fungus trouble. The pecan scab is the most typical fungus parasite of
the pecan. It attacks the leaves, fruit, etc. It attacks the vessels or
veins of the leaves and frequently enters by means of aphis punctures
which break the skin so that there is no doubt but that this particular
disease is favored by an aphis. We have investigated this disease quite
carefully and carried on a series of spraying experiments for some three
years and there is no doubt about our ability to control it. It can be
prevented by spraying with Bordeaux mixture. You never can tell how many
sprayings will be required. It may take three to ten sprayings to
protect the nuts. The leaves are grown mostly within a month--the leaves
are pushed out within thirty days and you can spray those leaves and
protect them. The weak point in the treatment is that the nut of the
pecan grows steadily from the time it starts to way into September. This
makes a hard problem in spraying as the nut keeps expanding and forming
a new and unprotected surface for an unreasonably long season and they
are susceptible to scab attacks all the time, so you have the problem of
spraying the nuts all summer. The spray does not stick very well on the
nuts. The result is that we advise dodging that parasite by planting the
non-susceptible kinds; it is much better and cheaper. It is certainly an
encouraging thing that you can plant good varieties, that do not scab
badly, and which at the very most require but two or three sprayings to
protect them entirely, and in a great majority of cases, no spraying at
all. Those already are the great nuts in cultivation, like the Stuart,
the Schley and the Frotscher. Most of those good varieties will be
occasionally attacked by scab because of a wet season, just as a variety
of apple which is very resistant to apple scab is occasionally attacked
by that disease.
The pecan has quite a number of leaf-spot fungi and most of those we
have tested by spraying. These experiments have been made in the
nursery where it is more convenient to spray and where the necessity is,
perhaps, a little more pronounced, and there it is, undoubtedly, a
proper practice to spray and fight out the pecan leaf diseases. Bordeaux
mixture is the thing to be used on all occasions. The pecan resists
copper poisoning almost as well as the grape and can be sprayed with
safety.
If a pecan tree has crown gall don't plant it. All nursery trees should
be rejected in planting if they show signs of this disease. The pecan
has fungus root-rot and various wood rot fungi besides the leaf
diseases. It also has several other troubles more or less serious.
Occasionally in the pecan groves you will find these remarkably white
mildewed nuts. That gives way to spraying. Another disease is an
internal spot on the kernel which Mr. Rand has been working on and which
seems to be due to a fungus. We don't know how to prevent that yet. The
pecan has a fungus attacking it that is very similar to the bitter rot
of the apple. The pecan anthracnose looks like the bitter rot, has the
same pink spore masses and you will be able to recognize it. That may be
prevented by spraying, but it is, fortunately, not a serious disease.
The northern nut grower will not have so much trouble with that, as it
is a southern disease. Here is a physiological trouble that causes
blackening of the young nuts on the inside. It appears to me to be due
mainly to wet weather, but I don't know its exact nature. It came
primarily on a pecan raised in the semi-arid section of Texas and
brought into South Carolina, and by the way you can get as much trouble
in adapting trees from the western to the eastern United States as in
bringing in trees from other countries. In parts of semi-arid Texas the
trees are supplied with moisture by sub-irrigation and when we move
those pecans to the humid East we get almost as much non-adjustment as
when we bring in foreign things. I would suggest that these pecans from
western Texas are the very ones to take to Utah and California rather
than those from the eastern part of the United States. They are adjusted
to dry seasons with moisture at their roots and you will get the best
results from them when grown under irrigation.
I will now take up the walnut, _Juglans nigra_, the common black walnut.
There are twenty species of fungi which are known to attack it. Quite a
good many of these attack the twigs and cause them to die, and probably
half are leaf diseases. One, commonly called white rust, a disease of
the leaves, attracts mycologists in collecting, but it has never been of
serious economic importance.
Now, as to the butternut, _Juglans cinerea_. It has about nineteen
species of fungi known to attack it, but probably many more will be
found when the nut is thoroughly studied.
_Juglans regia_, the cultivated Persian walnut, has only about twelve
species of fungi recorded from it in this country. There are,
undoubtedly, more to be found. Of these fungi the walnut bacteriosis,
caused by a bacterial germ is more important than all the rest of the
parasites put together we can easily say. The California walnut
bacteriosis has turned up at various points in the East. The twig blight
form of this disease is also prevalent in various states. The walnut
blight or bacteriosis is therefore to be figured with in planting the
Persian walnut in the East.
* * * * *
PROFESSOR SMITH: Is it worse or better here than in California?
PROFESSOR WAITE: There have not been enough walnuts grown here in groves
to allow the disease to accumulate--to have a fair test for that,
Professor Smith. I don't believe we know; but it is, undoubtedly, a
parasite of our native black walnuts. It occurs in Texas and Louisiana,
and I think we have it in or near Buffalo, N. Y., and in New Jersey, so
if I were planting extensively I should expect that disease to be
serious. That would be my forecast of the matter. The humidity and the
cloudy weather in the East ought to be more favorable to the disease
than the climate of California.
MR. JONES: For that reason I should think the disease would work fast in
the Gulf Coast.
PROFESSOR WAITE: Yes, those specimens of yours seem to show a very
serious condition.
We must not pass over the chestnut without noting that there are thirty
species of fungi attacking it, and that does not include the new one,
the bad one, the chestnut bark disease.
The filbert blight belongs with the diseases of the European grape and
sweet cherry. The filbert is an example of a European plant introduced
into the eastern United States attacked by a native parasite which
almost drives it out of cultivation. In fact, there are so few filberts
in cultivation even now that if we were trying to plan a spraying
experiment on them we would not know where to find a plantation suitable
for carrying on the experiment. If any of you know of any such
plantations I would like you to let me know about them.
THE CHAIRMAN: We will have some in two or three years.
PROFESSOR WAITE: Here is a sample of the filbert fungus taken from our
pathological collection. It shows the mature fruiting bodies of the
fungus and it also shows that the twigs are killed. This fungus is
known as _Cryptosporella anomala_. It was described as _Diatrype
anomala_ by Peck of Albany, N. Y., but was afterwards found to belong to
another genus. There have been two or three articles published on it,
the best one probably by Humphrey in Massachusetts. I have an abstract
of that which can be copied in the proceedings, if you wish.
(See Appendix.)
The fact that this _Cryptosporella_ is related to the black knot of the
plum is an interesting feature; and that it attacks the growing canes
during the growing season and fruit during the fall and winter. He
suggests the treatment of removing all the infected branches during the
fall and winter. I would add to that, complete eradication of all
diseased branches of the host, and they are rather easily seen, in the
fall as soon as the leaves are off--then a thorough spraying with strong
Bordeaux mixture, at least 5-5-50, preferably stronger than that, of
course burning all the material that you cut out. One is at a
disadvantage if there are wild hazelnuts in the neighborhood. How to
handle that problem I am hardly prepared to state; perhaps, by
eradication of the wild hazelnut in the vicinity.
THE SECRETARY: I think that would be impossible in most regions.
PROFESSOR WAITE: Mr. Kerr had his growing on the eastern shore on an
island where there are no wild hazelnuts and they were not attacked by
the fungus.
A MEMBER: They are all dead now.
PROFESSOR WAITE: The number of sprayings during a season is an
undetermined question. It will be necessary, probably, to spray two or
three times. You can certainly protect the two-year wood in that way by
making a fall spraying and a spring spraying. This will keep them
thoroughly covered with Bordeaux mixture but whether or not three or
four sprayings are necessary remains to be tested.
THE CHAIRMAN: Are any varieties of European hazels immune?
PROFESSOR WAITE: I have not studied them enough to answer that question.
I don't know. They all seem to go down. Perhaps Dr. Deming can answer.
THE SECRETARY: I don't know.
PROFESSOR WAITE: I think that is all I want to say, except one thing,
and that is about the physiological aspect of these, diseases. I touched
upon that phase in discussing the matter of environment in the
introduction of foreigners to places where they are not adapted. In some
particular seasons and circumstances even the native trees suffer. One
type of injury which has caused great trouble with the English walnuts
and pecans, and also with apple trees and has also caused trouble with
our native red oaks, is freezing when the trees are in a non-resistant
condition. There is an example of this within three minutes' walk of
this building. Here are the climatic and temperature conditions that
bring about disaster, particularly if preceded by a dry season. Let us
start with a dry season. The season of 1911 was conspicuously dry in
this locality and the adjacent states of Virginia, West Virginia and
Maryland, but about the first of September the rains came. Up to that
time even the native forest trees such as oaks and chestnuts showed the
stress of lack of moisture very seriously and were somewhat yellow and
pale looking, mainly from water and nitrogen starvation. When the rains
came the wilted trees all greened up, every tree in the parks brightened
up, and we had fine growing conditions until October and no cold weather
up to New Year's. It was warm that fall and even on New Year's day the
warmth was noticeable. On the 12th of January we had the record cold
temperature for this locality in the history of the weather bureau,
except one year. We had fifteen or seventeen below zero and it was as
low as thirty-eight in low spots in the Potomac Valley in West Virginia.
Those trees had never been fully shocked into winter conditions. The
cambium growth and sap flow had not been stopped and the physiological
changes needed to get the trees ready for cold weather had never
occurred. They were not ready, not only as to the bark, but in the trunk
and wood. The result was that the trees were seriously injured, the less
matured twigs died back, and the trees were frozen on the trunks down to
the ground line. In the freeze of 1904 in New York I was surprised to
find that the peach trees were not all killed. They were frozen through
and through and yet the trees did not die. The question of winter injury
hinges not alone on low temperature, but it also depends on the
condition which the tree has reached when the cold strikes it. Now, to
tell you still further about what that cold wave did, I will ask you to
look at that row of red oaks near the Smithsonian which I just alluded
to and see the big ribs of dead bark where the cambium layer has been
shocked, and checked in other places. You will find these trees ribbed
and ridged to about half way down the row. Those trees are subject to
special disadvantages; they lack subsoil drainage and they have an
excess of manure draining down through the paving stones. They have an
excess of nitrogen and lack of drainage. The subsoil is a heavy clay.
That brings up another thing that I want you to notice in regard to
winter injury. Plant not only hardy varieties, but select localities
with good subsoil drainage. The walnuts and hickories, belonging to the
two great families of juglans, and the oaks and chestnuts, want good
subsoil drainage. Where the underlying rocks are vertical the conditions
are ideal. They do not like a heavy clay subsoil, but do best where
water and excess nitrogen can get away.
The general summary I want to make is this: Nut trees have a large
number of fungus parasites. In a few cases the native fungus parasites
attack European or Old World species and varieties to such an extent as
to make very serious problems, so much so that they can not be regarded
as solved, the walnut bacteriorosis and filbert blight being examples of
these. On the other hand, most of the native fungus parasites of our
native trees are not to be feared as enemies of these trees, not only in
the northeastern United States where this body is endeavoring to further
a good cause, but over the whole eastern United States. These parasites
in some cases may be serious enough to justify spraying and other lines
of treatment, especially in the nursery. On the other hand, considering
the nature of nut trees and considering the results of work on the pecan
scab, the object of the nut grower should be to breed and select as far
as possible resistant sorts, to work on and select native species and
hybrids particularly where the native trees will give the necessary
hardiness, immunity and resistance. The outlook, therefore, is promising
for the cultivated varieties of hickory nuts and walnuts that I know you
are all working for. Foreign parasites are always dangerous. This
chestnut blight fungus comes into any such scheme as that like a
bombshell. When it comes to an introduced parasite like that we can not
tell what will happen. I thank you for your attention.
* * * * *
THE CHAIRMAN: I think everybody here will agree with me, when you come
to look over this list of amounts appropriated for work in nut culture
investigation, that there will be no further criticism of the Department
of Agriculture from any member of the association for not doing more in
the interests of the nut grower.
THE SECRETARY: We are all indebted to Professor Waite for his clear way
of stating facts, for resisting the temptation to give a technical talk
and for enunciating principles of wide applicability.
This question of the blight on the hazel is a most important one for the
northern nut growers. Mr. Reed was telling me yesterday about a man from
California who went out near some city there and bought 10 acres of land
at six hundred dollars an acre, planted almonds and in a few years had
the place paid for and was making a good income, two or three thousand
dollars a year from his ten acres of almonds. We can do almost that in
the East, I believe, if we can cultivate the European hazel. If it were
not for this blight, we could have splendid crops of the hazel. If the
government would grant larger appropriations for nut culture
investigations it might enable us to find a way to control this disease.
Dr. Morris is breeding hazels, however, and hopes to get one which will
be immune.
PROFESSOR SMITH: It is a great pleasure to listen to a man who knows
what he is talking about. I figured out some years ago that I was going
to be a teacher and I decided that I would like to have a chestnut farm
also. I got along very nicely, planted my trees and then the chestnut
blight came along, and I regard the business, at least as to profits, as
in abeyance. We are in a period of particular danger from the
importation of foreign plants; we are bringing in perfectly
innocent-looking things from other countries which are causing us great
damage. I want to suggest to any one here who wants to plant an orchard,
to plant two kinds of trees. If my nut orchard had been planted with
something besides chestnuts, I would now have that something else. I
would suggest the possibility of having two things on the same
ground--say chestnuts and English walnuts--so if the planter finds he
cannot raise one he can still have the other. Then he will not be in the
same place I am with my chestnuts.
THE CHAIRMAN: I understand we have Mr. Fullerton of Long Island here,
and we would be pleased to have him give us some of his experiences.
[Illustration: DR. WILLIAM CHAMPION DEMING
Secretary-Treasurer of the Northern Nut Growers Association]
MR. FULLERTON: I just came in to see what you folks are doing and I
don't think I can pose as a nut expert. I live on an island that has a
great many varieties of nuts on it that have become native. We have
quite a plantation of hazelnuts; nobody knows who planted them. They are
used by nurserymen to fill orders. Also quite a plantation of magnolias
which came from the South a couple of hundred years ago. They are
thoroughly acclimated. We have also some of the very largest--and I am
going to catch it here because I have never used a tape line--we have
some of the very largest and oldest of the Persian walnuts in the United
States, which produce annually a big crop of the so-called "English"
walnuts. The trees produce the largest walnut I have ever seen, with the
thinnest shell. They have been there about one hundred and fifty, two
hundred and fifty or three hundred years. They are very large, larger
than the black walnuts. Whether they were planted or not I don't know.
Their history is probably this: Long Island was a sea-faring community a
few hundred years ago. These sailors who went out from the island, some
of them, loved nuts and they would bring back from other countries nuts
or other plants, and now we have a most remarkable mess of trees. We
have planted the Japanese walnut, I don't pretend to know which variety,
and it began yielding the third year and has yielded every year since,
bearing nuts in bunches like grapes.
THE CHAIRMAN: Is it a heart-shaped nut?
MR. FULLERTON: Yes. We have some pecans and some almonds. Against the
advice of everybody we planted some almond trees; they started to bear
in their third year. The trees are one solid mass of glorious big red
blossoms every spring. They bear very heavily and have for three
distinct seasons. Hard winter or easy winter, nothing has affected their
bloom and they have never had a particle of San José scale until this
year. The almond grows all over the island. Also the pecan. I planted
five varieties of pecans and they are still living and growing very
slowly. They have been moved three or four times. Last year we planted
seven varieties including the Van Deman and the Stuart and one Indiana
variety. One of these trees died and the others were killed back, but
they have sent up big shoots.
Two years ago an old fellow came up from the middle of the island to see
if our pecan trees were the same kind as his. His story was very
remarkable. He didn't know anything about trees. He went into town one
day and got interested in pecans and bought all the different kinds he
could find, all the different shapes. He didn't care what they
were--didn't care whether they came from Canada or Mexico--he was the
kind of a man who would plant bananas,--and he planted all those pecans
and he told me that every one of them grew. He said they all produced
nuts.
MR. POMEROY: The first Persian walnut nursery ever established in the
United States was at Flushing, Long Island.
THE SECRETARY: I should like to ask how old and how big are the pecan
trees that are bearing?
MR. FULLERTON: I think he said seven or eight years.
THE CHAIRMAN: The insect question is one of great interest. Professor
Quaintance can give us a good insight into the insects that attack pecan
and other nut trees.
INSECTS INJURIOUS TO NUT TREES
A. L. QUAINTANCE, WASHINGTON, D. C.
I have not very much to say because we have not yet accumulated much
information on the subject of nut insects. I am glad to appear before
you, however, and to assure you that attention is being given to the
insect enemies of nuts by the Department. We are not nearly so far
advanced in the subject, however, as Professor Waite, since our specific
study of nut insects began only, this last spring. At that time we
established a laboratory in the South, especially to study pecan
insects, as the demand for information concerning these pests has been
very strong. The Bureau of Entomology, however, for a number of years,
has published more or less on nut insects, as opportunity offered, and I
think I should call your attention to a few of the papers treating of
nut insects, and which I recommend that you obtain, if possible:
The Nut Feeding Habits of the Codling Moth, Bulletin 80, Part 5, Bureau
of Entomology.
The Fall Webworm, Farmers' Bulletin 99, U. S. Department of Agriculture.
The White-Marked Tussock Moth, Farmers' Bulletin 99, U. S. Department of
Agriculture.
The Bag Worm, Circular 97, Bureau of Entomology.
The Apple-Tree Tent Caterpillar, Circular 98, Bureau of Entomology.
Nut Weevils, Circular 99, Bureau of Entomology.
The Red Spider, Circular 104, Bureau of Entomology.
The Leopard Moth, Circular 109, Bureau of Entomology.
The Walnut Borer, Fifth Report, U. S. Entomological Commission, page
329.
The Oak Pruner, Circular 130, Bureau of Entomology.
Insects Injurious to Pecans, Bulletin 86, Mississippi Agricultural
Experiment Station.
Insects of the Pecan, Bulletin 79, Florida Agricultural Experiment
Station.
The Walnut Weevil or Curculio, Twelfth Report, State Entomologist of
Connecticut, page 240.
The Walnut Bud-Moth, Twelfth Report, State Entomologist of Connecticut,
page 253.
The above list will furnish information on most of the important nut
insects thus far known. Inasmuch, however, as the walnut, pecan, etc.,
are native trees, it is probable that when these nuts are cultivated
they will be attacked by many of the insects which prey upon them in
nature. This we have found to be true to a considerable extent in the
case of the pecan. Many of the pests of hickory, for instance, are
becoming important enemies of the pecan.
We have few requests for information as to the insect enemies of the
hazelnut or filbert, practically none as to the almond. I surmise that
there is comparatively little injury to the two former crops in the
United States, and that in the case of the almond it is largely free
from insect pests. The secretary has suggested that I make reference
particularly to the insect enemies of the walnut. We have had complaints
of severe injury to walnuts in California from the codling moth and
walnut aphids. In this state and in the arid sections where walnuts are
commercially grown, the codling moth, the well-known apple pest, has
turned its attention to the walnut, and under some conditions does
serious injury. If walnuts are growing adjacent to pears, the marketing
of the crop, which occurs about the time the second brood of larvæ is at
its height, deprives these insects of further food and they turn their
attention to the walnut. The walnut plant lice in California have just
been investigated by an agent of the Bureau of Entomology and we now
have a paper in press on these insects. We think it probable that
spraying will be a satisfactory remedy where the trees are not too
large.
In the East injury is confined largely to certain caterpillars infesting
the foliage, as the white-marked tussock moth, the fall webworm, a
species of _Datana_, and occasionally reports of severe injury from red
spider are received. Rather recently a good deal of interest has been
aroused in the so-called walnut curculio by reason of its attacking the
shoots and leaf petioles of the Japanese walnut. It attacks also other
species of walnut, including the English walnut and the butternut. This
pest has been well treated by Doctor Britton in his report as State
Entomologist of Connecticut for 1912.