The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
COOPERATIVE EXTENSION WORK IN
AGRICULTURE AND HOME ECONOMICS
UNIVERSITY OF FLORIDA DIVISION OF AGRICULTURAL
EXTENSION AND UNITED STATES DEPARTMENT
OF AGRICULTURE COOPERATING
P. H. ROLFS, Director
DELIVERED BEFORE THE
Eighth Annual Meeting of County Agents
Tenth Annual Citrus Seminar
UNIVERSITY OF FLORIDA
COLLEGE OF AGRICULTURE
October 10-17, 1919
Address by Dr. A C. True......................................... ........... .......... .... 1
Address by Dr. Bradford Knapp............................ ..................... 4
Branch Experim ent Station ......................... ...... ................................... 6
Spraying in a N ursery......................................... ............................................ 8
The Use of Stable Manure in the Citrus Grove................................... 10
The Value of Brands in Marketing Citrus Fruits-...-.......--..............-----..... 12
Refrigeration in Relation to Fruit in Transit..------............... .................. 14
The Importance of Florida Rates to the Florida Grower............................ 17
The Decay of Citrus Fruits in Transit From the Standpoint of the
Railroad .................................------------------- -- .......------ ..--...... 18
Decay of Citrus Fruits in Transit From the Standpoint of the Packer 20
Causes of Decay in Citrus Fruits.................-----........-----....----..................... 22
Some Problems of the State Plant Board --------.................... -------...... 25
The Citrus Canker Situation............................ ....------.-------- ...... 27
The Dust Method for Controlling Rust Mites on Citrus Trees................ 29
Citrus Scab---...................----------- ----------------................. 33
The Whitefly Eating Delphastus......-----.........---.. ..-.--..--................ 35
The Conservation of Corn for the Citrus Grower Who Feeds Live Stock 38
Some Grove Practices in Disease and Insect Control......---------.......................... 39
The Use of Vedalia and Fungi in the Citrus Grove...................................... 41
Citrus Scab-Cause and Control.........................----- ----- ---- .. 43
Irrigation Practices------- --------------.......................----...... 45
There has been an increasing demand for copies of the addresses made
at the annual meeting of the County Agents and the Annual Citrus Seminar,
these requests coming both from men who were present at the meetings and
those who were unable to attend. Therefore, an attempt was made at the
last meeting (held jointly) to either get copies of these addresses or have
stenographic notes made of same. While it was not possible to secure every
one, the majority of them have been compiled and some of the essential
points discussed reproduced in this bulletin. Unfortunately, it is financially
impossible to give a complete report of this meeting. It is hoped that the
present bulletin will prove more acceptable than would have been the case
if no report had been published.
By DR. A. C. TRUE
Director States Relations Service
I have been introduced as having charge of the States Relations
Service. -That deals with all the Agricultural Colleges and Ex-
periment Stations in the forty-eight states. We are charged
with looking out for the interests of the Federal Government in
the expenditure of funds given by the Government to the Agri-
cultural Colleges, for Experiment Station and Extension work.
We have stations in Hawaii, Porto Rico, the Island of Guam, and
now we have taken the Danish Station in the Virgin Islands.
That gives us a great deal of interest in the progress of tropical
agriculture, and we are dealing with a good many matters which
have definite relation to Florida agriculture.
I want to speak to you about some of the things which, from
my point of view, seem to be permanent results of the war.
One of the things which has grown out of the war, and which
affects agriculture in a very marked degree and will, I think, per-
manently affect the progress of agriculture in the United States
is this: that the war has given the world its greatest and most
impressive lesson on the power and effectiveness of concerted
action for practical ends. In the raising of vast armies; in the
operation and support of those armies as regards their food
supply and their equipment, we have had the most tremendous
lesson of the effectiveness of concerted action in a common cause.
This has had a powerful influence already upon the mental atti-
tude of our people toward cooperative action, and it has affected,
not only our industrial classes, but our agricultural people, as
never before. It is true, of course, that we have had many agri-
cultural associations and other organizations in the United States,
but they have never realized as they realize today the benefits of
associated action. The evidences that come to us on every hand
are that at last the agricultural people are bound to be quite
thoroly organized and to use the power of organization for the
benefit of agricultural and country life, and that this must be
taken into account as one of the permanent effects that have
grown out of the great war.
Another thing which has grown out of war is that the farmers
have waked up as never before to see that it is absolutely useless
to conduct agricultural operations unless they give them a profit.
Of course that was the supposition long before, but actually dur-
Florida Cooperative Extension
ing a considerable portion of our history a very large amount of
agriculture had been carried on as a non-profit industry. Now
the farmers do not intend to carry it on that way any more and
they are putting forth strenuous efforts with reference to making
sure that farming enterprises shall be profitable.
The city man does not yet understand this very well, and he is
still talking about increasing production so as to bring prices
down for his benefit. In other words, he is thinking in old terms
to a considerable extent, not about his own business, but about
the business of agriculture as if, forsooth, agricultural people
were ordained by Heaven to carry on their operations merely that
there might be plenty of cheap food for people who work in fac-
tories, stores and other industrial operations. Thus the discus-
sion of this matter in many ways thru our metropolitan press
and otherwise, is very apt to be on a false basis. And these people
do not seem to realize yet that the farmers are now determined
that agriculture shall no longer be carried on without profit. Of
course, even from the standpoint of the city people, this idea that
there shall be an enormous production regardless of cost is a
great economic mistake. If we are to be a generally prosperous
people, the great agricultural millions must have success finan-
cially in the conduct of their business; and when they do, they
will help all other people in whatever industry they have engaged.
Another great lesson which is growing out of the results of the
war is that multitudes of our people have learned in a new way
the disadvantages of ignorance and the benefits of definite knowl-
edge, especially when it is applied to practical affairs.
You are, of course, already familiar with the great movement
of the extension work, which is essentially an educational move-
ment, and which is bringing to great numbers of our people-
boys and girls as well as adults-information and knowledge of
a practical kind; but that isn't sufficient. We must go further,
and develop not only our colleges and secondary schools, which
are growing in strength, but also a far better system of elemen-
tary education in our rural communities, and this is the greatest
of our educational problems. I believe that we are going to do
this, and that it will be one of the great factors in the future
prosperity of our agriculture and agricultural people.
Another lesson that has been enforced among our people be-
yond any measure that we thought possible before the war is that
there is a tremendous benefit to industries in the application of
science to practical purposes. Of course, something had been
Bulletin 24, Addresses
done along that line for a good many years, and we had Agricul-
tural Experiment Stations for a long time, but we didn't really
learn the lesson of the absolute necessity of science, as applied
to agriculture and other industries. But the war came along,
and as the war developed it became more and more a contest of
And so our people have come to have a new sense of the im.
portance of scientific work in their industries. They have begun
to show this already in a very marked measure, and it has already
affected, to a certain extent, our agricultural institutions because
our commercial concerns, having caught up this idea more fully
and promptly, are devoting large sums of money to the employ-
ment and equipment of well trained scientific men to aid in their
industries. A considerable number of these industries directly
relate to agriculture, and they are employing agricultural experts.
Thus we are having a hard time to hold, in our Department at
Washington and in the State Experiment Stations, a sufficient
number of well trained scientists. Yet the demand from the
farmers themselves for the employment of such people in the
public agricultural institutions is growing apace all over the
These are some of the things which have appealed to me as
permanent and fundamental results growing out of the war and
which will affect the progress of agriculture in the United States.
If taken advantage of, they may in a large measure overcome the
difficulties of our economic situation, and may help us to avoid
such disasters as have come to nations in the past.
In the end, I believe that we shall look forward to a highly
organized and profitable agriculture in this country, supported by
powerful cooperative associations, and to a system of elemen-
tary, secondary and advanced education suited to the environ-
ment and needs of our rural people; extension forces in agricul-
ture and home economics operating in every rural county; and
experiment stations and other institutions for agricultural re-
search, thoroly manned and equipped. As these forces and insti-
tutions grow in power and efficiency, American agriculture will
increase in permanent prosperity, and multitudes of people will
remain in the country and find a large measure of enjoyment
and success in living there.
Florida Cooperative Extension
DR. BRADFORD KNAPP
Chief, Extension Work in the South, Washington, D. C.
In war time, Extension work was put under the heaviest strain
any work was ever put under in this country. We grew from a
small number, relatively speaking, in 1917, to a tremendous maxi-
mum of power and strength of manhood and womanhood in 1918,
far better than what we are now. But we have problems, like
the army; the shaking down process, the coming back to the
starting point, the getting back to the principles and the methods
and the things of the time of peace.
This campaign business is played out. The mental psychology
of the country is such that it is not a good thing now. Before the
war, talk did not put over any agricultural proposition, and it
will not put it over after the war. Agriculture is a great busi-
ness that is conservative, and changes its ways gradually, and
farmers as a rule learn more from actual living examples of bet-
ter methods than they do from all the talk in the world.
During the war, we just threw over this business of having
demonstrations. Let me tell you, we must get right back to them.
Demonstrations conducted by the farmer will go further than
anything else towards getting the work across.
In any program of constructive work in a county, there is the
problem of organization. We cannot hope to reach all the farm-
ers of the county unless the farmers are in some way organized
for us to reach them. The man who reaches out by actual con-
tact with farmers will not get far, if he is taking the individual-
istic method of approach. You may be interested to know that,
in the state of Oklahoma, within the past year, every county has
what they call the community and the county council of agricul-
ture. They are made a recognized legal body, authorized by a
statute of the Legislature passed last Spring, and in August when
I was there at their State Roundup meeting, they organized the
State Council of Agriculture of the State. It is entirely a farm-
ers' organization. In Texas, they are rapidly rounding things
up so that they will have a Council of Agriculture in every county
where there is a County Agent. They have had a Texas Farmers'
Congress, which has been made into a cooperative body really
representing the Councils of Agriculture in the state. In those
states where the organizations exist, the farmers themselves are
participating in the fixing of the program of Extension work.
Bulletin 24, Addresses
Now, that is easy, if the farmer understands what Extension
Some people get confused between vocational and Extension
work. That is simply because they do not know about Exten-
sion work. Vocational education is the organized system of meth-
odical teaching of a vocation to a man, woman or child in schools
or classes, accompanied by a certain amount of practical work. Al-
ways it requires the person who is going to learn to go to the
class or the school. Always, its object is a full rounded training
in a vocation. That is not Extension work; it has not to my
mind, the faintest semblance to Extension. When you examine
the Extension work, it does not care whether or not a man has
ever been trained in his vocation. Extension work presumes
that he has a certain amount of training. It always benefits
educationally; that is all true, but what Extension work is doing
is looking for the problems. You find something that is giving
the farmer trouble, and you can get his confidence and interest
immediately. Extension work is just going around hunting for
trouble. It is looking for things the farmer is having difficulty
with, and trying to bring to him the solution of that difficulty-
whether it be individual, community, county or state.
Now, Extension work does not require a man to move one peg
beyond his every day routine; it absolutely requires nothing ex-
cept the recognition that here is a problem, and that here is a
ready means of supplying information to meet that problem.
Sometimes people think of farming as just a man's business;
let no thought like this get into your head. Agriculture is essen-
tially a family business, and the success of agriculture depends
upon the cooperation and the co-planning of the entire family.
I can take you into sections of this country, and show you two
farms side by side, where the man is practically equal to his
neighbor in the administration of the things in the field, but one
man is making money and the other is not. It is the poultry, the
home orchard, the small fruit, the gardening, canning, preserving,
drying, storing of vegetables for future use; possibly the curing
of the meat, and these incidental things that make one farmer a
success and the other farmer, because they are absolutely absent,
The South is rich today, if it is rich at all, more because of
the large amount of its own food and forage it produced in the
last two years, than it is rich because of the high price of cotton,
and other of its productions. In 1910 the cotton of the South
Florida Cooperative Extension
was more than two and one-half times the value of the corn,
oats, rye, barley, flax seed, rice, tobacco, hay, potatoes and sweet
potatoes put together. In 1918 the other crops exceeded the
value of cotton at its high price, by millions of dollars. Were
it not for that change the South would today be the poorest sec-
tion in the United States.
My knowledge of the whole progress of this country leads me
to say that there has been, in the last three months especially, a
very marked change in the minds of the farmers generally.
There is marked tendency toward that national conservatism
which has always made the farmer the strong bulwark of our
whole work. I believe today that most of the farmers are more
interested in that conservatism and in that careful, thoughtful
working out of agricultural problems than ever before.
BRANCH EXPERIMENT STATION
P. H. ROLFS
Director Experiment Station, Gainesville, Fla.
As the name indicates, this Station is a branch of the Experi-
ment Station located with the Agricultural College at the Univer-
sity of Florida. Practically the entire support of the main Sta-
tion is from Federal funds, but the condition of this fund is that
the money must be spent at the central Station. The Experi-
ment Station has done a large amount of work during the 31
years of its existence; 153 bulletins and 31 reports have been
published. Citrus investigations have always been one of the
leading employment of its scientists and much of the best work
that has been done in the State has been accomplished thru the
efficient work of the Station.
The Legislature of 1917 passed a law providing for the estab-
lishment of a Branch Experiment Station to be located in or near
Winter Haven. I herewith give the law, which is brief and to the
"BE IT ENACTED BY THE LEGISLATURE OF THE STATE OF
"Section 1. That the Board of Control be authorized and directed to
locate, establish and maintain a Branch Experiment Station, in or near
Winter Haven, Polk County, in the citrus-growing section of the State,
where insect pests, diseases and other agencies affecting the production
of citrus fruits and citrus trees shall be studied.
"Section 2. That the supervision and direction of the research work
of such a laboratory shall be vested in the Board of Control.
"Section 3. That the Board of Control is hereby authorized to accept
donations of lands, groves, moneys, or other things of value that may be
utilized in conducting the aforesaid in estigations; provided, that no branch
station shall be established if such lands, groves, moneys, and other things
of value be of less than ten thousand dollars ($10,000) value.
Bulletin 24, Addresses
"Section 4. That all laws and parts of laws inconsistent herewith are
"Section 5. That this Act shall go into effect immediately upon its be-
coming a law."
The people of Polk County were especially interested in the
establishment of this Branch Station, raised the funds and se-
cured an option on several sites. On July 14, 1919, the Board of
Control in a session, accepted the present site, located near Lake
Alfred. As soon as complete title to this land can be passed to
the State, work will be started on the clearing of the land, erec-
tion of the Superintendent's cottage and erection of the labora-
tory. The tract includes 84 acres of land, 10 acres of which are
in a one-year-old citrus grove and 41/2 acres in a five-year-old
citrus grove. This makes an excellent beginning as it saves a
most valuable amount of time.
WORK TO BE DONE
The region in which the Branch Station is located is reason-
ably free from dangerous colds to citrus trees, consequently we
can go ahead with a great deal of confidence in building up a cit-
rus orchard as well as in testing out various other experiments.
This factor has been a rather strong deterrent in conducting long
time experiments. No private individual owning a valuable
citrus grove would be willing to make a ten or fifteen year con-
tract for carrying out certain lines of experimentation.
The workers connected with the central Station will find a
splendid field here for conducting various lines of experimenta-
tion that cannot readily be expected from private individuals.
Necessarily much of the work is of such a nature that some of the
trees will be more or less injured. If these are owned by the
Station itself, no special fault can be found with such proceed-
ings. As we have had years of experience in attempting to carry
on experiments of a rather critical nature, it becomes increasingly
more important that the State possess at least a portion of its ex-
The testing of various chemicals, their effects upon trees, root
systems and soils are especially valuable in the development of
the citrus industry. Under the ordinary grove condition, it is
almost impossible to know definitely what the preceding treat-
ment in the way of chemicals has been. Starting with the foun-
dation of a new soil and keeping accurate records, this difficulty
will be obviated.
A considerable amount of most valuable work along the breed-
ing line is contemplated, especially in the nature of bud selec-
Florida Cooperative Extension
tion and the selection of better stock. As soon as the labora-
tory shall have been established, much valuable assistance can
be given to people connected with the U. S. Department of Agri-
culture, by giving them headquarters and laboratory facilities.
It is especially desirable to have some definite headquarters for
people who are assigned more or less temporary work in the
The laboratory will be found a very convenient place also for
scientists from other Stations, who will find here the necessary
equipment of gas, lights, microscopes and other scientific ap-
Every cooperation has been given by interested people in Polk
County and for this reason it will be an especially desirable
place in which to make investigations that last over a period of
years. Investigations that are of short duration can readily be
made in the nearby citrus groves.
SPRAYING IN A NURSERY
F. M. O'BYRNE
Nursery Inspector, State Plant Board
In spraying, as in other things, a man must have the proper
equipment. One must remember that spraying, even in a small
nursery, is a two man job. It is a one man job to keep up the
pressure and it requires a good man at that. It is a one man
job to handle the nozzle and see that the spray is properly applied.
Therefore, we may as well abandon consideration of a one man
sprayer. They are about as well suited to a spraying job of any
size as a hand bicycle pump is suited to the inflation of an auto
tire. Spraying is almost useless without sufficient pressure; at
least 125 to 175 pounds pressure should be maintained. A poorly
constructed pump without a guided piston will never maintain
such pressure and will soon be leaking badly. Under-sized,
poorly constructed hose and connections will not stand such pres-
sure. One-half, five-eighths or three-quarters inch hose of the
best grade should be used. Poor hose on any sprayer means
trouble and terribly expensive losses of time spent making re-
The nozzle is important. Never use a fish tail or Bordeaux
nozzle. Only those throwing a conical spray or fog are satisfac-
tory here. This is called the Vermorel type nozzle and is made
in many styles. A very high percentage of poor results in spray-
Bulletin 24, Addresses
ing may be charged directly to straight nozzles. When using
an angle nozzle a simple twist of the rod will direct the spray to
the upper or lower surface of the leaves as desired. For nursery
spraying the extension rod should not be over three or four feet
in length and should be furnished with a cut off. In fact, a cut
off is essential in all spraying. The outfit should have a pres-
sure gauge by all means.
For the man with a horse the problem of getting a suitable
spraying outfit for a small nursery is somewhat simpler than for
the man without. He can build a sled sufficiently narrow to pass
between the rows of nursery stock and mount on it a barrel
sprayer or one of the many double action platform sprayers that
are on the market. The latter are generally more powerful and
satisfactory than barrel sprayers. Such a pump should have a
good big air chamber, guided piston, outside stuffing box and
should be thoroly substantial without being too heavy to handle.
The Nursery Inspection Department of the State Plant Board
needed a sprayer for use in its experimental nursery. Finding
nothing on the market that was satisfactory a sprayer was rigged
up. It has proved so satisfactory that a description of it is here
It consists of a double action platform or deck pump weigh-
ing about 115 pounds mounted on a board a foot wide, 4 feet
long and 2 inches thick. The piston is guided and has an outside
stuffing box and the lever works in a racket on the piston. It has
a 11/2 inch cylinder, a long lever and a good big air chamber. It
is no trick to maintain 150 pounds pressure on one line of hose
with an ordinary nozzle, and 175 pounds can be maintained
with some effort. When a spray gun is used, 125 pounds can
This outfit we have is mounted on a set of wheels. The rear
wheels are 20 inches in diameter, the front ones 16 inches, the
axles 11/ round steel, 30 inches long over all and the tires are 3
inches wide so they will pull easily thru sand. The local black-
smith provided a fifth wheel, king pin, and tongue. The resulting
sprayer is cheap, strong and efficient and will maintain sufficient
pressure to do good work. It has been used a year steadily and is
still as satisfactory as when new. We can recommend such an
outfit to a man with a small nursery. The man with a horse could
mount such an outfit on a sled. It has an advantage over a barrel
sprayer so mounted, in that the barrel or bucket holding the solu-
tion can be moved without having to handle a heavy pump in
Florida Cooperative Extension
addition. But those who can afford it should purchase a power
sprayer by all means.
Most small nurserymen are also grove owners, and some of
them would feel that they could afford a power sprayer if they
could use it satisfactorily in their nursery. To such men the
roller type of nursery sprayer should solve the problem. A
number of these are in use in nurseries over the state. They
seem to be the best nursery sprayer so far developed.
Now a word about when to spray: Spray when it is necessary.
If you want to accomplish results you must learn something
about the pest you want to fight, find out what spray is the most
effective and when and how to apply it and then apply the spray
in that fashion.
If a man sprays and fails to get results he should not blame
some outside cause. It is not that the spraying idea is wrong,
for the proper spray properly applied will give results and is
doing it every day. If you fail, ask yourself the questions, did
I use the proper spray and apply it at the proper time, and in the
proper way to control this pest?
THE USE OF STABLE MANURE IN THE CITRUS GROVE
B. F. FLOYD
Plant Physiologist, Experiment Station
I believe that there are a good many groves in this state where
stable manure has a place in keeping the groves in, or bringing
them into, good condition. Of course, a great many have held to
the idea that it is absolutely harmful to use stable manure in
the citrus grove, and talked very hard against its use. During
recent years growers have been hearing it from the other direc-
tion, and they are using stable manure to a greater extent, per-
haps, than ever before.
Stable manure may have two effects on trees; if you have a
grove which is very backward in growth, it is quite likely that
the judicious use of stable manure would be very helpful in
bringing those trees back into good growing condition, other
conditions being equal. In the second place, if you have a soil
on which the cover crop will not grow, it is pretty likely to be
what we term a dead soil. On such soils, stable manure will
give good results, but it is not necessary to use it in such amounts
as when it is used as a fertilizer. Probably all that is necessary
is to have a sufficient amount well scattered and turned under
Bulletin 24, Addresses
to re-inoculate the soil with a live soil so the cover crop will grow
I have had an experiment under way in Pinellas county. The
soil in the grove was essentially a dead soil. Not only would
the cover crop not grow, but the citrus trees did very poorly. One
evidence of injury to the trees was frenching, not only of trees
themselves, but also of the sprouts coming up from exposed roots
in the middles. The sparse spring cover crop in the middles
would grow to a few inches in height, become mottled and die.
The soil was what we might term a dead soil. Where stable man-
ure was applied in quantity to the soil, the soil conditions became
changed in a few months' time from that where cover crops did
not grow, to one where cow peas grew almost to the height of
this table. The citrus trees did not respond so rapidly to the
treatment, but after two years' time the trees have recovered,
and now they show very little frenching, and look as well as any
other grove in the community. In this time it has not borne
any fruit, but next year there will probably be a good crop.
If you have soil upon which cover crops will not grow, stable
manure is the thing to use in order to remedy that condition.
However, it is not necessary to use large amounts; apply enough
to make a layer about 2 inches thick. After the first cover crop
is produced, turn it under to add humus to the soil. One of the
characteristics of a dead soil is its lack of humus. The manure
to be obtained from the stable at home is often not enough, and
so it sometimes pays to get it in larger quantities from the cities.
We have no very definite data on that subject, concerning where
it may be obtained.
It is possible that green cover crops could turn under with
safety on Florida soils if we knew more concerning how to handle
the situation, but as at present practiced the turning under of
a green cover crop often proves injurious. It is better to cut
the cover crop and allow it to die before turning it under.
These practices are not particularly for the benefit of the trees,
but to bring the soil into good condition. A good soil extending
all the way from one tree to the next is what is needed. It too
often happens that there is an area in the extreme middles that
is very poor in fertility.
In this experimental grove the injury to the soil and to the
trees was due to ground limestone added in such quantities that a
dead soil was produced. This dead soil was put back into good
condition by the use of stable manure. The stable manure was
Florida Cooperative Extension
used not as a fertilizer, but as a soil builder. Its use was accom-
panied by regular applications of a complete fertilizer for the
benefit of the trees and cover crop.
The use of stable manure about backward, slow-growing citrus
trees will never prove injurious and will often prove beneficial.
One characteristic of citrus trees is that they are subject to over-
growth. Stable manure applied to normal growing trees may
prove injurious by giving excessive growth that may develop
Dieback. For the same reason, it can be used with safety about
trees that are backward in growth.
THE VALUE OF BRANDS IN MARKETING CITRUS FRUITS
GEO. A. SCOTT
As far back as the middle of the eighteenth century, every
trade had its particular brand, and at the beginning of the nine-
teenth century the use of brands became so prevalent in Europe
that it was necessary to pass laws to protect them.
What is the primary purpose of a brand? A brand, as you
know, is a symbol or device consisting of a figure or word or
numeral which is attached to a commodity for the purpose of
distinguishing it from similar goods. That is the primary pur-
pose of a brand. It is a protection to the owner, because, under
certain conditions, he can go into the courts and prevent his
competitor from duplicating his brand, or offering his product
under some other brand.
We must understand how very prevalent the use of brands has
become, especially with food products. Practically everything
that enters the home is in a container and under a specific brand.
If the supply of any one or all commodities is greater than
the demand, the result will be lower prices; if the demand is
greater than the supply, the prices will advance. As the supply
of citrus fruits became greater it was felt by the thinking men
that there must be some change in the presentation of the fruit
in the markets, in order to get results, or else the time would
come when the prices would be so small that it would hardly pay
the grower to produce.
The citrus crop of last year, I am told, figured about eight
million, three hundred thousand boxes. The crop of the coming
year will range from ten, to as high as twelve million boxes,
and it does not require any stretch of the imagination to look
Bulletin 24, Addresses
forward to the time when the output of Florida will be, or pos-
sibly exceed, twenty million boxes.
Now, the question coming before the intelligent distributor of
citrus is, "Just how will we market this fruit in order to get
the best results?" The needs of the markets must be consid-
ered; there are peculiar conditions in each one. Just how shall
the fruit of any one particular organization be distinguished from
that of another? Now, there is a wide difference in organiza-
tions; some are made and created for wholly selfish purposes;
others are not. Any of these organizations, however, are inter-
ested in so distributing their fruits to get the greatest possible
returns either for themselves or for the growers. The organiza-
tion that produces the best results will be the organization, in my
mind, that studies for the development of new markets, increases
the output in the old markets; and makes such an impression
upon the minds of everyone that they will come back and ask for
more and more. The only answer to that is brands.
In looking over any branch of commerce, we find the same an-
swer, the use of brands; definite marks and symbols that will
distinguish the product of that particular organization from the
similar product of any other organization.
On account of the rapid increase in the production of citrus
fruits in Florida, we are all convinced that there must be some
definite effort made to create a market for that product. It is
generally an accepted fact that New York will take about three
times as much as Boston. In looking over the New York market
recently, I found that on one day this month, 168 cars of fruit
were offered thru one channel. On the following day, there were
about 127 cars, and on the following day about 110; an aggregate
of 398 cars in three days, offered thru a single channel, and those
398 cars were principally one single commodity.
This will give you some idea of the tremendous value and quan-
tity of the produce going thru the markets. Now, these 398 cars,
as they came in from day to day, were unloaded in one place and
laid up for examination and sale. With only one hundred cars
there would be anywhere from one thousand to two thousand dif-
ferent lines or shipments to be examined by the purchaser, or the
intended purchaser. It would be almost a physical impossibility
for one man to examine each and every particular line. But since
the immense volume of fruit is handled practically by six organ-
izations, and each of these organizations has a brand, the deter-
mining factor in the sale of this enormous quantity of fruit is
Florida Cooperative Extension
not the name of the shipper or the grower, but the brand under
which it is offered.
It isn't the organization; it is the brand of the organization
that keeps up the demand for the fruit. That organization may
at times err, but that brand is the personal guarantee of the
integrity of the concern. The point is that in the great centers,
brands are absolutely a necessity. The volume coming into those
markets is so great that it is a physical impossibility for any
man to inspect or attempt to examine all the different marks that
come in. And so he must, and he inevitably does, depend more
and more upon the brand, and that brand is based, and stands
upon, the reputation and character of the organization, be it what
Every organization handling Florida fruit should attempt,
first, to advertise and to make clear to the consuming public that
their products are second to nothing produced in this country;
that they have a product of sufficient volume that they know, de-
spite the great demand that can be made, they can fully supply
the demand created; and, last but not least, that the organization
which presents that brand to the public is determined to keep to
the highest standard in the grading, the packing and the quality
of that fruit.
REFRIGERATION IN RELATION TO FRUIT IN TRANSIT
S. F. DENNIS
For a number of years we have been studying the matter of
refrigeration affecting the behavior, and especially the decay and
deterioration of perishable fruits and vegetables in transit from
the shipping point to the market.
The differences of temperature in transit have been very care-
fully studied, and we have given special attention to two forms
of decay which have been found especially troublesome, the
Blue Mold decay and the Stem-End rot. These are two forms
of decay which are affected a great deal by temperature.
In shipping oranges under regular icing in insulated refrig-
erator cars, the usual practice is to load the fruit in whatever con-
dition it happens to come from the packing house, which usually
means at a fairly high temperature. We load the fruit without
much space for air circulation thru the cars, and the bunkers
are filled with ice. To get the. benefit of that ice the heat which
Bulletin 24, Addresses
is contained in the packed fruit must be carried over to the ice
in some way. The method of carrying the heat over to the ice
is by convection, or circulation of the air. The air in the bunkers
of course, becomes chilled and heavier, settles and flows out slowly
and gradually thru the packed fruit. The hot air then rises, and
circulation is set up. The air from the bunkers travels a very
little way before it heats up, and it takes a long time before the
cooling effect of the ice is realized. That means in shipping a
carload of oranges under refrigeration by ice, at least four or
five days pass before the average temperature of the fruit is re-
duced low enough to have any moderate effect in reducing the
decay which causes loss in transit.
The shipments from Florida cars under refrigeration become
well cooled about the time they reach the northern markets.
During the time the fruit is still warm any fruit mechanically
injured has a chance to develop Blue Mold spores, which allows
them to gain a foothold into the damaged tissue of any fruit which
has become infected in the groves with stem-end decay. In those
fruits, the decay begins to develop and progresses far enough to
cause the losses which occur during the time that the fruit is in
In order to reduce this decay a more prompt reduction of
temperature is called for, and that is where the reason for pre-
cooling comes in. Pre-cooling is nothing more or less than the
prompt reduction of a temperature, to a point sufficiently low to
materially check or arrest these forms of decay. That means a
temperature of below 40 degrees, practically.
Pre-cooling has been established with citrus fruit in southern
California, and has been carried on for a number of years. Spe-
cial equipment is provided in the form of small portable pre-
cooling outfits which could be shipped to all parts of the country.
One of these was operated in Florida for two seasons, in
the winter of 1913-14 and the following season. I will give you
the results which we obtained in the Florida pre-cooling experi-
We found that pre-cooling applied to Florida oranges, was
particularly effective in reducing those two forms of decay which
I mentioned, and which were really the only two which we inves-
tigated at all thoroly.
In our experiment, the average decay in the non-precooled
cars was in the vicinity (average decay included Blue Mold and
Stem-End rot) of 11 per cent. In the precooled cars from the
Florida Cooperative Extension
same grove picked and packed under the same conditions, and
going forward on the same train, the decay was reduced to less
than 3 per cent.
Now, as to methods by which precooling is accomplished. There
are two general methods by which the temperature is reduced.
One of these is what is known as car-precooling, where the fruit
is loaded warm in the usual manner, then brought into the pre-
cooling plant. By means of large pipes, cold air is blown with
high velocity thru the car so that the car temperature is reduced.
The other method we have named warehouse precooling, in
order to distinguish it from car precooling. Under that system,
we have a series of cold rooms, located preferably at the point
where the fruit is packed. Into these rooms the packed fruit is
run immediately, and kept until the precooling is produced. It
is on the order of a cold storage room, but differs materially in
the amount of refrigeration necessary to supply a room of given
size, and also in regard to the air circulation. *
In order to reduce the temperature of a large amount of fruit
such as we have to deal with in a precooling room or car of fruit,
very large volumes of air must pass over the fruit. In the case
of oranges that air must be very cold-far below the freezing
point of oranges-in order to bring the temperature down for
any length of time. In car precooling, it is very necessary to use
very low temperatures, as it is important from all points of view
that the car shall be sent on its way as quickly as possible.
Where the cold air is blown in at one end and the warm air
out at the other end, it means that the fruit near the door be-
comes cold long before the fruit at the other end of the car is at
all sufficiently chilled. To overcome that, one method is to re-
verse the circulation and blow in at one end then at the other;
that cools both ends, but leaves the middle too warm. To over-
come that, two California plants arranged to blow it in the mid-
dle. That leaves the ends too warm, so car precooling is not the
ideal method. In our experiments we were led to the conclusion
that warehouse precooling is the only proper solution for the
shipper who intends to precool his own fruit.
There are only two precooling plants in Florida, one in Or-
lando and the other in Winter Park. The plant in Orlando was
built on the suggestion of the Department, based on our experi-
ence in California, and on the experiment which we had con-
ducted in Florida up to that time. The plant was built on the cold
blast system, the air being forced to circulate rapidly by means
Bulletin 24, Addresses
of a large fan. The plant at Winter Park is arranged more on
the order of the cold storage room, except that the refrigeration
is much heavier, the air circulation being by gravity from the
lofts down thru the fruit on the floor below, then the warm air
circulated up to the ice bunkers, as in any cold storage room
where the ice is located on the loft above. Both of these plants
have been successful.
I believe, gentlemen, that that gives you the principal facts as
I see them at this moment.
THE IMPORTANCE OF FLORIDA RATES TO THE FLORIDA
GEORGE R. WILLIAMS
I am afraid that Florida growers, as a whole, do not realize the
importance of Florida rates to the industry. During the past two
months, the railroads have introduced tariffs which have made
effective an increase of $1,500,000 in the Florida rates. The
growers will receive just that much less money. Suppose there
should be an epidemic of canker, or some other disease, Florida
growers would fight there and win out, but in Florida rates we
do not always do that. At the present time, there is an epidemic
of increasing Florida rates. Unless we cooperate, Florida rates
will put us out of business. We have the competition of Cali-
fornia, with higher prices and better rates. They get it their
own way, in rates.
Mr. Dowall, of the Florida Citrus Exchange, and I have made
four long trips in the past two months and have been on the
witness stand twice in an effort to keep rates from increasing.
We went to Atlanta in September to fight an imposed increase
on refrigeration on citrus fruits and vegetables.
The proposed rate was $15 to $30 per car, and that means an
increase of $500,000 a year from Florida growers. We made
a hard fight against this, and hope we will get it reduced. We
are now waiting for a decision from the Commissioners.
To show you how unjust the rates are, the rate on a car of Cali-
fornia celery will be $85. The rate on a car of Florida celery
from Sanford to Detroit will be $95. The California car is in
transit twelve days; the Florida car, about sixteen hundred miles,
in transit about five days.
Mr. Dowall and I were in Washington in September to fight
Florida Cooperative Extension
an increase on the rates of all fruits and vegetables to all markets
in the North. Inasmuch as 60 per cent of our fruits and vege-
tables go to the North, this will be a serious proposition. The
increase is $16 per car, which means that $650,000 per year will
have to come out of the pockets of the Florida growers. We
went on the witness stand in Washington and tried to explain to
the Commission what this would mean to Florida.
We were again sent to Washington October 18 in connection
with the consignment charge. If the railroad's program is put
into effect, $2 for the first reconsignment, $4 for the second, and
$5 for the third, it will mean that Florida will pay $4,000 per year
for reconsignments alone, a total increase, on the coming crop,
of $1,500,000. That is very serious, and the sentiment is for
more increase. It is very necessary for Florida growers to get
together and fight these increases. What we need is a Florida
growers and shippers' league. We will have to organize and
employ a good traffic manager to be on the job all the time, and
attend all these meetings. We can get much better results by
THE DECAY OF CITRUS FRUITS IN TRANSIT FROM THE
STANDPOINT OF THE RAILROAD
W. C. WOODWARD
Wilmington, N. C.
This matter of decay in transit is of very vital concern to the
railroads. My observation and my experience have taught me
that the causes for this possible deterioration of citrus fruits
while in transit cannot always be chargeable to the shipper or
the grower; and it is equally so, to my mind, that not all cases of
decay in transit are caused by neglect on the part of the railroad.
As peculiar as it may sound, I can remember cases where decay in
transit was not, apparently, the fault of the grower, the shipper
or the transportation company, but the decay was there, never-
theless. The railroad has found it difficult to locate the trouble,
and has never done this satisfactorily.
When a railroad man hears of decay in transit to fruit, his
trained mind will naturally resolve itself into a question of what
is the cause of this decay, and with that thought in mind, he
necessarily thinks of some means of prevention that might be
of use, and should be put into effect for the purpose of preventing
Bulletin 24, Addresses
A great many of the unfortunate situations that the growers
and shippers and railroads find themselves in by reason of this
matter of decay to citrus fruit in transit might be prevented by
the application of a truthful percentage of all the facts that sur-
round the individual cases. It is hardly a matter of any set rule
or any particular remedy that can be applied to any case, but if
the railroads, growers, and shippers were equally frank in their
statements, there is no reason why we could not make this matter
of handling citrus fruits an easier matter than it has been in all
the years that are past.
There are conditions affecting citrus fruit known to the grow-
ers and the shippers, not within the ordinance of the railroads.
The railroads have no means at their command to determine
what these conditions are, and they must have this information
in order that they may intelligently remedy the trouble. It goes
without saying that it is the duty of the growers and shippers
to safeguard every possible avenue that might cause deterioration
to their fruit. It is equally evident that the railroads should
properly function in every particular in handling your perishable
product from the groves to the markets, where they are to be
Neglect or improper performance in the method of picking,
packing or inspecting will be reflected in the condition of the
fruit at destination, and in the returns that you will receive from
same. Under all circumstances, proper consideration should be
given to the selection of suitable equipment for the handling of
your fruit, and it should be the pleasure and the duty of the rail-
roads to provide and have available such equipment as will carry
your fruit to market.
The car should be loaded with the idea that it may have to
stand the hazard of the most distant market. I have seen cars,
which, if the shipper had had any idea it was to be shipped to
Northwest Canada, the contents would have been inspected in a
different way and certainly loaded in a way that would insure
that car taking transit as far from Florida as a market can be.
Give the railroads your friendly cooperation; cooperation in
every line will do more to make your handling of the citrus fruit
a success and the successful handling of the fruit on the part
of the railroads than anything else. The day has come when we
must have men who realize that they are working for the same
end, and shape their business so that it will bring the desired
Florida Cooperative Extension
DECAY OF CITRUS FRUITS IN TRANSIT FROM THE
STANDPOINT OF THE PACKER
C. E. STEWART, JR.
The decay of citrus fruits is usually caused from the methods
of handling between the tree and car. With the mechanical con-
trivances used and the large number of people handling the fruit,
it is an easy matter to injure the skin or inside of the orange un-
less rigid care is exercised.
It is hardly necessary to state that in picking the fruit, decay
will result from clipper cuts and long stems. The grower's suc-
cess in picking fruit will depend largely on the kind of field fore-
man he has. If the field foreman takes proper interest in the
work and can handle labor successfully it does not matter whether
your hands pick by the day or by the box.
In putting the fruit from the bags into the boxes, it is possible
to avoid bruising if one is careful. We have always taken care
in the field to see that it is kept below the level of the top, and to
see that in piling the boxes one upon the other that the bottom
of one box does not touch the fruit in the box below.
The standard Florida field box is too large for one man to han-
dle. It is far better, both for the fruit and for the equipment, to
have a field box that one man can handle. However, if standard
field boxes are used they should be handled by two men.
Watch the condition of your field equipment cosely. Watch
out for nails and splinters caused by the rough handling of the
boxes, also caused by tying the boxes on to the wagons and by
the general abuse of the box.
Quick handling of the fruit after it leaves the trees is essential.
Since the truck has come into common use, much time is saved in
hauling from the grove to the packing house. The truck has
another great advantage over the wagon in that the fruit is not
bruised so badly when hauled over rough roads. Where a wagon
is used it should have springs, and the teams should never be
allowed to trot over rough roads.
The unloading of the fruit in the packing house must be done
in exactly the same manner as it is loaded on the wagons in the
field, that is, by two men. Great care must be taken in stacking
the fruit in the house where it waits its turn to be put thru the
machines. Decay is often caused by holding the fruit in the
Bulletin 24, Addresses
house, awaiting packing. Oftentimes this is unavoidable by hav-
ing the house full of fruit and more fruit coming in rapidly.
A clean packing house and machinery are necessary to prevent
decay. Beginning with the floor of the house, every part of the
machinery, whether it comes in contact with the oranges or not,
should be cleaned daily. Well managed packing houses usually
have one man who does nothing but keep the place clean. I have
seen machinery in packing houses covered with blue mold from
the washer to the bins. This may be avoided by using a small
grading table between the dump and the tank or sprinkling rack.
Such a grading table permits the soft and poorest fruit to be
taken out before it enters into the system of handling. This is
an economy, as well as a prevention of decay, because it elimi-
nates the handling of unnecessary fruit.
The dumping place in many packing houses is in a dark, se-
cluded corner. Arrange to have plenty of light where this work
is done. If necessary, put a sky-light over the spot where the
fruit is started on its journey.
Proper grading means more than dividing the fruit into two
or more grades. The first thing to do is to get out the fruit that
has shown up weak as it comes thru the first part of the machin-
ery. I have spoken about taking out, as far as possible, all the
weak fruit before it enters the washing machine, but of course
100 per cent cannot be taken out; some is bound to show up after
it has been handled. This must be taken out on the grading table,
and also all culls showing creases, etc.
Culls should not be allowed to accumulate in the house, but
should be removed every day, and the bins into which they have
been deposited should be thoroly cleaned and disinfected.
If a high standard is maintained in the packing house, the
packers sometimes become interested in their work and will throw
out soft or bruised oranges, but unless considerable interest is
awakened in the packers, everything goes into the box. All em-
ployees of the packing house, as well as the field, should wear
gloves so that bruising the fruit with the finger nails will be
avoided. I have seen packers, especially in packing 200s, jam
the corner orange down so hard that it would wet his hand, and
yet he did not have the interest to take out that orange and rectify
the damage. Such practices can only be overcome by eternal vigi-
lance on the part of the manager.
Florida fruit is packed under what is commonly known as the
"bulge pack." There are two ways of packing the bulge pack.
Florida Cooperative Extension
One is to pack the oranges absolutely horizontal and allow them
to stick up over the top on the last layer, to the desired height.
These are then put under the press and the ends of the lids forced
down. If the oranges are pushed down gradually and carefully,
this can be done without damage that is ruinous, but it cannot be
done without some damage. On the other hand, if the bulge pack
is started in the first layer in the box and the fruit packed as is
designated by a "pyramid pack," when it is brought up to the
last layer it is practically even at the ends of the box and the
desired height in the center.
In loading cars, I believe it is the consensus of opinion that
six across, thirty in the tier, and two tiers high, gives a most
satisfactory load. This gives us, in what is commonly known
as an F. G. E. car, 360 boxes. The boxes should be lifted into the
car carefully and not slammed into place. Stripping in place
should be done there carefully, precautions being taken so that
the nails do not injure the fruit.
Summing up the whole thing will say that to avoid as much
decay as possible requires eternal vigilance on the part of the
grower in looking after field equipment and labor, and of the
manager of the packing house in looking after the machinery
CAUSES OF DECAY IN CITRUS FRUITS
DR. O. F. BURGER
Bureau of Plant Industry, Washington, D. C.
Fungi and bacteria are the most dreaded enemies of the citrus
grower. Any grower if he knew that thieves were in his neigh-
borhood would cooperate with his neighbor to either watch them
or drive them away.
Some diseases originate in the field, do considerable damage
in the field and are also able to develop and cause more damage
on the way to market, such as Stem-end rot, Anthracnose, Black
rot, Gray mold, Cottony soft rot and Black pit. But the worst of
these is Stem-end rot. I believe that this disease is the worst
of citrus pests at the present time, and it can be ranked second
only to citrus canker. Concerted action was obtained in controll-
ing citrus canker and vigorous prosecution of the work has re-
duced this disease in the state. There needs to be vigorous pros-
ecution against Stem-end rot. The habits of this fungus are
Bulletin 24, Addresses
not fully known altho several years of hard work have already
been spent studying the disease.
One of the great troubles with the selling of citrus products
is that on account of Stem-end rot the buyer does not know what
he is getting. This fungus develops on the way to market to
such an extent that the loss runs as high as 50 per cent. There-
fore, the buyer must take this fact into consideration, and buy on
a margin so that he is protected. The grower and not the buyer
is the loser. Therefore, let me state again that the work on Stem-
end rot needs vigorous prosecution. This disease is getting worse
each year, and until a control is found your losses will be great.
There were only one hundred inspections of citrus fruits asked
for up to January 1, 1919, last season. This does not mean that
only one hundred cars arriving on the market showed Stem-end
rot, but it does mean that there was a dispute about the settle-
ment of one hundred cars of fruit. Therefore the U. S. Depart-
ment Inspector was called in to give a third opinion. About the
middle of October the Stem-end rot showed up worse; 42 per
cent of the fruit examined showed the disease. At the middle of
November there was a 28 per cent loss. The amount kept on de-
creasing until the first of January when there was no Stem-end
rot showing up in cars for which inspection was asked. An aver-
age of 24 per cent of Stem-end rot showed up in cars inspected
up to January 1. This disease kept appearing on the market
thruout the year, but there was more decay before January 1
than after that date.
Fruit may be picked and packed showing no signs of decay
before shipping, and when it arrives on the market a goodly per
cent shows decay. This is the reason so many growers do not
believe the receivers when they state that a certain per cent is
affected with Stem-end rot.
All fruit should be packed as quickly as possible and precooled
or shipped out under refrigeration so as to check the growth of
the fungus. The Stem-end rot fungus grows best at about 80
degrees. If the fruit is already infected when it enters the cars,
refrigeration will not stop, but will check the growth of the
When cars are inspected on the markets by the U. S. D. A. in-
spectors, the temperature of the fruit is ascertained by thrusting
a thermometer into the fruit. Since the temperature of optimum
growth of the fungus is about 80 degrees, we thought it would
be possible to correlate the amount of decay with temperature.
Florida Cooperative Extension
This was impossible because, as stated above, low temperatures
only retard the growth. If infection has taken place in the field,
the chances are small that the fruit will arrive on the market
The other diseases, Blue Mold, Rhizopus rot, and Gray
Mold, are those which arise during the process of marketing.
It has been shown time and time again that careful hand-
ling is essential to the marketing of good fruits. We
might find fault with the pickers; clipper cutting, long stems,
carrying too many oranges, the picking boxes in a dirty condition
which might infect fruit, all aid to make a poor fruit. Fruit
which remains in the field too long before going to the packing
house, is liable to be injured by the heat. Fruit standing in the
sun will reach a higher temperature than fruit hanging on the
tree. This high temperature injures the rind, and I believe in
many cases kills those portions thus exposed.
In the packing house the fruit is handled in too rough a man-
ner. When running the fruit thru the machines many times it
has to drop from such a height that it injures the rind. In wash-
ing, often a lot of oranges badly affected with Blue mold are
thrown into the tank, and the spores are scattered over all the
good fruit, which is the best means of increasing Blue mold.
The average loss due to this disease up to January 1 last season
was about 15.8 per cent.
The records of cars inspected for six firms shipping fruit to
the north out of Florida, show the following per cent of decay
due to Blue mold: A, 6 per cent; B, 12; C, 13; D, 15; E, 16; F, 26.
If you could stand in a jobber's establishment and watch the
sorting of oranges, grapefruit and lemons, and see the barrels
of refuse carried away you would change your ideas about some
of your brands. At times it looks as if you men were sending
slush to the market.
Many of you say that you have made a success in your business,
and you will not change your methods. This is what you are
doing; from the kind of handling you give the fruit, you have
learned by experience that a certain per cent is lost during mar-
keting. You buy your crop on a certain margin. Has it not
occurred to you that if you would improve your methods you
could afford to pay the grower more for his product?
There is still another wrong which needs to be righted; that
is, the right men to handle your fruit on the market. Be sure
when you pick that man that he can be trusted, and that he has
Bulletin 24, Addresses
the proper facilities for handling your products. Always remem-
ber this agent never loses, you are the one who must pay for such
mismanagement. Deal with a reliable concern that is able and
willing to protect you.
Growing the product is not half of the produce game. You
must fight disease in the orchard, fight poor handling, fight dis-
eases arising during transportation and marketing. Find the
right man to sell your goods.
SOME PROBLEMS OF THE STATE PLANT BOARD
Plant Commissioner, Gainesville, Fla.
The importance of protecting Florida against new insect pests
and diseases is becoming more and more evident every day. We
had a meeting down at the courthouse last night at which we
discussed the new sugar cane disease. As far as I know, that
is the first instance of a destructive and serious plant pest getting
into the State of Florida since the State Plant Board organized
and commenced its work, and it was not the fault of the Plant
Board that this disease got in either. We realize full well that,
with the resources at our disposal, we have reached the point
where we cannot give complete and efficient protection to the
agricultural interests of Florida. For one thing, there has ap-
peared in the New England States and in New York a foreign
insect, the European corn borer, which is undoubtedly the most
serious insect pest that has yet appeared in the United States.
It has already been found to attack 49 different plants, and if we
were to expend every dollar that we have for the Plant Board's
work in the State of Florida we could not close every avenue by
which that same insect, the European corn borer, might get into
Sometimes we see that there is some confusion in the minds
of growers about the work of the Plant Board. They do not real-
ize, except in a general sort of way, the distinction between the
work of the Plant Board and of other agricultural agencies. The
work of the State Plant Board is that of preventing, controlling
and eradicating especially destructive insect pests and plant dis-
eases. The dissemination of educational matter or of general
information regarding insects and plant diseases is work for the
Extension Division and work which is very efficiently done by
that division. Scientific research work falls naturally to the
Florida Cooperative Extension
University of Florida Experiment Station. If you will bear these
distinctions in mind you will not be confused at times when you
are considering the work which is done by these different agencies
or when you are seeking assistance. They are in no way com-
peting with each other in the State of Florida. On the other hand,
they are working in the fullest and most hearty cooperation, but
each has its distinctive and useful field of effort. The Plant
Board cooperates with the Extension Division and with the
County Agents in the most harmonious manner; also with the
University of Florida Experiment Station and the College of
Agriculture; also with the Department of Agriculture at Talla-
hassee. You can understand that there are a great many situa-
tions and problems in which it is necessary for more than one
of these organizations to take a hand. The Plant Board also co-
operates with the Bureau of Plant Industry of the United States
Department of Agriculture in the eradication of citrus canker.
We are cooperating with the Federal Horticultural Board in the
quarantine work and also in the eradication of an insect in South
Florida, the banana root borer. We cooperate with the Bureau
of Entomology of the National Department of Agriculture in a
fight on the sweet potato weevil. We have received a certain
amount of cooperation from the Bureau of Plant Industry in the
preliminary fight against the sugar cane mosaic disease.
The big task of the Plant Board was, of course, that of citrus
canker eradication, but as that work has progressed it has be-
come evident that there are a great many things for the Plant
Board to do, and other lines of work have been taken up. I can-
not take the time to discuss these at this time, except very briefly.
Our work against the banana root borer has apparently been suc-
cessful. This insect was found in Dade, Manatee and Polk coun-
ties and we believe that it is now eradicated. It is primarily a
pest of bananas and was introduced from the West Indies, in all
probability prior to the organization of the Plant Board.
The fight against the sweet potato weevil has been carried on
as extensively as the resources of the Board have permitted, and
I think I can safely say that the pest has not succeeded in en-
larging its territory. In Baker county I feel that we are at least
very rapidly decreasing the infested area and will presently free
that county from the pest entirely.
The last session of the Legislature also handed us a little task
on the side, that of eradicating and preventing infectious and con-
tagious bee diseases in Florida. That work is now under way,
Bulletin 24, Addresses
with a small appropriation. We believe that the prevention and
eradication of bee diseases is the first step in building up a very
important honey industry in Florida, where every natural condi-
tion is favorable to the development of this industry. In the bee-
keeping work in general we are cooperating with the Extension
Division with the result that the beekeeper not only gets protec-
tion from bee diseases, but he also gets information on many
other phases of beekeeping work which will help him.
Even if citrus canker had never occurred in the State and if it
is eradicated hereafter, there will always be plenty of work in a
state like this, with conditions such as we have here, for an or-
ganization like the Plant Board.
To me the most serious thing confronting the future of this
work is that we will not be able, without more adequate financial
support than we now have, to continue to render efficient service
to the fruit growers and agriculturists of the State.
THE CITRUS CANKER SITUATION
State Plant Board, Gainesville, FIa.
Five and a half years have passed since the campaign of eradi-
cation against citrus canker began. For a long while the Florida
citrus growers have felt that on account of this disease they were
unfortunate. However, it now seems that Florida is more for-
tunate than most any other citrus section in the world. The dis-
ease is present in countries of India, Siam, Indo-China, China,
Malayan Archipelago, Philippine Islands, many of the South Sea
Islands, Japan, Formosa and the Union of South Africa. When
canker is finally eradicated from this State, Florida will be one
of the very few citrus sections enjoying freedom from this dis-
As is well known canker was brought into this State on dis-
eased nursery trees and distributed before an efficient force for
its detection and eradication could be organized. It had spread
to and become established in some 481 citrus groves and nurseries
in 22 counties.
The encouraging feature of the situation at this time is the
fact that of the 481 infected properties 479 (we believe) have
been cleaned up. Of the two remaining, but four trees showing
canker have been found during the past 16 months, and it is con-
Florida Cooperative Extension
fidently hoped that a complete elimination of the canker in these
two groves will be accomplished within the very near future.
It appears advisable to attempt, in a few words, to give in-
structions how to distinguish the "citrus canker" in order not
to confuse its characteristics with those of several other diseases
often found in the groves.
It is desirable that every "beginner" in grove culture should
know what citrus canker is, and every citrus grower should be
familiar with the general appearance of the disease; for it is a
fact that there is always a possibility of canker being introduced
into a grove.
Citrus canker attacks all kinds of citrus with the possible ex-
ception of the kumquat. Any part of the tree may be infected.
Grapefruit seems to be most easily attacked. Citrus trifoliata
comes next in susceptibility, lime and lemon next, and then follow
most of the common round oranges. Almost all of the citrus vari-
eties have been found severely infected when conditions were
favorable for the development of the disease, and in all cases
the young growth seems to be the most readily attacked.
This disease is primarily a leaf-spot and fruit-spot, altho it
also affects twigs and even old bark and wood. In its early stages
it resembles the scab of citrus trees.
The spots, or cankers, occurring on leaves, fruit and twigs are
not especially difficult to recognize. The cankers may vary from
less than one-eighth to about one-fourth of an inch in diameter,
and they may occur on green fruit (especially of lemon, grape-
fruit and orange), on the bark (especially of young twigs), and
upon leaves. By far the greater number of cases are found at
first affecting only the leaves. The spots are reddish brown,
raised slightly above the level of the healthy surface, and fre-
quently are surrounded by a rather indistinct narrow yellowish
zone. Leaves are especially characteristic, for the spots go thru
the leaf and are almost equally prominent on the upper and lower
surfaces. They may be slightly mottled, and usually the older
spots at least have broken thru the thin outer layer or epidermis
of the leaf. Before breaking thru the leaf surface the cankers are
smooth and almost waxy, but they afterwards have a corky ap-
As usually seen the infections show as small, light brown spots;
they are generally round and may occur singly, or several may
run together, especially when found on the fruits. The spots
are composed of a spongy looking mass and in old cankers the
Bulletin 24, Addresses
surfaces are bulged or raised, biscuit-shaped and crater-like, sur-
rounded by a narrow yellowish zone. Canker does not penetrate
into the rind of the fruit but is mostly on the outer skin. It does
not cause the fruit to rot, but opens the way for certain fungi
to enter which causes the fruit to decay.
Scab in its early stages resembles canker, but scab wrinkles
the leaves while canker does not. Scaly bark also resembles
canker, but the difference is that in scaly bark the bark is gen-
erally smooth, while in canker it is open and has a rough, crater-
like appearance. Anthracnose also resembles it, but this gener-
ally has a sunken appearance while canker is always raised with
the pustules most always circular. A tree affected by lightning
injury shows at times the appearance of canker but it is never
corky nor has it the raised appearance of canker. It has been
very difficult to distinguish black melanose from canker, for the
appearance does not differ much except that in size the canker
is much larger and malanose does not at first open up crater-like
as does canker.
Canker is at this time almost entirely eradicated from Florida.
It now appears that a complete elimination of the disease from
the State will be possible within the near future, but it will de-
pend, to a large extent, upon the vigilance of the ordinary grove
operator as to whether Florida groves will be troubled with can-
ker in the future.
THE DUST METHOD FOR CONTROLLING RUST MITES
ON CITRUS TREES*
W. W. OTHERS
Bureau of Entomology, Orlando, Fla.
The results of several experiments conducted this past season
show that mites are so sensitive to sulphur that dusting as a
method may be considered very promising. We placed leaves
heavily infested with rust mites on the microscope. A towel
was placed over our head to prevent the sulphur from getting
into our eyes. While the mites were being observed sulphur was
blown from a hand duster over the leaves. It was very easy to
see the grains of sulphur fall on the leaves and settle near the
mites. There was on the whole, no unusual activity among the
*Published by permission of the Assistant Chief of the Bureau of Ento-
Florida Cooperative Extension
mites as the grains of sulphur settled near them. A few reared
themselves on their anal end and a few crawled very short dis-
tances, but the majority remained motionless and died without
any movement visible thru the microscope. A great percentage
was dead at the end of five minutes, while no life could be de-
tected at the end of 20 to 25 minutes. These results show that the
effect of the sulphur is practically instantaneous. The tempera-
ture ranged from 90 to 92 degrees, sun bright, but the observa-
tions were made outdoors in the shade.
While no doubt the nearer the sulphur comes to the mite the
sooner death will result, it is not necessary to have it come in im-
mediate contact. We put two large heavy paper sacks over two
branches, each having about six fruits heavily infested with
mites. Into one a fairly large quantity of sulphur was placed so
that it did not come nearer than from 6 to 8 inches to the infested
fruits. The other sack did not contain any sulphur. At the end
of three days no mites had died in the sack without sulphur while
nearly all were dead in the sack containing the sulphur. These
latter fruits are fairly bright while there is much rust on those
fruits in the sack without sulphur.
This method was used on a fairly large scale to control rust
mites in two groves. One grove consisted of about 300 large
seedling trees. It was dusted June 18 from 11:30 in the morning
until 2:30 in the afternoon, the hottest and dryest part of the day.
The sun was very bright and there was a slight breeze from the
Northeast. The actual time required was about two hours. The
team was not permitted to stop except to fill the hopper. An
effort was made to blow sulphur in each tree. To do this the
machine was always operated on the windward side of each row
and the blow or exhaust pipe of the fan was directed as near to
each side of every tree as possible, so that the sulphur would fall
on the foliage and fruits. We used 100 pounds of an impalpable
powder consisting of 80 per cent sulphur and 20 per cent hydrated
lime and also 200 pounds of flowers of sulphur. This would make
the average quantity of material about a pound per tree. The
80-20 product came out somewhat more readily than the fine sul-
phur and did not settle so quickly. Enough of the pure sulphur
came out, however, to kill the mites. The sulphur and lime ma-
terial is most injuriouA to the eyes, but if goggles are worn or a
cheese cloth wrapped over the head it can be applied with a rea-
sonable degree of safety .and comfort.
By using a hand lens much sulphur could be seen on the foliage
Bulletin 24, Addresses
and fruit immediately after the dusting and practically all of it
appeared to remain until washed off by a drenching rain 41/2
days later. Altho some sulphur was not washed off, so little re-
mained that it could not have been very effective in killing young
mites if any hatched from the eggs. The odor of sulphur in the
grove was very evident immediately after the dusting but was
most pronounced just after the heavy rain when it could be-de-
tected several yards distant from the grove.
Examinations made within an hour after dusting indicated that
all mites had been killed. The examination made 24 hours later
also showed this to be the case. Some of the dead mites had a
normal appearance while others had changed to a brownish color.
As a sort of a check on the above examination, living mites could
be most readily observed on an undusted portion of the grove.
In the other grove there were 250 trees of medium size and the
application was made June 20 between 8:30 and 10 in the morn-
ing. The sun was bright, temperature 85 degrees, a slight breeze,
and some dew was present when the work began. We used 100
pounds of flowers of sulphur and 100 pounds of the 80-20 mate-
rial. In this grove the average was somewhat less than a pound
per tree. The sulphur and the 80-20 mixture came out about
the same as they did in the former grove. Some sulphur was
found more than 50 feet distant from the grove on the top of an
automobile where it had been blown by the breeze. It should be
carefully noted that a drenching rain fell 21/2 days after the dust-
Examinations made within 30 minutes after the dusting showed
practically all mites had been killed. The effect of the sulphur
was immediate. On June 24 or four days after the dusting the
brown dead bodies of the rust mites could be seen in great abund-
ance on the leaves and fruit.
Practically no mites were present in either of the groves for
a month after dusting. The results show that flowers of sulphur
was as effective as the finely ground mixture of sulphur and lime.
In fact, there were always a few less mites on the sulphur tests
than on the mixture tests. Examinations were made in the tops
of several trees and sulphur was found on the leaves and the
mites were dead.
It is interesting to know that the mites are killed on the lower
surfaces of the leaves as well as on the upper surfaces and fruit.
Of the 30 mites found on the four examinations made in Grove
1, 23 were on the fruit, five on the lower surface and one on the
Florida Cooperative Extension
upper. In Grove 2 of the 300 mites found in four examinations,
188 were on the fruit, 32 on the lower and 81 on the upper sur-
It has been noted that a drenching rain fell 41/2 days after
Grove 1 was dusted and 21/2 days after Grove 2 was treated,
which accounts for the larger number of mites having been found
in the latter grove. The test shows conclusively that if dusting
is to be of the greatest value it should be applied when there is
the least liability of rain. In all probability if no rains fall for
8 to 10 days after the application the mortality would be practi-
On October 13, Grove 1 with an almost complete mortality of
mites, had about 60 per cent bright and 40 per cent golden, no
russets. The portion of the grove sprayed with lime sulphur
nearly two weeks after the dusting, had at least 90 per cent bright
and 10 per cent golden. The owner said the russeting had taken
place during September. The percentage of brights and russets
was about the same in Grove 2 and in Grove 1. The fruit on
the undusted trees is about 95 per cent black russets.
It would appear that one dusting is not enough to produce
bright fruit, but in all probability two will be satisfactory.
It is hardly fair to compute costs of dusting based on the above
groves, since an entire day's charge for the team and labor must
be made for only two hours' actual work. Even if such is done
the cost for treating this grove is about 7 cents per tree. It is
reasonably certain that a pound of sulphur is sufficient for a tree
and that a team and two men can dust 40 acres per day. The
approximate cost for treating 40 acres would be: Sulphur, 2,400
pounds, 1 pound per tree at 4c, $96; team one day, $6; two men,
$6; machine one day, $5; total, $313. This would average 4.7
cents per tree. Perhaps this estimate is somewhat too high. At
any rate, the cost would scarcely be less than 4 cents per tree
nor more than 5 cents per tree per application.
The machine used was mounted on a four-wheel regular wagon
truck. The fan revolved about 3,500 revolutions per minute, and
was run by a gasoline engine. One of the main objects is to get
the material high enough so that it will fall on the leaves. To
do the best work the delivery pipe should be within 5 or 6 feet as
high as the trees.
While any method for controlling citrus pests should be tried
out for more than a single season to decide its merits, it would
appear that dusting may have a place in Florida citrus groves.
Bulletin 24, Addresses
H. E. STEVENS
Plant Pathologist, Experiment Station
Citrus scab is a fungus disease chiefly of the fruit and foliage.
It is characteristic and distinct from other citrus diseases, still it
resembles melanose to some extent and may frequently be con-
fused with it. Scab is probably not so serious a disease as mela-
nose. However, we find scab widely distributed over the state and
it occurs in practically all citrus growing sections where grape-
fruit is grown. It is probably more prevalent in the southern
part of the state, where the climatic conditions appear to be more
favorable for the development of scab.
Scab is often severe in nurseries, especially on the stock (such
as sour, rough lemon and grapefruit) and even on the buds of
grapefruit. From the growers' standpoint the disease is more
important on grapefruit than on other commercial citrus variety.
Scab also attacks young trees that have been recently planted
and frequently in such plantings it is a rather difficult and per-
nicious disease to handle. On bearing trees it injures both fol-
iage and fruit, but the injury is more apparent on the fruit and
probably results in a greater loss to the grower. Scab either
makes culls or unsightly fruit which may have little or no
The remarkable adaptability of this fungus to different host
plants is shown in its attack on the avocado, a plant far removed
from the citrus group, and from all the information we can gain
scab has passed to the avocado within the past 5 or 6 years. Prob-
ably a strain from the sour orange or grapefruit has adapted it-
self to the avocado and thus a new strain has been created which
promises to cause serious trouble to the avocado industry.
Of the citrus varieties affected with scab we find the sour
orange, rough lemon, grapefruit and tangelo badly attacked by
the fungus. It occurs more moderately on the Satsuma, tangerine
and lime, and thus far we have noted scattering infections of
scab on seedling sweet oranges, Parson Brown, Pineapple and the
Lue Gim Gong. However, the disease has not developed suffici-
ently on any of the last named varieties to be of any consequence
The cause of scab is a parasitic fungus known as Cladosporium
citri. It grows and propagates on the scab masses and warty
projections produced on the leaves, green twigs and fruits. The
Florida Cooperative Extension
spores can only be detected by means of a microscope and then
only under favorable conditions. The peculiar warty projections
or scabby masses on leaves, young stems and fruits are the char-
acteristics by which the disease is recognized. If we follow the
life history of this fungus from spore to spore we find that the
following takes place: the spore falls on the young succulent
tissue of the citrus, whether fruit or leaf, and if a drop of mois-
ture is present the spore germinates and punctures the tissue.
Further growth takes place within the affected plant cells, form-
ing an irregular mass or wart-like projection of the tissue. The
surface of this later becomes scab-like and the inner mass is
interwoven with fine threads. Under moist conditions some of
these fungus threads come to the surface in the scabby masses
and produce small round or oval shaped spores, completing the
life cycle of the fungus. These spores will infect new growth
and the scab development is thus continued as long as growth of
the citrus tissue continues and moisture is present. The spores
are readily carried by the wind from tree to tree and in many
localities from grove to grove. No doubt insects and birds carry
the fungus a greater distance.
After the succulent tissue of the citrus tree or fruit has become
hardened no further scab infections will occur on that particular
growth. However, the fungus on the scab-like masses may be
carried over in the dormant stage thru long periods, and under
moist conditions a new growth of spores is produced. So the
necessary conditions for the development of scab are the presence
of the fungus spores, moisture, and young, tender growth. It
has also been found that the fungus seems to develop more rap-
idly under cool temperature and frequently the heaviest infection
of scab occurs in the spring.
New growth may be infected from the time it begins to put out
until 5 or 6 weeks later and probably the fruits are not subject
to infections for a longer period than 4 to 6 weeks after the
bloom has dropped. By taking advantage of this it is possible to
protect the fruit thru this susceptible period by spraying with
fungicides. Where it is desired to have clean fruit this will be
necessary, especially in seasons where the rainfall is abundant.
To protect the fruit for a period of a month or six weeks would
not require too many sprayings to make it prohibitive and where
this is the main object in view probably the following number of
sprayings would be sufficient:
The first spraying should be made just before the petals open.
Bulletin 24, Addresses
using lime sulphur solution of 32 degrees Baume, 21/2 gallons in
100 gallons of water. A second spraying should be made when
from a third to a half of the petals are off and a third spraying 7
to 10 days after the second, using the lime-sulphur solution in
each case. If, however, the previous growth has been seriously
affected with scab and the trees are full of scab infected leaves,
it would probably be well to make a thoro application of Bordeaux
mixture previous to the first flush of growth in the spring, then
to follow with three applications of lime-sulphur.
A spray schedule, Extension Bulletion No. 18, has been pub-
lished by the Station which takes into account the control of
scab. By following this schedule the citrus grower may be able
to avoid a very large percentage of scab that occurs in his grape-
fruit grove. By systematic spraying each season it should not be
difficult to grow grapefruit free from scab.
Young grapefruit trees that have not yet come into bearing
offer a more complex problem in the way of control. Young
trees usually put out growth at an untimely season and if scab
is present it will continue to develop at frequent intervals thru-
out the year. To spray such trees at regular intervals thruout
the season would be too costly. A more desirable plan would be to
go over such trees during the dormant period in winter and prune
out as far as possible all scab infected twigs and leaves. Then
a thoro application of Bordeaux mixture, 3-3-50 formula, should
be made previous to the new flush of growth in the spring. This
may be followed by a second spraying about the time the new
growth puts out, using lime-sulphur solution in a dilution of 21/2
gallons to 100 gallons of water.
In the nursery scab can be kept completely under control by a
systematic spraying with Bordeaux mixture. This will require
constant spraying thruout the season at intervals of a week or
ten days during the period that the growth is putting out or de-
THE WHITEFLY EATING DELPHASTUS
J. R. WATSON
Entomologist, Experiment Station
During the year 1915 our attention was called to a little lady-
beetle in California which was feeding upon a California species
of whitefly. Upon the mere chance that this insect might take
to our citrus whitefly, an effort was made to secure specimens.
Florida Cooperative Extension
Not until 1916, however, were we successful, thru the cooperation
of the California State Insectary, in securing a small colony, and
found that they took readily to the eggs and young larvae of the
citrus whitefly. We attempted to breed these in the insectary,
but altho we raised them for a generation or two we did not suc-
ceed in bringing them thru the winter.
In 1917 a larger number of beetles were imported and some
of these were liberated in different parts of the state. Of these,
at least three colonies were able to establish themselves, one at
Bradentown, and one near Lakeland, multiplied rapidly and
passed the winter successfully. From the Bradentown colony
several hundred shipments of beetles have been made during the
past two seasons to different parts of the state.
About the first of October the writer made an inspection of the
Bradentown grove, and it is chiefly with the conditions found here
that the present paper has to deal. We found that the beetles
were becoming very scarce due apparently to the scarcity of food,
there being so little whitefly in the grove that were it not for
purple scale, spraying would be entirely unnecessary. Except for a
partial spraying for purple scale in June the grove had not been
sprayed for a couple of years, and whitefly was scarcely notice-
able, except a few cloudy winged ones on water sprouts. No
material damage was being done to the grove by whitefly. As
there was very little fungts in the grove it was apparent that
the clean-up was not caused by entomogenous fungi.
The beetles have been extremely abundant in the grove all
summer and it was apparent that the very satisfactory clean-up
of the grove was due to the results of their activities. We may
then say that in the course of two years these beetles have, in one
grove at least brought the whitefly under at least temporary con-
The beetles do not appear to breed as rapidly during the win-
ter and judging from last year's experience we will expect a
considerable increase in the spring brood of whitefly. However,
the beetles have been of very distinct value in this grove.
Early in the summer a colony of these beetles was established
in a grove at Crescent City, and the owner of the grove reports
that they are there in large numbers.
The beetles have been spread over the state fairly well, but it
is our desire to continue this distribution as soon as arrange-
ments can be made which will probably not be until spring. For
Bulletin 24, Addresses
the present, the beetles are so scarce at the original grove at
Bradentown that their collection is impractical.
Just how far these beetles will spread of their own accord we
are not able to say. I have found them in practically all the trees
examined in Bradentown. We cannot say how much this spread
has been due to the flight of the beetles.
Some of the early colonies were too small-that is, a good
many of the beetles died in transit and only a few were found alive
on opening the box. For this reason we have recently doubled
the number of beetles sent and charged fifty cents instead of
twenty-five cents for a colony. Even then it has sometimes been
necessary to import the beetles a second and third time before a
catch was obtained. Doubtless a larger number of beetles would
make the catch more certain.
The chances of their becoming established and multiplying are
much better if they are liberated in one place. When they become
established in one grove the owner can, if desired, readily carry
them to other groves.
All that is necessary upon receiving the beetles is to open
the box and let the adult beetles fly away, this being done under
a tree in the grove. It is best then to tie the box onto a leafy
twig so that any larvae that may be present in the box, or may
later hatch out from the eggs can make their way to the whitefly
eggs. A water sprout is probably the best situation for the box.
If it is desired to spray a grove in which these beetles are pres-
ent, we recommend that the water sprouts be left unsprayed as
far as possible. One can cut off the water sprouts directly in
front of the spraying outfit and carry them into the trees that
have already been sprayed, thus insuring that some of the beetles
and larvae will escape.
The oil emulsions used for whitefly and purple scale will cer-
tainly kill all the larvae that are hit and a large portion of the
adults. Some of the adults will undoubtedly escape by flying from
one tree to another which has been sprayed.
The beetle is a minute insect about a twelfth of an inch long
and very dark brown, almost black in color. The larvae are dirty
white, grub-like creatures.
There is a native lady beetle belonging to this same genus
which is often found feeding upon whitefly eggs, but for some
reason never becomes abundant. This insect is about the same
size as the California lady beetle but is lighter in color.
Florida Cooperative Extension
THE CONSERVATION OF CORN FOR THE CITRUS GROWER
WHO FEEDS LIVE STOCK
RICHARD T. COTTON
Stored corn is subject to injury by numerous insects, all of
which take their toll of the crop at the expense of the farmer.
Aside from the loss of weight occasioned by the ravages of the
insects, the infested grain is undesirable as food for live stock.
In the State of Florida last year 880,000 acres were planted to
corn yielding a crop of 14,080,000 bushels and valued at $19,-
430,000. It has been estimated that at least 10 per cent of the
crop was destroyed by granary insects, a loss to the farmers of
Florida of nearly $2,000,000.
The greater part of the damage was caused by two insects,
the corn weevil and the so-called Angoumois grain moth, altho
others such as the Indian meal moth, the broad-nosed grain wee-
vil and the coffee bean weevil were locally abundant and caused
Practically all of the aforementioned insects infest the corn
while it is yet in the field, laying their eggs in or on the kernels
of corn just when they are beginning to harden. When the corn
is harvested the insects in their various stages are carried in
with the corn to the crib where if unmolested they continue their
depredations until the corn is reduced to dust. In the warm cli-
mate of Florida these insects breed and multiply with such
astounding rapidity that a slight infestation in the field if uncared
for at harvest time will in a very few weeks reach alarming pro-
The loss caused by these insects is due mainly to poor storage
conditions and lack of proper treatment to destroy the insects.
As an illustration of the advantages gained from a proper treat-
ment of infested corn I will cite the following instance: A farmer
in Marion county, who found that his corn was weevilly when it
was harvested in 1917 and not having a tight crib, spent $13.45
to convert a carriage shed into a gas tight crib large enough to
hold 150 bushels of corn. For less than $1.00 he treated the 100
bushels of corn placed in this crib in the fall. After holding the
corn 45 days he sold it at 25c per bushel more than the price he
was offered for it at harvest time. Without fumigation he could
not have saved his corn without loss. By proper treatment he not
only got back the cost of the crib, but made a profit of about 75
Bulletin 24, Addresses
per cent on his investment for the year and still had his crib left
for another year.
With the $2,000,000 lost in 1918 weevil proof cribs could have
been built to house the entire crop for that year.
Corn should be harvested as soon as it is fit to be brought in
from the field since the longer it stands in the field the greater
the resulting infestation. As soon as it is harvested it should
be sorted, if possible, and the badly damaged ears should be kept
aside for immediate use, the rest should be fumigated with car-
bon bisulphide in a gas tight crib at the rate of 4 to 6 pounds to
each 1,000 cubic feet of space in the crib. If corn is only slightly
infested one fumigation will be enough, but if heavily infested
another fumigation should be given in about three weeks. The
carbon bisulphide should be placed in shallow pans on top of the
corn to evaporate.
SOME GROVE PRACTICES IN DISEASE AND INSECT
H. G. CLAYTON
It is the intention here to briefly discuss some practices carried
out by the leading growers of Manatee county in controlling a
few diseases and insect pests.
Most of the spraying is done with hard sulphur water from
artesian wells which makes it difficult to get good results from
oil emulsions without the aid of a softener. Nearly all brands
of emulsions and miscible oils are used including government
formulae and none have proved entirely satisfactory alone. The
water varies at times and what will mix one day will not the next
Whitefly and scale are two difficult insects we have to control.
Our spraying is governed in the field by the insect that is the
more numerous. For example, if we have a heavy scale infesta-
tion and very little fly as is more common in young groves, we
spray for the scale and pay little attention to the fly, and where
the whitefly and scale are both numerous we spray for the white-
fly and this also takes care of the scale. A one percent oil emulsion
is used and for bad infestations a second application is given in
about four weeks. This oil spray is used in the spring, usually in
May when fruit is one inch in diameter and again in the fall. The
time of the fall spraying is influenced by two factors, especially
Florida Cooperative Extension
when whitefly is present in numbers; first, most growers wait
until the red scale fungus has about ceased working on the scale
which may be the last of October or first of November some years,
and in late September or early October during other years. Sec-
ond, if the fruit is an early variety and sooty mold is plentiful,
spraying is done at least two weeks before shipping is to begin,
as the spray causes the mold to loosen and it may then be readily
removed by the washing machine.
For groves where the whitefly is the more serious of these
two pests the practice is to spray sometime in late April or May
(with oil emulsion) when most of the adult flies have disappeared.
Where fungus is present or has been introduced it holds the fly
in check until September or October, when another spraying is
For rust mites the leading growers spray early in the spring
as they become numerous and when they begin to appear on the
fruit. Lime sulphur is used at the rate of 1 to 50 and 1 to 66,
depending upon the grower and weather. Some like it stronger
than others and the cool weather makes the stronger solution
safe. A number of growers add soluble sulphur to the oil emul-
sion, using 5 to 6 pounds per 200 gallons. Spray when an oil is
to be used and in this way save an extra spraying. The number
of sprayings given for this pest varies with the season. Some-
times one or two sprayings are sufficient and other years three
or four are necessary to get bright fruit. Dry weather is most
favorable for rust mites to multiply. After fruit has been kept
clean and bright all summer some growers spray again in Sep-
tember rather than give the rust mite an opportunity to russet
the fruit at this late date.
Melanose was prevalent in Manatee county this summer and
pruning is the chief reliance for control. Very few growers use
Bordeaux for this disease. They simply prune and try to keep up
the vitality of the trees by good cultivation, fertilization and the
controlling of insect pests.
Delphastus lady beetles which live on the whitefly eggs and
larvae have multiplied rapidly this summer in a number of groves
and have proved their worth as an aid in controlling this pest.
They have been introduced into a number of groves and appear
to be gaining a good foothold.
An experiment with dry lime sulphur and barium tri-sulphide
was made, but is not conclusive at this time. One plat of 51 trees
was sprayed with dry lime-sulphur 6 pounds to 200 gallons of
Bulletin 24, Addresses
water. Another plat of 57 trees was sprayed with barium tri-
sulphide 6 pounds to 200 gallons of water. The rest of the grove
was sprayed with ordinary lime sulphur.
All sprays appeared equally effective in killing rust mite, but
were less lasting on the two plats sprayed with the compounds
than on the trees sprayed with ordinary lime-sulphur. The bar-
ium tri-sulphide mixed with the hard water better than the dry
THE USE OF VEDALIA AND FUNGI IN THE CITRUS
E. W. BERGER
Entomologist, State Plant Board
It is well known that insects have natural enemies among
other insects, and that they are also subject to diseases, all of
which at times destroy large numbers of them. Diseases of in-
sects are mostly due to fungi, whereas among higher animals
most diseases are caused by bacteria.
The Vedalia, or Australian lady beetle is the principal insect
enemy of cottony cushion scale. In Pinellas county, where the
scale was first introduced, and where the Vedalia has had the
longest time in which to show its worth, outbreaks of cottony
cushion scale are very rare.
Vedalia may be introduced at any time when the cottony cush-
ion scale is getting abundant. I do not believe, however, that it
is worth while to introduce it before the scale is so abundant that
about half a cup full can be easily scraped from the bark. Grow-
ers sometimes order Vedalia when they find a mere trace of scale
in a few trees. In such instances there is not enough scale pres-
ent to supply food for the Vedalia. I should not advise introducing
it just prior to spraying with oil or soap insecticides, but wait and
introduce it two or three weeks after the spraying, as spraying
with oil or soap solutions will also reduce the cottony cushion
scale. In case one feels it absolutely necessary to introduce
Vedalia and at the same time spray with oil emulsions or soap,
a few trees that are the most heavily infested with the scale
may be left unsprayed and the Vedalia introduced into
them. After the Vedalia has become established in these trees
they will rapidly spread to all parts of the grove.
In so far as we know, Vedalia feeds only on cottony cushion
Florida Cooperative Extension
scale and attempts at feeding it on other things have so far failed.
It is probably unnecessary to introduce Vedalia in any locality
a second time, as it appears able to continue its existence on the
few scales remaining after an infestation is under control. In
actual practice, however, growers, when they rediscover cottony
cushion scale, at once order Vedalia. That is a safe practice, and
the price is not great. However, this situation will gradually
change, and growers will be less nervous when they rediscover
scale, knowing that the Vedalia will soon come along and clean
In so far as possible, the Vedalia is mailed out in the pupal or
resting stage. As they do not consume food in this stage, and
remain dormant for several days, this allows time for them to
reach their destination in better condition than if the live beetles
or live larvae were sent.
The spore-spraying method of introducing fungus consists in
washing the spores from the fungus material into water and
spraying it into the trees infested with the insects.
The principal fungi that may infect the common and cloudy-
winged whiteflies of citrus are, the red and yellow aschersonia,
brown, cinnamon and the white fringed fungi. The principal
fungi that infect and assist in the control of the common scales
of citrus are the red-headed scale, pink scale, white-headed scale,
black scale, and the turbinate aschersonia.
Briefly stated, any one of these fungi can be made to infect
its corresponding host insect by spraying it into the trees. In
doing so avoid the use of spraying machinery which has pre-
viously been used in spraying Bordeaux mixture, lime sulphur,
or other fungicide. Neither should mixtures of spores and water
be allowed to stand in brass containers but a few minutes.
While the spore-spraying method is emphasized here, the
method of tying pieces of twigs with fungus on them is more
generally employed for the scale fungi. All the fungi used for
the control of citrus whiteflies and scales may be mixed together
and sprayed on at one spraying. Fungi require considerable
moisture and a high temperature. These conditions prevail dur-
ing the summer rains from perhaps the middle of June thru the
middle of September, and that is the time for introducing fungus.
Still another fact favors introduction of the fungi during that
period. Spraying with oil or soap insecticides is less practicable
at that time on account of the frequent rains which are apt to
Bulletin 24, Addresses
wash them off before they become effective. The writer there-
fore advises, that if some or all of the fungi known to infect white-
fly and scale insects are not present in a citrus grove that they
be introduced, or if present but not sufficiently abundant, fungus
spores be distributed to those trees having little or none. By so
doing the insect pests may be so controlled by the fungi that
other treatment will be unnecessary. On the other hand, after
fungi have been generally introduced or sprayed thruout a grove
and it is found at the end of the season, say by October, that the
insects are not under sufficient control, the job should be com-
pleted by spraying with a good oil emulsion as a final cleaning up.
Moisture conditions in hammock groves are much more favorable
for fungi than in groves on high pine land. Trees in a thrifty
condition, dense with foliage, retain an atmosphere more replete
with moisture, and therefore are a better place for the entomo-
genous fungi to thrive than trees out of condition. Satisfactory
results from the use of the fungus parasites of insects in trees
and groves decidedly out of condition or in trees not over
three years from planting need not be expected.
The red and the yellow aschersonia, can be successfully grown
in pure culture in the laboratory. The use of pure cultures be-
came important when citrus canker was discovered in the state
and it became dangerous to use fungus material collected from
other trees. The growing of pure cultures of the red aschersonia
by the Entomological Department of the State Plant Board is
now in its fourth year and some cultures of the yellow aschersonia
have been grown during the past three years. During the first
years when less than a thousand cultures annually were produced
the demand considerably exceeded the supply. Last year a spe-
cial effort was made to produce a larger supply and about four
thousand cultures were grown. The advantage of using pure cul-
tures of fungus consists in obviating all danger of introducing
other injurious diseases, as nothing but the special kind of fungus
grown occurs in the pure cultures.
CITRUS SCAB-CAUSE AND CONTROL
CHAS. M. HUNT
State Plant Board
Citrus scab, known generally as Scab or Rough Lemon Scab,
is a disease of the citrus tree caused by a fungus. It was intro-
duced into the United States about 1885. At this time it was
Florida Cooperative Extension
first noticed in the heart of the citrus growing region of Florida,
and spread rapidly to all parts of the state. It is supposed to
have been brought into Florida on Satsuma stock from Japan,
and is now one of our common and well known fungus diseases.
Citrus scab attacks young tissue, such as leaves, stems and
fruit, forming characteristic scab-like masses, or warty projec-
tions that are easily distinguished from injuries produced by
other agencies. In these injuries the fungus survives from one
season to the next.
The scab fungus arises from a microscopic spore or seed-like
body. From these spores there grow out short tubes which pene-
trate the skin, feed on, and injure the growing tissue of the citrus
tree. In consequence the tissues of the plant become swollen
around the point of infection, breaking the skin and causing
warty and scabby projections. These spores may be blown or
carried by insects to the vigorous young leaves and fruit of
healthy trees and infect them. In severe attacks projections of
a dark grey or tan color will be seen. As the leaves develop the
spots get larger and darker, depressed on one side of the leaf and
raised on the other, making the leaf much distorted. The more
mature leaf tissue is seldom affected, however old leaves will be
found bearing spots that were formed when the tissues were
It has been known for a long time that scab attacks sour
orange, rough lemon, Satsuma and tangerines, but not until re-
cent years was it reported as attacking grapefruit and oranges.
It seems to be doing most damage to grapefruit at present.
In the last two years a new and apparently undescribed dis-
ease was reported infecting avocados. It was called Avocado
Scab and was found on investigation that the same fungus that
causes the citrus scab is the cause of Avocado scab. This fact
shows that this fungus is capable of attacking plants of an en-
tirely different genus than that of the citrus family and may re-
sult ultimately in its attacking a great variety of subtropical
The damage done by scab is thought by many as being confined
to the fruit only, but it also retards the growth of young trees.
On new growth the young leaves and stems are attacked so badly
sometimes that complete defoliation takes place and the new
wood which should become bearing wood the following season
The climate of Florida has a great deal to do with the spread
and extent of the disease. If the season is dry, there is very little
Bulletin 24, Addresses
scab present on the new growth and fruit. If the season is wet,
scab spreads very rapidly.
Leaves and shoots may become infected any time within three
or four months after the growth puts out and fruits are probably
subject to infection for a month or six weeks after the bloom
drops. The comparatively short period during which the foliage
and fruit are subject to infection makes it possible to protect the
fruit fairly well by spraying during this period; first, just be-
fore the new growth starts; second, about the middle of the
blooming period; third, two to three weeks after the second
Bordeaux is without a doubt the best fungicide to use. Lime
sulphur is probably next in effectiveness. However, when spray-
ing a grove with Bordeaux it must be followed with an insecticide
or oil spray, regardless of whether the grower believes it is
needed or not. Another good spray schedule for scab is to spray,
first, with Bordeaux adding oil; second, Bordeaux without oil;
third, with lime sulphur; fourth, with an insecticide.
Watching a grove and pruning out and burning the attacked
limbs and stems as they appear infected is another method of
control. This method should be used only in case scab is just
getting started, or the grove is very lightly infected.
A. O. KAY
Bureau of Public Roads, Washington, D. C.
The first consideration in irrigation is to be certain of a con-
stant and adequate supply of water. The condition of the water
must also be ascertained-whether it is always clear or at times
contains suspended matter. In some irrigation systems it is
positively essential that no solid matter be in the water, while in
others it is immaterial.
The next consideration is the method of irrigation to be fol-
lowed. This will depend to a very great extent upon the
topographical condition of the land, whether flat, gently sloping
or rolling; upon the soil conditions, whether it is light or heavy,
of coarse or fine texture and structure; and upon its water hold-
ing and transporting capacity.
The nature of the crop is also important, as shallow rooted
plants will require the moisture near the surface, while the deep
rooted crops will permit of a deeper source. The subsoil will also
be a determining factor as upon the nearness of an impervious
substratum to the surface will depend the amount of water re-
Florida Cooperative Extension
quired for one type of irrigation which may be adaptable to the
grower's needs. The nature of the crop, however, will be the
primary factor in determining the system to be adopted.
There are three general types of irrigation methods namely:
SUBSURFACE, SURFACE and OVERHEAD.
SUBSURFACE irrigation (as its name implies) is an under-
ground means for supplying the required moisture. This is
very popular in the Sanford district, and from it good results
have been obtained. The water is supplied thru underground
pipes or by means of open ditches. The underground pipe
system as generally adopted consists of mains of 6-inch terra
cotta sewer pipe, joints cemented and made water tight and laid
along the highest point or ridge, and sub-laterals of ordinary
clay drain tiles 3 or 4 inches in diameter and 12 inches long.
The sub-laterals are laid with open joints, placing the short
lengths end to end. Cinders or saw dust is generally placed over
the joints to prevent fine sand from entering the pipe and causing
a stoppage. The grades for the laterals vary from 1 to 3 inches
per 100 feet and are ordinarily obtained by turning the water
into the trenches before the tile is laid so that the water can
remove all irregularities from the bottom of the trench. The
laterals are spaced from 18 to 24 feet apart and from 12 to 20
inches deep. The closer spacing has been found to be best.
In the operation of the subsurface method the water is turned
into the main feed lines and divided among the laterals, the water
being turned on until the ground is saturated. These laterals
will also serve as drains during seasons of excessive rains.
The cost of this system ranges from $100 to $150 per acre,
exclusive of the water supply or drainage outlet to the field.
In the open ditch method of subirrigation the ditches are
spaced about the same distance apart as the pipes. It is a more
crude and less costly way, but answers the purpose until the other
system is obtainable. It takes considerable land out of cultiva-
tion. This type ranges from $10 to $15 per acre.
Excessive irrigation is a common practice and is more costly
than ordinarily realized, for upon opening the tile lines to drain off
the excess water considerable fertilizing elements are carried
The most necessary condition for subsurface irrigation is a
porous'soil overlying an impervious substratum. The land must
be reasonably level otherwise the hollows will be filled while the
high spots will not have sufficient moisture. Care must be
Bulletin 24, Addresses
exercised where shallow rooted plants are under this type of
irrigation, to see that the water is sufficient for their needs.
This system requires an abundance of water and can only be
applied under that condition. The common practice is to
irrigate every ten days or two weeks, during the growing season,
depending upon the rainfall.
SURFACE irrigation may be divided into two parts: flooding
and furrow. Flooding itself may be subdivided: check and
border. In using the flooding method the field should be quite
even and be either flat or have a very light slope. The water is
let into the field in a thin strip from ditches around the field. In
check irrigation the tract is divided into blocks either rectangu-
lar, or according to the contours, and a low levee made around
each check. Large heads of water are turned into each check
until enough has been supplied, when the water is then turned
into the next check. This method is inexpensive and is mostly
applied and best adapted to grains and grasses.
Nearly all crops planted in rows and cultivated are irrigated
by the furrow method. In this method the water is supplied to
the rows by means of ditches in or around the edges of the field
or thru underground pipes with riser and hydrants spaced at
certain intervals. The grades or slope of the field should not be
less than 6 inches or more than 18 inches to the 100 feet in a
light sandy soil. If of less slope there will be difficulty in getting
the water to the end of the furrow, and if greater than 18 inches
there will be a great tendency to scour. Where the open ditch
method is used notched boards may be placed along the side of
the feed lines to regulate the amount of water going into each
row. These boards will not necessarily be level but will vary in
height according to the slope of the ground in the individual row.
Where the slope is slight more water will be required to reach
the end of the row than where the slope is greater, as the velocity
of the water moving in the row increases with the grade.
Where the pipe system is adopted the mains, except where
under great pressure, are usually of terra cotta sewer pipe, joints
cemented and made water tight, spaced from 100 to 200 feet
apart, with risers or hydrants spaced at intervals. On steep
slopes the closer spacing is used. The water as taken from the
hydrants is conducted to the furrows by means of hose or slip
joint pipes. These pipes are connected to the hydrant by quick
attaching methods and as each furrow receives its required
amount of water the pipe or hose sections are either added or
reduced as the case may require.
Florida Cooperative Extension
Where the pipes are under great pressure iron pipes have
mostly been used, but the Office of Public Roads, U. S. Depart-
ment of Agriculture, has been experimenting with a reinforced
terra cotta pipe and meeting with good success. This pipe will
cost less than the iron pipe, particularly for the larger sizes.
In the OVERHEAD SYSTEM of irrigation the water is distri-
buted thru pipes, set on posts, containing small nozzles spaced
at 3 or 4-foot intervals or by means of spray and revolving
nozzles. These pipe lines are spaced according to the water
pressure available at the distributing point. In the overhead
pipe system a pressure of 40 pounds to the square inch at the
nozzle will throw the water about 25 feet at an angle of 45
degrees, so that by spacing the lines 50 feet apart all the land
in the section will receive moisture. A reduction in pressure
must necessarily mean a closer spacing of the lines. There is a
limit to the amount of pressure, however, as too great a pressure
will reduce the discharge at the nozzle.
In the spray and revolving nozzle method the discharge pipes
are vertical with the nozzles placed on top. The piping required
amounts to the same in all overhead systems. The overhead
piping system has an advantage over the spray and revolving
nozzles in that it results in a more even distribution and is more
readily cleaned out should there be a stoppage at the nozzle. In
the overhead piping system by removing the cap at the end of
the line the obstruction may be forced out while the other system
requires individual treatment.
In the overhead system of irrigation clean water is positively
essential. This system is best adapted to trucking as it applies
the water at the top for shallow rooted plants. It is also useful
in setting young plants and where the soil is light can be used
to prevent it from blowing and cutting the tender leaves. This
system is the most costly and can be installed for from $300 to
$500 an acre.
The designing of an irrigation system should be left to those
who are competent and reliable in that line of work. Pump
manufacturers in their catalogs give tables for designing irriga-
tion systems, but these are mostly based on theoretical values,
whereas the actual construction varies greatly.
In closing permit me to state that the Bureau of Public Roads,
U. S. Department of Agriculture, maintains men in this state
who are at the service of the growers in their farm drainage and