Group Title: Circular ;
Title: Insects and mites of Florida citrus /
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00102078/00001
 Material Information
Title: Insects and mites of Florida citrus /
Series Title: Circular ;
Physical Description: 1 folded sheet : ill. (some col.) ; 23 cm.
Language: English
Creator: Brogdon, James
Lawrence, Fred P
Florida Cooperative Extension Service
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville, Fla
Gainesville, Fla
Publication Date: 1972
Copyright Date: 1972
 Subjects
Subject: Citrus -- Diseases and pests -- Florida   ( lcsh )
Insect pests -- Florida   ( lcsh )
Mites -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by James E. Brogdon, Fred P. Lawrence.
General Note: Caption title.
General Note: "November 1972."
 Record Information
Bibliographic ID: UF00102078
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 - 232325135

Full Text

Circular 137-C


November 1972


InaeM Wud M&
OF FLORIDA CITRUS
by
JAMES E. BROGDON FRED P. LAWRENCE
Extension Entomologist Extension Citriculturist
This public document was promulgated at an
annual cost of 780.00 or .078 ea per copy by the
University of Florida Institute of Food and
Agricultural Sciences to help citrus growers
become better acquainted with citrus insects
and mites and their injuries. Some beneficial
ladybeetles and several fungi are illustrated
and discussed.


TOP-Russeting of oranges (1/ natural size) caused by
citrus rust mites.
BOTTOM-Citrus rust mites, Phyllocoptruta oleivora
(Ashm.), magnified 15 times. These mites are so small that
they are difficult to recognize under a 10-power magnifying
glass. They are lemon-yellow and wedge-shaped. (See
further discussion of rust mites under photographs on back
of this circular.)


FLORIDA COOPERATIVE EXTENSION SERVICE,
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES,
UNIVERSITY OF FLORIDA, GAINESVILLE f





































(MITES AND EGGS IN CIRCLES ARE MAGNIFIED 36 TIMES)

TOP.-Texas citrus mite, Eutetranychus banksi (McG),
showing eggs, young, and adult female and male. The
adult female, about 1/60-inch long, has a shiny body
without conspicuous hairs. The color varies from tan to
brownish-green with dark brown to greenish spots or bars
near the lateral margins. The adult male, which has
longer legs than the female, has a somewhat triangular-
shaped body smaller than the female. The female lays flat,
disc-like eggs along the midrib and near the lateral margins
of the leaves. The eggs vary in color from light yellow
when laid to tan and green as they mature, turning to
reddish brown just before hatching. Newly-hatched mites
are light yellow to tan with pale legs. Populations of mites
are much heavier on the upper leaf surface. Injury to
leaves is caused by mites sucking out the juices which
may give the leaf a scratched or etched appearance as
shown above. Injury may result in collapse of leaf cells
and leaf drop, particularly during fall and winter. The
mites are most numerous May through July, but most
injurious October through February because of dry weather
and less vigorous tree condition.
BOTTOM-Citrus red mite (purple mite), Panonychus
citri (McG.), showing eggs, young, and adult female and
male. The adult female is about 1/50 inch long, rose to
deep purple in color with prominent light-colored hairs,
and lays a round, reddish-colored egg. Both eggs and mites
occur mostly on the upper leaf surface, but also are
found on the under surface and on green twigs. Eggs
laid on leaves are most abundant along the midrib and
petiole. The life cycle is short and there may be 12 to 15
generations per year. The mites are most numerous May
through July, but most injurious October through February
because of dry weather and less vigorous tree condition.
Leaf injury is similar to that of the Texas citrus mite.

















































TOP.-Upper surface of leaf showing early six-spotted
mite injury.
CENTER.-Injury to underside of leaf. (Mites and eggs
in circle magnified 36 times.)
BOTTOM.-Upper surface of leaf showing severe six-
spotted mite injury. (Leaves are 1/2 natural size.)
Six-spotted mite, Eotetranychus sexmaculatus (Riley),
is about 1/50-inch long, pale grayish-yellow in color, and
lays a round, yellowish-white egg. It usually has four or
six dark spots arranged in two rows on the body. With
a 10-power magnifying glass, the spots are barely visible
on the adult mites and few or none can be seen on the
young. Mites and eggs are found in colonies, often covered
with a webbing, and located only on the under surface
of the leaf. Feeding causes yellow or chlorotic areas,
usually along the veins, and results in leaf drop. These
mites are usually most numerous March through May, but
may build up in January and February after a cold De-
cember. Although grapefruit varieties are preferred, they
can be found on other types of citrus. Inspections should
be made with a magnifying glass, although the yellow
spotting of the leaves can be seen with the naked eye.




NOV 4 t978OCT 2 0 1975


(SCALES IN CIRCLES ARE MAGNIFIED 6


TIMES


TOP. Glover (long) scale, Lepidosaphes il. P'r
(Pack.), and (BOTTOM) purple scale, Lepidosaphes becki
(Newm.), are very similar in appearance and habits, bu
Glover scale is longer and narrower. These scales fee
on leaves, fruit and wood, and are often overlooked because
they are found primarily on the inside of the tree and on
the wood. They like shady areas such as the under -urfa-li.
of leaves and collect especially along the midrib aiiJ a
the base. Residues of any type encourage heavier .nl-tl
tions. Yellow, chlorotic areas on the leaf result in deluIiu
tion and subsequent twig death. Infestations on th: Iruil.
particularly near the stem end, cause fruit loss, as -11. w
green spots which can not be removed in the coloring r.,irn
Inspections of groves should be made at intervals, partit
cularly prior to post-bloom and summer spray periods.
The female purple scale lays grayish-colored eggs in a
sac-like enclosure under her armor, while Glover scale!
eggs are pink in color and found in two rows. Cr ,l.-r-
of both scales are oval and have an off-white col.:r Iliih
a posterior brown tip. Peaks of young stages occur in
March-April, June-July and September-October.















































(SCALES IN CIRCLES ARE MAGNIFIED 6 TIMES)



TOP.-Florida red scale, Chrysomphalus aonidum (L.),
and (BOTTOM) yellow scale, Aonidiella citrina (Coq.),
feed on leaves and fruit, preferring exposed surfaces. Their
feeding results in yellow areas on leaves and fruit which
may often be followed by heavy leaf and fruit drop. The
denuded branches may be killed the following fall and
winter. Inspections of groves should be made at intervals,
particularly from May through October.
The adult female Florida red scale is circular in outline,
about 1/12-inch in diameter, and dark reddish-brown in
color, with a conspicuous lighter-colored center. She lays
bright yellow eggs under her armor that produce bright,
lemon-yellow, oval-slraped crawlers. There are usually four
generalliont per year.
Yellow scale can be distinguished from Florida red
scale by the lighter color of its armor and the shape of
the scale body. The adult female is circular, yellow to
light orange in color and noticeably flatter than other
armored scales on citrus in Florida. The body, which
can be seen through the semi-transparent armor, is lemon-
yellow and kidney-shaped. No eggs are found, as the
females give birth to living young.















































(SCALES IN CIRCLES ARE MAGNIFIED 6 TIMES)


TOP.-Black scale, Sassetia oleae (Bern.), as an adult
female is nearly circular, hemispherical, dark-brown to
almost black, with two lateral ridges and a longitudinal
ridge forming a pattern on the back resembling the letter
"H". She lays approximately 2,000 eggs in a cavity under
her body. The eggs are oval and pink in color changing
to reddish-orange before hatching. The light brown, flat,
oval crawlers travel about considerably before settling on
twigs or leaves and to some extent on fruit. Later the
young move from leaves or fruit to small twigs, particularly
stems that hold fruit. There are two or three generations
a year. Black scales excrete large quantities of honeydew.
BOTTOM.-Brown soft scale, Coccus hesperidum L., is
oval and flat, and light brown in color. No eggs are laid;
pale yellow crawlers are born alive. Young female and
male scales are similar in shape and color, but smaller
than adult females. These scales infest young twigs and
often gather along the midrib of the leaf. They are highly
parasitized by tiny wasp-like insects and rarely become
abundant except on young trees, either in newly-planted
groves or in a nursery, where ants feed on the honeydew
Sand drive away the parasites. Brown soft scales excrete
lrge amounts of honeydew.








)


.-- -

'

(i
/" j

."
v II t


-1.I


*1


TOP LEFT (enlarged 10 times).-Cloudy-winged white-
flies, Dialeurodes citrifolia (Morg.), with immatures and
eggs. The eggs, which are commonly laid on young leaves,
are yellow when first laid but soon turn dark. The surface
of the egg is netted with ridges. The flat transparent
larvae (young) settle on the under surface of the leaves.
The citrus whitefly, Dialeurodes citri (Ashm.), and the
woolly whitefly, Aleurothrixus floccosus (Mask.), are also
common on citrus. There are others of lesser importance.
Peak broods of whiteflies usually occur about March-April,
June-July and September-October.
TOP RIGHT.-Sooty mold fungus, Capnodium citri
Berk. and Desm., develops primarily on the sweet, syrupy
excertions (honeydew) of immature whiteflies, but to a
lesser extent on the honeydew of aphids, mealybugs, and
certain soft scales. Control of these insects will prevent
the development of this fungus.
BOTTOM.-Red Aschersonia (left), Aschersonia aley-
rodis Webber, and brown whitefly fungus (right), Aegerita
webberi Faw., are beneficial fungi that kill immature
whiteflies. The latter is often mistaken for Florida red
scale. (Both one-half natural size.)


e-ihj

i)






































LEFT CENTER AND TOP. Aphids (magnified
times) and aphid injury to young growth. Aphids, or p
lice, are particularly injurious to young trees. The gr
citrus or spirea aphid, Aphis spiraecola Patch., is the n
common. Others including cotton or melon aphid, A
gossypii Glover, black citrus aphid, Toxoptera aura
(Fonsc.), and green peach aphid, Myzus persicae (Su
are found at times. Ants feed on a sweet, syrupy excre
(honeydew) of aphids and may move them around, ai
in their spread. Aphids injure young tender growth in
spring, especially on temples and tangerines, causing le
to curl. Inspect for these insects at frequent inter
when new growth starts, especially during the sp
months.
TOP RIGHT.-Cottony-cushion scale, Icerya pur
Mask. (about twice natural size), is most damagin
young trees. It is usually kept under control on citr
the vedalia or Australian ladybeetle, Rodolia car
(Muls.), shown feeding on the scale. The large illus
of the vedalia ladybeetle is magnified 6 times.
BOTTOM ROW (all magnified 5 times).-Left to r
Twice-stabbed ladybeetle, Chilocorus stigma (Say)
beetle larva; covergent ladybeetle, Hippodamia con
Guer.; blood-red ladybeetle, Cycloneda sanguinea
Ladybeetle adults and larvae feed on many citrus
including scales, aphids and mites.
'i 1.I v
.ip'
'"
^'~




































including scales, aphids and mites.
















MITES AND EGGS MAGNIFIED ABOUT 20 TO 25 TIMES


:itrus rust mites, Phyllocoptruta oleivora
;hm.), are so small (about 1/200-inch long)
t they cannot be recognized with the unaided
SUnder a 10-power magnifying glass they ap-
r as lemon-yellow, wedge-shaped objects, but
tinct features cannot be seen. Rust mites can
seen more easily on green leaves and fruits
.n on ripe fruits. A heavily-infested leaf appears
be fuzzy or dusty. Eggs of whiteflies are often
taken for rust mites. The life cy requires
ly about a week in summer, whici. -ounts
the rapid build-up often noted.
ust mites infest leaves, fruit and tender green
-., causing russeteA rusty-colored fruit.
avily-infested leaves lo, .heir gloss and dark-
een color and may drop prematurely. Heavy
festations may develop on the leaves just before
oom and cause severe injury to young fruits soon
ter they are set. Rust mites seem to prefer
-posed locations and are numerous in the tops of
ees. They are more numerous on fruit from
>ring until late summer. Inspect the fruits and
iderside of leaves with a magnifying glass.
Melanose, a fungus disease, causes blemishes on
trus fruit often confused with russeting or rust
iite injury. Lesions caused by the melanose fungus
re blacker, more rounded and raised, and have a
RUST MITE AND EGGS GREATLY MAGNIFIED





rough or sandpapery feel. Scab, another fungus
disease, causes spots that are usually rougher,
larger, more irregular and lighter in color than
rust mite injury.
Citrus mealybug, Pseudococcus citri (Risso), lays
its eggs in a mass of cotton which it secretes.
Mealybugs are often confused with cottony-cushion
scale. They also excrete large amounts of honey-
dew in which sooty mold fungus (see other side
of circular) develops. They may get into crevices
in the bark on the limbs and trunk and in such
sheltered places as the angle between the petiole
of the leaf and stem. Mealybugs often collect
around the stem end and under the button (calyx)
of the fruit (especially grapefruit) and cause fruit
drop. Another favorite place for mealybugs is the
sheltered area formed by clusters of two or more
fruits, particularly grapefruit. Controls should be
applied before mealybugs have settled under the
fruit calyx.
MEALYBUGS (NATURAL SIZE) ON FRUIT














S

MEALYBUGS MAGNIFIED APPROXIMATELY 5 TIMES
















CHAFF SCALE CITRUS SNOW SCALE

Chaff scale, Parlatoria pergandii Comst., forms
a light brown nearly round armor which is slightly
smaller than that of a mature female Florida red
scale. The eggs and crawlers are purple. This scale
infests leaves, wood and fruit where it causes green
spots which lower the grade. It is especially im-
portant on tangerines and early varieties of oranges
that must be degreened. Heavy infestations are
most likely to develop during late summer and
through the winter.
Citrus snow scale, Unaspis citri (Comst.), gets
its name from the white color of male scales.
Female scales are brown to blackish with a length-
wise, roof-like ridge. They are very difficult to see
against the tree bark. Scales are largely confined
to the trunk, limbs and twigs.
Florida wax scale, Ceroplastes floridensis
Comst., is a soft scale that is white to pinkish-
white when not stained by sooty mold or other
foreign matter. The adult female is 1/8-inch or
less in length, oval in general outline but present-
ing an angular appearance due to dome-shaped
masses of wax on the back. The pale-brown
crawlers collect on the lower leaf surface along
the midrib. Young larvae are star-shaped. This
scale is highly parasitized.
The orange dog, Papilio cresphontes Cram., is

FLORIDA WAX SCALE (MAGNIFIED 5 TIMES)





often a pest of citrus trees. Two or three may
defoliate a young tree in a few days. They are
most important on young trees and nursery stock.
The caterpillar is dark brown with light yellow
patches, growing to a length of 11/2 to 2 inches.
The front part of the body is enlarged and when
not feeding the caterpillar pulls the head back into
these large segments and causes the whole front
part of the body to resemble, somewhat, the head
of a dog-hence the name. The orange dog can
push out a fold of skin back of the head which







ORANGE
DOG CATER-
PILLARS ON
CITRUS LEAF










ORANGE
DOG
BUTTERFLY


forms two long, red, horn-like projections. This
organ gives off a strong, disagreeable odor which
repels natural enemies. The adult is a beautiful
large, yellow and black butterfly.
The broad-winged katydid, Microcentrum rhom-
bifolium (Sauss.), lays its eggs along the margin
of the leaf and there are several generations a
year. Other kinds of katydids occur in citrus
groves, but only the broad-winged kaydid is of
any economic importance. They sometimes feed
on the rind of growing oranges, causing large,
smooth sunken areas to develop on the fruit. Occa-






sionally they cause severe defoliation of young
trees.
Grasshoppers (several species) may be found
in citrus groves, causing injury to fruit and foliage.
Eggs are laid in the ground and, after hatching,
young nymphs may migrate to the cover crop and
trees in the grove. Injury is most important on
young trees. In some instances they have complete-
y defoliated newly set trees. The eastern lubber


J/i


)AD-WINGED KATYDID (TOP)
AND LUBBERLY GRASSHOPPER (BOTTOM)

sshopper, Romalea microptera (Beauv.), pro-
:es one generation per year and may be found
*ing spring and summer in groves adjacent to
, marshy land.
'rue bugs of several kinds, including stink bugs


EGGS OF THE BROAD-WINGED KATYDID






and leaf-footed plant bugs, puncture the fruit
rind, often causing premature color break and drop.
They may cause considerable damage to all va-
rieties of citrus but injury is most common on
tangerines and early and midseason oranges. These
insects move to mature or nearly mature fruit from
host plants in or near the grove, particularly when
the cover crop is chopped or is beginning to dry
up or harden. Pods of leguminous cover crops,
such as beggarweed and crotalaria, as well as the
citron melon, are attractive to these pests and often
induce heavy infestation.
Fuller's rose beetle, Pantomorus godmani
(Crotch.), gray-brown in color and 1/4- to 1/3-
inch in length, and the citrus root weevil, Pach-
naeus litus (Germar), blue-green in color and 1/2-
to 3/4-inch in length, may occur in sufficient num-
bers to cause severe injury to both roots and foliage
of all varieties of citrus. Injury from these pests
has been noted most commonly along the Florida
east coast. Growers should familiarize themselves
with these insects and the injury symptoms of both
the larval and the adult stages.
Injury by the larval stage is by far more serious
than injury by the adult stage. The legless white
larvae of both species eat canal-like channels in
the roots. This injury is usually more prevalent
on the underside of the lateral roots, although
where high populations occur many primary roots
may be girdled near the main trunk root. Adult
injury to leaves typically appears as notches cut
out along the leaf margin. Injury is usually more
prevalent on the lower 6 feet of trees and on
leaves of sprouts near the main trunk. Adults also
feed on small fruit during and shortly after bloom.
Ants (several species) are found in citrus groves.
Some may cause injury to newly-budded trees in
the nursery; others are a nuisance to pickers. Ants
may damage the trees indirectly by protecting and
caring for scale insects, aphids and especially
mealybugs. Ants carry them from place to place
and feed on the excreted honeydew.
Termites sometimes damage citrus trees, especi-
ally young trees banked for cold protection. If
banking soil contains cellulose material, such as
roots, chips and paper bags, termites may attack
this material and later injure young trees.
The pink scavenger caterpillar, Pyroderces rileyi
Wlsm., is a small caterpillar with a deep wine-
red abdomen, brownish head and black mouth
parts. It has a dark brown area just behind the
head. The pink scavenger worm feeds primarily
on dead insects and decaying areas of fruit, but
also may feed on the rind of sound fruit, causing





a lowering of grade. They may be present during
heavy infestations of mealybugs, and are sometimes
numerous on fruit with heavy infestations of
scales.


(LEFT TO RIGHT), BROWN STINK BUG, LEAF-FOOTED PLANT
BUG, AND BIG-LEGGED PLANT BUG


THREE TYPES OF


HAND LENS USEFUL IN MAKING SCALE
AND MITE SURVEYS.


Suggestions on How to Inspect
A Citrus Grove for Mites
Some growers make periodic inspections for rust
mite, citrus red mite (purple mite) and Texas citrus
mite and apply the recommended materials only
when needed. When properly done, this procedure
is more economical and gives better control than
when miticides are applied by the calendar. Mites
often build up in certain areas of a grove. These
areas should be learned by the inspector and ex-
amined first.
* Travel through the grove to cover all parts of


rfC~",

5:* ~ic~






the block. Some people use a figure "8", others
a "Z" pattern.
* Inspect at least 20 trees in a block (10 to 20
acres). Examine leaves and fruit from the north
side of the first tree, alternating the east, south
and west sides of succeeding trees.
* With a 10X lens, examine 5 full grown leaves
from terminals in the outer canopy of each tree
inspected. Examine one lens field on each surface
of each of these leaves for rust mite. Examine
entire surfaces of each leaf for citrus red mite
and Texas citrus mite. From spring to late
summer when the fruit is green, examine a
lens field on both the sunny and shady sides of
5 fruit for rust mite.
* If one or more mites are found on a leaf or fruit
it is counted as infested. Fifteen infested leaves
or fruit in 100 inspected indicates a 15 percent
infestation.
* Records for rust mite should be tabulated
separately from citrus red mite and Texas citrus
mite. Such records should be maintained through
each growing season.
In general, damage is likely to occur soon after
a mite infestation reaches 20 percent. Control
measures should be started when the mite in-
festation reaches 15 to 20 percent.
CONTROL
Since new pesticides are constantly being intro-
duced, no attempt is made here to list specific
recommendations of insecticides and miticides.
Commercial growers should refer to the Better
Fruit Program Spray and Dust Schedule, while
growers of dooryard citrus may refer to Agricul-
tural Extension Service Circular 139B, Control
of Insects and Diseases of Dooryard Citrus Trees.
These circulars may be obtained from your County
Agricultural Agent or by writing to the Agricul-
tural Extension Service, University of Florida,
Gainesville.
ACKNOWLEDGMENT
Appreciation is expressed to Marion Ruff Sheehan for
the color illustrations, to Milledge Murphey, M. W. Tyler,
the Citrus Experiment Station and USDA for the photo-
graphs, to workers of the College of Agriculture, Citrus
Experiment Station and Agricultural Extension Service for
helpful suggestions used in the preparation of this cir-
cular. Helpful information was taken from Agricultural
Experiment Station Bulletin 591, Insects and Mites
Found on Florida Citrus; Bulletin 640, Mites Associated
With Citrus in Florida; and Florida Guide to Citrus
Insects, Diseases and Nutritional Disorders in Color.
(Originally Printed June 1955)
COOPERATIVE EXTENSION WORK IN
AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Cooperative Extension Service, University of Florida
and
United States Department of Agriculture, Cooperating
J. N. Busby, Dean



















































TOP.-Upper surface of leaf showing early six-spotted
mite injury.
CENTER.-Injury to underside of leaf. (Mites and eggs
in circle magnified 36 times.)
BOTTOM.-Upper -urlace of leaf showing severe six-
-pllttd mite iniurN. i lr3 e- ,r, ,_ r,.u lr.fl -.1'.1
S't\ r..l.d r;.., Eotetranychus sexmaculatus (Riley),
is a...l "i1 .,,,. long, pale grayish-yellow in color, and
lays a round, yellowish-white egg. It usually has four or
six dark spots arranged in two rows on the body. With
a 10-power magnifying glass, the spots are barely visible
on the adult mites and few or none can be seen on the
young. Mites and eggs are found in colonies, often covered
with a webbing, and located only on the under surface
of the leaf. Feeding causes yellow or chlorotic areas,
usually along the veins, and results in leaf drop. These
mites are usually most numerous March through May, but
may build up in January and February after a cold De-
cember. Although grapefruit varieties are preferred, they
can be found on other types of citrus. Inspections should
be made with a magnifying glass, although the yellow
spotting of the leaves can be seen with the naked eye.
















































(SCALES IN CIRCLES ARE MAGNIFIED 6 TIMES)




TOP. Glover (long) scale, Lepidosaphes gloverii
.PjIk. iand (BOTTOM) purple scale, Lepidosaphes beckii
INemni.V. are very similar in appearance and habits, but
Gloaer scjle is longer and narrower. These scales feed
an leaves, fruit and wood, and are often overlooked because
they are found primarily on the inside of the tree and on
the wood. They like shady areas such as the under surface
of leaves and collect especially along the midrib and at
the base. Residues'of any type encourage heavier infesta-
tions. Yellow, chlorbtic areas on the leaf result in defolia-
tion and subsequent twig death. Infestations on the fruit,
particularly near the stem end, cause fruit loss, as well as
green spots which can not be removed in the coloring room..
Inspections of groves should be made at intervals, p'-
cularly prior to post-bloom and summer spray periods.
The female purple scale lays grayish-colored eggs int a
sac-like enclosure under her armor, while Glover scale
eggs are pink in color and found in two rows. Crawlers
of both scales are oval and have an off-white color with
a posterior brown tip. Peaks of young stages occur in
March-April, June-July and September-October.








At


TOP LEFT (enlarged 10 times).-Cloudy-winged white-
flies, Dialeurodes citrifolia (Morg.), with immatures and
eggs. The eggs, which are commonly laid on young leaves,
are yellow when first laid but soon turn dark. The surface
of the egg is netted with ridges. The flat transparent
larvae (young) settle on the under surface of the leaves.
The citrus whitefly, Dialeurodes citri (Ashm.), and the
woolly whitefly, Aleurothrixus floccosus (Mask.), are also
common on citrus. There are others of lesser importance.
Peak broods of whiteflies usually occur about March-April,
June-July and September-October.
TOP RIGHT.-Sooty mold fungus, Capnodium citri
Berk. and Desm., develops primarily on the sweet, syrupy
excertions (honeydew) of immature whiteflies, but to a
lesser extent on the honeydew of aphids, mealybugs, and
certain soft scales. Control of these insects will prevent
the development of this fungus.
BOTTOM.-Red Aschersonia (left), Aschersonia aley-
rodis Webber, and brown whitefly fungus (right), Aegerita
webberi Faw., are beneficial fungi that kill immature
whiteflies. The latter is often mistaken for Florida red
scale. (Both one-half natural size.)























'I-


.54



















LEFT CENTER AND TOP. Aphids (magnified 10
times) and aphid injury to young growth. Aphids, or plant
lice, are particularly injurious to young trees. The green
citrus or spirea aphid, Aphis spiraecola Patch., is the most
common. Others including cotton or melon aphid, Aphis
gossypii Glover, black citrus aphid, Toxoptera aurantii
(Fonsc.), and green peach aphid, Myzus persicae (Sulz.)
are found at times. Ants feed on a sweet, syrupy excretion
(honeydew) of aphids and may move them around, aiding
in their spread. Aphids injure young tender growth in the
spring, especially on temples and tangerines, causing leaves
to curl. Inspect for these insects at frequent intervals
when new growth starts, especially during the spring
months.
TOP RIGHT.-Cottony-cushion scale, Icerya purchase
Mask. (about twice natural size), is most damaging to
young trees. It is usually kept under control on citrus by
the vedalia or Australian ladybeetle, Rodolia cardinalis
(Muls.), shown feeding on the scale. The large illustration
of the vedalia ladybeetle is magnified 6 times.
BOTTOM ROW (all magnified 5 times).-Left to right:
Twice-stabbed ladybeetle, Chilocorus stigma (Say); lady-
beetle larva; covergent ladybeetle, Hippodamia convergens
Guer.; blood-red ladybeetle, Cycloneda sanguine (L.).
Ladybeetle adults and larvae feed on many citrus pests,
including scales, aphids and mites.
















RUST MITES AND EGGS MAGNIFIED ABOUT 20 TO 25 TIMES


Citrus rust mites, Phyllocoptruta oleivora
(Ashm.), are so small (about 1/200-inch long)
that they cannot be recognized with the unaided
eye. Under a 10-power magnifying glass they ap-
pear as lemon-yellow, wedge-shaped objects, but
distinct features cannot be seen. Rust mites can
be seen more easily on green leaves and fruits
than on ripe fruits. A heavily-infested leaf appears
to be fuzzy or dusty. Eggs of whiteflies are often
mistaken for rust mites. The life cycle requires
only about a week in summer, which accounts
for the rapid build-up often noted.
Rust mites infest leaves, fruit and tender green
shoots, causing russeted or rusty-colored fruit.
Heavily-infested leaves lose their gloss and dark-
green color and may drop prematurely. Heavy
infestations may develop on the leaves just before
bloom and cause severe injury to young fruits soon
after they are set. Rust mites seem to prefer
exposed locations and are numerous in the tops of
trees. They are more numerous on fruit from
spring until late summer. Inspect the fruits and
underside of leaves with a magnifying glass.
Melanose, a fungus disease, causes blemishes on
citrus fruit often confused with russeting or rust
mite injury. Lesions caused by the melanose fungus
are blacker, more rounded and raised, and have a
RUST MITE AND EGGS GREATLY MAGNIFIED




rough or sandpapery feel. Scab, another fungus
disease, causes spots that are usually rougher,
larger, more irregular and lighter in color than
rust mite injury.
Citrus mealybug, Pseudococcus citri (Risso), lays
its eggs in a mass of cotton which it secretes.
Mealybugs are often confused with cottony-cushion
scale. They also excrete large amounts of honey-
dew in which sooty mold fungus (see other side
of circular) develops. They may get into crevices
in the bark on the limbs and trunk and in such
sheltered places as the angle between the petiole
of the leaf and stem. Mealybugs often collect
around the stem end and under the button (calyx)
of the fruit (especially grapefruit) and cause fruit
drop. Another favorite place for mealybugs is the
sheltered area formed by clusters of two or more
fruits, particularly grapefruit. Controls should be
applied before mealybugs have settled under the
fruit calyx.


MEALYBUGS (NATURAL SIZE) ON FRUIT


MEALYBUGS MAGNIFIED APPROXIMATELY 5 TIMES






sionally they cause severe defoliation of young
trees.
Grasshoppers (several species) may be found
in citrus groves, causing injury to fruit and foliage.
Eggs are laid in the ground and, after hatching,
young nymphs may migrate to the cover crop and
trees in the grove. Injury is most important on
young trees. In some instances they have complete-
ly defoliated newly set trees. The eastern lubber


D KATYDID (TOP)
AND LUBBERLY GRASSHOPPER BOTTOMI


grasshopper, Romalea microptera (Beauv.), pro-
duces one generation per year and may be found
during spring and summer in groves adjacent to
low, marshy land.
True bugs of several kinds, including stink bugs


EGGS OF THE BROAD-WINGED KATYDID


'"






and leaf-footed plant bugs, puncture the fruit
rind, often causing premature color break and drop.
They may cause considerable damage to all va-
rieties of citrus but injury is most common on
tangerines and early and midseason oranges. These
insects move to mature or nearly mature fruit from
host plants in or near the grove, particularly when
the cover crop is chopped or is beginning to dry
up or harden. Pods of leguminous cover crops,
such as beggarweed and crotalaria, as well as the
citron melon, are attractive to these pests and often
induce heavy infestation.
Fuller's rose beetle, Pantomorus godmani
(Crotch.), gray-brown in color and 1/4- to 1/3-
inch in length, and the citrus root weevil, Pach-
naeus litus (Germar), blue-green in color and 1/2-
to 3/4-inch in length, may occur in sufficient num-
bers to cause severe injury to both roots and foliage
of all varieties of citrus. Injury from these pests
has been noted most commonly along the Florida
east coast. Growers should familiarize themselves
with these insects and the injury symptoms of both
the larval and the adult stages.
Injury by the larval stage is by far more serious
than injury by the adult stage. The legless white
larvae of both species eat canal-like channels in
the roots. This injury is usually more prevalent
on the underside of the lateral roots, although
where high populations occur many primary roots
may be girdled near the main trunk root. Adult
injury to leaves typically appears as notches cut
out along the leaf margin. Injury is usually more
prevalent on the lower 6 feet of trees and on
leaves of sprouts near the main trunk. Adults also
feed on small fruit during and shortly after bloom.
Ants (several species) are found in citrus groves.
Some may cause injury to newly-budded trees in
the nursery; others are a nuisance to pickers. Ants
may damage the trees indirectly by protecting and
caring for scale insects, aphids and especially
mealybugs. Ants carry them from place to place
and feed on the excreted honeydew.
Termites sometimes damage citrus trees, especi-
ally young trees banked for cold protection. If
banking soil contains cellulose material, such as
roots, chips and paper bags, termites may attack
this material and later injure young trees.
The pink scavenger caterpillar, Pyroderces rileyi
Wlsm., is a small caterpillar with a deep wine-
red abdomen, brownish head and black mouth
parts. It has a dark brown area just behind the
head. The pink scavenger worm feeds primarily
on dead insects and decaying areas of fruit, but
also may feed on the rind of sound fruit, causing




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs