next, nuts too dry and loose in the hull at time of falling, which is present in four or five trees, some of which retain nuts in the burs and some which do not. The dry textured nuts seem to spoil more easily than plump well filled ones. Some trees produce too small nuts but the trees which produce extra large nuts do not usually yield nearly so heavily as those producing small to medium size nuts. I consider too early ripening as undesirable, for those that ripen later are usually better keepers, but this does not always hold true as some of the later ripening ones are also poor keepers.

This year my trees have an excellent crop of burs and show promise of a good average yield on each tree. Considering all things, I am highly pleased with my Chinese chestnuts and believe they have a good future in our section if no greater troubles arise than I now know of although there is much room for improvement.

Other Tree Crops

Although Chinese chestnuts are my largest producing tree crop, I am working with a number of other trees and shrubs for both nut and fruit production, as well as other purposes. I have several Thomas black walnuts which I set about 1938. Three of these have grown quite rapidly and are beginning to produce nice crops of nuts, although the kernels have a tendency to be spongy at times.

Of course, I have a small orchard of budded pecans, which do so well in our section. These trees, which are young, are just coming into production. Some other nut trees which I am trying in field plantings include native chestnuts, chinkapins, hazel nuts, native black walnuts, and scaly bark hickory (Carya ovata). Since most of these are young and grow so slowly, I cannot say much about their production yet. I have also planted quite a large number of white oaks from a high production tree in hopes of producing acorns for hogs and wild life, also some cork oaks on an experimental basis.

Among non-nut producers I am trying honeylocust, persimmons, and mulberries. I also grow catalpa and black locust for fence posts. This makes no mention of the great variety of native timber trees such as pines, tulip poplar, and others which I try to protect from fires so as to get as great a variety of trees as possible to use for various purposes. I also encourage the growth of ornamental trees and shrubs such as dogwood, redbud, and holly to add beauty to the landscape in season.

Dr. J. Russell Smith's book, "Tree Crops" has been a great inspiration to me along these lines, and I am attempting to study and use as many trees, shrubs, and plants here on my place as possible because I believe we can live easier and better and make better use of the land both for ourselves and nature when we learn how to use our various native plants to the best advantage along with many of the exotic ones.

I might end by saying that I would much rather work in the shade of trees than in the open sun and benefit by their long life and varied uses than to depend so heavily on short lived crops which often require such intensive care.

* * * * *

President Davidson: Thank you, Mr. Jones. A very interesting paper with details that are worth listening to.

Professor J. C. Moore of the Department of Horticulture, Alabama Polytechnic Institute, will give us a talk on Processed Chestnuts on the Market throughout the Year.



Processed Chestnuts on the Market throughout the Year

J. C. MOORE, Alabama Polytechnic Institute, Auburn, Ala.

Professor Moore: Mr. President, members of the Association: I have a few packages here that I just wanted to pass around after we get through with a short discourse on processed chestnuts. It might be somewhat of an inspiration to look while I talk a few minutes about it.

These nuts, of course, have been put up from the 1947 crop, but I have nuts put up in 1945 that are still in fair shape. The quality on the 1945 product is not too good. The quality on the 1947 product is excellent when the nut is hot. For instance, a toasted chestnut, I think, has a quality that no other nut has. When the nut sits in a bag sealed for several weeks and gets cold it still is good, but it doesn't have quite the crispness that it has when it is really fresh and hot.

We were very much disappointed with Chinese chestnuts when they first began to bear at Auburn. We got some plants from Mr. Gravatt and the Bureau of Plant Industry in Beltsville in 1938. They were planted; some of them started bearing in 1941. The nuts were large in size; the trees seemed to be perfectly healthy. The early bearing habit gave us a great deal of encouragement. Then we sampled these nuts, and the quality was not good. While the nuts were green and in storage the nuts decomposed in just a few days' time.

The first nuts that we harvested in 1941 were picked, placed in paper bags, set in the office, and we forgot about them, because they were not good when we put them in the bags, and we just put them back for our record purposes. A few days afterwards they were moldy and ruined. In 1942 we had a little better crop, but again the nuts rotted. In 1943 we had a still larger crop, and the nuts rotted again. We did not know how to take care of those nuts at the time.

In 1944 Mr. L. S. Holden was with the Soil Conservation Service. He was transferred to Auburn at the time I was transferred down into Haiti to do some work on rubber production, and he took my place at Auburn on the hillculture project. In the fall of 1944 Mr. Holden had an idea that he could can those chestnuts and preserve them. So he took the nuts, cracked the hull off of the nut, ground it with a little food chopper, and placed the nuts in cans, pints and quarts, put them in a pressure cooker at 15 pounds pressure and cooked them for 15 minutes.

During the fall of 1944, or after the crop was produced, Mr. Holden left Auburn, and he told me when he left that he had sent some of the samples to different parts of the United States and had gotten favorable replies from the samples that he had sent out. That gave me a renewed courage, and along with that in 1945 we sold quite a few raw nuts on the market at Auburn. Those nuts sold just like hot cakes for 40 cents a pound. There were quite a few comments came back to us about those nuts. They were the most beautiful nuts the people had ever seen, and several different ones made comments that the nuts toasted had excellent quality and the nuts boiled had excellent quality, and raw nuts after they were cured had an excellent quality.

Those few different peoples comment on the material and Mr. Holden's work that he had done on canning gave me an idea that maybe he had something, and I have worked since that time trying to perfect a product that would be edible from the hand from a cellophane-bag standpoint. At the present time we have a plan worked out whereby we can produce large quantities of Chinese chestnuts in Alabama.

The thing that is going to confront us in the near future is the marketing possibility. We have to handle Chinese chestnuts rapidly if we put them on the market raw. This processed method that we have has been worked out to perfection, we think, for cold storage purposes.

Now, you can put Chinese chestnuts raw in cellophane bags and seal them with a hot iron. These bags are not sealed. It is a non-sealable cellophane. I didn't get hold of the type of cellophane that you can seal. They are unsealed. They have been in this package about a week, and the nuts are in good shape. On cold storage I have held those nuts for 40 days. Last year was the first time that I tried them in sealed cellophane, but sealed in cellophane bags in cold storage last year they remained perfectly good for 40 days. At that time the cold storage plant went bad, and, of course, the nuts molded.

We think that on the cold storage proposition, and if you have followed food processing and cold storage possibilities on strawberry shortcake, strawberry pies, apple pies and other types of cold storage products, I think when you go to the locker and pick out a little bag of lima beans in a cold storage locker or any other kind of cold packed foods, if you see a pack that looks attractive, chestnuts, after you get accustomed to their flavor especially, it will be a difficult thing for you to fail to pick up a bag of chestnuts and walk out with them among your other grocery purchases. That type of marketing has possibilities throughout the year.

With that possibility from last year this crop came in. We had an excellent crop. I contacted Mr. Harris, who is one of the professors working with food processing at Auburn, and we went over the work quite carefully together, what I had done and the possibilities for the work in the future, and with some suggestions from him and with his help we think we have just about fixed a product that will be a permanent thing on the grocery shelves throughout the year.

Up to the present time all of the nuts that were canned in cans with the shells on developed throughout the year somewhat of a soured condition. When you opened the can and smelled, the odor was foul. When you cracked the shell and tasted the nut, the flesh had just the least bit of a foul odor. Mr. Harris suggested that probably that was a flat sour. We weren't sure that it was flat sour, but we haven't had the bacteria check to find out whether it was caused by one of the thermophilic bacteria or not, but we are pretty confident that it was a flat sour that caused the foul odor. With careful heating and careful drying we have developed some products here that I think have a possibility, and these products will maintain their quality throughout the year.

Nuts Cured Before Canning

I have canned chestnuts that have been canned for three years, and the quality is just as good as it was a month after they were canned. The product, however, when it is canned green does not have the quality that it does when it is canned after curing. The way we handle these, to begin with, is to take the nuts from the field, put them on a woven wire and elevate the wire so that air can go under and over, cure at room temperature for about three days. If you cure longer than three days you will lose quite a few of your nuts. That is a rapid cure. We have not tried curing under cooler conditions to see if we can eliminate part of the damage that is caused by deterioration, but curing the nuts rapidly you get a deterioration on quite a few of the nuts after the third or fourth day. If you take the raw nuts three days cured rapidly where the air can circulate over and under, the quality is excellent raw, and I have those nuts cured for three days in cellophane bags on cold storage that can be sold throughout the year. Those nuts must be heated enough to stop the deterioration, whatever it is. It may be a physiological condition, I am not sure, it may be a vitamin reaction, I am not sure, but when the nut dries too fast it turns white on the inside, gets hard, loses its flavor, and it is no good.

This nut (indicating) canned in cans, I will give you the treatment for it. I told you we cured them on those drying racks for three days. Then we put them in a pressure cooker and run the temperature up to about 10 pounds pressure for 30 minutes, take them out of the pressure cooker and hull them, and at that stage they hull quite easily. The hull itself will turn loose from the nut quite easily if you heat it a little while before you try to hull. A machine which can thresh the hulls off very easily will be simple to develop. After the shell is taken off, then they are put in an oven (a drying oven that has an automatic control at 270 degrees), for about 10 minutes in order to evaporate the excess moisture that you get in the steaming process. Then they are put in the cans hot, set back into the oven and heated for just a few moments to get your temperature up again and you put lids on at a boiling temperature. You get quite a vacuum created by sealing them hot. We have had as high as fourteen and a half pounds of vacuum on those cans the third day after they were canned, and if you can get a vacuum like that by sealing the nuts hot, you can preserve their quality for a long period.

I don't care if you open any bag that's here and taste these products. You will find that the ones with the shells off are much better than the ones with the shells on. I believe you will find that. However, the quality of the nut with the shell on is excellent.



Chestnut Growing in the Southeast

Max B. Hardy,[2] Leeland Farms, Leesburg, Ga.

Introduction

Just about forty years ago the first blight resistant chestnuts were introduced into the Southeast. This event was to have more far-reaching effects than could be foreseen at that time, as is illustrated by the present extensive interest in the growing of these chestnuts as an orchard crop.

Chestnut blight, a fungus disease of the native American chestnut (Castanea dentata (Marsh) Borkh), first appeared on Long Island in 1904 and destroyed this magnificent nut and timber tree. A Phytophthora root disease added its toll so that a bearing tree of this species is a rarity in the East at the present time. The U. S. Department of Agriculture began making introductions of two species of chestnut from the Orient in 1906, both of which were resistant to the blight which was then destroying the native American chestnut. Of the two species, the Japanese chestnut (C. crenata Sieb. and Zuce.) and the Chinese chestnut (C. mollissima Bl.), only the latter proved to have much merit other than blight resistance and chestnut growing in the eastern United States in recent years has been confined almost entirely to the Chinese chestnut.

About twenty-five years ago, after the first introduction from the Orient of seed nuts of blight resistant chestnut species, the U. S. Department of Agriculture distributed a few seedling trees to various interested growers in the Southeast. Some of these trees are still growing and bearing good crops of nuts and have reached rather large size. The distribution of trees produced from nuts imported at subsequent intervals was continued by the U. S. Department of Agriculture until rather widely scattered planting of several species under varied soil, climatic, and cultural conditions was attained. As time passed it became clear that only the Chinese chestnut had promise as a commercial crop for the production of nuts. As a timber tree none of the introduced species has as yet shown outstanding merit.

[Footnote 2: Formerly Associate Pomologist, U. S. Pecan Field Station, U. S. Department of Agriculture, Albany, Georgia.]

General Observations

The Chinese chestnut grows well throughout the southern part of the natural range of the American chestnut and southward to the Gulf Coast, and possibly even into central Florida. Farther north it apparently grows and produces better crops along the Atlantic Coast than inland, thus indicating the need of this species for a long growing season and freedom from late spring and early fall frosts. In the plantings in Georgia, from Atlanta to the southward, no loss of crop from late spring frosts has ever been noted. In the Gulf States and northward along the Atlantic seaboard the Chinese chestnut tree is vigorous, healthy, and productive, coming into bearing at a fairly early age and thereafter producing regular crops. The trees grow to be rather large in size, developing a somewhat rounded form with a spread of branches about equal to the height. Without pruning when young many sprouts usually develop near the ground so that the mature tree has numerous trunks of about equal size, with the lower lateral branches resting on the ground.

Nearly all of the Chinese chestnut trees being grown at the present time are seedlings and exhibit a wide range of tree and nut characteristics. A few trees develop a somewhat more upright type of growth than that commonly seen, but this type is generally less productive than trees of more spreading habit, and the nuts are smaller and less desirable. Some trees showing the most upright type of growth originated from nuts imported from the more northern provinces of China and may represent a distinct strain or form of Castanea mollissima. The degree of incompatibility exhibited when southern China strains are grafted on northern China strains would indicate the same conclusion. Unfortunately, several different species or strains have been included in the plantings of most cooperators with the U. S. Department of Agriculture so that seedlings resulting from cross-pollination of these types may exhibit an even wider range of characteristics and performance from the standpoint of commercial production than is commonly seen at present. A few of these hybrids may be superior to pure C. mollissima seedlings in certain important respects because of hybrid vigor, but taken as a whole the best types of C. mollissima seedlings are superior to the other blight resistant species for purposes of nut production.

The earliest introductions of blight resistant chestnuts from the Orient are represented by very few trees in the Southeast, but a small number of plantings of trees distributed in 1926 have been observed. These are producing good nuts and the trees are quite healthy, regardless of conditions of planting except when they have been given no attention of any kind. In one planting the trees were planted about 10 feet apart on the square with the result that they are tall and spindly with nut production only in the tops and very light on a per tree basis, which indicates the need of adequate spacing if the trees are to be vigorous and productive. Incidentally, this close spacing has not resulted in a desirable timber type of growth.

In two other plantings the trees are planted in cleared areas in cut-over timber and then given no further attention. In both locations a few trees are still living but are of no value either for timber or nut production. In still another planting on a bench about halfway up a mountain, where infrequent cultivation or mowing is practiced, the trees are growing and producing moderately well but the nuts are small. A few other scattered plantings of a few trees each are doing well around homes though receiving only moderately good care.

The distribution of trees by the U. S. Department of Agriculture in 1935 and 1937 has resulted in a few plantings that have done moderately well. In one planting the trees are growing fairly well without care but are producing few nuts. In another planting the trees are planted on rather heavy soil that is terraced; they are given applications of commercial fertilizers and infrequent cultivations and have been producing fairly good crops of nuts in recent years. Still another planting of a considerable number of trees has been entirely removed through lack of interest of the new owner. The plantings described have all been on private property.

Plantings at various experiment stations have received somewhat more attention in general than those on private property; but because of lack of keeping quality of the nuts have not for the most part been accepted as a promising crop and have been the subject of very little study.

From the foregoing observations it is evident that the Chinese chestnut cannot withstand the effects of crowding either in a solid planting or in competition with native growth. The trees have performed moderately well with a minimum of care, but respond to good care by increased production and nut size. The rotting of the nuts soon after harvest as a result of improper methods of handling and storage has prevented an earlier acceptance of the crop as of potential economic importance in the Southeast.

Experimental Studies at the U. S. Pecan Field Station, Albany, Georgia

In 1926, twenty-eight seedling trees of Castanea mollissima were planted in the Champion experimental block at Philema, near Albany, Georgia. These trees grew well and began producing nuts in 1932. In 1935, an additional 16 trees were planted in the same block. The trees in both plantings have shown good vegetative vigor and have been fairly productive. All the variations common to any group of Chinese chestnut seedling trees have been in evidence. One or two trees have lacked vegetative vigor but have produced heavy crops of nuts for their size. Type of bur opening has varied from free dropping of nuts to those burs from which the nuts are removed with difficulty; nut size has varied from about 35 to about 90 nuts per pound; the date of earliest and latest ripening of the nuts varies by about three weeks; nut color has ranged from light browns to dark mahogany and dark chocolate brown; and keeping quality and eating quality have ranged from good to poor. However, nut production, as shown by the data presented in Table I has been good and nut quality has been acceptable, so that with increasing knowledge of the storage requirements of the nuts the trees have paid a good profit in recent years. One of the older trees has consistently produced close to 150 pounds of nuts each year for the past few years.

Some of the trees in this planting have been topworked to selections from other plantings, including the variety Carr which showed up very poorly in comparison with most of the seedlings. Some of the trees have been culled out because of poor yield or nut size; and some have died as a result of poor drainage.

An additional planting at Philema in the Brown tract was made in 1938. The trees were planted in a portion of a five-acre block at some distance from the original plantings, with a spacing of 25 feet apart on the square in soil of rather light and sandy texture with fair subsoil drainage. The fertility was low but has been improved through the use of winter leguminous green manure crops and commercial fertilizers. Some of the trees planted consisted of trees grown from carefully selected Castanea mollissima nuts imported from south China and designated by the initials MBA, MAY, MAZ, and MAX. Others carried the designating letters of "FP." The nuts from which these trees were grown were imported by the Division of Forest Pathology of the U. S. Department of Agriculture which also grew and distributed the trees. Still others were selections of C. crenata, the Japanese chestnut; and C. mollissima selections from an experimental planting in California were also included. In 1940 the remainder of the five-acre block was planted with trees grown from seed produced by the original Philema planting.

Table I. Summary of chestnut yields at Philema, Georgia.

_________ HARVEST DATA _____ 1926 and 1935 Planting[3] Length _____ Date Harvest Year Harvest Period Yield No. Trees Av. Yield Began in Days in Lbs. Bearing per Tree _____ _____ 1932 14 3 4.7 1933 7 7 1.0 1934 80 16 5.0 1935 8-29 22 222 22 10.1 1936 8-26 33 379 25 15.1 1937 8-26 37 278 18 15.4 1938 8- 6 42 480 21 22.9 1939 8-15 42 995 26 38.3 1940 8-27 38 740 34 21.8 1941 8-14 51 1,467 38 38.6 1942 9- 3 41 876 32 27.4 1943 9- 9 26 1,335 38 25.1 1944 8-15 44 560 29 19.3 1945 8-18 34 1,450 27 53.7 1946 8-20 41 1,455 28 52.0 1947 8-26 43 1,975 27 73.1 _____ _____

___________ HARVEST DATA _______ 1938 and 1940 Planting[4] Length _______ Date Harvest Year Harvest Period Yield No. Trees Av. Yield Range in Began in Days in Lbs. Bearing per Tree Yields _____ _______ 1941 8-14 51 44 63 .7 .1-6.9 1942 9- 3 41 30 46 .7 .1-5.2 1943 9- 9 26 357 108 3.3 .1-29.7 1944 8-15 44 716 136 5.3 .1-37.0 1945 8-18 34 3,025 208 14.6 .1-50.7 1946 8-20 41 1,447 173 8.4 .1-48.3 1947 8-26 43 6,615 188 35.2 .1-108.5 _____ _______

[Footnote 3: 28 trees planted in 1926 and 16 planted in 1935, at spacing of 25 to 40 feet.]

[Footnote 4: 274 trees planted in 1938 and 60 in 1940, at spacing of 25 feet on square.]

The yield's produced in the 1938 planting have been outstanding, as indicated by the data in Table I, The trees began bearing when younger and developed heavier production than those of the 1926 planting, whether judged by age of tree or years of bearing. Many of the trees have produced nuts of outstanding size, attractiveness, eating quality, and keeping quality. There has been the usual degree of variation common to any collection of seedlings, but the best trees in this planting have been superior to any previously seen. Nut size has varied from 23 to more than 100 to the pound; the color of the nuts has varied from light tan to deep mahogany, and a few are nearly black. All have been of good eating quality. The keeping quality has varied materially, some keeping very well and others quite poorly.

Bur opening, has likewise varied so that at one extreme the nuts drop entirely free from the burs on some trees and at the other extreme the burs drop with the nuts in them and considerable work is required to remove the nuts. It is out of this group of trees that the three seedlings have been selected that the U. S. Department of Agriculture is considering worthy of variety status. These have not yet been officially released and no official description is yet available. The yield data for these three selected Seedlings are given in Table II.

Table II. Yield data by years, of three seedlings tentatively proposed for variety status, Philema, Georgia.

————————————————————————————————————- Tree Proposed Yield in Pounds by Years Total yield No. Nuts (in Lbs.) per Lb. ———————————————————- No. Name 1941 1942 1943 1944 1945 1946 1947 1948 from Planting ————————————————————————————————————- 7880[5]Meiling .2 3.6 20.9 36.9 23.9 73.1 36.9 195.5 38-43 7919 Kuling 4.0 3.8 5.8 6.5 13.8 34.2 50.2 38.2 168.5 35-43 7930 Nanking .1 3.8 28.0 37.8 1.0 87.7 54.6 213.0 30-43 ————————————————————————————————————-

[Footnote 5: Meiling ("Beauty") is the first name of Mme. Chiang Kai-shek.]

The trees of the "FP" designation and, of other species were grown to fruiting, but have since been removed or topworked in entirety because of their lack of desirable characteristics and because they produced pollen for cross-pollination which would result in undesirable progeny when the Castanea mollissima nuts were used for seed. Furthermore, a number of trees of the three-letter designations have been removed or topworked because they produced very small nuts, or showed poor keeping quality, or because of some other undesirable characteristic. Therefore, the nuts now being produced in this experimental orchard are of pure C. mollissima inheritance of the best type, and, as such, represent some of the best and purest seed nuts available in this country today. This procedure is being continued so as to maintain the quality of the nuts for seed purposes at its present standard.

Unfortunately, many of the nuts offered in the general trade for seed purposes at the present time are coming from orchards composed of a mixture of species or types comparable to the 1938 Philema planting before culling. This is very undesirable because of the great variability in the nuts produced by trees with such an origin. When grafted or budded trees of the newer and improved varieties are available to orchardists chestnut growing for nut production may be based on the same sound practices as the other fruit industries.

In the topworking of "FP" trees at Philema with scions from other strains of Castanea mollissima the degree of incompatibility has been so great, that the scion tops will have either blown out or died at the end of four or five years from grafting. At the present time this failure can only be attributed to the fact that the stocks were of mixed ancestry. On the other hand, scions of pure C. mollissima placed on the same stock strains have made good unions and are entirely normal after as long as 13 years from grafting. This problem of incompatibility between stock and scion is one that yet remains to be completely solved.

The topworking of trees in the five-acre block at Philema has been generally successful where incompatibility is not a problem. Bearing-size trees topworked one spring will generally produce a few nuts in the second subsequent growing-season. Growth the first year after grafting will frequently be as much as 12 feet long and very stocky. Both cleft grafting and inlay bark grafting have been practiced, the latter method proving to be the more satisfactory from all standpoints. In this method of grafting scaffold limbs from 1 to 6 inches in diameter are cut off square across. Scions 6 to 8 inches long are prepared by making a slanting cut 2 to 3 inches long and ending about three-fourths through the scion at its basal end. A strip of bark just wide and long enough to receive the scion, with about one-half of the upper end of the bevel showing above the cut surface of the stub, is then removed from the stub. The scion is then nailed into place with 5/8-inch nails and painted over with melted grafting wax. Two or three scions are required for most stubs. This work is done just as growth is starting in the spring and the bark is slipping well. The scions may generally be cut directly from the trees, but sometimes they may need to be cut several days earlier and stored in damp material in a refrigerator to keep them dormant.

In south Georgia the Chinese chestnut normally begins growth soon after March 1, but in some years it has started as much as a month after this date. Between south and north Georgia there is a differential in the time growth starts in the spring of one to two weeks. This differential also carries over into the date of blossoming and the date the harvest period begins. In south Georgia pollination generally occurs during the latter part of April and early part of May, and the harvest period begins about 100 days later. The peak of harvest averages 185 days after the initiation of growth in the spring. Dormancy comes only after the first frost sufficiently heavy to kill the leaves, usually about two months after nut harvest is completed. This period between harvest and leaf fall is undoubtedly an important factor in the annual bearing habit of the chestnut in the Southeast since it permits the food reserves in the tree to be replenished after the crop is mature. This is true under favorable conditions but does not hold under conditions of crowding, low soil fertility, or premature defoliation. For best growth and production the tree should be in foliage approximately nine months out of the year.

ORCHARD MANAGEMENT

The planting of chestnut trees in the Southeast should be done as soon as possible after the trees become dormant in the nursery. They should be planted on fertile soil which is well drained but not subject to serious drought injury. The Chinese chestnut cannot withstand a high water table, or free standing water, but appears to be somewhat resistant to drought injury when once well established. The chestnut trees have not yet reached an age at which their largest potential size has been attained, but trees of 50-foot spread have been observed. It appears likely, then, that orchards should be planted at 50 to 60-foot distances on the square, unless closer planting and subsequent thinning is resorted to in order to build up high nut production per acre at an earlier age of the orchard. Planting distances of 25 x 25 feet, 30 x 30 feet, 25 x 50 feet, and 30 x 60 feet are recommended for this reason, but only if the orchardist will plan to thin the stand at 10 to 15 years of orchard age and at later intervals as required. In no case should the branches of adjacent trees be allowed to touch as under such conditions competition between trees will reduce the yield per tree and nut size, and induce alternate-year bearing.

In planting the young tree it is usually advisable to fill the hole in which the tree is to be set with top soil, packing it firmly around the roots as the hole is being filled. Usually no fertilizer is used at the time of planting, although mixing about a handful of bone meal with the soil around the roots has given a higher percentage of living trees and has increased growth the first year. A shallow basin around the tree to facilitate watering when necessary during the first growing season, or the application of a mulch around the tree, or both, will be helpful in obtaining a high percentage of living trees and good growth. Adding water at the time of planting is good insurance that the soil will be well settled around the roots. A wrap of newspaper tied loosely around the trunk of the young tree will aid in preventing winter injury and sun-scald.

Under conditions of little or no care the seedling chestnut tree will generally develop several trunks as a result of the forcing of multiple sprouts from near the ground line. The tree should be trained to one trunk, as such a form seems to be less susceptible to winter injury while young and makes a much more desirable orchard tree when older. Pruning of the young trees subsequent to the development of the head at a 4 to 5-foot height should be confined to the removal of crossing branches and those so near to the ground as to interfere with the necessary cultivation and harvesting work under the tree.

Most soils in the Southeast are somewhat low in fertility and must receive good care if chestnuts are to grow well. The annual application of commercial fertilizers is generally required as is the growing of a winter green manure crop, preferably a legume. One of the most satisfactory systems is to plant hairy vetch, Austrian winter peas, or blue lupine[6] in late October or early November, applying broadcast at the time of planting from 400 to 600 pounds per acre of a 0-14-10 or 0-14-7 fertilizer mixture. This green manure crop should then be disced in by April 15 of the following spring, with subsequent shallow cultivations at about six-week intervals through the growing season. The ground should be clean by the middle of August to facilitate harvesting the nuts. If such a system of culture is not feasible, as on too steep slopes or around buildings, mowing or mulching can be used to advantage, but the trees must be given annual applications of a complete fertilizer mixture, such as 4-8-6, 6-8-8, or 5-7-5. These should be made each year about a month before growth starts at a rate of 2 to 3 pounds for each year of tree age. This should be broadcast under and slightly beyond the spread of the branches.

It has not yet been found necessary to spray the trees for the control of any disease or insect. This does not indicate that control measures may not be required at some time in the future, for it is the history of horticultural crops when planted in any concentration that diseases and insects increase in number and degree of injury. As yet, the chestnut weevil has not been found at the lower elevations in the Southeast.

In a few plantings a condition causing some premature defoliation has been observed at infrequent intervals. The condition begins as a leaf scorch which may or may not develop to the point where the leaf drops. It is thought to be caused by some mineral deficiency or unbalance associated with erratic weather conditions, but the exact cause is yet unknown. A leaf spot disease has been observed but has caused no appreciable defoliation and no control measures have been thought necessary.

[Footnote 6: Blue lupine is winter-hardy only in the warmer coastal areas, not adapted north of Columbus, Georgia, Meridian, Mississippi, or Shreveport, Louisiana. Ed.]

Harvesting and Nut Storage

Harvesting of Chinese chestnuts has proved to have definite requirements if the nuts are to be obtained in the best possible condition. The nuts are quite susceptible to rots of several kinds and must be properly handled to keep losses at a minimum. They are also very easily and quickly injured by exposure to the sun, with the consequent, high temperatures and drying. If the nuts are to be stored for any length of time, as is necessary when they are to be used for seed purposes and as will be necessary when they are to be marketed for eating purposes during the Thanksgiving and Christmas holiday seasons, it is paramount that they be picked up from the orchard at not more than two-day intervals. Cleaning up all dropped nuts at daily intervals is most desirable.

At the end of each day the harvested nuts must be placed in cold storage at temperatures between 32 deg.F. and 45 deg.F. It has been found that a nearly air-tight container is required in order to maintain a relative humidity of 100% and prevent too much drying of the nuts. A 50-pound tin lard can with one 20d nail hole in the side near the lid has proven to be a good container for large quantities and these same cans also make good shipping containers merely by wiring on the lids. One-gallon friction top syrup cans with a single nail hole in the side make a good container for smaller quantities. In air-tight containers the nuts do not decay but germination capacity is quickly destroyed and bitter flavors develop quite rapidly. Nuts to be used for eating purposes shortly after harvest may be stored at lower relative humidities but should be placed in cold storage. A loss of about 15% in weight from the fresh weight of nuts is necessary to reach proper eating quality. Nuts dried to this extent are sweet and palatable but cannot be stored for any length of time and fail to germinate well when planted.

The experimental study of chestnut storage problems is being continued with the hope of working out still better methods. The manner of marketing chestnuts so that they will reach the consumer in a desirable condition also is still to be worked out, but it appears possible that retail cold storage and packaging in moisture-proof bags which are pervious to CO{2} and O{2} give promise at present. Probably the most promising aid to an increased storage life of chestnuts will come through the selection of trees for propagation and planting that produce nuts of superior resistance to storage rots. There is rather great variation among seedlings in this respect, some being-quite superior, although no completely resistant seedlings have yet been found.

Discussion and Conclusions

The perishable nature of the nuts of the Chinese chestnut has probably been the greatest drawback to an earlier acceptance of this crop as an adjunct to the horticulture of the Southeast. It has been only in the past few years that enough has been learned about the harvesting and storage requirements to permit the storing of these chestnuts so that they can be marketed in an orderly manner either for eating or for seed purposes. Storage losses through periods up to six months have been held to less than 10% for a mixture of nuts from all the trees at Philema. Storage tests of nuts from individual trees have shown a range in keeping quality from no loss after six months' storage to nearly 100% loss. By culling out the trees producing nuts with a high rate of spoilage under the best storage conditions it should be possible to reduce storage losses to a minimum. Every grower of seedling trees should follow this same process of culling out or topworking trees producing nuts of poor keeping quality if the industry is to grow and prosper, since otherwise the offering of spoiled nuts for sale to the consumer will soon destroy the demand for the nuts.

There is no question but that the Chinese chestnut tree is very well adapted to the Southeast. It has proven to be healthy, vigorous, and productive. Yield records at Philema show actual yields of more than 1,000 pounds per acre and potential average annual yields of 1,500 or more pounds per acre are not out of reason. In 1947, in the Brown tract at Philema, if all the trees that bore nuts had been collected into a solid block the yield per acre would have been nearly 2,500 pounds. Crowding of the trees in the Brown tract is becoming serious at 11 years of age with a 25 x 25 foot spacing. Alternate-year bearing is becoming apparent and the stand of trees must be thinned immediately. Because of such potential yields and because rather extended storage of nuts of varied keeping quality is now economically possible the future of the chestnut industry in the Southeast is very promising.

The selection and propagation of selected seedlings is desirable as a means of advancing the industry at a more rapid rate. The propagation of selected seedlings offers a problem because of lack of compatibility between some stocks and scions. Since the chestnut is almost completely cross-pollinated it may be necessary to develop special plantings of two or three selections as a source of seed nuts for the production of stocks. Such plantings might possibly produce seedlings of quite uniform and desirable characteristics, but this prospect, is not very promising. Certainly, the evidence points to the conclusion that scion selections must be worked on stocks of the same strains if incompatibility is to be held at a minimum.

There is a further problem in the propagation of varieties on seedling rootstocks in the nursery. Only one propagator appears to be having much success in this art but others must learn it. Topworking of older trees by the inlay bark graft is generally successful and older seedling orchards can be worked over to improved selections without difficulty so long as the stocks are of compatible strains. Time will be required to work out the details of the solution for this problem but they will be worked out.

In the selection of improved seedlings for propagation the strictest attention should be paid to the important characteristics of tree vigor, precocity, productiveness, nut size, attractiveness, and keeping and eating quality, and type of bur opening. These characteristics have been previously discussed but it is well to emphasise their importance. The tree that comes into bearing at an early age seems likely to be more productive in later years. The nuts should be no smaller than 45 nuts to the pound and be attractive to the eye of the buyer. Most individuals prefer nuts with a bright and shining surface free of fuzz and with a fairly rich mahogany or chocolate color. Keeping quality is, of course, of great importance and should be carefully determined. Eating quality is generally good but distinctly superior selections may be found in the future. For the most part eating quality is dependent on the proper curing of the nuts. The type of bur opening is more important than usually considered, as it materially affects the satisfactory harvesting of the nuts. From the commercial standpoint it appears that the most desirable bur should drop from the tree with the nuts still in it but be well split so that the nuts can be readily removed. Such a bur type prevents exposure of the enclosed nuts to the hot sun while on the tree and reduces injurious drying to a minimum yet permits rapid gathering of the nuts in the burs for later mechanical separation. Nuts that drop free from the burs are more subject to injury by drying and require more hand work in gathering. Burs that do not split readily would be more difficult to separate mechanically; and mechanical aids will be necessary for the economical daily gathering of the nuts in commercial orchards.

If is encouraging to note that many of the present new plantings in the Southeast are being made by orchardists rather than hobbyists. Many home owners are planting a few trees but the acceptance of the Chinese chestnut for commercial production by men already growing other orchard crops portends the future success of the industry. The hobbyist has been of great service and should be given full credit for his far-sighted interest in a crop that now has commercial promise, especially in the Southeast. Much experimental work is still needed by both State and Federal agencies and by individuals. This work needs be concerned now more with details of refinement rather than with basic possibilities of the crop.

* * * * *

President Davidson: Mr. Carroll D. Bush, of whom I am sure you have often heard and whom very few of you, including myself, have met, of Grapeview, Washington, will now tell us something about the Marketing of Chestnuts on the Pacific Coast. Mr. Bush.



Marketing Chestnuts on the Pacific Coast

CARROLL D. BUSH, Grapeview, Washington

Mr. Bush: Friends of the Association: There are so many here that I have known through correspondence that I have welcomed this opportunity to say something to you today. I don't think that I will add very much to anything that has been said. I hope perhaps we will have some ideas from what we have been doing on the Coast.

We were in the nursery business near Portland, and during the war we went out of it, but we are working back in trees again[7], and all this time we have been preaching the gospel of nut trees, and we find that we can't preach a gospel unless there is some reward. There is no market for chestnuts in our section of the country, and yet we had quite a few of them around Portland. We could not talk about chestnut trees when there was no market. Buyers there had been offering as low as three cents a pound or not buying them at all, and we, ourselves, had quite a few nuts to sell. So I took a trip up to Seattle and found a commission man there that would take our nuts and arranged with him, and we have sent nuts to Seattle ever since that year and got a very good price. Then a neighbor had me send some of his, and we are still sending nuts.

Introduced on Mid-West Markets

The next year through Carl Weschcke of St. Paul I got in touch with a reliable Minneapolis firm. They evidently had been burned and they were somewhat skeptical. They said if we would send a sample there they would look them over. So I went out and picked up a mixed sample and shipped to Minneapolis, and they said if we could send nuts as good as the sample they could use some.

We began to send them. When we shipped them we made sure we sent nuts that were considerably better than the sample, and the rewards for shipping there were also very good. Then we went on to Chicago, and we have been shipping to Chicago over since. At this time I am out here to find a little more market for some of the nuts that we have in Oregon.

At first we put the nuts in cold storage at about 32 degrees, expecting to get a better price on the Thanksgiving market. We found out that we were making a mistake and that the earliest nuts on the market brought us our best price. So now we are shipping just as early as we can ship.

We first adopted the western cranberry box as being open enough to allow a little drying off and tight enough so that it wouldn't allow too much and yet we didn't get any mold. We were very much afraid of that, because a good many of the California chestnuts had molded on the way to market. Later we turned to the splint bushel basket, and lately we have been in favor of the half-bushel basket. There seem to be buyers who don't like to stock up more than a half bushel at a time, chestnuts being of a rather high price. They dry out too fast.

We found that cold storage above 32 degrees keeps chestnuts in good condition with little dry-out. One dealer in Oregon we know of wraps his cold storage nuts in waterproof paper, keeps them that way clear on into January. A very little mold will develop on chestnuts kept in storage from 32 to 35 degrees, but not enough so we take any precaution. We have had a few batches that people have stood in sacks on damp nights, and they started to mold, especially on the open end, and we find we can kill the mold with Clorox. We have just used a little Clorox in water. We think this would prevent mold from developing on all nuts if they were put through a chlorine bath. We haven't taken the trouble to do that. I might say our walnuts, and filberts have been put through a chlorine solution, and, of course, after a chlorine solution is used you have to put the nuts through water again and wash that off.

We have on our place a nice washer. We have graded the European varieties, which we handle mostly, into three grades: standard, fancy, and extra fancy, by size. All our grading has been done by hand, except we expect to have a simple grader this year.

[Footnote 7: Mr. Bush informed the secretary by letter, early in 1949, that he did not then have any nursery stock ready for sale at his Eagle Creek, Oregon, nursery. From that location about 10 years ago he introduced, under numbers, three selections of Chinese chestnuts grown from seed imported in the early 30's. Two of these, in 1941, were named Abundance and Honan. The Abundance is now considered one of the most desirable varieties from Oklahoma to Pennsylvania, while Honan is slightly less desirable.—Ed.]

"Sweet" Nuts Sell Faster

We have a few "sweets." All of those on our farms are Riehl varieties, hybrids, I think. All of our European chestnuts have an astringent pellicle, heavy with tannic acid. We classify as sweets any of those that have a pellicle that is sweet enough to be eaten. We label these the sweets and mark them as they go into the market. And while, I say, we don't seem to get a better price for the sweets than for the European, they do sell faster. There are some people in the eastern cities that are grabbing these in preference to the large ones. While the large nuts sell very well, I suppose they go to the Italians and Europeans who are used to cooking them, and out on the West Coast nothing but the large nut goes; the larger the better. In the Seattle market we try to send in large nuts.

We also grade out all "cracks" by hand. They mold easily, and we have a lot of cracked nuts in our climate there, but we have been able to dispose of all of these through the Seattle market where they move off very fast and are lower priced.

California Supplies Distant Markets

Last winter we went to California and looked into the chestnut market there. We found them in the Sierras and found them growing in the Coast Range without irrigation, but the largest growers were in the San Joaquin Valley near Stockton. The largest grove was 30 acres at Linden owned by Caesar De Martini. He gave us our best insight into California chestnut growing. He used to grade and package his own, and he still has his cylinder grader. It has three different size holes, one inch, one and a quarter and one and a half. Anything that goes through the one-inch hole is discarded as a cull. That leaves three sizes, the size that goes through the one and a quarter, the one and a half, and the size that goes out the end, which is, of course, a class of jumbos.

All the chestnuts in California, I think, now go to buyers to do the grading and packing much as De Martini worked out. All of the California nuts have to be soaked in water just as Mr. Jones does, as they come to the packer dried out. The largest buyer that we found in California shipped about seven carloads, and he shipped them all over the world, the Philippines, Honolulu, Alaska, and other places where the chestnut hasn't been growing.

Early Autumn Best Marketing Season

Now, I am going to sum up what our experience has been and what we recommend as general from our experience. Your experience may be different. We clean the nuts, wash them, if necessary, grade them; large and small nuts do not sell well together. We would pack in baskets, half bushel for sweets. We are trying to make that half bushel basket the mark of the sweet nut in the markets where we sell, so that when a buyer comes in there and sees a half bushel basket he knows that's sweets. Then we ship as wet as possible, and they dry out on the way. And just as fast as we can get those nuts off the ground we pack them and ship them. Our greatest trouble now is, of course, the imported chestnut. They are beginning to come in in great quantities, and they hit the market in Chicago last year at about the 20th of October, and we tried to beat that line if we possibly can with our nuts, because just the minute the carloads of chestnuts come in on the East Coast the market drops right down.

Without question we could use some of the preparations that we use on filberts to put a gloss on the chestnut, run them through, I think it is a paraffin mixture, put a gloss on the shell and give us a better chestnut in the market, make it look nicer and, of course, make it sell better.

"Stick-tight" Burs Preferred for Pacific Coast

I disagree, I think, with two of the former speakers in regard to the chestnut that falls free from the bur. I would prefer a chestnut that sticks tight to the bur. We have threshers out there that thresh them out. We can pick up those nuts in the bur with a shovel or fork, throw them into the wagon, take them in the wagon, thresh them out. You have a cleaner nut, you don't have to pick around on the ground with rubber gloves that we use, which is easy enough, but it certainly adds a great deal of work as compared to threshing them out easily after they are once picked up.

I thank you.

* * * * *

President Davidson: Thank you, Mr. Bush. We are glad to have that western angle. It is going to be very useful to us.

Next on the program is a paper on the Control of the Chestnut Weevil, the author of which is absent, but I believe Mr. Gravatt is going to read that.



Chestnut Weevils and Their Control with DDT

E. R. VAN LEEUWEN

United States Department of Agriculture, Agricultural Research Administration, Bureau of Entomology and Plant Quarantine, Division of Fruit Insect Investigations.

Failure of the American chestnut to resist the chestnut blight has resulted in the planting of a few blight-resistant species obtained from foreign lands. These foreign chestnuts would now be planted more extensively in certain districts, were it not for the fact that the nuts are injured by two species of weevils, for which heretofore there has been no practical control.

The 1947 season marks the fourth year of the experimental use of DDT for control of the chestnut weevils. During these years our knowledge of the spray and how best to use it has been advanced by conducting laboratory and field tests. Unfortunately, few chestnut orchards now exist in the Eastern States, and the scattered plantings consist mostly of a large number of Asiatic seedlings, some of which had to be top-worked to other Asiatic species and varieties. Many of these trees are grown for ornamental, shade, or timber purposes rather than for nut production. Owing to these conditions and to a series of spring frosts since 1945, it has been impossible to conduct insecticide experiments on an adequate basis of replicated plats.

Although much is to be learned regarding time of application of the sprays and the proper dosage, the use of DDT can be recommended as a standard practice, because it has proved highly valuable in protecting chestnut trees from heavy losses due to the chestnut weevil. It is the purpose of this paper to discuss some of the experiments that have been made with DDT and the observations made on the time of egg deposition.

Nature and Extent of Injury

The worms attacking chestnuts are the larvae of two very similar species of weevils, one larger than the other. The adults are medium-sized beetles having extremely long, slender beaks. With these they drill through the husk of the nuts, making openings through which they insert their eggs into the nuts. From these eggs the familiar worms develop. Weevil injury varies greatly in different chestnut-growing localities. It is not unusual for 50 to 75 percent of the nuts to be wormy, and often infestation reaches 90 to 100 per cent. The small weevil does the most damage, but there are indications that this may not always be true. Because the mouth parts of the adult are situated at the end of an extremely long and slender beak, it can obtain most of its food from beneath the surface of the host plant. For this reason, stomach poisons applied to trees have not been eaten by these weevils, and hence have been of no practical value. As DDT kills by contact, it is necessary only for the body of the insect to come in contact with DDT.

Life Histories of the Weevils

In the vicinity of Beltsville, Md., the adults of the large chestnut weevil[8] leave the soil about August 15. The date will vary, of course, with season and locality. Both males and females soon begin to feed by piercing the burs with their long beaks. Mating begins soon after the weevils collect on the trees, and egg laying follows shortly. The eggs hatch within a few days and the worms develop within the nut. A few of the worms will complete their growth and leave before the nuts fall, but most of them emerge from the nuts after they have fallen. The worms then enter the soil, where they build cells and remain until they change to pupae the following summer. This weevil has a one-year cycle, or one generation a year.

The life history of the small chestnut weevil[9] is somewhat similar, except that in the vicinity of Beltsville the weevils leave the soil late in May or early in June, when the trees are in bloom. Several weeks later the females deposit eggs in the nuts. At Beltsville, egg laying begins late in August and continues for several weeks. After the nuts have fallen from the tree, the full-grown larvae leave them and enter the soil. Earthen cells are constructed at a depth of 4 to 12 inches, where some of the larvae remain for two winters.

The small chestnut weevil completes its life cycle in two years, and a small percentage requires three years, whereas the large chestnut weevil completes its transformation from egg to adult in one year. The large weevils pass the winter as larvae, whereas the small weevils pass one winter as larvae and the second winter as adults. With the few individuals of the small weevil which require three years for transformation, the first two winters are passed in the ground as larvae and the third in the same location as adults. This habit of the small weevil complicates control measures, as one season's spraying with DDT does not reduce the entire infestation of weevils.

[Footnote 8: Curculio proboscideus Fab.]

Proper Time for Spray Applications

Application of DDT sprays at the proper time is very important. An examination in 1944 of many unopened chestnut burs disclosed the fact that eggs of the small chestnut weevil were being deposited many weeks before the burs would open. It was also noted that great numbers of the larvae were leaving the nuts soon after the burs cracked open. Evidently these full-grown larvae had hatched from eggs deposited several weeks before the burs split.

In 1945, 1946, and 1947, cloth bags were tied over developing burs at various intervals during the season to prevent further egg laying in the nuts. At harvest time, the bags were removed and the nuts examined. Occasionally adults were hidden among the spines of the burs and were inadvertently enclosed in the bags; therefore, all nuts in bags containing female adults that might have continued ovipositing were discarded. The data in Table 1 show the approximate time prior to which the nuts were infested.

Because of difficulty in obtaining sufficient burs for bagging, and other orchard conditions, the results of these studies were far from conclusive. They indicated, however, that many eggs had been deposited in the nuts before the burs had reached maturity. They also suggested that the seasonal histories of the two species are closely parallel. At Glenn Dale, Md., and Fairfax, Va., the small weevils predominated, constituting about 69 to 90 per cent of the total numbers taken. At Elkton, Md., only 42 per cent of the weevils were of the small species.

[Footnote 9: Curculio auriger Casey.]

Table 1. Results of studies to determine the time of oviposition of the chestnut weevils.

Nuts Infested with

Date of Total Small Large Wormy Bagging Nuts Chestnut Chestnut Nuts Nuts Bagged Weevil Weevil Year and Orchard Number Number Number Percent 1945 July 9 52 2 5 13 Glenn Dale, Md. Aug. 1 46 4 2 13 Aug. 15 107 18 11 27 Fairfax, Va. Aug. 21 110 22 13 32 Sept. 12 123 63 11 60 1946 July 12 65 0 0 Glenn Dale, Md. July 18 40 0 0 July 26 67 0 0 Aug. 1 71 0 0 Aug. 9 29 1 0 3 Aug. 14 88 3 2 6 Aug. 23 53 18 2 38 Aug. 29 53 23 11 64 Fairfax, Va. July 26 98 0 0 0 Aug. 15 168 0 0 0 Sept. 4 164 139 16 95 1947 Aug. 15 54 5 1 11 Glenn Dale, Md. Aug. 25 38 8 0 21 Sept. 2 24 7 1 33 Sept. 9 42 18 4 52 Sept. 15 56 29 7 64 Sept. 22 90 27 11 64 Sept. 29 143 83 22 73 Fairfax, Va. Aug. 26 35 9 1 29 Sept. 10 58 25 4 50 Sept. 28 50 35 7 84 Oct. 7 217 177 22 92 Elkton, Md. Aug. 21 139 11 13 17 Sept. 4 83 22 25 57 Sept. 18 116 21 35 48 Oct. 1 108 31 44 69

Spray Experiments in 1944

Shortly after adults of the large chestnut weevil first appeared in the orchards in 1944, six trees isolated from other chestnuts were selected for treatment. Five trees were sprayed with from 1 to 5 pounds of technical DDT plus 1/2 pound of sodium lauryl sulfate to 100 gallons of water, and the sixth tree was left untreated as a check. A thorough application of a coarse, drenching spray at a pressure of 400 pounds per square inch was used in an attempt to force the DDT between the many spines of the burs. The DDT used was very coarse, and difficulty was experienced in getting a proper suspension. This formula was used, however, in preference to one which contained other ingredients that might have formed a protective coating over the particles of DDT. Heavy rains prevented later spray applications.

Adult weevils obtained by jarring untreated trees were then confined in screen cages placed over the lower branches of the trees. At the end of each cage was a cloth sleeve which was tied to the limb to hold the cage in place. The treatments used and the results are given in Table 2.

Table 2. Percentage mortality of chestnut weevils placed in field cages on trees at different intervals after they had been sprayed with with DDT, 1944.

Strength of DDT (lb. per Small Chestnut Weevil Large Chestnut Weevil 100 gal.) 48 Hrs. 96 Hrs. 144 Hrs. 48 Hrs. 96 Hrs. 144 Hrs.

1 0 61 100 25 50 100 2 19 69 100 0 34 100 3 4 50 100 0 40 100 4 27 87 100 0 50 100 5 18 50 100 30 46 100 Check 0 0 0 0 7 7

Although the results obtained the first few days in the cages containing treated foliage were somewhat irregular, because of the small numbers of tests made, all weevils were killed within 6 days. The results indicate definitely that DDT is toxic to the adults of both species of weevils. No consistent differences between species were noted.

As the matured nuts dropped from the treated trees, daily collections were made, and one-third of each collection was used as a sample in determining the percentage of wormy nuts. At the time the nuts drop, the holes in the shell through which the eggs were inserted are very difficult to detect. The nuts were therefore held in wire baskets to permit most of the larvae to emerge before the final examination. All nuts not showing exit holes were cut open to find out whether they were wormy. The marked increase in clean nuts after all treatments indicates that DDT is a promising insecticide for use against the weevils. The treatment and infestation records for the sprayed trees and the check tree are given in Table 3, which also includes the results obtained in later years.

Spray Experiments 1945 to 1947

Spring frosts in 1945 destroyed 95 per cent of the crop of chestnuts in the Eastern States. Only six trees of different species and ages in the Government orchard at Glenn Dale, had sufficient nuts for experimental purposes. Applications of a 50 per cent DDT wettable powder in the proportions of 4 and 6 pounds plus 1/2 gallon of summer oil as a sticker to 100 gallons of water were made on August 20 and September 9.

Spring frosts again damaged the orchards in 1946, destroying about 80 per cent of the possible chestnut crop, and leaving only eight trees in the Government orchard that were suitable for experimental purposes. The remaining trees having a small scattered crop were disregarded. A mixture consisting of equal parts by weight of DDT and kaolin 41 was used in the strength of 2 pounds of DDT to 100 gallons of water. The time and number of applications were varied.

Table 3. Results of spray tests with DDT against chestnut weevils, 1944-1947.

Larvae Emerging from Sample Reduction Nuts Small Large Wormy of DDT (per Application in Chestnut Chestnut Nuts Injured 100 gal.) Sample Weevil Weevil Nuts Year Pounds Number Number Number Percent Percent

Government Orchard, Glenn Dale, Md.

1944 1 Aug. 14 533 1896 21 44 42 2 646 402 45 25 67 3 712 421 5 18 76 4 951 814 5 22 71 5 1844 850 10 16 79 0 976 3238 100 76 1945 2 Aug. 20 & Sept. 9 660 434 38 30 57 3 305 285 58 22 69 0 297 1164 61 70 1946 2 Aug. 15 & 30, Sept. 11 621 131 12 9 90 2 Aug. 15 & 30 371 171 23 19 79 2 Aug. 30 & Sept. 11 292 87 21 26 71 2 Aug. 15 & Sept. 11 949 553 190 43 53 2 Aug. 30 1267 1407 98 43 53 2 Aug. 15 1212 3207 66 43 53 2 Sept. 11 368 1832 53 58 36 0 870 5364 134 91 1947 2 Aug. 13 & 29, Sept. 12 4084 3817 234 30 66 2 Aug. 13 & 29 2618 4255 151 52 40 2 Sept. 12 3029 9498 402 79 9 2 Aug. 13 2639 5049 198 51 41 0 974 4714 121 87

Van Reynolds Orchard, Elkton, Md.

1947 2 Aug. 21, Sept. 4 & 18 1153 264 64 14 84 2 Sept. 4 & 18 338 5 118 67 23 2 Aug. 21 & Sept. 18 149 18 59 34 61 2 Aug. 21 & Sept. 4 669 102 12 51 41 2 Sept. 18 324 63 129 77 11 2 Sept. 4 270 303 67 56 36 2 Aug. 21 500 192 127 57 34 0 338 152 118 87

Sprays containing DDT were applied in two orchards in 1947, the Government orchard at Glenn Dale, and the Van Reynolds orchard at Elkton, Md. Spring frosts injured 50 per cent of the chestnut crop at Glenn Dale and 70 per cent at Elkton, and as a result only a few trees suitable for tests were available. The remaining trees were not sprayed. Four pounds of the standard mixture of equal parts of DDT and kaolin were used to 100 gallons of water in all applications.

In Table 3 will be found information on the quantities of DDT used, the schedules followed, and the results obtained during the period 1944 through 1947.

These results indicate clearly the effectiveness of DDT in chestnut weevil control, in spite of numerous discrepancies brought about by the small number and variability of the trees available for the tests. As might be expected, programs of three applications were more effective than those of only one or two. Of the single applications, those put on during the latter half of August were much more effective than those made during the first half of September, presumably because most of the eggs had been laid by the early part of September.

These experiments gave fairly exact information on the relative abundance of the two species of weevils. At Glenn Dale the small chestnut weevil constituted 92 to 98 per cent of the population; at Elkton, 61 per cent.

The matured nuts that fell from count trees were collected daily, and one-third of each lot collected was used as a sample for determining the percentage of wormy nuts. It was possible, therefore, to obtain a rough estimate of the numbers of larvae produced on each tree. In 1946, from 1,863 nuts on a tree sprayed three times, 429 larvae emerged; and from a comparable unsprayed tree having 2,610 nuts 16,494 larvae emerged. In 1947, 1,350 larvae were produced on 9 trees with an average crop of 1,361 nuts sprayed three times, compared with 14,505 larvae from 2,922 nuts on an unsprayed tree. These figures indicate that DDT sprays bring about large decreases in the numbers of weevils and that the proper use of DDT sprays on all host trees over a period of a few years would doubtless reduce the infestation to a point where fewer applications would be necessary for effective control of the chestnut weevils.

Tentative Recommendations

For the benefit of those who wish to try DDT for chestnut weevil control, the following tentative recommendation is made:

Thoroughly apply to all parts of the tree 2 pounds of DDT in 100 gallons of water. For example, use 4 pounds of a wettable powder that contains 50 per cent of DDT, or 8 pounds of one that contains 25 per cent of DDT. Make three applications, the first about 30 days before the first nut is due to drop, and the second and third after intervals of 12 days. Unless the entire bur, especially that portion near the stem end where most of the feeding punctures are made, is thoroughly covered with a film of DDT, the weevils may feed without being affected by the insecticide. In handling DDT, one should use the same care as with such well-known poisons as lead arsenate, Paris green, calcium arsenate, and nicotine.

* * * * *

Mr. Gravatt: I might say that Mr. Van Leeuwen has used only a small section of our experimental orchard, and right near-by would be large sections not used. The weevils are not killed quickly by the DDT, they are somewhat resistant, and so we think quite a number of weevils come over and deposit eggs before they are killed by this DDT, because they don't lose any time getting to work on the nuts. He hopes to have much better results where the entire orchard is sprayed. This year we sprayed our entire orchard twice, and it is a real pleasure to go out there now and gather up nuts and not be eating weevils when we do eat them.

President Davidson: Well, Mr. Gravatt will now give us a talk on Diseases Affecting the Success of Tree Crop Plantings, and I am sure we all are on our toes to hear about that. Mr. Gravatt.

Mr. Gravatt: I only ask a few minutes to show a few slides.

(Slides shown.)



Diseases Affecting the Success of Tree Crop Plantings

G. F. GRAVATT and DONALD C. STOUT

Division of Forest Pathology, Plant Industry Station, Beltsville, Maryland.

Mass plantings of many trees of the same kind frequently result in an increase in the severity of insect pests and diseases. Leaf diseases, for instance, spread quickly through such plantings when weather conditions favor growth of the causal organisms. Plants on sites unfavorable to a specific tree species also are responsible for disease increases. Chinese chestnuts grown on a site where they are subject to early-fall and late-spring frosts will fail. Not only will crops be reduced by the killing of buds or blooms, but the twigs, or even whole trees, may be killed by freezing. The blight fungus develops rapidly on such injured trees and may mislead people into thinking that the blight fungus is the primary cause of the killing.

Still another factor that determines the damage by diseases, and thus the success or failure of nut tree plantings, is the ignoring of soil and fertilizer requirements. Trees weakened by drought, because they are on a site having a soil too shallow for good root growth, are much more subject to attack even by weakly parasitic fungi than those growing on a site with deeper soil. Innumerable dying twigs and branches with fungi growing on them are sent to the U. S. Department of Agriculture or State experiment stations with requests that the disease be identified, when the real trouble is lack of water for the roots. Weak trees are much more subject to winter injury than vigorous ones.

Trees require a good supply of plant food materials and water to produce profitable crops. Tho heaviest bearing chestnut trees we have observed were grown in an irrigated orchard in California and in a poultry yard in the East where chicken droppings actually formed a mulch under the trees. However, if you wish to kill a young chestnut tree quickly, just apply a very heavy application of chicken manure; the point is that trees must become adjusted to chicken manure by gradual applications.

Another way to damage a tree is to keep it growing late in the fall by cultivation and fertilizers so that it does not harden off properly. Many plantings, representing heavy investments, fail because of lack of organic matter in the soil. This is related to water-holding and water-supplying capacity of the soil, and lack of proper fertilizer. Dr. Harley L. Crane and his assistants, in their work with tung and pecan trees, have shown the vital need for certain elements on some soils. Trees weakened by the lack of these elements are early prey for some diseases. The element most frequently deficient is nitrogen, but sometimes boron, copper, or iron is lacking; or the elements are not in balance, because of the excess of some, or the lack of others.

By adjusting the various soil, water, and site factors necessary for a continuous, vigorous growth of trees, many so-called disease conditions are eliminated. Many fungi and viruses, however, will attack trees in the pink of condition; a few of the more important of these are treated in the following sections.

Chestnut Blight

The destruction by blight of the native stands of the American chestnut, and of the small eastern orchard industry based on European and American chestnuts and their hybrids is almost complete. Blight has been found in the planted European chestnut orchards of the Pacific Coast from time to time, but it has been kept under control by eradication. Chestnut trees or nuts from the eastern States, where blight is common, should not be shipped into the Rocky Mountain or Pacific Coast States.

Finding the Asiatic chestnuts resistant to the blight, the Division of Forest Pathology sent R. Kent Beattie to Asia to make selections of chestnuts for introduction into this country. Later Peter Liu, a Chinese collector who worked with Mr. Beattie, continued to select Chinese chestnuts for introduction. These introductions, together with the earlier ones made by the Division of Plant Exploration and Introduction, were grown at Chico, Calif., Savannah, Ga., and Bell, or Glenn Dale, Md. Altogether some 300,000 chestnut trees, of pure species and hybrids, were distributed to cooperators for forest and orchard plantings. (Fig. 1.) These constituted a fine lot of material from many parts of Asia as a basis for selecting the best ones for our use. Private nurseries and State game and forestry departments are now growing these chestnuts and the Division of Forest Pathology has discontinued general distribution of trees to cooperators.

Chinese chestnuts have proved to be the most valuable for forest, orchard and ornamental use. The Japanese chestnut is being discriminated against because of the poor quality of its nuts. Orchardists having mixed plantings containing Japanese chestnuts are advised to top work the trees or remove them, if the seed is to be used for plantings. In fact, for orchard plantings, nuts should be used only from the best individual trees of the Chinese chestnut.

The Chinese chestnut should be planted on sites with good air drainage as it is very susceptible to injury from early-fall or late-spring freezes. Many persons think their trees have been killed by the blight when the primary cause of the trouble was injury to the trunk by freezing followed by growth of the blight organism over the injured parts. This fungus may grow for many years in the outer layers of the bark without doing any material damage to the tree. An important factor in resistance of the Chinese chestnuts to the blight is to keep the trees growing vigorously. Avoid late growth in the fall as this favors fall freezing damage.



Nut Spoilage

In the Southern States one of the most serious problems with some selections of the Chinese chestnut is the spoilage of the nuts. Marvin E. Fowler made a study of this trouble at Savannah, Ga., and found that most of the trouble in that restricted area was caused by a Gleoesporium-like fungus that infects the nuts at the tip.[10] Because spraying experiments did not give control, the more susceptible trees have been removed. In most parts of the South, however, this fungus is not the primary cause of nut spoilage and the limited work so far carried out has not revealed the cause. Part of the trouble may be due to physiological break-down. As individual trees vary greatly in susceptibility to this deterioration of the nuts, orchardists are advised to top work or eliminate the more susceptible trees. Some people have believed that exposure of the nuts to the hot sun while in the bur or on the ground may cause damage. The market for Chinese chestnuts can be ruined by shipping nuts that are partly spoiled by the time they reach the consumer.

[Footnote 10: Gravatt, G. F., and Marvin E. Fowler. Diseases of chestnut trees and nuts. Northern Nut Growers Assoc. Rept. (1940) 31: 110-113. 1941.]

Phytophthora Root Disease of Chestnut

Phytophthora root disease, caused by Phytophthora cinnamomi, is treated briefly here, and interested nut growers can consult the detailed earlier article.[11] Briefly, this fungus is considered as introduced into this country over a hundred years ago. It killed the chestnut and chinkapin growth over large areas in the southern States. Asiatic chestnuts are highly resistant to this disease, and when grown on well-drained soils have not been damaged. Our test plantings of Chinese chestnuts growing in the same soils where susceptible trees of American and European chestnuts were killed, continue to make a vigorous growth. The European and American chestnuts and their hybrids growing in the western States are in danger from this fungus as it has now been reported in the West. This same fungus sometimes kills thousands of young nursery trees of the black walnut, but these epidemics are usually brought on by unusual weather conditions. Poor soil aeration, induced by excessive rainfall and poor drainage, makes ideal conditions for damage to the walnut and other hosts by Phytophthora. Even the very resistant Chinese chestnut roots are invaded by the fungus when the soil remains waterlogged for extended periods.

Brooming Disease of Walnut

A systemic brooming disease, observed on planted walnuts as early as 1917, has been the subject of considerable discussion during recent years, because it has now spread widely into the native black walnut growth. In 1932 Waite published that he had been observing the disease for some 15 years but that "it was unknown on the black walnut in the wild in this country or on planted trees away from the Japanese walnut." The disease has continued to increase in prevalence in recent years and is now widely distributed in native black walnut growth in Tennessee, Virginia, District of Columbia, Maryland, Delaware, and New Jersey. This extensive spread into the native growth during the last 15 or 20 years and the fact that reports indicate that all of the early cases of the disease were found near nursery-grown trees offer some evidence that the disease is an importation from another area or continent into the eastern black walnut zone. From the literature and oral reports, it seems that the disease is now present also in North Carolina, West Virginia, Pennsylvania, New York, Ohio, and Michigan. Surveys probably would uncover the disease among native wild and planted walnuts in other States.

[Footnote 11: Crandall, B. S., G. F. Gravatt, and M. M. Ryan. Root diseases of Castanea species and some coniferous and broadleaf nursery stocks, caused by Phytophthora cinnamomi. Phytopathology 35: 162-180. Illus. 1945.]

Economic Importance and Hosts

The black walnut is a valuable native forest tree, widely but not abundantly distributed in the eastern United States. It is extensively planted as a forest tree. The numerous plantings and natural stands around farm homes, along fences, and in pastures are also very valuable. More and more grafted ornamentals, and orchards of black walnut are being planted. For these the per-tree investment is high.



The ultimate effect of the brooming disease on the black walnut is not known. Dr. Waite stated, "Trees even moderately attacked soon become worthless for nut production." Some affected black walnut trees, however, continue to produce small crops of nuts. Visible symptoms have been known to disappear. In addition, some seedlings, and probably large trees also, are infected without showing symptoms. Such observations indicate the complex nature of the disease. Detailed studies are needed, but at present this Division is not in position to do more than limited, part-time work on the disease.

The butternut, a widely distributed forest tree of minor importance, is seriously injured or killed by this disease. The disease severely damages or kills the Japanese walnut, which has been planted to a limited extent but is of little importance. According to Dr. Waite's report, the Persian, or English, walnut is attacked, but very few trees of this species are planted in the eastern States. Precautions should be taken to prevent the introduction of this disease into areas where it is not now present, particularly the western states.

Symptoms expressed by infected trees are viruslike, and Hutchins and Wester[12] were able to produce the brooming symptoms on a small number of trees by means of bark patch grafts, indicating that the brooming disease probably is caused by a virus.



Description of Symptoms

The entire range of symptoms of the brooming disease has not been determined. Symptoms are recognizable during mid-July but they are most pronounced during September and October. Curling and cupping of leaflets, chlorosis, narrowing and basal tapering of leaflets appear to be associated with early stages of the disease. On severely affected trees there are distinct broomlike growths at branch terminals, along primary or secondary branches, or on the main stem to the ground line (Fig. 2). The broomlike growths are formed by the continuing abnormal development of normally located buds into short, succulent branches. Upright, suckerlike branches appear on primary and secondary branches and on the main stem of the affected tree. (Fig. 3).

The broomed parts usually die back during the dormant period following their appearance. The dead brooms on trees that appear to be healthy during the early months of the growing-season indicate that the trees are infected. Usually the diseased trees, even those severely affected, exhibit normal growth during the early summer months.

Evidence that walnut trees may be infected for a considerable time prior to appearance of recognizable symptoms was obtained when 37 per cent of a total of 300 severely pruned trees exhibited brooming disease symptoms. These trees had looked healthy until they were pruned. Unpruned control trees showed a 4 per cent increase in disease during the same period.

[Footnote 12: Hutchins, Lee M., and Horace V. Wester. Graft-transmissible brooming disease of walnut. Phytopathology. 37 (1): 11. (Abstract) 1947.]

Summary

There is strong evidence that a virus disease is active among certain species of walnut in central and eastern United States. The disease exhibits distinctive symptoms and appears to damage infected trees, sometimes severely, over several growing seasons. Present data indicate that recognizable symptoms of the disease may not appear for some time after infection, unless the host is subjected to severe shock. Thus, nursery stock may be one means of spreading the disease into new areas. It is recommended, without experimental work to back up the recommendation, that walnut nurserymen remove infected trees in the vicinity of their nursery sites.

Investigation of this disease to the present time has been limited. General observations indicate that severely broomed trees produce poor nut crops. Mortality caused by the disease appears to be quite low among black walnut trees. Butternut and Japanese walnut trees are, in general, more severely affected by the disease than the black walnut and many seem to be killed by it, although the killing process is slow. As a result of experience with other virus diseases, orchardists who have only a few infected trees among their black walnuts are advised to remove them. Whether the disease can be kept under control by repeated roguing is uncertain. If an owner has just a few trees of value as ornamentals as well as nut producers, one hesitates to advise him to remove a lightly infected tree until more information is obtained concerning the disease.

This Division will welcome information from persons having experience with the brooming disease of walnut, as it is in a position to do only a limited amount of work on the disease.