which shall replace our now practically extinct American chestnut. The
loss in money value from this timber tree has amounted to millions of
dollars in comparison with which the value of its nut crops is very
small indeed.
"However, we are interested in the nut problem, and whenever any
particularly fine nuts appear we note the fact. We have now a strain of
Chinese chestnut which has not yet come into bearing which we believe
will have nuts as sweet as the old American chestnut, but much larger."
With this forward-looking note we close our report. We have a foundation
upon which to build that is substantial and tried. The pioneering work
of a patient, far-sighted, and distinguished group of workers has shown
us much of what to do and what not to do. It is now up to us, the
farmers, the planters, to multiply their work and continue it.
Side-lights on the 1943-4 Survey
Very many interesting bits of information have been included in the
survey reports; so many that the committee has regretfully omitted some
that hardly seemed properly to belong with the material of a survey,
which after all must have some limits. One such item is from J. C.
McDaniel, of Haines City, Fla., and has a special interest for members
of this Association. He says:
"Perhaps you will be interested in data on one of America's largest
Chinese chestnut trees, even if it does grow in Florida, at Monticello.
It stands adjacent to a lot in which the late J. F. Jones had a nursery
for a short time in the early years of this century, and apparently was
planted at that time, around forty years ago. The trunk is now more than
25 inches in diameter below where it divides 6 feet above the ground.
From this level, the tree branches profusely and has a symmetrical,
rounded crown. It is healthy, not having a sign of the bark disease,
although a native chinkapin 100 feet away is badly infested. It has
abundant bloom and sets heavy crops of burrs but, lacking another
variety for pollination, the number of nuts matured is small. Nuts are
about average size for the species, of typical sweet flavor, and
separate readily from the pellicle. Many of them become infested, before
ripening, with a fungus which rots the kernel, apparently the same one
which infests chestnuts and chinkapins at Savannah and Albany, Georgia.
Mr. Paul Goldberg, of Monticello, the present owner, states that the
tree has been bearing annually during the twenty years his family has
owned it."
This nut-rot among the oriental chestnuts is one of the diseases that
have become troublesome elsewhere. It is being studied and efforts are
being made to combat it. Thus far, so far as we know, no effective cure
has been found. A report upon present progress would be worth while.
Oscar E. Swan, Jr., Tulsa, Okla., reports an enviable situation. He
says: "My nut trees are growing on a farm where more than 30 years of
cultivation have failed to kill the native pecan sprouts. They come up
year after year from the top roots. Since acquiring the place in 1936, I
have allowed the pecan sprouts and the few native walnuts to grow
unchecked except where necessary to cut them out to avoid crowding. The
growth of these sprouts is quite vigorous, and they are ideal for
top-working. I have top-worked a few trees every spring and now have
about 300 grafted trees all the way from 6 to 30 feet tall. Many are too
close together for full grown trees and I plan to thin them. My
problems, so far, are the mechanical ones of top-working. I have settled
upon a modification of the Biederman bark graft, which gives very good
results. After the grafts are well established, the trees get very
little attention except for cutting out the crowding trees. They are
literally growing 'wild', yet the growth has been better than
transplanted trees would have made with the best of care, because the
root systems are well established in a situation which suits them.
"This system of neglect probably explains why I have failed with some
species and varieties such as the butternut and some of the hickories.
Occasionally I am pleasantly surprised, as in the case of some seedling
Carpathian walnuts which, grafted upon some established black walnut
sprouts, came through the severe 1943 drouth in fine shape without
benefit of mulch, cultivation, fertilizer, or watering. The same applies
to the Helmick hybrid. (A two year old tree, a hybrid walnut, grafted
and growing well on black walnut stock, and which Mr. Swan says will
bloom next year.) I have pampered my Chinese chestnut trees with
cultivation, mulch and manure, as they are located in poorer, drier
soil. They were badly hit by the drouth. Some died in spite of the
attention.
"As to varieties, I am far enough south to grow all the standard
southern pecan varieties, although several do not have a long enough
season to mature their nuts. I am trying the northern varieties and, so
far, am well pleased with their growth as compared with the southern
kinds. It will be a few years before I can report on the size and
quality of their nuts."
J. C. McDaniel again: "Source and variety of seed in Chinese chestnuts
have a great influence on the performance of seedlings. Numerous
seedlings from the original Hobson tree began fruiting in their second
season of growth, and half of the ones I have are fruiting during their
fourth season. On the other hand, I have a tree from imported seed which
grew nine seasons before setting and ripening its first burr. The above
data refer to my planting near Hartselle, Morgan County, Ala., and that
vicinity. I have several black walnut trees under observation, native
trees, on which data are not yet complete enough for evaluation."
If any man deserves a bright N. N. G. A. medal, it is A. L. Young, of
Brooks, Alberta. Lowest temperature expected in winter, 45 deg. below;
lowest known, 62 deg. below. Highest expected in summer, 101 deg.. Frequent
drouths? Yes. Hot, dry winds? Yes. Native nuts found plentifully? None.
Sparingly? None. Yet Mr. Young plants nut trees. It is men like that who
have made Canada what it is. It takes more than mere weather to stop
them. The never-say-die spirit of pioneers speaks throughout his report:
"Black walnuts, butternuts, some oaks, hazels and American chestnuts
(Ohio buckeyes) all came through last winter well. However, late frosts
reduced the nut crop. Of these species, filberts are not getting
anywhere. Winkler, I believe, will eventually make a go of it. Heartnuts
got a rough deal last winter, and European buckeye chestnuts were hurt a
little by late spring frosts. Some Manchurian walnuts also got a setback
with spring frosts, and some did not. Carpathian walnuts killed back
quite a lot, so did most of my hybrid walnuts. Hybrid hazels seem
perfectly hardy. Pecans, beechnuts and sweet chestnuts almost passed out
of the picture last winter. Giant hickory from Ontario seems hardy but
particular about the kind of soil and conditions. When irrigated, too
much water will kill them. And this is true also of walnut and butternut
seedlings. I have no acreage of nut trees. I grow seedlings and plant
them wherever I find a place protected from the stock and within reach
of moisture from the irrigation ditch, as this is a desert, cactus
country.
"I always have a stock of seedling trees on hand, and whenever visitors
show any interest, I give or send them fruit or nut trees and a few
perennial flowers. So there are sure to be a few nut trees, some day,
growing successfully throughout Alberta.
"There is more benefit from this northern seed, especially as I am using
a commercial pollen with the hope of getting a hardy white walnut with
possibly a coarse bark like the black to ward off sun-scald in this
climate. They are on their way. I don't know when we'll be eating these
imaginary nuts. However, it is not so long ago that fruit growing on the
cattle range was a dream. I grew the first pears in Alberta, so far as
we know. Now we are insulted if there is not a crop of fruit every year.
I have many seedlings of standard apples, unnamed, that are really
choice fruit, and, of course, a few named varieties that are doing
fairly well. Minnesota has done great work in apple and plum breeding
for the north. We are enjoying some of them right here.
"I am sorry that I have no data on husking, cracking, etc. Really even
the hardiest, best trees bear nuts that, while of fair size, do not have
fleshy kernels, and some have three sections instead of two. Butternuts
are very sweet with fair size kernels. I was surprised, after a long
hard winter, to find the Ginkgo trees still alive and gaining growth.
Credit some or all this result to J. U. Gellatly and Paul Crath for
supplying me with seed, seedlings, and pollen to carry on with. I am
greatly obliged to them and also to George Corsan of Echo Valley,
Islington, who has a wealth of nut interest.
"We have had a mighty dry year here, so, between irrigating and tending
the largest herd of Ayrshire cattle in the prairie provinces, I have
been busy. The town of Brooks is probably the only town in Canada on
straight Ayrshire milk; and the change in Brooks from a box-car on a
siding years ago to the Brooks of today, with its hundreds of healthy
children now on the streets, is the marvel of a man's lifetime."
George H. Corsan, Echo Valley, Islington, Ont.: "Last winter, 1942-43,
was by far the coldest ever recorded. No damage to filberts. A few
inches of twigs were hurt on certain English walnuts. The Stranger
heartnut, a tender variety, passed through unscathed. Persimmons and
pawpaws passed without a bud killed. These are perfectly hardy
varieties. Jujubes passed O. K., but that may be due to the very deep
snows."
Dr. Oliver D. Diller, Associate Forester, Ohio Experiment Sta., Wooster,
Ohio: "You will be glad to know that the experiment station has set
aside some land for improved varieties of nut trees. If you find some
promising walnuts which might be tested in this part of the state, we
should be glad to have you keep us in mind." This is indeed welcome news
and will be appreciated by all growers in this area.
J. G. Duis, Shattuc, Ill.: "A chicken yard is one of the best places to
grow nut trees."
J. U. Gellatly: "I do not believe in selling nuts for seed purposes
except on a very large scale."
J. C. McDaniel: "A neighbor lost some 5 year old Chinese chestnut trees
following a summer drouth on silty loam soil, rather shallow to
hard-pan. It is my observation that deeper, sandier soils (not too
extremely sandy) are best for chestnuts in the coastal plain and other
regions subject to summer drouths. In the mountains where summer
rainfall is more uniform, they thrive also in clay soils."
G. H. Corsan: "Best success in grafting (hickories) has been in juicy,
wet springs. Heartnuts must not be budded until late August (in
Islington, Ontario). Heartnuts must not be pruned."
A. L. Young, Alberta: "There is a demand for young walnuts for
pickling." (Does anyone know the details--when to pick, how to pickle?)
(Note by Ed. Several recipes and methods in Am. Nut Journal now out of
print but indexed by Ed. Copies of this index in his hands and those of
Mr. C. A. Reed at Washington. Also recipes in 33rd Ann. Report p. 95).
Sterling A. Smith, Vermillon, O.: "With me, summer budding is the most
successful means of propagating black walnuts."
J. Russell Smith: "Chinese chestnuts will blight some if
under-nourished." Which includes the wrong kinds of soil, if
uncorrected.
"Does anyone know for sure how to get pawpaw seed to germinate?" Several
have asked this question. The chairman has had the same trouble, so can
not answer. (Note by Ed. See "Nut Puttering in an Offyear" in this
report.)
So far as the correspondence shows, no state or federal department buys
seed on a large scale (with the exception, now, of chestnut seed) from
trees of the better named varieties with which to grow seedlings for
distribution by state nurseries for forest planting. All nut seed seems
to be gathered haphazardly.
W. G. Tatum, Lebanon, Ky.: "A nut tree with plenty of root, top cut back
one third, promptly set, roots protected, stem wrapped, 4 inches, mulch
applied, set either spring or fall, grows for me 99% of the time.
Failures are not worth mentioning if the above conditions are met."
Carl Weschcke, St. Paul, has a dozen or so extra hardy Persian walnuts
by selection from some 12,000 seedlings. Also is introducing the hardy
"Hazelbert," result of crosses between wild varieties and filberts.
"Dip wire screen guards in red lead and they will be good for twenty
years."
Thomas and Stambaugh, among the black walnuts, are, with justice,
entrenched leaders, but it will be well to watch Patterson, Mintle,
Elmer Myers, Eureka, Creitz, Todd, and other promising new ones less
well known. Thomas is more prolific in the south (generally) than in the
north, which indicates that its bloom may possibly be out nearly enough
to suffer in the north from late frosts.
Among chestnuts, the weight of evidence favors Hobson, Carr and
Reliable, though J. Russell Smith says he has something he likes better
than the first two.
Among pecans, Major, Greenriver, Pleas; among filberts and hazels,
Winkler, Jones hybrid, Cosford, Gellatly, Brixnut; among Persian
walnuts, Broadview, one or two Crath varieties, Payne, Breslau; among
hickories, Stratford, Fairbanks, Barnes, Glover, Weschcke. These seem,
so far as the returns show, to have outstanding points of superiority.
In any such survey, injustice is bound to be done to some not fully
reported.
Outside of filberts in the northwest, no northern grown nut can yet be
said to have reached the status of a profitable commercial crop.
(Exception: The narrow pecan belt along the southern terminus of the
Ohio river valley; mostly wild trees.) Dr. A. S. Colby, University of
Illinois says, "The report from the State Statistician at Springfield
indicated a crop of 575,000 pounds of pecans for Illinois in 1943. I
don't know just where they came from." Short crops were reported in
Calhoun and Gallatin, leading nut producing counties. No reports have
been received as to the size of pecan crops in the Kentucky and southern
Indiana portions of the same belt.
The search for better varieties must continue, but it is also altogether
likely that with an orchardist's attention, with cultivation, mulching,
fertilizing, spraying one to three times yearly with Bordeaux and lead
sprays, we might approach the commercial goal more closely with what we
have today. Is anyone treating a bearing nut orchard as well as he would
treat an apple orchard? That's the test.
S. H. Graham of Ithaca, N.Y. says: "The Ohio is commonly regarded as
hard to hull. With a chained tire husker it hulls as well as any." He
rates it for hardiness and a percentage of 90 to 100 for filled nuts,
while Thomas yields only 0 to 90%.
[Illustration: Seasonal Zones Compiled from the U.S. Department of
Agriculture Records, Based on the Average Date of the Last Killing Frost
in Spring]
Juglone--The Active Agent in Walnut Toxicity
_By GEORGE A. GRIES, Connecticut Agricultural Experiment Station_
The problem of walnut toxicity dates back at least to the writings of
Pliny. In his "Natural History," this Roman philosopher stated that "the
shadow of walnut trees is poison to all plants within its compass" and
that it kills whatever it touches.
The first rebuttal to the existence of such a toxicity was forwarded by
Evelyn in the 17th century. This author discussed the high regard in
which walnuts were held in Burgundy as field trees. The roots of these
trees were below the plow sole and thus did not affect either
cultivation nor the growth, of grasses and cereals beneath them.
The pros and cons of the problem have been reviewed several times in the
recent proceedings of the Northern Nut Growers Association. (Greene,
1930; MacDaniels and Muenscher, 1942; Brown, 1943.) That the roots of
walnut trees are toxic to the roots of certain crop plants in direct
contact with them is widely accepted. In nature this toxicity seems to
be limited to plants with tap root systems such as tomato and alfalfa
(Davis, 1923) and those with other types of deep root systems such as
apple trees (Schneiderhan, 1927), rhododendrons (Pirone, 1938), and
privet. This toxicity is exhibited only when there is a direct contact
between the roots of the two plants involved. (Jones, 1903; Massey,
1925). That the wilting observed under walnuts is due to a toxic product
from the bark of the walnut, and does not result from a lack of water,
is substantiated by the fact that the vascular or water conducting
system is discolored for several inches above the point of contact with
the walnut root. This symptom is very similar to that produced by
vascular disease fungi. No such discoloration results from wilting due
to competition for water. This symptom of toxicity has been overlooked
by many workers in the field.
Massey (1925) suggested that the toxic component of walnuts might be
juglone. This idea was further supported by Davis (1928). Today this
concept is widely held. Chemically this substance is known as 5,
hydroxy-1, 4, naphtho-quinone and belongs to a group of strong oxidizing
agents with commercial uses, including tanning agents, medicinals,
poisons, etc.
A knowledge of the physiology of juglone in the walnut is essential to
an understanding of the divergent results obtained by various
experimenters. Juglone, as such, occurs probably only in minute
quantities in the inner root bark, and in the green husks of the nuts.
These regions are, however, rich in a substance known as hydrojuglone.
This compound, the colorless, non-toxic, reduced form of juglone is
immediately oxidized to its toxic form upon exposure to the air or some
oxidizing substance from the roots of other plants. Upon standing in the
air juglone again disappears, being either changed back to hydrojuglone
or broken down into other non-toxic substances.
This sequence of events may be noted in a fresh green husk of a black
walnut. When the fresh husk is cut, the interior is white but
immediately turns yellow as the colorless hydrojuglone is transformed
into the yellow juglone. Upon standing or drying the husk becomes black
as further chemical changes occur. It is impossible to extract juglone
from these dried husks without first reoxidizing them.
It now becomes possible for us to understand some of the discrepancies
in the studies on walnut toxicity. If walnut bark or other plant parts
are allowed to become desiccated, no toxicity may be found. If the roots
of plants do not contact plant parts containing juglone or hydrojuglone,
their oxidizing ability can not produce the toxin. Further the relative
amounts of juglone in various species of _Juglans_ has not been
completely investigated. It does occur definitely in _J. nigra_ and _J.
cinerea_ and has been reported as being in _J. regia_. Other species
need investigation before being included as sources of juglone.
It is known that many plants are not adversely affected when grown under
or near walnut trees. Some of these have root systems too shallow to
contact the roots of the walnuts, especially in plowed ground. Some
plants may send out sufficient surface roots to keep the plant alive in
spite of injury to the deeper roots. The possibility that the roots of
some plants are capable of withstanding the oxidizing power of the
juglone is currently under study.
In early American folklore, the inner bark and the husks of the nuts
were used as a source of a yellow dye for cloth. This yellow dye is
juglone. The ancients also used this method of dying both cloth and
hair.
Another property of juglone is its toxicity to fish. A few years ago it
was a common practice in the South to cut the husks from young nuts and
throw them immediately into a still pond of water. The fish, stunned by
the juglone, would rise to the surface and were collected and eaten. No
one seemed to worry about the effects of such poisoned food on the
consumers.
Juglone is toxic to fungi and bacteria. Of all the medicinal powers
attributed to walnuts by the Greeks and Romans, its use in curing
certain skin diseases including ringworm has held up through the ages
until many today can recall the use of the green husks for control of
ringworms. Brissemoret and Michaud (1917) reported the use of juglone in
clinical cases for the cure of eczema, psoriasis, impetigo and other
skin diseases and concluded that juglone deserves extensive use in
dermatology. To our knowledge the medical profession has not followed up
the possibilities which this substance offers. The author is familiar
with one case in which pure juglone was applied to a persistent ringworm
infection. The infection disappeared within a month after treatment was
begun. Though conclusions can not be drawn on a single case, certainly
this observation lends credence to the medicinal lore of the ancients
and the American pioneers.
During the fall and winter of 1942-43, investigations on juglone were
started at the Connecticut Agricultural Experiment Station in
conjunction with studies of the effect of other plant toxins on the
roots of higher plants. When the toxicity of this oxidizing compound was
established, it was produced in some quantity both by extraction from
walnuts after the method of Combes (1907) and by synthesis after the
method of Bernthsen and Semper (1887). Working on the assumption that
the killing of germinating fungus spores and root hairs are similar
phenomena, juglone was subjected to standardized laboratory tests for
fungicidal value. In a series of experiments, this compound proved to be
equally toxic with the copper in Bordeaux mixture. Such a high degree of
toxicity was deemed worth further investigation, so juglone was tested
as a seed protectant and as a spray in field trials for the control of
black spot of roses.
As a seed protectant, juglone failed miserably. It's toxicity to the
noncutinized surfaces of root tissues was so great that germination was
abnormal and greatly impaired. The injury noted here was apparently the
same as that discussed by Brown (1943) and that which occurs normally in
the field.
In field tests on the control of black spot of roses juglone stood up
well. No phytotoxic activity could be noted on the cutinized stem and
leaf surfaces. On the variety George Ahrens, juglone gave equal control
with 2-1/2 times as much 325 mesh sulfur, the standard control for this
disease.
SUMMARY
1. Under certain conditions walnut trees exhibit toxicity to those
plants whose roots are in intimate contact with the roots of the walnut.
2. This toxicity is due to the action of juglone, the oxidized form of
hydrojuglone, a non-toxic substance occurring in the inner bark and
green husk of walnuts.
3. Juglone has been used in dermatology to cure various skin disorders
including both bacterial and fungus diseases.
4. As a seed protectant, juglone is unsuitable because of its inherent
toxicity to the non-cutinzed root surfaces.
5. Laboratory and field tests have shown juglone to be an excellent
fungicide
LITERATURE CITED
1. Bernthsen, A. and A. Semper Ueber die Constitution des Juglons
und seine Synthese aus Naphtalin. Ber. d. deutsch. Chem. Gesellsch.
20: 934-941. 1887.
2. Brissemoret et Michaud Sur une nouvelle classe de medicaments de
la peau; les quinones peroxydes. Jour. pharm. et chim. 7e ser.
16:283-285. 1917.
3. Brown, Babette I. Injurious influence of bark of black walnut on
seedlings of tomato and alfalfa. Northern Nut Growers' Assn., Proc.
1942:97-102. 1943,
4. Combes, R. Sur un procede de preparation et de purification des
derives oxyanthraquinoniques et oxynapthoquinoniques en general, du
juglon et de l'emodine en particulier. Bull. soc. chim. 4c ser. 1:
800-816. 1907.
5. Cook, Mel T. Wilting caused by walnut trees. Phytopathology
11:346. 1921.
6. Davis, Everett. The toxic principle of _Juglans nigra_ as
identified with synthetic juglone, and its toxic effects on tomato
and alfalfa plants. Amer. Jour. Bot. 15: 620. 1928.
7. Greene, K.W. The toxic (?) effect of the black walnut: Northern
Nut Growers' Assn., Proc. 1929: 152-156. 1930.
8. Jones, L. R. and W. J. Morse The shrubby cinquefoil as a weed.
16th Ann. Rpt, Vt, Agr. Expt. Sta. 188-190. 1902-03.