Front Cover
 Board of control and staff
 Climatic factors and soils
 Planting - Fertilizing non-bearing...
 Fertilizing bearing trees - Pruning...
 Harvesting - Diseases
 Historic note

Group Title: Bulletin - University of Florida Agricultural Extension Service ; 170
Title: Growing guavas in Florida
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00020521/00001
 Material Information
Title: Growing guavas in Florida
Physical Description: 20 p. : illus. ;
Language: English
Creator: Ruehle, Geo. D ( George D )
Publisher: Florida Agricultural Extension Service
Place of Publication: Gainesville
Publication Date: 1959
Subject: Fruit-culture   ( lcsh )
Genre: non-fiction   ( marcgt )
General Note: Cover title.
 Record Information
Bibliographic ID: UF00020521
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 01313310
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Table of Contents
    Front Cover
        Page 1
    Board of control and staff
        Page 2
    Climatic factors and soils
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
    Planting - Fertilizing non-bearing trees
        Page 12
        Page 13
    Fertilizing bearing trees - Pruning and irrigation
        Page 14
        Page 15
    Harvesting - Diseases
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
    Historic note
        Page 21
Full Text

Bulletin 170



Vice-Director in Charge, Sub-Tropical Experiment Station, Homestead, Fla.

Fig. 1.-Unpruned guava tree 8 years old growing on limestone soil
in Dade County.

March 1959


James J. Love, Chairman, Quincy
Ralph L. Miller, Orlando
J. J. Daniel, Jacksonville
W. C. Gaither, Miami

S. Kendrick Guernsey, Jacksonville
James D. Camp, Ft. Lauderdale
J. B. Culpepper, Ph.D., Executive Director,


J. Wayne Reitz, Ph.D., President of
University 1
Willard M. Fifield, M.S., Provost for
Agriculture 1
Marshall 0. Watkins, D.P.A., Director
J. N. Busby, B.S.A., Assistant Director
Forrest E. Myers, M. Agr., Assistant to
the Director


J. Francis Cooper, M.S.A., Editor 1
M. H. Sharpe, Ph.D., Assistant Editor
William G. Mitchell, M.A., Assistant Editor 1
Jack W. McAllister, B.S., Assistant Editor
K. S. McMullen, M. Agr., District Agent
F. S. Perry, M. Agr., District Agent
W. J. Platt, Jr., M.S.A., District Agent
C. W. Reaves, M.S.A., Dairy Husbandman
T. W. Sparks, B.S.A., Assistant Dairy
H. B. Young, M.S.A., Asst. Ext. Dairyman
N. R. Mehrhof, M. Agr., Poultry Husband-
man 1
J. S. Moore, M.S.A., Poultryman
A. W. O'Steen, B.S.A., Supervisor, Egg-
Laying Test, Chipley
L. W. Kalch, B.S.A., Asst. Poultry Husb.
G. E. Williams, B.S.A., Asst. Supervisor,
Egg-Laying Test, Chipley
T. J. Cunha, Ph.D., Animal Industrialist
J. E. Pace, M.S.A., Animal Husbandman
R. L. Reddish, Ph.D., Asso. An. Indust.
K. L. Durrance, B.S.A., Asst. An. Indust.
Thomas G. Herndon, M.S.A., Farm Forester
A. S Jensen, B.S., Assistant Forester
H. G. Hamilton, Ph.D., Agri. Economist
E. W. Cake, Ph.D., Marketing Economist
R. A. Eastwood, Ph.D., Economist in
Clifford Alston, M.S.A., Farm & Home
Development Specialist
C. C. Moxley, Ph.D., Associate Economist
E. W. McElwee, Ph.D., Ornamental
Horticulturist 1
R. W. White, Jr., M.S.A., Asst. Hort.
S. A. Rose, M.S., Asst. Ornamental Hort.
Fred P. Lawrence, M. Agr., Citriculturist
Jack T. McCown, M. Agr., Assistant
W. H. Mathews, M. Agr., Asst. Horticulturist
W. W. Brown, M. Agr., Boys' 4-H Agent
G. M. Godwin, M. Agr., Asst. Boys' 4-H
Club Agent

Cooperative, Other Divisions, U. of F.
SOn leave.

B. J. Alien, M. Agr., Asst. Boys' 4-H Club
T. C. Skinner, M. Agr., Agr. Engineer
A. M. Pettis, M.S.A., Assoc. Agricultural
En in eer
John D Haynie, B.S.A., Apiculturist
J. Russell Henderson, M.S.A., Agronomist
James Nesmith, Ph.D., Asso. Agronomist
S. L. Brothers. B.S.A., Assistant Agronomist
F. S. Jamison, Ph.D'., Veg. Crops Spec. 1
Stanley E. Rosenberger, M. Agr., Assoc.
Marketing Spec. in Veg. Crops
James Montelaro, Ph.D., Associate Vegetable
Crops Specialist
J. D. Norton, M.S., Assistant Vegetable
Crop Specialist 2
Bruce Barmby, M.S., Interim Asst. Veg.
Crops Specialist
Mason E. Marvel, M.S., Assistant Vegetable
Crop Specialist
James E. Brogdon, M. Agr., Entomologist
John H. Herbert, Jr., M.S.A., Assistant Soil
Granville C. Horn, Ph.D., Soils Specialist
R. S. Mullin, Ph.D., Plant Pathologist

Anna Mae Sikes, M.S., State Agent
Eunice Grady, M.S., Assistant to State HDA
Helen D. Holstein, M.A., District Agent
Mrs. Edith Y. Barrus, B.A., District Agent
Joyce Bevis, M.A., District Agent
Mrs Gladys Kendall, B.A., Home Industries
and Marketing Specialist
Emily King, M. Ed., State Girls' 4-H Club
Agent 2
Anne Elizabeth Thompson, M. Ed., Asst.
State Girls' 4-H Club Agent
Alice L Cromartie, M.S., Extension
Susan R. Christian, M.S., Assistant Nutr.
Farm & Home Development Spec.
Elizabeth Dickenson, M.A., Clothing and
Textile Specialist
Alma Warren, M.A., in L.S., Asst. Editor
and Visual Aids Specialist
Frances C. Cannon, M.S., Asst. Health
Education Specialist
Bonnie B. McDonald, M.S., Asst. Economist
in Food Conservation
Ruth E. Harris, M.S., Family Life Specialist

Floy Britt, B.S.H.E., District Agent
J. A. Gresham, B.S.A., District Agent



The common guava (Psidium guajava L.) is native to the
American tropics, but has been distributed to practically all trop-
ical and sub-tropical areas throughout the world. It belongs
to the Myrtle family and thus is related to the common species,
clove, cinnamon, allspice and nutmeg; to many well known orna-
mentals such as myrtle, callistemon, cajeput and eucalyptus;
and to a large number of small fruits well known in Florida, in-
cluding surinam cherry, rose apple, Cattley guava, feijoa, jabot-
icaba, jambolan, and downy myrtle.
The common guava compares very favorably with many of
the better known fruits in nutritive value and its wider use in
the diet is justified from this standpoint. It is primarily a proc-
essing and home garden fruit in Florida, although a small volume
of the fresh fruit is shipped to markets outside the state. People
in increasing number are learning to use and enjoy the better
types of guava, eating them as either fresh fruit or cooked or
preserved in various ways.
Manufactured guava products are being produced in a com-
mercial way and it is likely that the demand for such products
will increase, provided they are advertised to widen the market.

Climatic Factors
Guavas are sensitive to low temperatures. Young trees may
be killed at 29 F. of several hours duration, while older trees
will withstand short periods as low as 260 F. Where older trees
are killed back to the ground, they sprout from the base and
usually are back in full production in 2 or 3 years.
The guava tree appears to thrive under extremes of annual
rainfall varying in southern Florida from 45 to 70 inches or more.
However, fruit production and quality are affected by extremes
of moisture. An ample supply of soil moisture during the fruit-
ing season is required for maximum yield. On the other hand,
heavy and prolonged rains at the time the fruit is ripening
usually cause considerable skin cracking followed by spoilage
and the fruit also tends to become watery and lacking in flavor.

The guava can be grown successfully on a wide range of soils.
It thrives on well drained loamy and muck soils, but will grow

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almost equally well on sandy flatwoods soils that are too wet for
avocados or citrus fruits. It will thrive on very acid (pH 4.5 to
5.0) light sands or on moderately alkaline (pH 7.6 to 8.2) lime-
stone and marl soils if properly fertilized.

Fig. 2.-Young

-' I.-;6MU.'#aisa. _FaIf
guava grove on limestone soil in Dade County.
Trees 22 months from seed.


If allowed to grow unmolested, the guava becomes a large
arborescent shrub or small tree, branching rather freely close
to the ground. It can be trained by pruning to grow as a rather
handsome, symmetrical, low-headed tree with a spreading top.
Trained thus, the tree may reach a height of 30 feet with an
equal spread, where growing conditions are favorable. The
trunk usually is rather slender and crooked with greenish brown
scaly bark.
The leaves are opposite, light green in color, oblong-elliptic
to oval in outline, 3 to 6 inches in length, and finely pubescent
below, with the veins prominently impressed above and raised
below. The white flowers are borne in the axils of leaves on
the 4-angled branchlets of recent growth, either singly or 2 or 3

Growing Guavas in Florida

Fruit from seedling guavas grown from unselected seed may
exhibit a wide variation in appearance, size, flavor, acidity, tex-
ture and color. The shape may be round to oblong, ovate, globose,
or pyriform, and weights vary from an ounce to more than a
pound. Skin color of ripe fruit ranges from green to bright
yellow, and in some types a faint pinkish blush occurs on the
exposed side. Flesh color may be white, yellowish, or some
shade of red from pale pink to carmine. Seedling fruits vary
from thin-shelled with a large mass of small hard seeds em-
bedded in a firm, soft pulp, to thick-shelled with few seeds, and
in flavor from sweet to quite acid.
The distinctive aroma and flavor of guava is possessed to
some degree by all types, but in some it is very mild and not un-
pleasant, whereas others are so strongly pungent that the pen-
etrating odor of the ripe fresh fruit is objectionable to some
Practically all Florida commercial plantings of guava are of
seedling trees. Local descriptive names, such as lemon guava,

Fig. 3.-Guava tree 15 months from seed which received a complete
fertilizer containing N-P-K and water-soluble magnesium, plus copper,
zinc and manganese applied as a spray.

Florida Cooperative Extension

pear guava, or apple guava, are in use for some of the common
types. Quality of the fruit, however, cannot be determined
from color, shape or size. Some processors have types of guava
which they prefer for the manufacturing of jelly or other prod-
ucts and propagate these by planting selected seed or by grafting.
Seedling guavas cannot be relied upon to produce fruit identi-
cal with that from the parent tree. Choice varieties can be in-
creased only by some vegetative means of propagation.

Fig. 4.-Guava fruits from Ruby X Supreme cross. Fruit on left is
pink-fleshed similar to female parent; that on right resembles the male

At present, only a few named horticultural varieties of
guava exist and trees of these are not yet offered for sale in
quantity by nurserymen. Red Indian and Ruby are red fleshed,
sweet, fairly large fruited, dessert-type guavas, producing good
crops of fruit of high quality. Supreme produces heavy crops of
thick-walled, sub-acid, white-fleshed fruit of good quality for
preserving or eating fresh. Ruby and Supreme were crossed in
1945, and several of the 130 seedlings grown to maturity appear
to have qualities superior to either parent. Air layered trees
from a number of these trees have been distributed to individuals
and to other research groups, and one nurseryman is propa-
gating and selling layered trees under the name Ruby X Supreme
Hybrid. Miami Red and Miami White are varieties somewhat
similar to the foregoing that were selected, named and released
by the University of Miami Experimental Farm.

Growing Guavas in Florida

In addition, several dozen unnamed clones are under study
at the Sub-Tropical Station. These include jelly types, and acid,
sub-acid and sweet large-fruited types selected from Florida
chance seedlings or from hand crosses, as well as seedlings of
foreign introductions. Several named varieties will eventually
be selected, named and released from this group. No doubt there
are many excellent seedlings in Florida which merit propagation
as varieties but which have not been brought to the attention
of propagators or horticulturists.

Seed.-Guavas are commonly propagated by seed, which
should be planted as soon as possible after removal from the
fruit. Sow them in flats or bulb pans filled with a 50-50 mix-
ture of vermiculite and peat moss or with a sandy loam, and
cover to a depth of about 1/4 inch. If you use soil not previously
sterilized, treat the seed with cuprous oxide or captain (75%)
before planting and spray the young seedlings and soil with
captain (50% wettable; 1 oz. to 3 gals. of water) to prevent

Fig. 5.-Portion of a guava nursery. Seeds were started in flats and
the seedlings transferred to small pots and finally to the field. Guava trees
do not transplant readily from open ground.

Florida Cooperative Extension

damping off. After the true leaves appear, transplant the
seedlings to individual containers and grow them there until
they are large enough to set in the field.

Fig. 6.-Air layering branches on a bearing guava tree.

Marcottage.-One of the easiest vegetative methods of pro-
pagating guavas is by airlayering or marcottage. The method
is quite rapid and is relatively simple. Girdle limbs of 1/ inch
or more in diameter by removing a strip of bark about 1.5 times
the thickness of the limb. Bind the girdled area with a ball of
moistened sphagnum several inches in diameter and 4 to 5 inches
long and then tightly wrap it with a sheet of translucent poly-
ethylene film and tie this securely at each end with rubber bands
or string. Leave the wrap attached until 5 or 6 roots are evi-
dent between the ball of sphagnum and polyethylene film. Usu-
ally roots begin to form in 3 to 5 weeks. If they do not begin
to show after 6 weeks, remove the wrap and examine the girdled
area. In some instances callus bridges the girdled area before
root development begins. Re-girdling and re-wrapping usually
is followed by root formation within a few weeks.
After rooting is well advanced, cut the branch from the par-
ent just below the ball of moss and roots. Remove the film be-

Growing Guavas in Florida

fore planting, but do not disturb the ball of moss and roots.
Prune back the rooted branch and plant it in a suitable container.
Grow it in partial shade until it is large enough to plant in the
field. It is important that the roots be kept moist during trans-
planting operations.

Fig. 7.-Air layered branch removed from parent tree
6 weeks after branch was girdled and layer was made.

Graftage.-Grafting and budding of guavas were formerly
rather difficult. Propagation was possible by shield and patch
budding and by side-grafting on young stock plants but it was
difficult to obtain a high percentage of success. An improved
technique in grafting recently developed by Mr. Roy Nelson at
the University of Miami has made the grafting of guavas as
easy as grafting of most other orchard tree fruits.
Use seedlings of 1/ inch to 3/8 inch stem caliper as stocks.
Select scions from terminal growth when the stems are still

Florida Cooperative Extension

green and quadrangular but with axillary buds well developed.
Prepare the stock by removing a slice of bark 11/2 inch to 2
inches long to the woody cylinder, leaving a slanting notch at
the lowest point where the scion is to be placed. Prepare the
scion, 11/ to 2 inches long, by cutting away a slice of bark on
one side to expose the cambium, leaving one bud located on the
upper half. Place cut surfaces of stock and scion together and
wrap the graft with vinyl plastic film strip about 1/2 inch wide
in such manner that the entire scion is covered with the excep-
tion of the bud itself. After 3 weeks, remove the top of the
seedling stock or lop it over. After 4 or 6 weeks remove the
film. Prune back the stub of the stock and cover the wound
with wax after the scion shoot has attained 6 inches in height.
The best time for this type of grafting is from March through
September, which is also the time when suitable scions are most

== WA ,&o, "

Fig. 8.-Layered tree 5 months after branch was girdled and girdled
area wrapped, ready for transplanting to the field.

Growing Guavas in Florida

Cuttage.-Leafy stem cuttings with 3 to 5 nodes of mature
or nearly mature wood will root with fair success in a mist pro-
pagating box. After removing the rooted cuttings from the box
and transplanting to soil, keep the plants in a mist chamber for
a few days and gradually remove to normal atmosphere. Com-
paratively little success has attended attempts to root stem cut-
tings in an ordinary cutting bench, even with the use of hor-

--- -.---. -- --. .:--, pLW

Fig. 9.-Guava scions (top row) and graftwood in green quadrangular
growth stage, with well developed buds.

A method of making a limited number of plants is to sever
roots 2 or 3 feet away from the trunk with a spade or mattock.
Sprouts usually will grow from the portion cut off which may be
transplanted later.
Topworking Old Trees.-Guava trees may be topworked in
the field by the same methods employed on the avocado. Cleft
grafting by the Medora method is laborious but quite successful
if done in the spring months. Completely remove the top; cut
clefts in the stumps by a hand saw and trim the cuts smoothly
with a sharp knife; spread the cut slightly with a hardwood
wedge; insert straight scions of round second year wood, trimmed
on both sides, in the clefts in such a way that the cambia of
stock and scion match; paint over the cleft and cut surface of
both stump and scion with grafting wax; wrap a paper collar and
tie it securely around the grafted stump to extend 6 to 8 inches
above the scions and fill it with damp peat moss or sawdust to
keep the scions from drying out.

Florida Cooperative Extension

Another method is to cut the trees back to stumps, allow
suckers to grow and side graft selected shoots with the same
method used for side grafting young stock plants.

The spacing of trees in most of the early plantings of guava
in Florida was too close. Spacings of 12 to 15 feet were common.
Overcrowding quickly occurred, and heavy pruning was required
to facilitate grove operations and harvesting. In commercial
plantings where heavy fertilization is to be practiced or where
the soil is naturally fertile, don't plant trees closer than 20 to
25 feet in rows 25 to 30 feet apart.
Clear and prepare the land some months ahead of planting.
In deep soils, plow and disk the land, and where drainage is poor,
ridge or mound the soil in the tree rows. In limerock areas,
scarify the land well and groove or plow it out where the tree
rows are to be located. On newly cleared sandy soils with a
strongly acid reaction, it is desirable to make a general applica-
tion of dolomite at 500-2,000 pounds per acre (the amount de-
pending upon the degree of acidity) broadcast and disked in just
before or after the trees have been planted. On newly scarified
limestone soils, an application of superphosphate at 500 to 1,000
pounds per acre similarly broadcast is desirable.
Guava trees are usually planted to best advantage during
late spring just ahead of the rainy season. Prepare a planting
hole large enough to easily accommodate the root system. Be-
fore placing the tree, mix the soil in the bottom of the hole with
some topsoil fortified with a small amount of well-rotted com-
post or with a natural organic fertilizer such as dried sheep
manure or milorganite. Place the tree so the roots are no deeper
than they were in the nursery or plant container. Pack the
soil well. Water the tree liberally as soon as planted to avoid air
pockets. When the hole is completely filled, form a basin around
the tree for water. It is advisable to mulch the basin heavily
with grass and weeds or sawdust to prevent drying out and
heating of the soil about the new roots.

Fertilizing Non-bearing Trees
Apply a complete fertilizer every 4 to 6 weeks during the
first year and every 60 days during the second year. The type
of mixture used should be modified or supplemented according
to the nature of the soil. For most Florida soils, mixtures an-

Growing Guavas in Florida

alyzing about 5 (nitrogen)-7-9 (phosphoric acid)-5 (potash)-1.5
(magnesium oxide) or 5-10-5-2, with about 25 percent of the
nitrogen from organic sources, are satisfactory. On soils that
contain marl, the mixture should contain 1 to 2 percent MnO
(manganese oxide). On muck soils, the nitrogen may be greatly
reduced in the feeding program.
The amount per application should begin with 1/4 pound per
tree and be gradually increased to about 3/ pound by the end of
the first year and 2 pounds per tree by the end of the second year.
For the first few applications, spread the fertilizer uniformly
over an area beginning 6 to 8 inches from the trunk of the tree
and extending to the edge of the watering basin. Widen the
fertilized area as the tree grows and the roots spread beyond
the watering basin.
Spray trees planted in May or June a month or 6 weeks
after planting and again in September with a spray containing
1 pound of tribasic copper sulfate or its equivalent in some other
neutral copper, 1 pound of neutral zinc, 1 pound of neutral man-
ganese and 1/2 pound of borax per 100 gallons of water. Ap-
ply the nutritional spray twice during the second year and once
a year thereafter.


Fig. 10.-Zinc-deficient foliage of guava on left, normal leaf on right.

Florida Cooperative Extension

Fertilizing Bearing Trees
Guava trees usually begin to bear fruit the second or third
year, and bearing increases rapidly after the fourth year. Ex-
perimental data are lacking regarding fertilizer requirements
for guavas growing on the diverse soil types found in southern
Florida. Fertilizer practices used successfully on citrus usually
will give satisfactory results with guavas. On limestone soils
fertilizer mixtures and amounts as used on avocados have been
satisfactory. Mixtures such as 6-6-6-3 are suitable for young
bearing trees. As the trees become older, mixtures such as
6-4-6-3, 7-3-7-3, and 8-4-8-4 will usually satisfy the actual re-
quirements. These mixtures may be made up mostly from chem-
ical sources with about half of the nitrogen derived from slowly
available and half from readily soluble materials. As a rough
guide, the formula of 1.25 pounds of a 6 percent mixture for each
year of the tree's age should be sufficient at each of 3 applica-
tions per year. If split into 4 applications, the amount per ap-
plication should be reduced accordingly.
In commercial groves as the trees become large enough for
the roots to occupy practically all of the ground area, fertilizers
are more efficiently applied by mechanical spreaders from trunk
to trunk. The poundage per acre should be varied somewhat ac-
cording to tree condition, size of crop and rainfall, but should
fall in the range of 150 to 200 pounds of nitrogen per acre per
year for good bearing groves. This amount may be split more
or less evenly into three applications per year at about the fol-
lowing periods: February or March, May or June, and October;
or some of the nitrogen may be applied during the heavy fruit-
ing periods.
Continue annual applications of a nutritional spray containing
at least the zinc and copper. If applied during early spring, some
disease control will be obtained from this spray.

Pruning and Irrigation
Some pruning of young trees is necessary. The guava ordi-
narily grows as a large bushy shrub, but can be shaped into
tree form by judicious pruning. As the bearing trees become
older, there is a pronounced tendency for the fruit to become
smaller. The largest fruit is borne on strong shoots of 1- to 3-
year-old wood. By moderate thinning out and heading back
of the top every 2 or 3 years, this type of shoot growth will be

Growing Guavas in Florida

encouraged. While total yields are reduced by such pruning,
large fruit size tends to be maintained.
An ample supply of soil moisture during the fruiting season
is required for maximum fruit yield. If needed and used at
this time, irrigation will increase production by increasing the
size of the fruit.
Clean cultivation the first year or two may prove desirable
for frost protection. After the second year on limestone soils,
the growing of a cover crop of native grasses or weeds, which
is mowed periodically, and allowing the cut material to decay
on the ground surface is the most satisfactory practice. On
sandy soils, following the practice used in citrus groves of al-
lowing the cover crop of native grass and weeds or of planted
legumes to grow during the summer period when rainfall is
abundant, should prove satisfactory. Mow the cover at least
once during the summer and work it into the top soil during
the fall. Plowing and deep cultivation whereby guava roots

Fig. 11.-Old commercial guava grove near Opalocka. Trees have
been pruned to facilitate grove operations. A permanent sod ground cover
was maintained.

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are cut is undesirable because of the danger of causing root
For immediate processing, part of the ripe fruit usually is
harvested from the ground and the remainder picked from the
tree. The fruits are tossed into boxes or baskets, with little
attempt to avoid bruising, and hauled directly to the factory.
For use in the home or for sale as fresh fruit, pick the mature
fruit by hand from the tree. The crop does not mature at one
time and in harvesting for market you must go over the trees
2 or 3 times a week. This may mean harvesting 18 or 20
times during a fruiting period if the bulk of the crop is to be
sold as fresh fruit. The fruit should have reached full size but
still be hard if it is to be packed and shipped to distant markets.
It can be allowed to become nearly ripe if picked for local market.
Avoid bruising by careful handling of the fruit from the tree
to the packinghouse as well as during the grading and packing
operations. Refrigeration at 45" F. will slow down softening of
the fruit in transit.
Guava trees are attacked and usually killed rather quickly
by a root and crown rot caused by the gill fungus, Clitocybe
tabescens (Scop. ex Fr.) Bres. This fungus is parasitic on many
species of living trees, and also flourishes as a saprophyte in old
roots or stumps of trees, especially of oaks. Thorough removal
of tree roots, especially of oak roots, when clearing timbered
land prior to planting, is the only method of avoiding the disease.
Clitocybe tabescens is absent in limestone soils from Miami south-
ward, and appears also to be absent in muck soils of the Ever-
glades and in typical flatwoods sections, where pine is the dom-
inant tree and oaks are uncommon or absent.
The guava is subject to rootknot caused by parasitic nema-
todes. Root damage or destruction can become so severe in
sandy soils that the top dies back and the tree fails to produce
satisfactory crops. Injury can be overcome to a considerable
degree by heavy fertilization, irrigation and the use of nutri-
tional sprays.
Spotting of leaves and fruits, caused by the alga, Cephaleuros
virescens Kunze, is often rather severe on some types and varie-
ties of guava, particularly in the humid coastal areas. Spraying

Growing Guavas in Florida

with the nutritional spray in the spring reduces the degree of
Mummification and blackening of immature fruit is observed
occasionally in Florida. Several species of fungi have been ob-
served fruiting on the mummies but they have not been proved
to be the primary cause of the trouble. The disease is not serious
enough to warrant special sprays for control. Colletotrichum
gloeosporioides Penz. and several unidentified fungi are associ-
ated with decays of mature fruit. Frequently such infections
are initiated at insect stings or at cracks developing in the
skin after heavy rains.

Fig. 12.-Rootknot on guava. Nematodes frequently destroy most of the
root system of neglected trees growing on sandy soils.

Zinc deficiency is characterized by little leaf and chlorosis,
and stunted growth, dieback, and chlorosis often develop follow-
ing heavy feeding of NPK fertilizers or associated with root-
knot. Whether the primary cause is unbalanced nutrition or
simply the inability of the damaged roots to obtain sufficient
of the minor elements from the soil is not known. Correction
usually follows the application of a nutritional spray containing
copper and zinc.

Florida Cooperative Extension

The guava is subject to attack by numerous insects. De-
tailed life history and satisfactory control measures for some
of these pests still remain to be worked out.

Fig. 13.-Guava fruit moth damage to mature fruit. No satisfactory
control is available for this very serious insect pest.

The guava whitefly, Metaleurodicus cardini (Back), and the
fairly numerous species of scale insects attacking guava are con-
trolled by the use of oil emulsion containing 11/4 percent actual
oil in the spray, or by spraying with parathion wettable powder
at the rate of 1 pound of 15 percent or equivalent per 100 gal-
lons of water. In the case of whitefly, time the sprays when
larvae are found on the leaves, or about two weeks after flights
of adult whiteflies. Apply sprays for control of scales when
severe infestations are first noted.
The redbanded thrips, Selenothrips rubocinctus (Giard.), is
often troublesome on the guava, causing defoliation and fruit

Growing Guavas in Florida

russetting when infestations are severe. This thrips excretes
over the surface small drops of a clear reddish fluid, which hard-
ens and turns rusty brown to black. Control with thorough ap-
plications of any one of a number of insecticides. Dieldrin is
particularly effective when used at 1 pound of 20 percent wet-
table powder or its equivalent per 100 gallons of water. How-
ever, dieldrin has not yet been approved for use on the guava.
Spraying with lindane wettable at 1 pound of active ingredient
or its equivalent per 100 gallons of water will give control. Fair-
ly effective control can be obtained with a spray of 40 percent
nicotine sulfate at 1 pint per 100 gallons of water.
Apply the sprays when the fruit is small or when infestations
are first noted.
In recent years the larvae of a tiny moth, Argyresthia eugen-
iella Busck, have caused considerable damage by tunneling
through the fruit. The life history is imperfectly known. It
has been observed that the incidence of tunneling increases
steadily during the fruiting season, so presumably the life cycle
is short. The larvae are whitish to pink in color with a black
head, and attain a length of about 1/4 inch. A satisfactory con-
trol of this pest has not been developed. Applications of DDT,
2 pounds of 50 percent wettable powder per 100 gallons of water
at approximately 2-week intervals from the time the fruit is
small until near maturity, apparently has reduced infestation
considerably, but the problem of spray residues on the mature
fruit must be considered.
A small weevil, Anthonomus costulatus Suffr., attacks the
young fruit from the blossom stage onward. Much of the fruit
may be damaged severely and drop from the tree when very
small. Small pit-like punctures through the skin of small green
fruit are caused by the adult females depositing eggs. Larvae
of the insect are sometimes found feeding inside these fruits.
Adequate control measures have not been worked out for this
insect, but parathion and benzene hexachloride sprays have been
reported to be effective in reducing the damage.
Other insects attacking guavas in Florida include an unidenti-
fied leaf-tier, a serpentine leaf miner and a false spider-mite.
These have not been serious enough to warrant special control
measures thus far. Parathion applied for whitefly control ap-
parently also gives some measure of control of these pests.
Several species of the larger plant bugs occasionally sting the
fruit, sucking the juices from the flesh. Th stung areas usually

Florida Cooperative Extension

decay as the fruit ripens. Satisfactory control measures have
not been developed for control. Since parathion at 2 pounds
of the 15 percent wettable powder per 100 gallons of spray is
effective for control of these pests on other crops, it should prove
effective for their control of guava, should they become numer-
ous enough to warrant the expense of spraying.

(Acts of May 8 and June 30, 1914)
Agricultural Extension Service, University of Florida,
Florida State University and United States Department of Agriculture, Cooperating
M. O. Watkins, Director


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
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site maintained by the Florida
Cooperative Extension Service.

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