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Group Title: Citrus Experiment Station, Lake Alfred, Florida
Title: The Citrus Experiment Station, Lake Alfred, Florida
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Permanent Link: http://ufdc.ufl.edu/UF00090279/00001
 Material Information
Title: The Citrus Experiment Station, Lake Alfred, Florida a branch of the Florida Agricultural Experiment Stations, Institute of Food and Agricultural Sciences
Physical Description: 14 p. : ill. ; 15 x 21 cm.
Language: English
Creator: Citrus Experiment Station (Lake Alfred, Fla.)
University of Florida -- Agricultural Experiment Station
Publisher: Florida Agricultural Experiment Stations
Place of Publication: Lake Alfred, Fla.
Publication Date: 1966?
Copyright Date: 1966
 Subjects
Subject: Citrus -- Research -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
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Bibliographic ID: UF00090279
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 268677747

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        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
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        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
    Back Cover
        Page 16
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A BRANCIe
FLORIDA Al
INSTITUTE


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First building at the Citrus Experiment Station was constructed in
1926, nine years before the first resident scientist in charge was
named. Dr. A. F. Camp (at right) served as vice director in charge
until 1957.


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History of the Station
The Agricultural Experiment
Station at Lake Alfred, known as
the Citrus Experiment Station, was
legally established by action of the
Florida Legislature in 1917.
The Board of Control was au-
thorized to establish this branch
station, administered by the Flor-
ida Agricultural Experiment Sta-
tions system, for investigation of
citrus problems, on the condition
that growers show sufficient inter-
est to donate land, groves, build-
ing, or money to a total value of
$10,000.
A committee of Polk County
growers raised $13,782.15 and in
1919 offered the Board of Control
a tract of land near Lake Alfred
consisting of 84 acres. On this
tract the offices and laboratories of
the Citrus Experiment Station are
now located.
The first money appropriated for
operation of the Citrus Station
came from the 1923 Legislature
which approved approximately
$15,000 per year. This first ap-
propriation was available for the
1923-24 fiscal year.


In 1926 the first permanent lab-
oratory building and a greenhouse
were built. Both are still in use,
although the laboratory was en-
larged in 1936. The administration
building, packinghouse, canning
plant, and shop-storage buildings
were built between 1945 and 1950.
The new production building was
built in 1957, and an addition to
the processing plant was begun in
1965.
During this time the station ac-
quired a total of 285 acres of citrus
land.
At first the Citrus Station was
operated through the Main Station
at the University of Florida, with
scientists residing in Gainesville
and carrying on work at Lake Al-
fred. Later, staff members respon-
sible to Main Station departments
were stationed at Lake Alfred.
In 1935 the policy was changed,
due largely to growth of the citrus
industry and increase of work load,
concentrating citrus research work
at the branch station.
At one time the Citrus Experi-
ment Station had only five research
staff members. The staff has ex-
panded steadily over the years,


Early type spray equipment




reaching 30 in 1948 and 59 in 1961.
Most of these scientists were em-
ployed by the Experiment Stations
system, but beginning in 1943 re-
searchers working for the Florida
Citrus Commission were assigned
to Lake Alfred.
In 1961, 17 of the 59 staff mem-
bers were employed by the Citrus
Commission. All of these are en-
gaged in packinghouse and pro-
cessing investigations.
From 1923 until 1935, when the
policy was changed, J. H. Jeffries
served as superintendent of the
Lake Alfred facility. With re-




The first Citrus Station
laboratory is shown at up-
per left along with the first
greenhouse (lower left).
Dr. Herman J. Reitz, right,
became horticulturist-in
charge in 1957 and still
heads the 59-man research
team.


assignment of all major citrus re-
search administratively to the
branch, Dr. A. F. Camp was trans-
ferred from the Main Station to
become the vice director-in-charge.
He served until his retirement in
1957.
Dr. Herman J. Reitz, present
Horticulturist-in-Charge, replaced
Dr. Camp July 1, 1957. He had
been stationed at Lake Alfred
since 1946.
Early investigations by the Cit-
rus Station were confined entirely
to problems encountered in the
grove, but as the industry became





more complex new emphasis was
placed on basic and applied re-
search in allied areas. These are
discussed in the pages to follow.
The Florida Citrus Experiment
Station is unique among citrus re-
search facilities in scope of pro-
gram. Its staff comprises the sec-
ond largest group of research per-
sonnel in the world devoted to the
study of citrus crops.

Production of the Crop
Soil Fertility.-Florida's citrus
growing region is one of the most
infertile areas in the world. In
many other parts of the United
States, early pioneers had only to
stir the earth and plant seed in
order to obtain bountiful crops.
Florida abounded in sunshine and
water, but neither sweat nor cour-
age alone could change the state
into a Garden of Eden.
Most of the early citrus growers
were not prosperous. Trees grow-
ing on the deep sands were plagued
with yellow leaves and few fruit.
Successful growers selected the
more fertile hammock soils rather
than the deep sands. Although the


trees produced excellent fruit,
hammocks were subject to frost
and water damage, and the amount
of hammock land was limited.
Beginning about 1930, research
scientists found that citrus trees
growing on Florida soils required
elements other than just nitrogen,
phosphorus, and potash. When us-
ing copper in fungicide sprays, re-
search workers noted tree growth
and yield response beyond that at-
tributable to copper's known fun-
gicidal properties. Eventually it
was found that copper was needed
as a nutrient and that copper de-
ficiency was cutting Florida's po-
tential citrus yield in half. As
time went on, more trace element
deficiencies were sorted out and
research workers began recom-
mending applications of magnes-
ium, boron, manganese, and zinc
to the trees.
By use of these trace elements,
citrus yields were doubled and then
tripled; and, as an added bonus, the
healthy trees were found more re-
sistant to cold injury. After it
was demonstrated that large
crops of fruit could be produced
relatively cheaply by adding trace


elements, the industry became
prosperous. (Outside capital w
brought in, and, particularly after
World War II, great fortunes we
started.)
Additional nutritional research
developments at the Citrus Exper
iment Station in recent years hav
taken even more risk out of grow
ing fruit. Use of molybdenum -
costing only about a penny per tre
- corrected a deficiency which
caused leaves to yellow and tre
defoliation.
Iron deficiency was solved whel
iron was combined with an organic
chelating acid. Only one-third o
an ounce of iron in this form wa
necessary to bring about complete
recovery of a tree within a fei
weeks. This treatment is now use(
not only on Florida citrus, but alsW
on many crops throughout th(
world.
Work with the major elements
has been just as important to the
citrus industry. There have beei
studies to determine the rates an(
sources of nitrogen, phosphorus
and potash. Scientists have de
veloped the method of leaf an(
soil analysis as useful guides ii




termining fertilizer practices.
these methods have included .a.
uick soil test for excess copper'.,:-
d a method to determine soii'
hosphorus.
Along with others, Citrus Ex-
eriment Station scientists have
developed the effective and eco-
omical fertilizer pr6rami now in
se in the state's prosprous citrus
roves -technology that has laid
e foundation by which Florida'
rowers have takeljRsome of th '
oorest soil in the world and maz k.
produce almost tlree-fourtts of
e world's citrus. a -
Chemical Control of Insects, '
ites, and Diseases. Florifa's
ear-'round warm, humid climate
also \ery kind, however, to in-
ect and mite pests and fungus
diseases that itasitii e leaves and
ruit of the egviEreen citrus trees.
roubles:ome i4) unliealthy, defi-
ient trees. these pests became
ven more serious on the thicklyX
oliated. luxuriant growth .pro-
uced by an adequate frter
program. .
Based on intensive screening of
-hemical, as ateUtial iSCti3 i
niticiles, anki suicide, itart
. : i


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Station workers have been pri-
marily responsible for developing
a spray program for effective
commercial control of citrus pests.
Annually, these researchers help
revise spray and dust recommenda-
tions published as the Florida Cit-
rus Commission's "Better Fruit
Program."
Major and minor citrus insects,
mites, and diseases are constantly
under statewide survey with re-
sults mailed twice monthly to
several hundred interested citrus
men. Quarterly, Station entomol-
ogists and pathologists write
articles summarizing the probable
population intensity of citrus pests
and make recommendations for
their control.
Residues of Pesticidal Chemicals.
- Chemical control of insects,
mites, diseases, weeds, and fruit
decays sometimes results in a pes-
ticide residue in that part of the
crop harvested. Since about 1950,
growers, research workers, regula-
tory agencies, and the consuming
public have been concerned that
chemical use does not result in
dangerous residues. The Citrus
Station has thoroughly investi-


gated many chemical pesticides to
determine the residues left, and
helped establish safe waiting peri-
ods between application and har-
vest. This research helped ensure
a safe product for the consumer,
while allowing use of these com-
pounds for pest control. The pro-
gram has included not only fresh
fruit shipments, but also processed
food products where essentially
no residue is found and feed by-
products, such as dried citrus pulp
for dairy cattle consumption.
Natural Enemies of Citrus Pests.
-Biological insect and mite control
is of great importance to Florida
citrus growers. Citrus Station re-
searchers, in cooperation with
other scientists, have identified
over 200 kinds of parasites of pred-
ators that are active in Florida
citrus groves. Some of these are
spectacularly successful in controll-
ing insect pests. One, the tiny wasp
called Aphytis holoxanthus, was
introduced by Citrus Station and
USDA workers from California. It
has almost eliminated a continu-
ing problem Florida red scale -
as a pest of commercial importance
in Florida citrus groves.


Citrus Tree Declines. Citru
trees die or "decline" of a wid
variety of causes, including fui
gus, virus, and nematode disease:
and physical causes such as lighl
ning, wind storm, and flooding.
A most important contribution
of the Citrus Station was the di,
cover of the cause and develop
ment of appropriate controls for sc
called "spreading decline." Statio
research workers discovered thi
most serious disease was caused b;
the burrowing nematode feeding o:
the tree's roots, thus leading t
their decimation by a variety o
soil-borne organisms. Following
this discovery, the push-and-trea
method of control was recom
mended. After over 10 years o
wide-spread use, it remains th,
only effective and thorough contrc
for "spreading decline."
Citrus Station researchers in co
operation with USDA scientist
have also discovered and release(
to citrus growers the Milam
Estes, and Ridge Pineapple nema
tode-tolerant rootstock varieties:
which bear great promise. These
discoveries are the basis for an ex
tensive state-and-grower-financec





















A mechanical harvester for citrus was developed at the Lake Alfred
Station.


Another Citrus Station development was this
mechanical hedger.


program to eliminate the spread of
burrowing nematode through cit-
us nurseries, reduce the number
Sf affected trees in commercial
,roves, and eventually replace all
declining commercial groves with
healthy, disease-free, productive
rees.
Irrigation. Considered on an
annual basis, Florida has abund-
nt rainfall. But at times extended
Brought periods occur and citrus


trees wilt from lack of moisture.
Citrus growers have been irrigat-
ing for a great many years, often
with little assurance of economic
benefit. A recent Citrus Station
project has for the first time de-
veloped sound guidelines showing
when irrigation can be expected
to pay dividends on the cost of
application. Marsh grapefruit has
responded greatly to irrigation ap-
plications, while the Pineapple


orange variety has responded very
poorly. This research has encour-
aged installation of hundreds of
acres of permanent irrigation sys-
tems in Central Florida citrus
groves.
Research has also shown that
long periods of irrigation with
water containing soluble salts of
over approximately 1,250 ppm will
result in salt toxicity to trees. This
limits the use of overhead sprink-




ler-type irrigation in the coastal
areas where salt content of the ar-
tesian water frequently exceeds
this level.
Mechanization. Increasing la-
bor costs and shortage of workers
motivate citrus growers to use
more machinery. The first mech-
anical hedger for citrus trees was
constructed in the agricultural
engineering shop of the Citrus Ex-
periment Station. This basic ma-
chine was used extensively in
California, and while the machines
have been greatly improved since
the first one was built, this Citrus
Station development was the foun-
dation of all mechanical pruning
machines.
Citrus Station workers have ac-
tively assisted sprayer machinery
manufacturers in improving their
equipment. Advice from Station
engineers and entomologists has
greatly stimulated development of
the air-carrier type sprayer most
common in Florida. Modifications
of spraying machinery have been
made in the Station's engineering
shop and field tested for improved
effectiveness in obtaining coverage
of leaves and fruit.


Evaluations of commercial as
well as experimental sprayer
models have been made for many
years. Results of these evaluations
assist manufacturers in detecting
deficiencies in performance of their
equipment, thus making possible
the production of improved models.
Evaluations have also extended to
aircraft for citrus mite control.
Herbicides. As mechanization
proceeds, a companion development
is the use of chemicals to do addi-
tional jobs. Herbicides offered by
chemical companies have been
screened by Station horticulturists
for safe, effective control of all
types of unwanted vegetation in
and around groves. Several of
these chemicals give excellent con-
trol of weeds in drainage ditches
and irrigation canals; few have
been very effective even for use
directly under young trees. A sin-
gle application of some of these
herbicides, made in the spring, will
control weeds satisfactorily
throughout the entire summer
rainy period. This obviates the
need for repeated cultivation and,
additionally, has been found to pro-
mote more rapid growth of trees


than when conventional cultivate
is used.
Air Pollution. As industry
plants move into Florida, th
bring benefits to the state as
whole and some problems to ag
culture. One problem is air pol
tion. Some processing plants i
known to emit fluorine into the
during normal operation. Stati
researchers have found this fli
rine produces a mottling of citz
foliage, sometimes a leaf-drop, a
a general debilitation of the tre,
Much research has gone ii
evaluating the practical effect
air-borne fluorides on growth a
productivity of citrus trees. Fli
ida must live with industry and,
fact, welcomes it, but this resear
will help to provide a basis
which both agriculture and indi
try can operate without muti
detriment.
Flatwoods Soil Development.
Generally people agree that cent
Florida's rolling sand hills cons
tute the best available citrus lai
Since there is a limited amount
such land, recent large plantir
have been developed in the inter
flatwoods of Southern Florida. I





t coastal soils used for these
rntings are largely different
)es from those formerly used.
ief problem is water movement
t of these soils to provide drain-
e and adequate depth of rooting
support productive citrus trees.
'search on different types of
linage systems and different ir-
ration methods has helped the
wly developing citrus areas at-
n a satisfactory moisture bal-
ce. Much work remains to be
ne in this area.

st-Harvest Horticulture
Citrus, perhaps more than any
her type of fruit marketed in
ash form, is particularly depend-
t on treatments after harvest.
) citrus fruit is naturally shiny,
,d color depends almost entirely
temperature conditions (largely
ght temperatures) during the
ieks prior to picking. Neverthe-
ss, the housewife expects to buy
firm, shiny citrus fruit of a
aracteristic color that she asso-
ates with oranges, grapefruit,
id tangerines.
Thus, as marketing has grown


more complex, researchers have
found they cannot consider their
job done with the production of a
crop of suitable yield that is rea-
sonably free from insect and fun-
gus blemishes.
Control of Decay in Fresh Fruit.
- The first major project employ-
ing a staff purely on post-harvest
horticulture was a decay control
project-the first of many projects
financed entirely by the Florida
Citrus Commission but using fa-
cilities at the Citrus Experiment
Station. The outstanding result of
this project was the Dowicide A-
hexamine fungicidal process now
widely used in citrus districts
throughout the world. A path-
ologist now works full-time study-
ing the life histories of fungi that
cause post-harvest decay and their
interrelations with peel disorders.
Bulk Handling.-The bulk hand-
ling project started in 1948 on a
grant from USDA's Research and
Marketing Act funds was highly
successful. When this project was
finally closed out, some 10 years
later, it was estimated that one
packinghouse alone was saving
more money for its growers each


year than the total cost of the re-
search.
Since 1952 an increasing number
of specialists, paid by either the
University of Florida or Florida
Citrus Commission, have worked
on post-harvest problems. In 1957,
this group was organized as a Har-
vesting and Handling Section un-
der a section leader who was a
specialist in post-harvest horti-
culture.
Current Research Program. -
Research within the Harvesting
and Handling Section follows two
broad, general approaches.
The first seeks cheaper or better
ways of carrying out present pack-
inghouse processes. This includes
an intensive study of the ethylene
degreening process, and develop-
ment of stable fungicidal fruit
waxes, now supplied by most of the
machinery and chemical compa-
nies. Much of this research is con-
cerned with solving immediate eco-
nomic problems.
Scientists working on current
packinghouse problems must co-
ordinate with those production re-
search workers responsible for
grove management programs. Typ-




ical results of this type of research
are explanations of "zebra skin"
peel injury in tangerines and stem-
end rind breakdown of oranges.
The second major line of en-
deavor in the Harvesting and
Handling Section includes a range
of projects aimed at building up
basic knowledge of the physiology,
pathology, chemistry, and other
sciences involved in post-harvest
citrus fruit handling. One typical
project seeks to understand the in-
ternal chemistry of the fruit.
Citrus Commission workers at
Lake Alfred made a major break-
through isolating citrus mitochon-
dria. These sub-cellular particles
control most of the enzyme activity
within the living cell. They have
now been isolated and made to
carry on a number of their normal
functions in the test tube. Scien-
tists hope such basic studies will
ultimately lead to producing sweet-
er and better colored citrus.
Florida did not have a lemon
industry until research workers on
processing developed cannery
methods that could provide an
outlet for processed lemons, and
research workers on citrus pro-


duction showed how lemons coi
successfully be grown in quanti
With increasingly enthusiasm
planting of lemons, the Harvesti
and Handling Section has promp
developed methods for picking
hard, green lemon and develop
it into a bright yellow, juicy fr
comparable to those from C,
fornia that have long set a wor
wide standard. Such teamw(
among various groups of reseal
workers will be increasingly nec
sary in years to come.
Work in post-harvest hortic
ture is expanding rapidly. This





a natural result of the success of
research workers in various fields
concerned with citrus production.
Now that they have shown how to
produce vast quantities of citrus
from lean sand hills, and what
were once flatwoods and swamps,
it becomes just as important to
find ways of successfully market-
ing these vast crops in the increas-
ingly competitive battle for a place
in the housewife's shopping cart
in the local supermarket.

Processing and By-Products
Cooperative research in process-
ing by the Citrus Experiment Sta-
tion and Florida Citrus Commis-
sion was begun during the 1947-48
season when citrus products were
first processed in the pilot plant.
Since then both basic and applied
research has been done, but more
emphasis has been placed on the
latter.
Stability of Frozen Concentrate.
-One of the first problems studied
was the stability of frozen citrus
concentrates stored at tempera-
tures above 0 F. The occurrence
of gelatin and clarification was
shown to be caused by demethyla-


tion of pectin in concentrates by an
enzyme, pectinesterase. When this
happened, low-methoxyl gels form-
ed in the concentrates and clarifica-
tion occurred in reconstituted
juices.
While attempting to find a so-
lution to this problem researchers
obtained much information con-
cerning inactivation of pectinester-
ase by heating citrus juices used
for concentrate production. They
also determined the quantities of
different types of pectic substances
in juices and concentrates and ob-
tained information on occurrence
of these s u b s t a n c e s in various
parts of citrus fruits of different
varieties including oranges,
grapefruit, tangerines, limes, and
lemons.
Microbiology of Citrus Juice
Products. Prior to the heat sta-
bilization of citrus concentrates,
various types of microorganisms
found in juices and concentrates
were identified and their effect on
the quality of such products de-
termined.
A rapid colorimetric method -
the diacetyl test was developed
and used to control microbial spoil-




age of orange juice during its
concentration in commercial evap-
orators. Diacetyl produced by the
growth of certain types of bacteria
resulted in a "buttermilk" off-
flavor in the concentrate.
Development of citrus "oxidized"
off-flavors in citrus concentrates
during frozen storage at 0 F. or
lower was found to result from
chemical reactions rather than
microbial growth.
Survey of Concentrate Quality.
-Since the 1953-54 citrus season
samples of commercial frozen con-


centrated orange juice have bf
obtained semi-monthly from 20
23 commercial plants. Scienti
have accumulated much data c
cerning many characteristics
such products from these samp
This continuing survey using st.
dardized methods has document
the changes in concentrate ju
during most of its existence as
commercial product.
Utilization of Frozen Fruit.
Realizing that freezing weather i
curs from time to time, Stati
scientists in 1954 began invest




ting use of freeze-damaged
ranges to produce frozen concen-
te. By the 1957-58 season when
d damaged large quantities of
uit, they had accumulated con-
ierable data. This information
is sufficient to advise processors
w to produce frozen concentrate
ice which would be acceptable in
ality to customers. Thus, this
investigation made it possible to
e most of the freeze-damaged
anges in '57, '58, and again in
)62.
Water Extraction of Pulp. -
)luble solids from pulp discharged
om juice finishers were first re-
vered by water extraction in
orida in 1958. The procedure
ed in commercial plants was
iefly a counter-current extrac-
n of the pulp with water. Small
tches of aqueous extracts of
ange pulp were made in the pilot
ant.
Characteristics of these ex-
*acts, as well as some from com-
ercial plants, were studied for
)out two years. Results showed
[creased yields of juice solids. It
as found possible to mix these
lueous extracts with orange juice


being pumped to evaporators with
little practical effect on concen-
trate quality if certain satisfactory
procedures are followed.
High-density Frozen Concen-
trated Orange Juices. Frozen
concentrated orange juices have
been commercially standardized at
42" Brix (percent soluble sugars,
acids, and salts), but concentrates
of 51, 53", and 58" Brix have been
made in the pilot plant. Such prod-
ucts were of good quality and had
better physical and flavor stability
than 42 Brix concentrate.
Volatile Flavor Components. -
The flavor components of orange
and citrus juices have been studied
intensively since 1958. Consider-
able progress has been made in the
recovery, isolation, and identifica-
tion of chemical compounds con-
tributing to aroma and flavor.
A pilot plant system to recover
flavor essences from citrus juices
has been used extensively to pro-
duce quality orange and grapefruit
essences. Such essences have been
added to concentrates resulting in
improved aroma and flavor.
Research with Grapefruit Prod-
ucts. The effects of storage tem-


perature, acidity, date of packing,
and fertilizer and spray practices
on the quality of canned grapefruit
sections have been determined. Re-
searchers find adding certain cal-
cium salts to grapefruit sections,
before processing, improves their
firmness.
They are studying "debittering"
of grapefruit for processing, and
what factors are involved in freez-
ing and preserving individual froz-
en grapefruit sections. One of
many probable causes for deterio-
ration of canned citrus juices dur-
ing storage has been found.

By-Products Research
Oils obtained from citrus fruit
peels by various forms of hydrau-
lic pressure have long been used as
flavoring materials-and have long
been one of the most important by-
products of the Florida citrus in-
dustry. These products at one time
were variable in quality and the
factors leading to the variation
were poorly understood.
Research by C i t r u s Station
workers has identified the factors
affecting peel oil quality and has




made it possible to produce large
volumes of high-quality peel oil
that will meet most exacting stand-
ards.
Recent research has helped to
foster development of a new in-
dustry utilizing oil expressed from
citrus seeds. This oil, when proper-
ly processed, makes a good food
product, as do many vegetable oils;
in the future it may add to the
gross income of the industry.















One major area of work for the Citrus
Experiment Station has been cold pro-
tection. This unique tree freezing
chamber has been used in cold toler-
ance studies of citrus.















































AL
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