your attention to two cases as illustrations, or to certain facts,
rather. One is that the disease, so far as our attention has been
directed to it, has developed over the area indicated on the map since
the fall of 1904. Another case is one which has occurred in Rhode
Island, where I have had a chance to watch its development a little more
closely than in other places, that is, more constantly. In the fall of
1908, after I had made over thirty excursions around Rhode Island, I was
unable to find a single trace of this disease, and no one else was able
to find a single case of the disease in Rhode Island. In May, 1909, I
happened to be about five miles west of the city of Providence, and I
found two or three cases, all in one rather restricted spot. Later, it
was discovered a little farther south, and soon, a little to the north,
so that at the end of the season of 1909 we knew of about ten cases in
Rhode Island. At the end of 1910, a season in which very few trips were
made with the special object of surveying for the disease, we had more
than doubled the number of infections found. That led to putting someone
into the field in 1910 to make a survey of Rhode Island. A man was also
put into the state of Massachusetts for the same purpose. Mr. Rankin, in
cooperation with the United States Department of Agriculture, made a
survey of New York State, which has resulted in this map. A man was put
into Pennsylvania and one into Maryland for the same purpose. As a
result of the survey in Rhode Island, where at the end of 1910 we knew
of less than fifty cases at the outside, we now know of very nearly 4000
cases. It has been much the same story in Massachusetts. At the
beginning of this year, there were four towns in which the disease was
known; now there are seventy-one. At present in Connecticut, the disease
is known in one hundred thirty-two towns of the one hundred sixty-eight
in the state, and the southwestern part of Connecticut is very badly
infected, just as badly as the adjoining portions of New York.[A]
[Footnote A: Since this statement was made the disease has been
definitely reported in approximately 164 towns in Conn. [J. F. C]]
So much for illustrations of the rapidity with which the disease
develops. I am not going to say at this time anything special about the
origin of the disease, simply because we haven't yet decided what was
the probable origin. I will merely say there are some different theories
in regard to the origin. One is that it was imported from the Orient,
another, that it is a saprophyte, a fungus which has lived normally upon
dead organic matter, but which has taken on the parasitic form, which
develops on living organisms.
In connection with any disease of this sort, one naturally inquires, how
are we going to recognize this disease? This past summer Pennsylvania
has put into the field thirty or more men who have been trained to
recognize this disease, with the idea of locating the infections in
Pennsylvania. As perhaps all of you know, the legislature of
Pennsylvania has passed a law relating to this particular disease, and
has appropriated $275,000 to see if the disease can be controlled. Their
idea is that they have perhaps fifty million dollars' worth of
chestnuts, and if $275,000 can show whether or not this disease can be
controlled, it is economy to try it.
So far as Pennsylvania is concerned, it means possibly the saving of the
chestnuts in the middle and western parts of the state; but it also
means that if they can check it there, it is likely to save the great
area of chestnut growth along the southern Appalachians. I don't want to
make any prophecy as to how that experiment is likely to come out, but,
however it comes out, it will be a very great object lesson as to what
can be done on a large scale with a disease of this sort.
One of the first things which had to be considered in Pennsylvania was
to train a number of men to recognize the disease, so as to go over the
country and locate the diseased spots. The method of recognizing the
disease I will briefly outline. Of course, over a large country, many
hundreds of square miles, it is a long, and laborious operation to look
over every tree. It is perhaps impossible without a very much larger
force than $275,000 could put into the field. But there are certain
clues to the location of the disease which can be seen a long distance,
a quarter of a mile, at any rate. The means of recognition is by what I
commonly call danger signals. This fungus, when growing through the
bark, starts from the common point of infection and grows in all
directions, up the stem, down the stem, and around the stem. Wherever
this vegetative stage, technically known as mycelium, penetrates, the
bark is killed; and of course, you all know what that means. When this
has succeeded in reaching around a twig, branch, or trunk, everything
beyond that girdled area dies, not immediately, perhaps, but sooner or
later it dies; and it dies in such a way that the leaves change color
during the summer. The first obvious change which can be noted is a
slight wilting of the leaf; then the leaf assumes a pale green color,
and from the pale green it takes on a yellow stage; from this a reddish
yellow stage, and then a brown, till the leaf is the ordinary dark dull
brown of the dead leaves. This coloration which takes place is
conspicuous. There is your guide, your danger signal. If the disease has
worked very long, half a season, in one locality, you are almost sure of
getting some of these danger signals. Where one is present, you can go
and look up the cause of that danger signal. It may be a broken twig,
but the point is to find out if it is this disease which has caused the
danger signal. We start by looking at the danger signal, then at the
base of the dead area. If we find here some of the reddish pustules
which have been shown on this bark we are quite sure that the disease
is present. Then by cutting into the bark a little, instead of the
normal buff or yellowish tint of the fresh clean bark, we get, when the
disease is present, a rather mottled effect, varying from a brownish to
lighter or even darker. There is a peculiar fan-like effect to this
mycelium which penetrates the bark, so that by shaving off the surface
of the bark, you get this mottled appearance, which gives you another
means of identifying the disease. So we look for the danger signals, and
then look for the meaning of the danger signals. If we find those two
things, the pustules and the mottled mycelium, we can very safely say
that this disease is present.
There are a few fungi which closely resemble this chestnut disease in
general appearance, but they are not very common, and are not confused
with the disease, as a rule, when you get the lens on them.
In regard to the experiments for the control of the disease. I want to
say a few words. As far back as 1907, the United States Department of
Agriculture began experiments on certain experimental plots,
particularly in Long Island near the region where the earliest cases of
this disease were known, to see if it could be controlled on individual
trees after they had become infected. Later, experiments were undertaken
along the same line in Lancaster County, Pennsylvania. Spraying was
tried, although there was no idea that it would be of any use, because
the vegetative stage of this fungus is running through the interior of
the bark, where no spray could reach it. Thus spraying was found to be
of no use whatever. Then the operation of cutting out the disease was
tried. Where the diseased spot appeared, it was cut out with a gouge.
Then the exposed area was covered in various ways with antiseptics.
This gave, for a year or two, very promising results, but about the
third year the disease appeared to get over on to the margin, where it
had been cut. This led to the later discovery that the disease had been
running in the wood, as we had previously suspected. So the cutting out
of the bark alone is not sufficient. This year cutting has been done so
as to include a portion of the sap wood.
There is just one other topic which I want to allude to. That is in
regard to the immunity question. It has been found that this disease
attacks the common native chestnut, the chinquapin, the various
cultivated European chestnuts, but very rarely the Japanese. In regard
to this point. I hope that Doctor Morris will tell us something about
his experiments on the breeding of chestnuts with the idea of producing
a new and immune variety.
You will understand that I have just made an outline of this disease,
and I hope that, if there are any questions to be asked, you will make
them easy, so that I can answer them.
President Morris: This very interesting paper is now open for
discussion, and I hope that we can get some points which will allow us
to know how to control the disease. With the wind-borne spores that are
carried miles and miles by a single sharp gust of wind, this disease is
a difficult matter to control. We must, I believe, find some natural
enemies, if we can. I don't know where to look for these. I will have to
ask the mycologists what we may anticipate along the line of natural
enemies. I would like to ask if it is common for a weak species to
become a devastating species. Have we many parallels in the field of
mycology? The point relating to raising immune kinds is one for
discussion. Are we to raise immune chestnuts? The history of most
plants, I think, has been this, that where they have met their enemies
in their natural environment, the fittest survive; and it seems to me
that this is a case in which we perhaps have survival of the fittest in
North Asia; for the North Asian chestnuts certainly resist the disease
better than any others, but the chestnuts of southern Asia are quite
vulnerable to it. In my own orchards, I have twenty-six kinds of
chestnuts, and have followed them along, for the purpose of determining
which ones would resist the blight best. I cut out last year 5000 old
American chestnut trees on my property. There is not a tree in all that
part of Connecticut, the vicinity of Stamford, that is not blighted, and
very few that are not dead. Now, in the midst of this disaster, what was
the behavior of my experimental chestnuts of various kinds? It was this.
I had about one thousand Koreans that lived up to five years of age,
growing in the midst of blighted chestnuts, and none of these blighted.
It occurred to me that it might be well to graft these on the stumps of
American chestnut, because these Koreans resisted the blight; but when I
grafted them on the sprouts of American stumps, at least fifty per cent
of the Koreans blighted, showing that the pabulum wanted by the
_Diaporthe_ seemed to be furnished by the American chestnut. I had some
chestnuts from North Japan that resisted the blight, and yet these
grafted on the sprouts from American chestnuts blighted. I had some
Chinese chestnuts, and none of those have blighted as yet; and in
grafting them, two or three have not been blighted. I have perhaps
twenty-four chinquapins, both the western form and the eastern, and only
one branch of one tree has blighted. Of the southern Japanese chestnuts,
very many are blighted. They are not as resistant as the northern. I
have a good many chestnuts of European descent, and among these some
resist the blight pretty well; and some of the American progeny, like
the Hannum and Ridgely, seem to resist well enough, so that now I am
grafting these upon many different sprouts. This should be worked out,
and I wish to know what men have tried experiments along this line. I
would like to ask Professor Reddick to discuss this question.
Professor Reddick: I have very little that I can add at the present
time. The points the talk has raised here are of the greatest
importance, and there is certainly room for a great many people to work,
though here in this state we have only one man who is devoting his
attention particularly to this disease. I find in connection with the
work that Professor Collins is doing, and in connection with the
Pennsylvania work, that there are some people engaged on these very
vital and important problems. They are not giving any particular
attention to field work, but are working on these special problems. I
think you all appreciate that progress of investigations on this kind of
subjects is rather slow, and in the meantime the man who has his trees
and his nurseries blighting is surely up against it.
I have only one thing in mind, a thing which I suggested to Mr. Rankin
when he first started on this work, and it is a thing which Doctor Peck,
our state botanist, suggested at the chestnut bark conference that was
held in Albany not long since. Doctor Peck says that he has lived a good
while, and he has seen epidemics come and go. Certain plants, certain
varieties were threatened with extermination, yet at the present time
they are still with us. I suggested to Mr. Rankin that, while it looked
as if chestnut blight was going to be with us indefinitely, the chances
were it would all be gone before he had a chance to find out all the
things he thought he was going to. Our friend Doctor Clinton of
Connecticut would have us think it is only a matter of a few years to
have conditions come around so that the chestnut blight will not be a
thing of serious importance. In other words, Doctor Clinton stoutly
maintains that, while this fungus is doing so much now, it is largely
due to the condition to which our trees have come, owing to a succession
of very unfavorable summers and winters; and as soon as the conditions
get around to normal, the disease will be no more. Some of us are not
inclined to agree with him entirely.
Professor Craig: Perhaps you can tell us what Mr. Rankin has been doing
this year.
Professor Reddick: At the beginning of the past summer, from the surveys
and observations that had been made almost entirely by the United States
Department of Agriculture authorities, it was known that the chestnut
disease had extended up the Hudson River perhaps as far as Poughkeepsie.
It was our idea that he would probably find the border line of healthy
and diseased trees somewhere in the vicinity of Poughkeepsie, so Mr.
Rankin located it opposite Poughkeepsie at Highlands. During the course
of the summer, the assistance of the State Survey Commission and the
State Department of Agriculture was enlisted, and there were six or
eight men who spent part of July and all of August surveying the portion
which now appears on this map in red. The results of this survey show
that the entire Hudson River Valley, with the exception of a small part
in the vicinity of Albany, is now infected. In fact, it is the general
opinion that there is no use whatever to attempt in any way to save the
trees in this locality. Very fortunately there is a strip of territory
which is almost solid spruce forest, and in which there are almost
absolutely no chestnut trees. We have already, then, abandoned the
Hudson River Valley, but with this great natural barrier, you see that
it is going to be relatively easy, so far as the State of New York is
concerned, to put some sort of an artificial barrier across the little
neck there. This all depends on what can be done in Pennsylvania. This
cross-hatching of red along the Delaware River represents an area in
which the infection is only partial, and the few dots of red shown about
Binghamton represent localities in which the blight has now been
exterminated. The diseased trees have been taken out, stumps killed, and
bark burned. We are in hopes the disease will not reappear there. I
don't believe things have been definitely settled at Albany in the
Department of Agriculture, where the control work naturally lies, but
Commissioner Pearson is very anxious that something be done to try to
control or prevent the further spread of the disease in our state. Plans
are being made so that a large number of men will be located in this
territory next summer, making very careful inspection, removing the
occasional diseased trees, killing stumps, and burning bark; and a
forester will be connected with the work, for the purpose of advising
with regard to the use of the diseased timber. I might call attention to
the fact that our state agricultural law, as it now reads, empowers our
Commissioner of Agriculture to quarantine against this or any other
dangerous fungous disease,--a very broad step from what it was before
that time, when the only fungous disease he had any power to act against
was the black knot of plums.
Mr. Reed: From the chart, it appears that the disease is more common in
the vicinity of streams and bodies of water.
Professor Reddick: That is an observation that has often been recorded.
Mr. Reed: How is it elsewhere than in New York?
Professor Collins? The question has been asked more often than
otherwise, why do we find the disease on the tops of hills away from the
water? I think there isn't a sufficient amount of evidence or
observation on that point to say whether it is more common near or away
from bodies of water.
I will call your attention to one experiment that can be performed by
anybody with the microscope. Take a piece of one of those spore horns or
threads, put it in a drop of water on a microscope slide. Inside of two
minutes, it will disappear entirely. It is dissipated in the water, and
the spores are so small you cannot see them with the naked eye. If you
let the water dry on the slide, then put that slide under the microscope
and try to blow those spores off, you can do it just about as easily as
you can blow the shellac off a door. You can brush that film under the
microscope, and you can't see that a single spore has been disturbed.
The explanation, I think, lies in the fact that these spores are of a
mucilaginous nature, and when they dry, they stick to whatever they come
in contact with. That does not mean that these spores cannot be blown,
because they may lie on fragments of leaves and be blown about by the
wind. Again, some of the spores may be detached in a mechanical way and
thus blown by the wind. But I am quite convinced that the spores are not
blown broadcast, simply because they are of a sticky nature.
Now, those spore threads are forced out under certain conditions,
moisture conditions, as a rule. It has been shown after repeated
observation that these spore threads are pushed out a day or two after a
rain. Of course, in the springtime, the atmosphere is much more moist
than later in the season. Consequently, we find more of these spore
threads in the spring than at any other time. You will recall that the
last week of August this year was a week of almost continuous rain. Two
days after that ceased, I saw as many of these spore threads as I had
seen at any one time all summer. So that, although conditions are best
in the spring for greater abundance of these spores, they may occur at
any time. If a bird alights on these spore masses, there is no reason
that I see why they should not be carried. We know the rain water
running down the trunk dissolves these spore masses, and they are
carried down, there to reinfect the tree when insects crawl around.
President Morris: My brother has some Japanese chestnuts twenty-five or
thirty years of age. By cutting off one branch at a time as fast as they
blighted, he has saved those trees.
Professor Collins: You spoke, Doctor Morris, of grafting Japanese on to
American stock. I have seen repeated cases where the Japanese has been
grafted on to American stock. The whole Japanese tree has been killed,
and we find the disease has killed the tree by girdling the American
stock below the graft.
President Morris: Yes, I find this over and over again. In one case
where I had a very choice variety of Burley's chestnut, the _Diaporthe_
attacked the American stock underneath this, and had practically girdled
it when I saw it. There remained a fraction of an inch of good bark. I
cut off all except that, and put tar over it, and grafting wax over
that, and this year the graft has grown a foot or more. So by giving a
great deal of attention to some one little injury, we can overcome the
effect of it.
Mr. Jensen: In your grafting, what was the relationship of the rapidity
of the growth of top after grafting, compared with the old stock?
President Morris: When these grafts are put on the stock, on rapidly
growing shoots from a large root, they grow enormously, and sometimes we
have had nearly one hundred feet of growth in one year. That, however,
would be a chestnut like the Scott or the Ridgely. We frequently get
thirty, forty, or fifty feet growth in one year.
Mr. Jensen: Does the plant grow more rapidly when it is grafted than on
its own stock?
President Morris: I have not grafted Japanese on Japanese stock, but the
Japanese and Korean grafted on American stock does grow more rapidly
than it does on its own roots.
Professor Craig: Mr. Hall has another interesting instance of chestnut
blight.
Mr. Hall: On the ground where the blight appeared, there were four
chestnuts set by a nurseryman, two Japanese and two European chestnuts.
Of the European chestnuts, one has succumbed to the blight, and the
other has been continually attacked for the past four or five years,
twice in a period of four years, and it is still alive and recently
appears to be in a more healthy condition than for the past four or five
years. During that time it has never borne any chestnuts. The companion
tree of the same kind was girdled in two or three years.
President Morris: There is comparative resistance. Some of my trees went
down instantly, and went all to pieces, while others stood up for four
or five years. Chestnuts of the Paragon type I hoped were going to be
fairly immune, but they are going pretty fast. I have advised people who
have asked about Paragon chestnuts to buy them, but be prepared to have
to cut out blighted branches as they appeared. It is a question whether
I can advise even buying them much longer, because I have lost nearly
all my Paragons, but they have not gone as fast as the Americans.
Doctor Deming: Ought we not before we leave this subject either to
appoint a committee, or to pass resolutions urging action on the part of
the state similar to the action taken by Pennsylvania in attempts to
limit this disease? I would make such a motion, that the Northern Nut
Growers' Association urge legislative action similar to that already
taken by the State of Pennsylvania to limit the spread of the chestnut
bark disease.
Mr. Littlepage: I second the motion. (Carried.)
Professor Craig: Should not the Secretary be empowered to send a copy of
those resolutions to the Commissioner of Agriculture? I think the motion
includes that.
Mr. Reed: It seems to me that this disease is of as much importance to
other states as it is to New York and Pennsylvania, and that this
sentiment, as this action can only be a sentiment of the Association,
should be sent to the Commissioner of Agriculture in other states, as
well as in New York. This is not the New York Nut Growers' Association.
I would make that as a motion, that the sentiment of this Association in
favor of state action similar to that of Pennsylvania be pressed upon
the Commissioner of Agriculture in each state where that disease is
prevalent.
President Morris: Shall we make Mr. Reed's motion take the place of
Doctor Deming's?
Doctor Deming: I would accept that as an amended motion. (Carried.)
Professor Craig: Inasmuch as we have gone that far, should we not take
another step, and that is, fearing lest the United States Secretary of
Agriculture should feel slighted, should we not as the Northern Nut
Growers' Association draw his attention to the fact that here is a
serious disease sweeping over the whole northern part of the country,
representing a very considerable portion of his domain, and ask his aid
and cooperation with the various states which are attempting to do such
good work?
President Morris: Will that have to go as another motion or as an
amendment to Doctor Deming's?
Professor Craig: I move that a resolution of a similar type be passed,
and forwarded to the Secretary of Agriculture of the United States.
(Carried.)
Mr. Wilcox: May I ask some of the gentlemen who have experience along
this line if we may look for any cure or help for it in the future, and
if so, along what lines will it be possible, along the lines of
isolation, of natural enemies, or some other preventive or cure?