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.
[Illustration: Figure 1.--F1 hybrids between the Chinese chestnut and
the American chestnut.]
+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.
[Illustration: Figure 2.--The brooming disease of walnut. Severe
brooming on Japanese walnut.]
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.
[Illustration: Figure 3.--Brooming disease on black walnut. Ascending
type, upright, sucker growth is typical of this species.]
+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.
+Persimmon Wilt+
Persimmon wilt is very destructive to the native persimmon (Fig. 4). It
is caused by the fungus _Cephalosporium diospyri_, which was described
in 1945 by Bowen S. Crandall[13]. The fungus grows in the wood of the
trees, producing discolored streaks. Most trees are rapidly killed,
with yellow, wilted leaves making quite a contrast to the normal green
trees.
This disease was found in spots from central Tennessee south to the
Gulf, east into Florida, and up the coast into North Carolina. The
American persimmon seemed to be in danger, as this quickly killing
disease appeared to be spreading. The limited work on this disease was
discontinued because of the war and the transfer of Mr. Crandall to
Peru. However, this summer Mr. Crandall and the senior writer spent two
weeks surveying some of the old infections and nearby territory, and
were pleased to note that the disease had made very little progress into
new territory. On several small areas where the disease was present some
six years ago practically all of the larger trees had been killed, but
some new small trees were coming up. At Chattanooga National Park, where
the wilt was rampant about six years ago, it is continuing to kill
trees, but many new ones are coming up. No northward extension of the
disease in Tennessee or North Carolina was noted in the limited time
spent in inspection.
[Illustration: Figure 4.--Small persimmon trees killed by the wilt.]
What does the disease mean to the grower of grafted persimmons, both
native and Oriental? The Japanese or Chinese persimmons do not grow as
well on their own roots, although they are quite safe that way as these
two species are very resistant to the wilt. In the East, most of the
Oriental persimmons are grafted on American root stocks, and trees in
one case were killed by the wilt fungus getting in on the susceptible
root stock. No attempts to control the wilt have been made, and these
recommendations are based on procedure with other diseases and on
knowledge of the spore production of this fungus. An owner of a valuable
planting of grafted trees in a region where the disease is present
should watch his trees for the first indication of trouble. The planting
will be safer, if there are no nearby native trees; and if native trees
are growing nearby and cannot be removed, they should be given a general
inspection. Prompt removal and burning of any infected trees found is
advisable. The fact that usually fungus spore production does not take
place until after the tree has been dead for a while makes the prospect
for control better than with most diseases. Care should be taken not to
bring in scions or trees from infected areas.
Most members of the Northern Nut Growers Association have only a few
grafted persimmon trees, usually located outside of the infected zone
and therefore in little danger. Persimmon scions and trees should not be
shipped from infected to healthy regions. The disease has not been
reported in nurseries, but it could occur there because it attacks small
trees.
[Footnote 13: Crandall, Bowen S. A new species of +Cephalosporium+ causing
persimmon wilt. Mycologia 37 (4): 495-498. 1945.]
+Thyronectria Disease of Honeylocust+
Honeylocust is widely distributed both in native stands and in
plantations. Some farmers plant this species or leave native trees in
their pastures for the pods, which have a high sugar content, up to 38
per cent. J. C. Moore, of the Alabama Agricultural Experiment Station,
reported preliminary tests indicating a per-acre yield of livestock feed
equal to that of oats.
In many areas the growth of honeylocust is seriously affected by a
canker and twig fungus, _Thyronectria austro-americana_. The disease
often kills many twigs and branches and sometimes results in death of
the tree. In most areas it causes only slight injury. Bowen S. Crandall
and Jesse D. Diller have made a few observations on the prevalence and
damage by this disease, which is present from New England south into the
Gulf States and west into the Great Plains States.
The fungus causing this disease is morphologically somewhat similar to
the chestnut blight fungus, having two spore stages produced in
reddish-brown pinhead-size fruiting bodies on the bark. Cankers are
produced on the smaller branches, but they usually are not noted until
some of the affected ones wilt and die. In the exposed outer wood of a
branch cut above or below the canker there are reddish-brown streaks
several inches long, indicating that the fungus has grown in the
vascular system.
As no control experiments are known, recommendations are based on
general knowledge of sanitation. If an owner has only a few valuable
planted trees, he should cut off the diseased parts a foot or more back
from the lower edge of the affected bark and burn or bury them in the
soil. If he has many trees scattered over extensive pasture areas, it is
questionable whether any action other than elimination of the more
susceptible trees is justified. We will be interested in the results
obtained from control work.
* * * * *
President Davidson: Now I will turn over the chairmanship of the meeting
to Mr. Chase, who will have charge of the Round Table Discussion.
Round Table Discussion on Chestnut Problems
SPENCER B. CHASE, Presiding
_Panel of Experts_: Max E. Hardy, Carroll D. Bush, H. F. Stoke, G. F.
Gravatt, J. C. McDaniel.
Mr. Chase: Gentlemen, in the last hour and a half we have heard perhaps
more about chestnuts from qualified specialists than we will ever hear
in any meeting of ours, and we requested each one to withhold questions
until this point. So now we will have some questions from the floor,
please.
Mr. Slate: What is the present status of breeding chestnut species for
timber purposes?
Mr. Gravatt: The prospects are coming along. We have one cross between a
none-too-promising Chinese chestnut and an American chestnut, with a
good bunch of hybrids and they are different from other hybrids. It
looks like they will stand up against blight. They will have blight
canker growth from 10 feet down to the ground but it doesn't go into the
cambium region. It is too early to evaluate the hybrids, but they do
have the upright form and rapid growth of the American chestnut.
Now when we take these first-generation hybrids, cross them back with
the Chinese and get more resistance, as we have done so many times in
the past, we lose that rapid and more upright growth habit of the
American chestnut. But we have a lot more work to do before we are ready
to say anything final on this question.
Dr. Arthur H. Graves, formerly at the Brooklyn Botanic Garden is now
consulting pathologist at the New Haven, (Conn.) Experiment Station. We
have been working with him and partially supporting his chestnut
breeding for a good many years. He has a lot of hybrids up there. We
expect to have something later, but have nothing to release yet.
A Member: Do you have any sprays to control diseases and insect pests in
the tree that when they go into the soil won't destroy our ground
friends?
Mr. Chase: Mr. Gravatt?
Mr. Gravatt: I don't know what insects you are after, in the first
place. We have a lot of trouble with Japanese beetles. Around
Washington, Dr. Crane's and my plantings there would be defoliated if
they weren't sprayed for Japanese beetle control, and it is the same way
with filberts.
A Member: The same sprays have a tendency to work against most of the
pests, do they not? Of course, DDT will take one, the arsenate of lead
takes another, Black Leaf 40 another, but if we had a spray that we can
use around on--well, not limited to the chestnut--that would be
neutralized in the earth. Now, we have a good deal of friendly bacteria
and insects in the soil that we want to keep.
Mr. Gravatt: I would say that I am a pathologist, and insect work is out
of my line.
Mr. Chase: Does anyone else have a comment on that? Dr. Cross, did you
hear the question?
Dr. Cross: I didn't get his question.
Mr. Chase: Would you stand and repeat your question?
A Member: Is there a spray that we can use for combating the insect
pests of our trees that when it is washed off and goes into the soil
doesn't kill our soil friends. We have the friendly bacteria in the
soil, as well as insect and worm life. Do we have a spray that will be
neutralized as it hits the soil so we can spray the tree and not kill
our lower friends?
Dr. Cross: Sorry, Mr. Chase, that's beyond me.
Mr. Gravatt: You are thinking of arsenate of lead poisoning the soil
where you keep on spraying with it?
A Member: Yes.
Mr. Gravatt: I think DDT may build up a little in the soil, but it is
broken down, isn't it, Dr. Crane?
Dr. Crane: Yes, DDT is broken down and it is not a fungicide and it is
not a bactericide. It is an insecticide that kills insects through
affecting the nervous system, according to my understanding of it. I am
not an entomologist, but that's what the entomologists say. So far we
haven't any evidence to my knowledge of any build-up of DDT in soils
that has been detrimental. I don't know what the situation would be if
DDT was used to the same extent as arsenate of lead. It was not uncommon
for some growers to put on anywhere from 6 to 15 lead sprays in a season
in order to control codling moth, as they used to do in certain apple
orchards, particularly in the West.
I was talking to Dr. Van Leeuwen just a day or two before I had to leave
for the meeting, and he is not ready yet to say anything about it, but
he has already tested some very promising insecticides as far as the
control of weevil is concerned. This DDT and some of the other new
insecticides are very easily decomposed, and, of course, that's one of
the disadvantages of them. Under certain climatic conditions they would
need to be less readily decomposed to give control over a longer period.
I know that we have not had enough experience to know all about those
new spray materials.
Mr. McDaniel: There has been one instance reported where DDT _in the
soil_ was injurious to fruit plant growth. That was Goldsworthy's and
Dunegan's work on strawberries. Where they used large amounts of
technical DDT in the soil, they found that it inhibited the growth of
the strawberry plant. I believe that's the only instance I've heard of,
where soil application of DDT hurt growth of fruit plants. Benzene
hexachloride, and some other chlorinated hydrocarbons, and parathion
actually appeared to have a stimulating effect on the berry plants.[14]
Mr. Frye: Why would there be any more danger of affecting the soil in a
chestnut orchard than there would in the apple and peach orchard by
spraying seven, eight and ten times? That's the only question that
arises with me.
Mr. Chase: Let's get back to chestnuts specifically, now, gentlemen.
Mr. Kays (Oklahoma A. & M. College): Since I don't come from a chestnut
area, my impression of the nut samples supplied by Mr. Moore of Auburn,
was: "I'd like them if they had salted them." I am wondering if it
wouldn't have affected their rancidity if they had been treated--salting
material added, prior to or in the process somewhere along the line.
Mr. J. C. Moore: I'd just like to say I have tried putting salt in the
water, to boil the nuts with salt, and then I have tried shelling them
and sprinkling salt, and I find that salt does not add anything to the
flavor. Tasting the nuts raw, I, too, get the impression salt is what I
want, but I haven't been able to add it satisfactorily. I don't say that
it cannot be done.
Dr. MacDaniels: Mr. Chairman, in view of the whole situation of chestnut
incompatibility of stock with scion, what would be the position that we
in the Northern Nut Growers Association can take in advising people what
kind of chestnuts they should plant? Should they be encouraged to try to
get grafted trees? What should be our position?
Mr. Chase: Mr. Stoke, would you care to comment on that?
Mr. Stoke: You are asking me to stick out my neck, and it seems as if I
have always done that. The Chinese chestnut is in the Johnny Appleseed
stage, in my opinion, and we are investigating to find out the best
varieties, that is, the best specimen, best performance, best quality,
best in blight resistance, growth, and other qualities and when we
winnow out all we have and arrive at the best, we are going to
find--now, this is just my personal opinion--I will say that for myself
I'd rather have one acre of the best selections we have budded or
grafted--asexually propagated, than five acres of seedling trees as a
financial good bet, because I say that one acre of our very best produce
virtually as many nuts as five acres of seedlings. I have trees from
seed I imported through the Yokahama Nursery Company, and I think it
came from Korea. The nuts run very small, and compared with those I am
sure the others will pay much better, and I think it would be profitable
to pay three or four or five times as much for your trees if you get
good trees of good, known varieties and grafted or budded.
Don't misunderstand me. We shouldn't ask the American public to wait
until those can be furnished, because they won't wait, and they
shouldn't. But I say as a commercial proposition, to plant trees
commercially, I would exercise caution and I would encourage my
customers to exercise caution unless they are willing to follow up and
do their own top working later on, and a Chinese chestnut doesn't top
work as readily as a black walnut.
Mr. Chase: I don't believe that's quite the answer he wanted. The
comment that I think Dr. MacDaniels is after is what position should the
Northern Nut Growers Association take in regard to planting seedlings or
planting grafted stock. Is that the point?
Dr. MacDaniels: Yes, it seems to be seedlings against grafted stock.
Mr. Stoke: May I answer? I don't think the Northern Nut Growers
Association should take _any_ position. They should present the facts
and let the buyer decide. I don't think we need to go on record, and I
don't think we should. There is too much diversity of opinion.
Dr. MacDaniels: Between ourselves--and this is not an academic
question--we get continual inquiries regarding the Chinese chestnuts and
what should they plant and where can they get the trees, and so forth.
It isn't good enough in most of these cases to write several pages
explaining what the whole situation is, the _if's_, _and's_, and
_but's_. But I just wonder what the opinion is of the people who know
best in this regard. Who has a good orchard of 20-year-old grafted
Chinese chestnuts? Where are they? I don't know: I am asking for
information.
Mr. Chase: Dr. Drain, are those trees you have grafted trees or seedling
trees?
Dr. Drain (University of Tennessee): They are seedling trees. They have
produced a rather nice quality nut, and we have enjoyed propagating
seedlings from them. That's really all we know. We haven't grafted any.
Mr. Chase: Mac, would you care to comment on this?
Mr. McDaniel: I am ashamed to say that at present we have no grafted
chestnut trees on my own north Alabama farms. We have about 50 trees
that are 8-year-old seedlings from imported (Chinese) nuts, growing next
to a commercial peach block, and find the production quite variable on
the different trees. I am aiming at top-working most of these with the
named varieties, beginning this year. At present I can't answer the
question of seedlings vs grafted trees. I have been advising people who
are interested in trying them in Tennessee that _for their first
planting_ (to test the adaptability of their locations) they can get the
seedlings generally quite a bit cheaper than the grafted trees. With the
experience we have had over the State and the high mortality of trees,
both grafted and seedling--killing of the tops and in some cases the
whole tree--the seedling might be best economically _to begin their_
experimenting with. I am _not recommending_ that anyone plant seedlings
commercially, but just in a small way for trial. They are well worth a
trial anywhere peaches are doing well. When we find a _suitable site_,
then is the time to think about using the more expensive grafted trees.
Pres. Davidson: I just want to give a little bit of my experience along
that line. Way back in 1934 I planted a few seeds that I got from Amelia
Riehl. They were nuts of the Riehl hybrids. [Ed. note: Mostly
American--European crosses.] She named one Dan Patch and another
Gibbons. They are now about 13 years old. Each of them is bearing burs
this year. They have borne burs, a few of them, in the past, but no
nuts. So far in 1948, the burs that have fallen to the ground, of
course, have no nuts, but whether the burs that are still on the trees
have nuts I don't know. I want to know whether those trees are
normal---whether a hybrid of that kind is likely to be sterile or not.
That's another matter that might be discussed. Anyhow, you are taking a
chance, no question about that, when you plant seedlings.
Mr. Stoke: Mr. Chairman, if you will pardon me for saying one more word,
here is a suggestion I will make. Now you can check for yourself. The
whole thing hinges on whether we can get _permanent_ grafts on the tree
and get the characteristics in the grafted tree that the parent has--in
the good selected tree. Now you take the reports sent us by Mr. Hemming;
you take the reports of the station at Albany--of individual trees in
those plots. You take the worst trees and you will find they are nothing
but boarders. You take the best and you will find they are very
profitable. You take the average and it will fall somewhere in between.
Now, why keep a lot of boarders that don't pay--free boarders--or why
use run-of-mine seedlings, _if_ we can graft successfully--and some
people like to dispute that--and produce nothing but the best? And you
can check it on any of those tables. [Mr. Hardy's paper.] We have a few
tables in our former Reports. You can check it and figure it out for
yourself.
Dr. Crane: To clear up this situation I wanted to ask Mr. Hardy a
question, and then I wanted to make a statement. In this report from the
1938 and 1940 planting at Albany, Georgia, in the Brown tract in 1947
there were 188 trees that bore crops, but that planting consisted of
274 trees planted in 1938 and 60 trees planted in 1940. Why weren't
those 274 trees plus those 60 trees represented in the 100 with the
yield records of 1947?
Mr. Hardy: Dr. Crane knows the answer, so I will let him ask the
question and answer it, too.
Dr. Crane: In 1936 we planted 1,000 trees of the same Peter Liu
selections on the Station farm at Beltsville, Maryland. They were of the
same number and letter designations as others that were distributed to
cooperators. Out of the thousand trees that we planted on the Station
farm some of them came into bearing at four and five years after
planting. But the nuts were small in size and were not much good. With
one or two exceptions, out of that planting there were none bearing
satisfactorily to suit us after ten years. In 1945 we applied the ax,
because a Chinese chestnut tree, from an orchard standpoint, if it's not
in bearing in ten years after planting is not worth keeping. We haven't
got time to wait. So out they came. And in addition to that we have had
other trees that have done the same thing.
Now, out of this 274 plus the 60 at Albany, Georgia, we have three trees
that we now figure are good enough to be raised to a variety status,
plus possibly two or three more. Now, you can figure your percentage of
good trees when you plant seeds.
Dr. Overholser: Mr. Chairman, may I ask a question, whether these three
seedlings to which they propose to give variety status have been
propagated in sufficient number that they are able to give distribution
in other areas.
Mr. Hardy: Dr. Overholser, they are not available yet in quantity. That
same answer is part of the answer I wanted to make to Dr. MacDaniels.
The present situation in the chestnut industry is that there are very
few nurserymen who know how to propagate nursery grafted trees
successfully. There is going to have to be quite a bit of work done on
that. If some of you here know how to do it, I would like to know,
myself. There are a lot of nurserymen who would like to know, according
to the reports I have, how to graft or bud a nursery chestnut tree.
As long as the situation is that way I would say to recommend seedling
trees because of their low price, but--and every grower who has trees
can fall in line with this--the seeds should be from properly culled-out
orchards of the highest type, leaving nothing in there producing nuts or
pollen but what is the highest type. I think all of you who have more
than one type of chestnut in your plantings should cull them all down to
the pure _Castanea mollissima_. I don't mean by cutting out the whole
tree, but go ahead and top-work them. If they won't take the top, _then_
cut them out. But if you can top-work them and the grafting is good, you
can increase your planting of good trees in that manner.
The improved quality of the seed will improve the quality of seedlings
going to the buyer, and the chances of a higher percentage of good
seedlings showing up will be greater. I think it will improve the
industry through a period of years.
Dr. MacDaniels: I think I agree with his position. In fact, that's
exactly what we are telling the inquiries that come in: At the present
state of our knowledge, better try seedling trees.
But I didn't hear anybody get up and say they had an orchard of
20-year-old grafted chestnut trees. I have tried to get them, I have
grafted successfully, I suppose, 7 or 8 different varieties on many
different Chinese stocks that I have bought, or had given to me, and
numbers of grafted trees. I have nothing left. They grow fine, 7 or 8
feet the first year, 3 or 4 feet the next year, then they go along for a
while and then they die. In other words, there is an unsolved problem
there, so that it seems to me at the present state of our knowledge we
had better admit it and say, "If you are an amateur, you better get the
best seedling trees that you can and wait awhile."
Mr. J. C. Moore: I just want to give some data on some of the class work
at Auburn with Chinese chestnuts. We were studying Chinese seedlings,
and we attempted to bud those Chinese chestnut seedlings, and on some of
the larger seedlings we top-worked. We had some 3-year-old seedlings,
and we top-worked the limbs. We put in patch buds, and we put in T-buds
or shield buds, and in practically every case on some of the trees the
buds stuck beautifully.
In June and again in August, with another class, we had the same
results, either with T-bud or shield bud or patch bud. Some of the
seedlings wouldn't take the buds at all. I can't think why one seedling
would take 100 per cent of the buds and another seedling growing right
by it wouldn't take any buds.
Mr. Weber: The oldsters here will remember Colonel C. K. Sober, one of
our former members who propagated what he later named the Sober's
Paragon chestnut. It was a grafted tree and apparently it was grafted
successfully on native stocks, and it grew until the blight got it.
Dr. MacDaniels: I am not talking about European or American, I am
talking about Chinese chestnuts.
Mr. O'Rourke: It may affect the nursery industry. The nurserymen are
looking to the Northern Nut Growers Association, Federal bureaus and
State experiment stations to guide them in the propagation of desirable
trees. We know now that the Chinese chestnut is becoming quite
prominent, is becoming quite popular in many sections of the country,
and many nurserymen are now getting requests to supply the public in
their states with Chinese chestnuts. They, in turn, would like to know
what they should do. If they sell Chinese chestnut trees which have been
propagated vegetatively and they only grow five, eight, 10 or 15 years
and then die, it's going to come back on the nurserymen. They should
like to know whether they should do that or whether they should rely
upon seedlings which they can develop into pure lines as best they may.
Now, that really is a serious question. I am wondering from what Mr.
Hardy has told us today if it may not be an understock problem, and if
it is an understock problem--if there are certain strains of understock
which are compatible with certain scions, possibly we should ask for
some investigations, some more research to be done in this direction.
Then possibly, on the other hand, we should also ask that certain
investigations be carried out so that we will have some idea of the
inheritable characters that may be "fixed" through seed selection. I
really think that this seed selection should be very seriously
considered, and that nurserymen in particular and the public in general
would benefit greatly by such consideration.
Mr. Hardy: Mr. Chase, may I make this suggestion: I think it is
something that a number of individuals could try, perhaps they should be
backed up by agricultural institutions, either Federal or State. We are
all interested and concerned with stocks, and I think a large part of
our trouble with grafting chestnuts is a stock-scion relationship.
We have some top-worked trees 13 years old that are just as healthy,
just as normal as they can be. We have some top-worked trees of various
ages below that. The graft-union is good; they are just as healthy and
continue to be as productive and vigorous as the parent tree. Where
there is incompatibility we run into difficulties very shortly. To a
large extent I think we are involved with two problems in the trouble
with incompatibility, or perhaps I should say the dying, of grafted
trees. One is a stock-scion relationship, the other a mechanical
problem.
I think there are these two types of incompatibilities. Now, as to the
mechanical part--that can be improved through developing the art of
grafting or budding, whichever works out best. The other will require
quite a lot of study, perhaps the development of certain strains of the
root stocks for certain scion varieties.
I have made this suggestion to two or three. I have started the work
myself by putting out with friends two or three or four trees. After
they get up to a size where I can top-work them, I will top-work with
two varieties. Perhaps I will put Nanking and Kuling on two trees at one
particular place. Two or three miles away I will put Kuling and Meiling
on two others. At another place I will put Nanking and Meiling. I will
get reciprocal pollination, because the chestnut is necessarily
cross-pollinating.[15] I can then plant seedlings from both parents,
each pollinated by the other. Then by grafting those varieties onto
those seedlings stocks I can find out whether there is any reason to go
into the work of developing seed orchards of two varieties whereby
Meiling pollinated by Kuling may produce the best, most vigorous, most
uniform seedlings on which Kuling can be propagated. And by propagating
Kuling on such seedlings--the seedlings of such inheritance--we may get
100 per cent of good grafts.
The industry needs a lot of help, and I think it is a matter of time
until those things are worked out, but it is going to take time and
money and plenty of good effort to work out that problem. I think it
probably should be worked out.
Mr. Bush: I don't like the word "incompatibility", and I hardly believe
in it, and I presume most of you know that. I have Chinese on European
stock, and it has been there for 20 years or more, _grafted high_. I
have Chinese on Japanese grafted _under the ground_. I think a good deal
of our damage is done from wind, from cold, and from sun on the graft
_just above the ground_. I suspect that grafting at that point is what
is the matter with many trees in the TVA plantings and others that had
low survival. Of late years when I did the grafting (in the last five or
six years) I cut the stock underneath the ground and stuck the graft
under the ground and seemingly I got far better results. Some of those
graft failures showed up. I laid that largely to mechanical damage, and
again with the Japanese, particularly, I laid it on the time when the
sap comes up. Call it what you will, but the timing of the growth of the
two trees is different and we had trouble there. I have grafted some
very widely different kinds of chestnuts on the tops of other chestnuts,
and am getting them to grow. When we see the break start, we take a twig
from below and break and put it above, cut through the cambium and nail
it on and they will heal over and the defect disappears. So, again, it
seems to be mechanical.
Mr. McDaniel: I believe from observations on a number of trees,
particularly Dr. Richards' in West Tennessee, that a large part of our
so-called incompatibility in this State is due to winter injury _to the
stock_. So what Dr. Richards meant, evidently, was that he was rather
successful in getting a "take" from last summer's propagation but the
stock then failed below the union this spring. I saw his trees, and they
had the typical discoloration of bark and the dying of various bark
areas--these girdling the whole tree in a number of instances. [See
Richards' paper in this report.] I would agree in general with what Mr.
Bush has just said, but there are certain other instances in which we
think the only word for what we see is "incompatibility."
Mr. Slate: What are the prospects of planting those low-grafted trees
rather deep?
Mr. Bush: I think that if the roots started to die the grafted tree
would start a root above the graft. The sap is going up from the root.
It will go down and the root will start above the graft and go out above
the graft, thus getting the tree on its own root.
Mr. Stoke: Since we got onto grafting, do you mind if I say a word? Here
is a four-branch, top-worked specimen that I chopped off and brought
with me. This first tree limb was still alive and had nuts on it, the
second was dying and a third dead. This fourth union was still alive,
but it was badly damaged, too. That's Illinois 31 -4 on Japanese. Here
is another graft of Illinois 31 -4 on Japanese in a small tree, and if
that's poor union, I am no grafter!
Mr. Hardy: Mr. Stoke, may I ask you this: Is this [small graft] on the
same tree as this? [Indicating larger tree first referred to.]
Mr. Stoke: No. Those four grafts, you see, all went bad. This one is in
perfect condition. But I am having a hard time keeping that Illinois 31
-4 alive. I had a union on _mollissima_ three inches in diameter and as
perfect as this, two years ago. Last year it began to bulge at the point
of union. The top wasn't feeding back to the root, and this year it is
in bad condition,--foliage very small and it put on a very full crop of
burs which will never mature, and it's going to pass out. It is about
four inches in diameter now.
Last year to try to beat this thing I cut out the crown of a small
_mollissima_ at the below-ground level and put in several grafts of this
same Illinois 31 -4, and I got a nice growth, at least four feet high.
When I dug it up to transplant it--it was right in my garden--I found I
had a large callus more than an inch and a half in diameter at the union
but no roots. I reset it, and I haven't ventured to see whether it was
all right or not. This spring I tried again.
I have four little trees, one as high as my head, the others smaller. I
grafted each one on branch roots just as they lay in the ground. Didn't
dig them up and they grew nicely, and along in July I went around and
spaded them deeply and thought perhaps that would produce roots. About a
week ago I examined one. I have a magnificent callus but no roots yet
above the union. What the ultimate results will be I don't know.
With that particular hybrid I want to try one more thing. I want to grow
seedlings of the European chestnut, cut them below the ground, graft
Illinois 31 -4 on the root and it may make a union that will not fail,
because the European is a very robust grower, and by being grafted under
the ground the stock will be away from blight organisms.
[Editor's Note: Mr. C. A. Reed is naming this variety (Ill. 31-4)
"Colby" in honor of the originator, Dr. Arthur S. Colby.]
Mr. Hirschi: I would like to say I put on hybrids similar to that
Illinois 31 -4 and they grew the first year, and just made a bulky knot
right at the point of union and died the second year.
Mr. McDaniel: What was that combination?
Mr. Hirschi: That was _mollissima_ stock.
Now, speaking about the varieties--this is in Oklahoma--I have tried
practically all the older varieties and I have tried some Abundance
grafts this last year. I have some Abundance grafts that are two years
old that are producing. They have the most vigorous growth of anything,
and in our climate we have to have vigor.
I grafted a lot of the Abundance scions on Hobson seedlings. I started
out to grow an orchard from Hobson seedlings, and I found out that out
of 50 splice grafts of Abundance that I put in Hobson seedlings in 1948,
forty-eight grew, and they were put on rather late, in April. That's a
little late for us. I have the idea--I don't know whether I am right or
not--that if the Abundance proves out as our best variety, we can grow
seed for stock of the Abundance and then graft the Abundance back on the
seedling from Abundance. If there is so much to this incompatibility, I
should overcome it by doing that very thing.
Personally I think it is a crime that thousands of trees--almost
millions--are being put out by nurserymen as seedling trees, and if you
will note in their price lists they have "6 to 12 inches" and "12 to 18
inches", "2 to 3 feet" and "3 to 4 feet." I venture to say that those
are probably all the same age. How would you like to plant some of those
12-inch trees? Somebody is going to get hurt!
Mr. Bush: I'd like to say that you can propagate the Chinese chestnut by
layering if you want to, and that will put it on its own. Put a wedge on
it or girdle it and keep it damp through the summer.
Pres. Davidson: I think Dr. MacDaniels' question is still not answered.
I do think that if a nurseryman sells a seedling he ought to definitely
_say that it is a seedling_ and not merely that it is a
"blight-resistant chestnut," or something of that sort. He should
actually tell the public what he is selling.
Now, then, there seem to be reasons why in some instances a man is
justified in planting seedlings when it comes to Chinese chestnuts, but
when it comes to the black walnut or filbert or some of these other
things, they are still selling seedlings without labelling them as such.
I think we should be on record against that practice, because it takes
us five or six years, or ten years sometimes, to find out that we have
been gypped, and it is so easy to gyp the public when you can't find out
about it any sooner than that.
Mr. O'Rourke: I quite agree with Mr. Davidson that the nurserymen should
state that a seedling is a seedling when it is a seedling. And I am sure
Mr. Hirschi will corroborate that the American Association of Nurserymen
is exerting all the influence they can to that end. Is that right, Mr.
Hirschi?
Mr. Hirschi: Yes.
Mr. Bregger: I would like to ask, if planters for some years yet will
have to rely on seedlings, is there a chance that from certain parents
or certain varieties we can get a larger percentage of good seedlings
than from others? How much has it been studied and is there a known
result from the parent trees in the percent of what their seedlings can
do?
Dr. Crane: I wish I could answer that one. It is a matter of time, to
find out the seedling characteristics reproduced by a certain
descendant. But we know that there is a difference in _uniformity_ of
trees in the way they grow, but as far as bearing is concerned, and the
type of nut produced, we haven't had enough time yet.
It's just like this: We have made selections for rootstocks in which we
have selected trees that were good, strong and vigorous--the most
vigorously growing trees that we have known about, and yet at the same
time produced a small nut or medium-sized nut that we could use for the
production of rootstocks. And we have made progress on that, and we have
demonstrated that there is a very marked difference between the
graftability or budability of seedlings from certain parent trees. We
have demonstrated that some varieties are much easier to propagate than
are others. But as for the proper combinations of stock and scion, we
still haven't got enough data to recommend any. We know that there are
differences, but it is going to take quite a long while, at least four
or five years or more, before we know.
Now, there is just one other thing that comes up on propagation. We have
found that if you bench-graft and make the graft into the transition
zone between root and top just like the old method that the apple
propagator used when he piece-root grafted and then plant deep, you can
get a hundred per cent of the grafts to grow. In such cases the scion
may root and the top will be on its own roots.
Well, there are a lot of these tricks to learn as time goes on. I don't
think that we should worry too much about this graft union problem. We
know that this Carr variety is a bear-cat. It is the one that gave us so
much trouble. When we tried to propagate that one we had a real, nasty
cat by the tail. But on the other hand, in answer to Dr. MacDaniels'
question if we go out to Dr. J. Russell Smith's plantings up at Round
Hill (Virginia), we can see a lot of the oldest grafted trees that I
know of anywhere in the country, and the unions are just as smooth and
just as slick as anyone would want to see. They are not 20 years old; I
don't think there was ever a _mollissima_ chestnut grafted 20 years ago.
The first grafting that I know of was about 15 years ago, maybe 18.
Mr. Stoke: In 1932.
Mr. R. C. Moore: Thomas Jefferson grafted European chestnuts.
Dr. Crane: No, I am talking about Chinese chestnuts. We didn't get in
any Chinese chestnuts until 1906. We have this problem of
incompatibility or graft union trouble, in apples, but do you hear
anybody hollering about it? We have it in peaches, plums and cherries.
One of the most important diseases they have out in the Pacific
Northwest and California on Persian walnuts, is what is called "black
line disease." We mustn't get excited about graft union failure. That
has been used, in my opinion, by a lot of people, to discourage the
propagating of grafted chestnuts. There are thousands of people in the
United States who are spending good money for seedling trees, and some
of them are going to get stung. We in the Northern Nut Growers
Association are going to have this thing backfire on us, just as true as
I tell you. I know there are some nurserymen today that are planting
unknown chestnut seeds, and they are selling the trees as Chinese
chestnut. They are planting seed out of mixed orchards, too, that have
_C. seguinii_ and _C. henryi_ and _C. crenata_ trees in them. The _C.
crenata_ Japanese has been introduced in the United States for over 70
years and it has never made the grade.
You know, there has been many a thing that has been promoted in the
United States--big for a few days and then she backfired, and then it
took the industry 50 or a hundred years to recover. You can sell people
gold bricks once, but you can't sell them gold bricks _all_ the time!
Mr. McCollum: Last year after Mr. Hemming's speech--you know, he is the
nurseryman who sells seedlings over on the Eastern Shore--I asked him if
he had been selling those long enough to have heard from customers.
"Yes," he said he had, "all satisfied." Now, I don't know anything about
that.
Dr. Moss: I am not an expert. They say an expert is someone who, the
more he studies, knows less about practically nothing at all. That's a
good deal my shape. I planted before the war Chinese seed in Kentucky
and a good many of those put on burs in the nursery row. I gave them
away in the community. Out of the whole bunch, some of them 20 feet
tall, I know of one outstanding nut in that bunch and it's off by
itself, apparently a self-pollinizer[16], and puts out a crop of good
nuts.
Dr. Cross: I should like to ask Dr. Crane if it would not be possible to
investigate the situation in China rather than wait to work this out.
Certainly, the Chinese have sufficient knowledge of grafting and
propagation to have been working on this long ago, and since these came
from there, let's look into that phase of it.
Dr. Crane: I did investigate the situation in China when I was there.
Unfortunately in China, although it is one of our oldest countries and
longest civilizations, they don't do much grafting. They grow their
trees from seed, but they have certain seed trees that they select their
seed from, and within a community, within a valley, you will have a
certain type of chestnut. They call them varieties. They are not
varieties. That's the situation. Most all of them are different, but
they have accomplished the fixing of certain characteristics.
Now, in South China the nuts are larger in size, they are stronger
growing trees than they are in the North. I think that we will find that
that's the situation in this country. The Chinese chestnut is one that
does have a high heat requirement, just like pecan, and grown under
conditions where they have high heat they are bigger in size and make
more growth and probably they come into bearing sooner.
But I didn't see anything grafted in China, and I was all over the
country from the most northern parts to the most southern parts where
chestnuts are produced. I could make a lot of observations myself, but I
had to talk through interpreters, and sometimes you couldn't tell what
the interpreter meant. But as near as I could tell, they were all
seedlings. When he would tell me there was such-and-such a variety, I
would ask him what it meant in English. He didn't know. When I found
how they were propagated I found they planted the seed. When I found
where they got the seed it was from a certain seed tree.
So we have within the valleys what they call varieties, but they are not
varieties, only seedlings grown from certain seed trees.
Now, with the Japanese, on the other hand, the situation is different,
because they propagated by budding and by grafting. I got a number of
the Japanese publications of propagation methods and their stocks, and
so forth, translated into English, and their problems are just the same
as we are going through right here now. They propagate true varieties by
asexual methods, but the Chinese do not to any extent at all.
Dr. Cross: Have the Russians got any?
A Member: That's the question I ask. Do we have any seed trees in this
country that are better than other seed trees?
Mr. Porter: Could the gentleman tell us whether the Chinese graft _any_
chestnuts.
Dr. Crane: Yes, they do so, I was told.
Mr. Porter: Well, the industry spends a lot of money, so do other
people, and so on, in a proper way to investigate that. Why don't you
find out where in that country they have been doing it?
Dr. Crane: I didn't see any grafted chestnut trees over there.
A Member: You said they grafted, and then you say, "I didn't see any."
Dr. Crane: That's quite right, and I talked to their best horticultural
authorities that they have. Practically all of it is produced by seed
and not by budding or grafting. It is just exactly as I said with the
Persian walnut. China has no varieties of Persian walnuts, although
sometimes you will find some farmer that will bud or graft his trees.
Mr. Porter: They graft up on the limb?
Dr. Crane: Yes, sir. Once in a while you will find one. They have a few
real horticulturists. I met one man over there that would compare very
favorably with Liberty Hyde Bailey.
Mr. Stoke: Dr. MacDaniels asked for concrete evidence. He wanted to know
where there was an orchard with 20-year-old grafted Chinese chestnut
trees. They haven't been planted that long, but I would like to give him
concrete evidence in my own experience.
In 1932 I got scions from the Department, got what ultimately became
known as the Hobson, from Jasper, Georgia. I grafted a tree in my front
yard which is still bearing nicely, and in fact I have got two grafts on
that tree about four feet from the ground, and it is very nice with
perfect union. At the same time I grafted a Carr right at the side of my
house that also has a perfect union about the same height from the
ground. I grafted a scion sent me by Dr. Morris as Morris' best (which
was pretty poor), and it is still living. At the present time I have
perhaps five Carr trees that will average six inches or more in
diameter. The oldest is the one by the side, of the house. The rest of
them were grafted about 1935. One out of those five, when it got to be
about six inches in diameter, in fact, about three years ago, it went
bad. It is girdled and dead. It was grafted about as high as this table
from the ground. The others are sound, and you'd find it very difficult
to find where they were grafted.
I have Hobson, perhaps a dozen trees anywhere from six to 16 years old,
and I have not had a failure on a Hobson that really was once healed
over properly and got to bearing, not one. That's concrete evidence,
Doctor, and that's all I wish to say.
Rev. Taylor (Alpine, Tenn.): Mr. Gravatt was about to answer a question
about our seed trees, wasn't he?
Mr. Gravatt: Would you repeat that question?
Rev. Taylor: Are some seed trees better than others in the high per cent
of good seedlings they produce?
Mr. Gravatt: Well, McKay has done some work and published it to show
that on seedlings of certain trees you get higher percentage of bud
takes than on others.
Mr. Chase: I think the question is a little confused. I think what you
are after is, are there parent seed trees from which seed can be planted
that would produce a good quality of seedlings.
Rev. Taylor: Yes, of good productive seedlings. No grafting to it.
Mr. Chase: I think that was answered. Apparently there are.
Rev. Taylor: Apparently there are in China, as Dr. Crane brought up.
Mr. Chase: He further brought up that those things are in the process of
being tested here now, and he hopes for some information in--what was
that?
Mr. Gravatt: We had Professor Beattie over in Japan, China, and Korea
for two or three years, and he found in Japan that there were certain
selections there, certain grafted varieties that they used for seed
stock. We imported those into this country. We were getting ready to go
ahead with the Japs. We also brought in a hundred varieties of Japanese
chestnuts. But the Japanese varieties didn't do well here. What would
produce well over in Japan didn't produce well here. But a number of
those scions that we grafted in 1932 and 1933 are still living. We have
had very good success with top-working chestnuts in our orchards. We
have some grafts there of pure Chinese chestnuts top-worked on some
worthless Japanese. Some of those have been there for 12 and 14 years,
with perfect unions. But we do receive a number of reports of trees
dying from blight and various other and sundry other causes and when we
examine them quite frequently these have died back to where the trees
had been grafted.
Rev. Taylor: I could enlarge on that question just a little bit to tie
in with what Mr. O'Rourke said. If the nurserymen are going to propagate
seedling trees for the trade for some time yet, where should they be
advised to obtain their seed to get the best possible seedling trees?
Mr. Gravatt: In a lot of our regional distributions we sent out
mixtures. In other places we would send out related seedlings, as "MY,"
"MZ," or "MAX," to different individuals. We have advised all
nurseryman, all of our cooperators, to eliminate the Japanese; eliminate
the hybrids. It gets down to pure Chinese. We have also advised again
and again to take out the more worthless trees and propagate seed from
the beat. But there are a lot of hybrid seeds with mixed parentage going
into nursery trees.
Mr. McDaniel: How many people are going to take out trees now when they
can sell the seeds for at least 50 cents or maybe even $2.00 a pound?
Mr. Gravatt: That's it. However, you take any of those Chinese trees
over there at the Eastern Shore Nurseries, for example--nuts from all 19
of them have been sent over here, and they are all good eating. I have
been over a lot of the seedlings of Hemming's trees. Mr. Hemming has
several hundred at his own place. I have been over other orchard
plantings. There is lot of variability among those seedlings. They are
not as uniform as the parent tree, for some reason. Why, I don't know.
Mr. Chase: Mr. Howell, as a nurseryman, has propagated the Chinese
chestnut tree. Would you care to make a few comments? Mr. Howell has
Howell's Nursery in Knoxville and at Sweetwater, Tennessee, and I
believe has some of Mr. Gravatt's early seedling trees and has produced
a great quantity of seedlings.
Mr. Bruce Howell: A good many years ago we got from the Department five
trees, and they grew and have all borne good nuts, and all chestnuts we
have propagated since have been grown from seed from those five trees,
and most of them are pretty good. One is a small nut, and among more
recent seedlings we have got two of them that don't bear at all, or
haven't so far. Now, we have got a bunch of them where they were set
several years ago in nursery rows. At each end of each row the trees
there bear very nice nuts, and when you get out through that row, the
crowded trees don't bear at all.
I think those seedlings and those trees practically all make fairly good
nuts and some of them excellent. I have got some samples. About six
years ago I got a pound of imported Japanese I planted. The third year
they bore and they have done very well, and all of them are about the
same size chestnuts. They are as good as any _after_ they are roasted or
boiled. That's about all. A good many years ago, I guess 30 years ago, I
grafted Paragon chestnuts, and they did well until the blight.
Rev. Taylor: Does anybody else have this trouble? In North Central
Tennessee we usually have a warm spell about the Middle of February,
plowing time. We expect it every year. And then these Chinese chestnuts
are the quickest trees to let the buds swell, and the bark softens up
all the way to the ground on the young ones. Then we nearly always have
a pretty hard freeze, afterward. So, for several years after our
experimental planting was set out there they would get killed clear to
the ground next year. Is that something others have the same experience
with? How do you go at correcting that?
After our trees got to be three or four or five inches in diameter they
didn't kill back that way. The bark seemed to be tougher.
Mr. McDaniel: That's very common experience in Tennessee and, I might
say, in north Alabama.
Rev. Taylor: Nothing you can do about it?
Mr. McDaniel: On some sites it is not nearly so bad as it is in other
locations. A northern or eastern slope with good elevation seems to be
best.
Mr. Frye: I have had some trouble and maybe, had a good education about
frost pockets. If you get them in high elevations you escape that. I had
that trouble two years ago. I got some Chinese trees from Dr. Smith, set
them out. They were his best seedlings, three of them, and they started
beautifully. I transplanted them. Just about that time they got nipped
off. Did that three times and failed to come out the third time.
Pres. Davidson: One other remedy for that that I remember reading about,
I am not quite sure in which of our Reports--maybe Mr. Becker was the
author, and that is this: He said that he cultivates until August after
which he plants cover crops, and he sows cover crops that grow and they
hold back this vegetative growth in the late part of the year, and it is
really the late vegetative growth that causes the destruction. After he
adopted that plan he had very much less winter killing in his
plantation. That might be one way of helping the situation.
Mr. Hardy: We have had some killing. Usually in the second year or the
first year after we get killing down to the ground, if we will keep the
stock pruned back to one shoot that one will make sufficient growth,
become hardy enough to withstand any cold, or perhaps sun scald. Also
wrapping the trunks of the trees with newspaper helps to prevent the
variations in temperature, which in our section is what causes the cold
injury. We don't have sufficient cold to cause absolute low-temperature
injury, but we do have sudden drops just as you do in Tennessee,
apparently, and wrapping with paper does help iron out those changes.
Mr. McDaniel: Wouldn't you suggest the paper wrap in the summer as well
as the winter and spring?
Mr. Hardy: Yes.
Mr. Stoke: It is not only the planter of the trees that has sorrows
along that line, but the nurseryman does also. I had some nursery
seedlings growing on flat land, and they looked all right, passed the
winter. When I went out to graft them I found that on these small stocks
anywhere from the size of a lead pencil to the size of a finger, the
cambium was discolored. It wasn't black nut brown. Any attempts I made
to graft those failed, and yet many of those same trees grew on. They
were stunted somewhat for a year or two, and they left a brown ring at
that annual growth.
I would say that the best guarantee against that kind of thing is to
plant your chestnut orchards--and the nurseries--to plant on land that
is well air drained. _Select the same site as you would for peaches._
Mr. Chase: I will say that we should have allowed more time for
discussion. However, we have used up our alloted time for this period.
Supper is at six o'clock, and we are due back here at 7:30. I don't know
how you folks feel about this little session, but I certainly did enjoy
it.
[Footnote 14: --Goldsworthy and his associates published several items
along this line in 1948 issues of +Plant Disease Reporter+. His October
15, 1948 item reported a similar result of 25% technical DDT (with 75%
clay) inhibiting growth of seedling peach roots on 1-year budded Elberta
trees. As low as 25 pound per acre application affected growth in quartz
sand cultures, whereas with certain soils, no significant difference was
noted until an 800 lb. per acre level of the DDT was reached. It was
surmised that possibly some unknown constituent in the technical DDT was
responsible for the suppression of new root growth, and consequent
slowing down of top growth. In the case of Blakemore strawberries, and
also with peaches, this effect has persisted for at least two crop
years. Goldsworthy and Dunegan say, "How many other economic crop plants
may be injured is unknown, but it appears certain that some caution is
necessary in the promiscuous use of the chemical on ... plants, either
as ... sprays or as soil additions...." In these experiments, of course,
the DDT-containing material was in direct contact with all the roots.
Spray residues ordinarily would be present only in the surface layer of
the soil, and should have much less effect on tree roots in that
case.--J. C. McDaniel.]
[Footnote 15: --Dr. McKay of the U. S. D. A. found one tree only about
2.5% fruitful to its own pollen.--Ed.]
[Footnote 16: --There is a possibility of pollination from American
chestnut sprouts in his vicinity.--Ed.]
Let's adjourn.
(Whereupon, at 5:30 p. m. the meeting was adjourned, to reconvene at
7:30 o'clock p. m. of the same day.)
+Evening Session+
President Davidson: The meeting will come to order, please. We first
have the pleasure of hearing from Dr. C. A. Moss of Williamsburg,
Kentucky, on Greetings from a Kentucky Nut. Dr. Moss.
Greetings from a Kentucky Nut
DR. C. A. MOSS, Williamsburg, Kentucky
I am glad to see all of these beautiful ladies here this evening. We
just had dinner, and I presume I should make an after-dinner speech. I
have always wanted to attend a Northern Nut Growers Association
convention. I am more or less of what you might call a convention addict
and speak on any occasion on slight provocation. I attended a convention
at Quebec earlier this year, and after that I went on to Rio de Janiero
in South America and attended another convention, but this privilege of
being able to attend the Northern Nut Growers Association tops all the
rest.
I am reminded of the tale of the man who rushed into the sheriff's
office in Texas, and his gun was smoking, and he says, "I have killed a
man." The sheriff said, "Who did you kill?" "Oh," he says, "I don't know
his name. He is one of these after-dinner speakers." "You are in the
wrong room," the sheriff said. "Go back in the hallway three doors to
the right to the bounty room. They pay $5 a head for those."
My family fortunes, if there be any, were founded on nuts. My father
when he was 16 years old was raised on Straight Creek near Pineville,
Kentucky, some hundred miles away from Lexington, and they gathered up a
wagonload of the old chestnuts, he and a hired man on my grandfather's
place, and they took an ox team and took them to Lexington to peddle
them out. It took them three weeks to make the return trip.
I come from Whitney County, Kentucky. It was named after old Colonel
Whitney, the man who built the first brick house in Kentucky. It was in
the fall of the year, and the mortar was freezing, and they mixed
whiskey with their mortar to keep it from freezing.