• TABLE OF CONTENTS
HIDE
 Copyright
 Title Page
 Board of control and staff
 Introduction
 Description
 Life history
 Host plants
 Aphid indicators
 Predators and parasites
 Artifical control






Group Title: Bulletin - University of Florida. Agricultural Experiment Station - no. 252
Title: The melon aphid, Aphis gossypii Glover
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027742/00001
 Material Information
Title: The melon aphid, Aphis gossypii Glover
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 23 p. : ill., chart ; 23 cm.
Language: English
Creator: Goff, C. C
Tissot, A. N ( Archie Newton ), b. 1897
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1932
 Subjects
Subject: Aphis gossypii   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 23.
Statement of Responsibility: by C.C. Goff and A.N. Tissot.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027742
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000924111
oclc - 18204742
notis - AEN4716

Table of Contents
    Copyright
        Copyright
    Title Page
        Page 1
    Board of control and staff
        Page 2
    Introduction
        Page 3
    Description
        Page 3
    Life history
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
    Host plants
        Page 9
        Page 10
    Aphid indicators
        Page 11
    Predators and parasites
        Page 11
        Page 12
        Page 13
    Artifical control
        Page 14
        Control when on watermelons
            Page 15
            Page 16
            Page 17
            Page 18
        Control when on okra, eggplant, and peppers
            Page 19
        Aphicides and their use
            Page 20
            Page 21
        Summary
            Page 22
        Literature cited
            Page 23
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida







September, 1932


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA
Wilmon Newell, Director

Property of The Department of
E.. EntomoIn~ and Pi. Pathology




THE MELON APHID
Aphis Gossypii Glover

By C. C. GOFF and A. N. TISSOT






Property of The Department of
Ec. Entomology and P1. Pathology











Bulletins will be sent free upon application to the
AGRICULTURAL EXTENSION SERVICE,
GAINESVILLE, FLORIDA,


Bulletin 252









EXECUTIVE STAFF
John J. Tigert, M.A., LL.D., President of the
University
Wilmon Newell, D.Sc., Director
H. Harold Hume, M.S., Asst. Dir., Research
J. Francis Cooper, M.S.A., Editor
R. M. Fulghum, B.S.A., Assistant Editor
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager
K. H. Graham, Business Manager
Rachel McQuarrie, Accountant


MAIN STATION, GAINESVILLE
AGRONOMY
W. E. Stokes, M.S., Agronomist**
W. A. Leukel, Ph.D., Agronomist
G. E. Ritchey, M.S.A., Associate*
Fred H. Hull, M.S., Associate
J. D. Warner, M.S., Associate
John P. Camp, M.S., Assistant

ANIMAL HUSBANDRY
A. L. Shealy, D.V.M., Animal Husbandman**
R. B. Becker, Ph.D., Specialist in Dairy Hus-
bandry
W. M. Neal, Ph.D., Associate in Animal Nutri-
tion
E. F. Thomas, D.V.M., Assistant Veterinarian
W. W. Henley, B.S.A., Assistant Animal Hus-
bandman
P. T. Dix Arnold, B.S.A., Assistant in Dairy In-
vestigations

CHEMISTRY AND SOILS
R. W. Ruprecht, Ph.D., Chemist**
R. M. Barnette, Ph.D., Chemist
C. E. Bell, Ph.D., Assistant
J. M. Coleman, B.S., Assistant
H. W. Winsor, B.S.A., Assistant
H. W. Jones, M.S., Assistant

ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agricultural Economist**
Bruce McKinley, A.B., B.S.A., Associate
SM. A. Brooker, Ph.D., Associate
Zach Savage, M.S.A., Assistant

ECONOMICS, HOME
Ouida Davis Abbott, Ph.D., Specialist**
L. W. Gaddum, Ph.D., Biochemist
C. F. Ahmann, Ph.D., Physiologist

ENTOMOLOGY
J. R. Watson, A.M., Entomologist**
E. F. Grossman, M.A., Entomologist
A. N. Tissot, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
P. W. Calhoun, Assistant, Cotton Insects

HORTICULTURE
A. F. Camp, Ph.D., Horticulturist**
Harold Mowry, B.S.A., Horticulturist
M. R. Ensign, M.S., Associate
A. L. Stahl, Ph.D., Associate
G. H. Blackmon, M.S.A., Pecan Culturist
C. Van Cleef, M.S.A., Greenhouse Foreman
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist**
George F. Weber, Ph.D., Plant Pathologist
R. K. Voorhees, M.S., Assistant
Erdman West, M.S., Mycologist
*In cooperation with U.S.D.A.
**Head of Department


BOARD OF CONTROL
P. K. Yonge, Chairman, Pensacola
A. H. Blanding, Bartqw
Raymer F. Maguire, Orlando
Frank J. Wideman, West Palm Beach
Geo. H. Baldwin, Jacksonville
J. T. Diamond, Secretary, Tallahassee



BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
L. O. Gratz, Ph.D., Plant Pathologist in Charge
R. R. Kincaid, M.S., Asst. Plant Pathologist
W. A. Carver, Ph.D., Associate Agronomist
R. M. Crown, B.S.A., Assistant Agronomist
Jesse Reeves, Farm Superintendent
CITRUS STATION, LAKE ALFRED
John H. Jefferies, Superintendent
Geo. D. Ruehle, Ph.D., Associate Plant Pathol-
ogist
W. A. Kuntz, A.M., Associate Plant Pathologist
B. R. Fudge,.Ph.D., Associate Chemist
W. L. Thompson, B.S., Assistant Entomologist

EVERGLADES STATION, BELLE GLADE
R. V. Allison, Ph.D., Soils Specialist in Charge
R. N. Lobdell, M.S., Entomologist
F. D. Stevens, B.S., Sugarcane Agronomist
H. H. Wedgeworth, M.S., Plant Pathologist
B. A. Bourne, M.S., Sugarcane Physiologist
J. R. Neller, Ph.D., Biochemist
A. Daane, Ph.D., Agronomist
R. W. Kidder, B.S., Asst. Animal Husbandman
Ross E. Robertson, B.S., Assistant Chemist
SUB-TROPICAL STATION, HOMESTEAD
H. S. Wolfe, Ph.D., Horticulturist in Charge
W. M. Fifield, M.S., Assistant Horticulturist
Stacy 0. Hawkins, M.A., Assistant Plant
Pathologist



FIELD STATIONS

Leesburg
M. N. Walker, Ph.D., Plant Pathologist in
Charge
W. B. Shippy, Ph.D., Associate Plant Pathol-
ogist
K. W. Loucks, M. S., Asst. Plant Pathologist
J. W. Wilson, Ph.D., Associate Entomologist
C. C. Goff, M.S., Assistant Entomologist

Plant City
A. N. Brooks, Ph.D., Plant Pathologist
R. E. Nolen, M.S.A., Asst. Plant Pathologist
Cocoa
A. S. Rhoads, Ph.D., Plant Pathologist
Hastings
A. H. Eddins, Ph.D., Asso. Plant Pathologist
West Palm Beach
D. A. Sanders, D.V.M., Veterinarian
Monticello
Fred W. Walker, Assistant Entomologist
Bradenton
David G. Kelbert, Asst. Plant Pathologist









THE MELON APHID, Aphis Gossypii Glover
By C. C. GOFF and A. N. TIssoT*

The melon or cotton aphid is one of the three most common
species of plant lice found in Florida. Its distribution extends
throughout the state. It has been recorded from Key West in
the south and Pensacola in the north, with numerous records from
many intermediate localities. The first record of Aphis gossypii
from Florida was made in July, 1878, when it was reported as
very numerous on the leaves of orange trees at Fort Reed(5)1.
In 1888 this insect did considerable damage to melon and cucum-
ber vines at Sarasota and Bonifay. Since that time there have
occurred in various Florida publications numerous references to
this aphid which gave accounts of the damage it was doing to
different cultivated crops and ornamental plants.
The melon aphid is the most serious insect pest of watermelons
in Florida. It usually attacks the plants when they are quite young
and does a great deal of damage or may even kill them if control
measures are not used. Cucumbers and cantaloupes are fre-
quently attacked and sometimes seriously injured by this aphid.
Okra is very commonly attacked while eggplant, peppers, and
potatoes are less subject to infestation. Among the field crops
commonly grown in Florida cotton is the only one that is injured
by this insect. Oranges, grapefruit, and other varieties of citrus
are sometimes severely infested by A. gossypii, though this
species causes a great deal less injury to citrus than does the
green citrus aphid, Aphis spiraecola Patch. Hibiscus, one of the
common ornamental plants of Florida, is very commonly infested,
the aphids being found in dense colonies on the under sides of
the leaves and especially on the young flower buds.

DESCRIPTION
The melon aphid is a small insect, a fully grown individual
being about one-sixteenth of an inch long. Seen from above, it
appears somewhat egg-shaped in outline, the head being at the
smaller end. (Fig. 1.) From the posterior end of the abdomen there
extend backward and upward two cornicles. The aphids vary in
color from pale yellow and light green to a very dark green in
the wingless forms. The legs and antennae are white with dark
*Names arranged in a1-' :-al --
1Figures in pare ehese, cited in the back of third
bulletin.









THE MELON APHID, Aphis Gossypii Glover
By C. C. GOFF and A. N. TIssoT*

The melon or cotton aphid is one of the three most common
species of plant lice found in Florida. Its distribution extends
throughout the state. It has been recorded from Key West in
the south and Pensacola in the north, with numerous records from
many intermediate localities. The first record of Aphis gossypii
from Florida was made in July, 1878, when it was reported as
very numerous on the leaves of orange trees at Fort Reed(5)1.
In 1888 this insect did considerable damage to melon and cucum-
ber vines at Sarasota and Bonifay. Since that time there have
occurred in various Florida publications numerous references to
this aphid which gave accounts of the damage it was doing to
different cultivated crops and ornamental plants.
The melon aphid is the most serious insect pest of watermelons
in Florida. It usually attacks the plants when they are quite young
and does a great deal of damage or may even kill them if control
measures are not used. Cucumbers and cantaloupes are fre-
quently attacked and sometimes seriously injured by this aphid.
Okra is very commonly attacked while eggplant, peppers, and
potatoes are less subject to infestation. Among the field crops
commonly grown in Florida cotton is the only one that is injured
by this insect. Oranges, grapefruit, and other varieties of citrus
are sometimes severely infested by A. gossypii, though this
species causes a great deal less injury to citrus than does the
green citrus aphid, Aphis spiraecola Patch. Hibiscus, one of the
common ornamental plants of Florida, is very commonly infested,
the aphids being found in dense colonies on the under sides of
the leaves and especially on the young flower buds.

DESCRIPTION
The melon aphid is a small insect, a fully grown individual
being about one-sixteenth of an inch long. Seen from above, it
appears somewhat egg-shaped in outline, the head being at the
smaller end. (Fig. 1.) From the posterior end of the abdomen there
extend backward and upward two cornicles. The aphids vary in
color from pale yellow and light green to a very dark green in
the wingless forms. The legs and antennae are white with dark
*Names arranged in a1-' :-al --
1Figures in pare ehese, cited in the back of third
bulletin.







Florida Agricultural Experiment Station


tips. The cornicles are black. The winged females have dark
antennae, black head and thorax. The anterior portion of the
abdomen is a greenish-brown in color with the posterior portion
a dark green.
LIFE HISTORY
Life history studies were made by the first author to determine
where the aphid carries over from one season to the next, and


Fig. 1.-Adult f -


Winged forn, (x 20) above;
-o) below.







Bulletin 252, The Melon Aphid


the rapidity with which an infestation is built up. Two series
were run in the life history work; a first-born series, in which
the first born of each generation was carried through; and a
last-born series in which the last born of each generation was
carried through. Thus data were secured on the maximum and
minimum number of generations during the year. The aphids
were reared on young melon plants grown in pots. These plants
were enclosed by lantern globes, the tops of which were covered
with a double thickness of cheesecloth. These cages were kept
in the insectary, a small building open on all sides except for
screen wire. This gave approximately outdoor temperature and
humidity. A weather instrument shelter, kept in the insectary,
contained a recording hygro-thermograph.
The series of aphids studied started with an aphid born on
May 20, 1930, and were carried through for a year. During that
time, 51 generations of the first-born series were born, of which
47 generations completed their life cycle; of the last-born series,
17 generations were born, of which 16 completed their life cycle.

TABLE I.-DEVELOPMENT AND REPRODUCTION OF THE FIRST-BORN SERIES OF Aphis
gossypii REARED IN THE INSECTARY DURING A PERIOD OF ONE YEAR.



->4 9 .S
3 >g 'AP5 P 0
1 5/20 5 13 79 5.4 71 8 77 26
2 5/25 4 80 14 78 4.6 64 6 78 24 78
3 5/29 5 77 15 78 4.3 64 3 81 24 78
4 6/3 6 77 23 80 6.5 150 7 82 36 80
5 6/9 5 77 17 81 .5.8 99 7 81 29 80
6 6/14 3 80 12 83 5.8 69 2 77 17 82
7 6/17 4 80 18 82 3.5 63 4 82 26 82
8 6/21 5 85 15 81 4.6 69 3 81 23 82
9 6/26 5 80 15 82 4.8 72 3 80 23 81
10 7/1 5 78 11 82 6.5 72 6 82 22 81
11 7/6 5 83 10 81 3.2 32 1 83 16 82
12 7/11 5 81 17 82 3.8 64 2 77 24 81
13 7/16 6 82
14 7/22 6 82 16 80 4.7 75 3 81 25 81
15 7/28 5 81 11 80 5.7 63 8 80 24 80
16 8/4 5 80 12 80 7.1 85 11 78 28 79
17 8/9 5 81 17 79 5.5 94 7 79 29 79
18 8/14 5 79 13 79 5.2 68 11 79 29 79
19 8/19 5 80 13 78 6.0 78 8 79 26 78
20 8/24 6 77 13 79 6.0 77 3 79 22 78
21 8/30 5 80
22 9/4 5 79 8 78 7.7 62 0 13 78
23 9/9 5 78 14 80 5.1 72 7 75 26 78
24 9/14 5 79 11 80 6.9 76 0 16 80
25 9/19 5 80 7 80 5.6 39 1 74 13 80
26 9/24 6 81 11 73 3.3 36 2 75 19 76







6 Florida Agricultural Experiment Station

TABLE I.-DEVELOYMENT AND REPRODUCTION OF THE FIRST-BORN SERIES OF Aphis
gossypii REARED IN THE INSECTARY DURING A PERIOD OF ONE YEAR.-Concluded.



a h -gn h p h


27 9/30 5 73 14 73 4.6 65 6 67 25 72
28 10/5 6 73
29 10/11 6 71 21 *64 4.4 92 11 68 38 66
30 10/17 8 69 21 63 3.4 71 4 73 33 66
31 10/25 11 63 16 67 5.0 61 0 27 65
32 11/6 9 61 9 72 2.4 22 5 59 23 64
33 11/15 9 78 6 56 1.7 10 1 50 16 68
34 11/24 13 58 31 54 2.1 64 7 55 51 .55
35 12/7 17 55 15 53 0.9 13 6 55 38 54
36 12/24 20 53 22 55 2.7 59 4 55 46 54
37 1/14 16 54 26 58 3.1 80 6 58 48 57
38 1/30 13 58 29 57 3.0 91 22 60 64 58
39 2/12 10 58 32 57 3.3 104 8 64 50 58
40 2/22 12 59 20 55 2.8 56 9 64 41 58
41 3/5 13 54 23 61 3.7 86 3 66 39 59
42 3/18 11 59 11 65 2.2 24 7 65 29 63
43 3/29 8 65 15 65 2.8 42 11 70 34 66
44 4/6 10 65 20 73 5.4 107 1 73 31 68
45 4/16 6 67 17 71 5.4 91 4 75 27 71
46 4/22 6 69 18 73 5.3 95 2 68 26 72
47 4/28 5 71
48 5/3 4 74 16 73 5.3 85 4 74 24 73
49 5/7 6 75 19 72 46 87 4 76 29 73
50 5/13 7 69 12 74 5.9 71 3 75 22 73
51 5/20 4 76 8 74 5.1 41 6 76 18 75


TABLE II.-DEVELOPMENT AND REPRODUCTION OF THE LAST-BORN SERIES OF Aphis
gossypii REARED IN THE INSECTARY DURING A PERIOD OF ONE YEAR.



I V E A
a w6 S aR a *c .e S s a

1 5 13 79 5.4 71 8 77 26
2 5 77 11 79 7.0 77 5 85 21 80
3 4 83 15 82 4.3 80 2 82 21 82
4 6 82 2 82 1.5 3 1 81 9 82
5 6 81 6 83 4.3 47 1 80 13 82
6 6 82 14 80 4.1 58 2 78 22 80
7 4 79 17 79 5.7 97 5 79 26 79
8 4 80 11 78 5.5 60 1 80 16 79
9 5 80 7 73 5.1 36 1 74 13 76
10 6 72 20 71 4.3 86 5 69 31 71
11 11 63 16 67 50 61 0 27 65
12 13 61 15 57 1.5 23 21 52 49 56
13 19 52 26 55 1.9 50 2 58 47 54
14 15 57 31 58 28 86 16 61 62 59
15 13 60 21 65 3.6 75 4 70 38 64
16 7 69 13 72 6.2 80 3 75 23 71
17 6 75 13 72 5.5 71 11 75 30 74









Bulletin 252, The Melon Aphid 7


Tables I and II give the number of days of the development
period, reproductive period, post-reproductive period, the length
of life, and the average temperatures at these periods, the average
number born per day during the reproductive period, and the
total numbers born. The developmental or nymphal period varied
from three to 20 days, the average of all the generations of both
first- and last-born series being 7.3 days. The reproductive period
varied from two to 32 days, with an average of 15.6 days. In
some cases young were produced on the day that the aphid died.
The longest post-reproductive period was 22 days, the average
being 5.3 days. The length of life varied from nine to 64 days,
with on average of 28.4 days.

o. of lirnt-born Generatlons Last-born Generations---- -
Genera-
tions y June July Aug. Sept. Oot. HNo. Deo. Jun. Feb. Mar. April May



10
12






15 --

14 ,_

16

18
19

21
21 ~ -





22
23
24
25
16



17
28
29
30
21
32
23



24
26
23




37 -
28 -







39
40 --

51
32








4
45May 20, 19
46
37
40
41
42








Fig. 2.-Graphic representation of the length of life of aphids of each suc-
ceeding generation of both first- and last-born series from May 20, 1930, to
May 20, 1931.







Florida Agricultural Experiment Station


Effect of Temperature Upon Aphids:-Temperature plays an
important part in the length of time the aphids live, the period
being much longer at low temperatures. The longest period that an
aphid lived was 64 days. The average length of life of 11 aphids
at average temperatures of from 54 F. to 59 F. was 48.6 days,
while it was 21.1 days for 18 aphids at average temperatures of
from 800 F. to 82 F. Figure 2 represents graphically the length
of life of each succeeding generation of both the first- and the
last-born series throughout the year.
The aphids lived in the insectary and continued to reproduce
all winter. The lowest temperature reached in the insectary was
270 F. One individual produced two young on a day when the
temperature range was from 410 F. to 450 F. However, the most
favorable temperature for development and reproduction seemed
to be from 780 F. to 800 F.
In one field in a rather low spot, the aphids lived on Eupatorium
petaloideum throughout the winter. The minimum temperature
at this place was probably lower than that recorded in the insec-
tary. In Mississippi the aphid is reported as living throughout
the winter on Lamium amphlexicaule and Rumex crispus(2).
On November 4, 1930, a series of aphids was started in the
greenhouse. From this date to June 8, 1931, a period of 217 days,
30 generations completed their life cycles in the greenhouse and
20 completed theirs in the insectary. The average temperature
for that period in the greenhouse was 740 F. and in the insectary,
610 F.
The number of young born in one day varied greatly, ranging
from 1 to 14. The average number of young born daily, during
the reproductive period, for all generations reared in the insec-
tary was 4.3. Low temperatures reduce the rate of reproduction,
few aphids being born on cold days. However, the reproductive
period is longer in cold weather and the total number of young
produced by an individual is about the same. Patch(4), in her
studies of this aphid in Maine, found that it passed the winter
in the egg stage on live-forever, Sedum purpureum Tausch, the
adults being killed by the temperatures that occur there. How-
ever, in Florida no sexual forms have been found and it appears
that this aphid passes the winter as viviparous females. All of
the aphids observed in this study produced young, the average
number in a brood for all of the generations reared in the insec-
tary being 67.






Bulletin 252, The Melon Aphid


Effect of Humidity Upon Aphids:-The average humidity for
the year recorded in the insectary was 74 percent. The lowest
average for a single day was 50 percent and the highest 97 per-
cent. It ranged from 18 to 100 percent, although most of the
time the average for the day was from 65 to 85 percent. No
correlation was apparent between the humidity and the rate of
development or reproduction.
Winged Forms:-During the entire year no winged forms were
produced on the plants used for rearing the aphids, except upon
plants which were set aside and which became crowded with
aphids. To determine whether the development of winged forms
was due to crowding or to the condition of the plant, the following
experiment was made. A young plant was allowed to become
overcrowded until practically all forms produced were of the
winged type. All aphids were then removed from the plant and
a half dozen newly born young from one of the aphids used in
the life history study were scattered on the plant so that they
were not in contact. However, they developed as winged forms,
while sisters of these on a plant in good condition did not develop
wings, showing that in this case it may have been due to the con-
dition of the plant and the food it furnished.

HOST PLANTS
The melon aphid is a general feeder, having been taken in
Florida from 64 different species of plants. In addition to the
above mentioned plants on which this insect is an economic pest
it is also found, though much less commonly, on other vegetable
crops, ornamental plants and vines, as well as on several kinds of
weeds and wild shrubs. During the course of this study three
new host plants of this aphid were found at Leesburg. These
are Eupatorium petaloideum Britt., Richardia scabra St. Hil.
(Mexican clover), and Solanum aculeatissimum Jacq. In the
following list of Florida hosts, those plants from which this
species has not heretofore been recorded are indicated by an
asterisk.
The aphids carry through from one season to the next on some
of these host plants. Citrus spp. serve as a source of infestation,
although it was found that watermelon fields widely separated
from citrus groves were infested as early as those close to groves.
In one field the aphids carried over through the entire winter on
Eupatorium petaloideum Britt. and were present in the field when
the young melons came up. In the field belonging to the Water-







Florida Agricultural Experiment Station


Acalypha sp.-Copper-leaf
Alsine media L.-Chickweed
Amaranthus viridis L.-Careless
weed
*Anona muricata L.-Sour Sop
*Antigonon leptopus Hook & Arn.-
Coral Vine
*Apium graveolens L.-Celery
*Asclepias verticellata L.-Milkweed
*Boerhaavia viscosa Lag. & Rodr.
*Bougainvillea
*Buddleia oficinalis Maxim
*Bursera simaruba (L.) Sarg.-
Gumbo Limbo
*Calophyllum inophyllum L.-Ball
Kamani
*Cassia tora L.-Coffeeweed
*Cestrum diurnum L.-Day Jessa-
mine
*Chrysanthemum sp.
*Chrysobalanus oblongifoliuz Micx.
-Pigeon Plum
Citrullus vulgaris Schrad.--Water-
melon
Citrus App. Orange, Grapefruit,
Satsuma, etc.
*Clerodendron siphonanthus R. Br.-
Turk's Turban
*Crotalaria striata DC.
Cucumis sp.-Cantaloupe, Cucumber
Cucurbita sp.-Squash, Gourd
Cuphea micropetala Hbk.
Datura stramonium L.-Jamestown
weed
*Erigeron ramosus (Walt.) B.S.P.-
Fleabane
*Eriobotrya japonica Lindl.-Loquat
*Eupatorium petaloideum Britt.-
Boneset
*Gerbera jamesonii Bolus-Trans-
vaal Daisy
*Gladiolus
*Gnaphalium obtusifoliwm L.-Cud-
weed


*Gnaphalium spathulatum Lam.--
Cudweed
Gossypium herbaceum L.-Cotton
Hibiscus esculentus L.-Okra
Hibiscus rosa-sinensis L.-Hibiscus
*Ipomoea batatas Lam.-Sweet Po-
tato
Ipomoea pandurata L.-Moon flower
*Lactuca sp.-Lettuce
*Lantana sellowiana Link and Otto-
Weeping Lantana
Lilium candidum L.-Lily
*Lilium longiflorum Thunb.-Lily
*Mammea americana L.-Mammee-
apple
*Monarda fistulosa L.-Bee Balm
*Nicotiana tabacum L.-Tobacco
Penstemon hirsutus (L.) Willd.-
Beard tongue
Persea persea (L.) Cockerell.-Av-
ocado
*Pittosporum tobira Ait.-Pitto-
sporum
Plantago virginica L.-Plantain,
*Pluchea sp.
Psidium guajava Radd.-Guava
Pyrus communis L.-Pear
*Richardia scabra St. Hil.-Mexican
clover
*Riedlea corchorifolia (L.) DC
*Scutellaria multiglandulosa (Kear-
ney) Small-Skull cap
*Sida acuta Burm.-Tea weed
*Sida cordifolia L.-Tea weed
*Solanum aculeatissimum Jacq.
Solanum melongena L.-Eggplant
Solanum tuberosum L.-Potato
*Solanum verbascifolium L.
*Spathodea campanulata Beauv.-
Santo Domingo Mahogany
*Strychnos spinosa Lam.-Kaffir or-
ange
*Tulipa sp.-Tulip
*Urena lobata L.
Verbena sp.






Bulletin 252, The Melon Aphid


melon Laboratory near Leesburg no aphids could be found at the
time of planting and the nearest orange grove was about a quarter
of a mile away. After the melons were up a few infestations
were found scattered pretty well over the field. Since this field
had been looked over thoroughly before this time, these infesta-
tions were probably due to winged forms coming from some
distance. Other workers have shown that winged aphids are
sometimes carried long distances by wind.

APHID INDICATORS
Generally, the aphids are present on the underside only of the
leaves of watermelons, cucumbers and squashes, and therefore
it is quite easy to overlook them. In case of a heavy infestation,
and even in lighter ones, the leaves are greatly curled. Honeydew
excreted by the aphids is often very conspicuous, showing on the
tops of the lower leaves as glistening droplets or making the soil
under the plants appear damp. Wasps and ants seen about a
vine often indicate the presence of aphids, as they are attracted
by the honeydew. A sooty mold develops in the honeydew, giving
the plants a characteristic dark color. However, this fungus re-
quires some time to develop, and its presence will not be'apparent
until the aphid infestation is at least a week to 10 days old. Lady-
beetles of various kinds feed on the aphids and the presence of
these insects on plants indicates an infestation of aphids.

PREDATORS AND PARASITES

There are a number of predators and parasites that tend to
reduce the number of aphids and often prevent a heavy infesta-
tion from developing. It is in the newly infested fields, early in
the season or during cool weather, that the grower must control
the aphids. Later in the season the number of parasites and
predators usually becomes great enough to hold them in check,
killing a very large percentage of the aphids.
The most important of these predators on the melon aphid are
the ladybeetles. Both the adult beetles and the larvae feed greed-
ily upon aphids. The most abundant of these is the convergent
ladybeetle (Hippodamia convergens Guer.). This is a compara-
tively large ladybeetle averaging a little over one-fourth of an
inch in length. The winged females are brownish-red with a
number of black dots (Fig. 3). The head and thorax are black.






Bulletin 252, The Melon Aphid


melon Laboratory near Leesburg no aphids could be found at the
time of planting and the nearest orange grove was about a quarter
of a mile away. After the melons were up a few infestations
were found scattered pretty well over the field. Since this field
had been looked over thoroughly before this time, these infesta-
tions were probably due to winged forms coming from some
distance. Other workers have shown that winged aphids are
sometimes carried long distances by wind.

APHID INDICATORS
Generally, the aphids are present on the underside only of the
leaves of watermelons, cucumbers and squashes, and therefore
it is quite easy to overlook them. In case of a heavy infestation,
and even in lighter ones, the leaves are greatly curled. Honeydew
excreted by the aphids is often very conspicuous, showing on the
tops of the lower leaves as glistening droplets or making the soil
under the plants appear damp. Wasps and ants seen about a
vine often indicate the presence of aphids, as they are attracted
by the honeydew. A sooty mold develops in the honeydew, giving
the plants a characteristic dark color. However, this fungus re-
quires some time to develop, and its presence will not be'apparent
until the aphid infestation is at least a week to 10 days old. Lady-
beetles of various kinds feed on the aphids and the presence of
these insects on plants indicates an infestation of aphids.

PREDATORS AND PARASITES

There are a number of predators and parasites that tend to
reduce the number of aphids and often prevent a heavy infesta-
tion from developing. It is in the newly infested fields, early in
the season or during cool weather, that the grower must control
the aphids. Later in the season the number of parasites and
predators usually becomes great enough to hold them in check,
killing a very large percentage of the aphids.
The most important of these predators on the melon aphid are
the ladybeetles. Both the adult beetles and the larvae feed greed-
ily upon aphids. The most abundant of these is the convergent
ladybeetle (Hippodamia convergens Guer.). This is a compara-
tively large ladybeetle averaging a little over one-fourth of an
inch in length. The winged females are brownish-red with a
number of black dots (Fig. 3). The head and thorax are black.







Florida Agricultural Experiment Station


On the thorax
are two yellow
lines which con-
verge toward the
back, giving the
insect its specific
name.
The second most
abuhnnrlnt lad v-


Fig. 3.-Convergent ladybeetle. Larva, left; pupa, beetl ithe bl d-
center; adult, right. (Bul. 183.) eee is the blood-
red ladybeetle
(Cycloneda san-
guinea Fab.) (Fig.
4.) This is some-
what smaller. It ,
gets its name from
the wing covers
which are blood-
red in color with-
out any spots. Fig. 4.-Blood-red ladybeetle. Adult, left; pupa,
The head. and the center; larva, right. (Bul. 183.)
thorax are black
in this species
also. These lady-
beetles will eat 35
or more adult
aphids in one day.
The grown larvae
of the convergent
S a ladybeetle are
also found to eat
about the same
Fig. 5.-Scymnus terminatus. Larva, left; pupa, number of adult
center; adult, right. (Bul. 183.) aphids in a day.
Other ladybeetles common among the melon aphids are several
species of the genus Scymnus (Fig. 5). These are very small
beetles, measuring from one-sixth to three-thirty seconds inch in
length, and jet black in color. Much more conspicuous than the
adult beetles are the larvae. These are covered with a dense
coating of white hairs which make them look like mealybugs or
trash bugs.


rr r(
1
~r







Bulletin 252, The Melon Aphid


Another ladybeetle sometimes found eating the melon aphid is
the two-spotted ladybeetle (Olla abdominalis var. sobrina Csy.).
This is a larger
ladybeetle, about
the size of the
blood-red, jet
black in color
with a triangu-
lar red mark on
each wing cover
(Fig. 6). Fig. 6.-Two-spotted ladybeetle. Larva, left; pupa,
Next to the center; adult, right. (Bul. 183.)


** q,~.
4


Fig. 7.-Syrphus fly, Baccha clavata. Left to right,
adult, pupa, larva. (Bul. 183.)

their elongated, glistening, white eggs among
the aphids on the leaves. These eggs hatch into
legless slug-like maggots which suck the juices
from the aphids. One larva was observed thus
to kill 29 aphids in one day.
The larvae of the lacewing flies are commonly
found as predators. They are small, slender-
bodied insects with strong, prominent jaws. A
nearly grown larva ate 17 aphids in one day.
The downy darkling beetle (Epitragodes to-
memtosus (Lec.)) (Fig. 8) is sometimes found,
although not as abundantly as other predators.


ladybeetles, the
most important
predators are
the larvae of
syrphus flies
(Fig. 7). The
adults do not
feed on aphids
but on the nec-
tar and pollen of
the flowers. They
are two-winged
flies. They lay









Fig. 8.-Epitra-
godes tomentosus
(Lec.) .Four times
natural size.
(Adapted from
Hubbard.)


Parasites are even more important than predators as a control
of these aphids. The chief one of these is Lysiphlebus testaceipes
(Cress), a small dark wasp-like insect. When the female stings






Florida Agricultural Experiment Station


the aphid an egg is deposited in the body of the aphid. The egg
hatches and the larva feeds there until full grown. After killing
the aphid, it pupates in the dead body and finally emerges as an
adult. In one field over 1,700 aphids were counted and more than
99 percent had been killed by this parasite. Aphids parasited by
this wasp-like insect swell to several times their normal size and
turn a brassy-brown
color, with a round hole
in the abdomen from
which the adult emerged.
(Fig. 9.)
An undescribed species
of Trioxys has also been
found to be a parasite of
the aphid. In many cases
the aphids are killed by
Si fungus diseases.
The life history-of
.t many of these insects is
given by Miller(3) and
Thompson(6, 8) in bulle-
o tins on the citrus aphid,
Bulletins 183 and 203 of
the University of Florida
Agricultural Experiment
Station.

ARTIFICIAL CONTROL
Fig. 9.-Parasitized bodies of Aphis gossypii. The melon aphid, in
(Bul. 183.) common with all plant
lice, is a sucking insect.
Its, food consists exclusively of plant sap which is drawn from
the tissues of the leaf or tender stem through a fine hair-like
tube projecting from the under side of the head. The presence
of lead arsenate or other stomach poisons on the surface of the
plant will in no way harm the aphids. They can be killed only
by the use of materials commonly known as contact insecticides.
It is not understood just how these substances bring about the
death of the insects but some have a caustic action on the outside
of their body while others seem to cause an internal poisoning
by penetration of their breathing tubes. Dust mixtures and






Bulletin 252, The Melon Aphid


liquid sprays are the two main classes of contact insecticides used
against the melon aphid.
The kind of material used and the method of application will
be largely determined by the character of growth of the plants
to be treated, the state of weather, and the kind of equipment
available for applying the insecticides. The equipment designed
by the first author for use on watermelons will prove entirely
satisfactory for use on cucumbers and cantaloupes, and other
plants while they are still small.
CONTROL WHEN ON WATERMELONS
Because of the roughness of the ground and the
difficulty of transporting water, dusting seems more
advisable than spraying for the control of aphids
on watermelons. A 3 percent nicotine dust is most
commonly used and under proper conditions good
control is obtained. Often it is difficult to find a
time not too windy for dusting.
Since the aphid infestation is often most serious
while the plants are still small, a
funnel (Fig. 10) may be used to
good advantage. The funnel is
made of light weight, galvanized
iron sheeting. First a pipe should
be made that is about two feet long
and of a diameter that will fit
tightly into the duster hose. A
second pipe two and a half or three
inches long and with a diameter
that will permit the first to fit
snugly within it is the next piece.
Next cut two rectangular pieces Fig. 10.-Funnel for dusting
with the dimensions 11/2"x21/`" into young melon plants.
the shape shown in Fig. 11. Fit
these together at right angles and solder at the center. Then
bend them into shape and fit and solder them to the short piece
of pipe as shown in Fig. 12.
For the funnel, mark off a half circle with a radius of 16 inches.
With the same center, mark off another half circle slightly smaller
than a cross section of the short pipe. Cut out and bend into
position and solder together. The short pipe may be inserted
into the upper end of the funnel after the opening has been slit






Florida Agricultural Experiment Station


on the edges and made to form a collar for the pipe. Solder these
together and then solder the long pipe to the protruding end of
the short one. The propeller-shaped piece on the short pipe gives
the dust a whirl as it comes into the funnel, giving a much better
coverage, the dust reaching the under surface of the plant as
well as the upper.
By holding the funnel over the plant for a few seconds, the
dusting may be carried on when the wind is too high to dust with-
out it. This may be a very important factor, for a few days' delay
in waiting for a windless day may give the aphids enough of a start





















Fig. 11.-Diagram of the two pieces that are soldered on the pipe in the
upper end of the funnel.

so that they may be very hard to control. It is very important
to prevent the development of a heavy infestation. In a short
time the leaves may become so badly curled that it is impossible
to reach the aphids with the dust (Fig. 13). When a plant becomes
heavily infested, winged forms develop in large numbers and
fly to other plants, spreading the infestation over the field.
When the aphids are found scattered through the field it is
probably best to dust every hill. Some hills may not be infested,
but nevertheless, if "spot" dusting is resorted to, many plants
with light infestations will be missed. Eventually the whole







Bulletin 252, The Melon Aphid


field must be dusted after the plants become larger, and thus
more time and dust will be required to cover it. As stated before,
it is of the greatest importance to control the aphid early.
The growers can make their own dust easily, although great
care should be taken in doing this. The common rotary barrel
dust mixer (Fig. 14) is probably the easiest and most practical
type of mixer to make. An iron pipe is fastened to each side of
the barrel. Two elbows are fastened to one of these so that a
crank for turning the
keg is made. The
stand or base is made
with two upright
boards at each end
standing parallel to
each other and with
V-shaped notches at
the upper end to re-
ceive the pieces of
.pipes on the sides of
the barrel. When the
barrel is at rest on the
stand it may then be
revolved. An opening
S about a foot in diam-
ui eter should be made
S in one end of the
barrel, with a close
fitting door so that
the dust and nicotine
Fig. 12.-The nozzle in the upper end of the fun-
nel for giving and even distribution of the dust. fumes cannot escape.
The frame for holding
the barrel should be high enough that a container for dumping
the dust into may be slipped under it. A number of round stones
or heavy objects an inch or two in diameter to roll about in the
dust as the mixture is being made should be added. A large
funnel with half inch hardware cloth across the lower opening
is very useful in taking out the stones when emptying the dust.
Dust may be made more cheaply than it can be bought but
unless it be done carefully it is not a safe thing to do. The right
proportions must be used, the mixing must be thorough, and the
dust must not be exposed to the air for any length of time, for it
loses its effectiveness very quickly under these circumstances.







Florida Agricultural Experiment Station


This latter precaution applies to ready-mixed commercial dust as
well as to the home-made dust.
A 2% dust may be made by the addition of 5 pounds of 40%
nicotine sulfate to 95 pounds of lime, or 4 pounds of 50% free
nicotine to 96 pounds of lime, while a 3 % dust requires 7.5 pounds
of 40% nicotine sulfate to 92.5 pounds of lime or 6 pounds of
50% free nicotine to 94 pounds of lime. The lime should be
weighed out and poured in the barrel and then the nicotine added,
pouring it over as much of the lime as possible. The barrel should
be only half or two-thirds full. The mixture should be rotated


Fig. 13.-Plant heavily infested with aphids, showing leaves badly curled
due to aphid injury.

for several minutes and then transferred to a closed container
with as little exposure to the open air as possible.
A 2 % dust made with 50 % free nicotine is equivalent in effec-
tiveness to a 3 % dust made with 40% nicotine sulfate, and it is
therefore cheaper to make the dust with the free nicotine. Some
tests were carried out to determine the effect of adding 1/2 of 1
percent ammonium sulfate to the dust. There was no appreciable
difference in the percentage killed by dust with or without the
addition of the ammonium sulfate,







Bulletin 252, The Melon Aphid


CONTROL WHEN ON OKRA, EGGPLANT, AND PEPPERS
This group of plants may be attacked and injured by the melon
aphid from the time they are first planted until the crop is har-
vested. While the plants are still small the apparatus and dust
recommended for use on watermelons will prove very effective in
controlling the aphids. However, as the plants grow larger their
upright habit of growth makes it very difficult to destroy the
aphids by dusting under ordinary conditions. If one can find a
time when the air is absolutely quiet, dusting in the open will
yield a good kill of aphids. If there is sufficient breeze to sway
the Spanish moss on trees the dust will drift away so quickly
that a large proportion of the aphids will escape.
After the plants have become so large as to make dusting under
a funnel impossible, the aphids can best be destroyed by the use
of liquid sprays. It is essential that all aphids be hit with the
spray as any that are missed will survive to reinfest the plants.
All parts of the plants must therefore be wet with the spray and
especial care must be taken to reach the under sides of the leaves
and the growing
tips where most of
the aphids will be
found. When a
hand sprayer is
used the nozzle
.> should be placed
.__ -at an angle on the
spray rod so that
the spray may be
directed upward
and from the
sides. If a power
sprayer is used
the gangs of noz-
zles should be so
arranged that the
spray will be di-
rected against the
plant from below,
and from each
side as well as di-
Fig. 14.-A home-made mixer for mixing nicotine
sulphate with hydrated lime. (Bul. 183.) rectly downward.






Florida Agricultural Experiment Station


Rather high pressure is desirable as the resulting fine mist is
more effective in thoroughly wetting the plants than is a spray
of coarser droplets.

APHICIDES AND THEIR USE
The common insecticides that are used for controlling aphids
are largely plant derivatives. The most widely used and one of
the most valuable of these materials that has been used for many
years is some form of nicotine. At first this was used as a
decoction made by steeping waste tobacco and stems in water
but this was not uniform in strength and was rather inconvenient
to prepare. But where the grower has access to a cheap source
of such material often he can use it economically. Enough water
should be used to cover it and the material should either be soaked
over night or allowed to simmer gently (it should not be boiled
violently) over a fire for an hour. This should afford a decoction
about the color of strong tea. About one part of this to 10 of
water usually is effective.
Commercial nicotine has now practically displaced the home-
made product. The most common form of nicotine now on the
market is a 40 percent nicotine sulfate solution. More recefitly
there has been available a solution of free nicotine containing 50
percent of nicotine in water. For controlling aphids the nicotine
sulfate solution is usually diluted with 800 to 1,200 parts of
water. If the nicotine is not combined with some other insecti-
cide or fungicide it is a common practice to add soap to act as a
spreader and increase the effectiveness of the nicotine. If the
water used in making the spray is fairly soft six pounds of soap
to 50 gallons of water is sufficient. With hard water, eight pounds
or more of soap will be more effective. For smaller amounts of
spray, one teaspoonful of nicotine sulfate and one ounce of soap
to one gallon of water will give the proper dilution.
Within recent years it has been shown by Tissot and Thomp-
son(7) and by other workers that the effectiveness of nicotine
sulfate or free nicotine can be very greatly increased by the use
of certain materials which serve as activators for the nicotine as
well as being excellent spreaders. Special kinds of soaps such
as sodium or potassium oleate soaps, pine tar soaps, and a sulpho-
nated oil product have been found to be especially effective. With
the use of these materials good control of aphids has been se-
cured with 40 percent nicotine used at dilutions as low as 1 to
3,000 or 1 to 4,000(7). This means an appreciable saving to the







Bulletin 252, The Melon Aphid


grower, since the activator costs considerably less than the nico-
tine which it displaces.
Another group of materials that have proven effective as
aphicides are extracts of pyrethrum. The active principle of the
pyrethrum flowers, pyrethrin, is held in stable form at uniform
strength in such a manner that it will mix with water. These
materials are apparently no more effective in controlling aphids
than is nicotine but they seem to be generally effective against
many of the larger soft-bodied insects such as caterpillars and
the young of the larger plant bugs. These properties render these
spray materials valuable for use on ornamental plants and for
small plantings of vegetables where cost is not such an important
item and other insects besides aphids may be present. The use
of the activators above mentioned seems to increase the effective-
ness of the pyrethrum sprays but to a much smaller extent than
in the case of nicotine.
The extracts of derris constitute another group of insecticides
sometimes used against aphids. These materials are somewhat
similar to nicotine in action and are used at about the same dilu-
tions. They are scarcely more effective than nicotine and as
there is little difference in cost their use has not become very
general. Like the pyrethrum sprays, the derris extracts are
somewhat more effective than nicotine against some of the larger,
more resistant insects. The activators mentioned increase the
effectiveness of the derris sprays to a very slight extent.
It is usually advisable in Florida to treat vegetable crops with
a fungicide to prevent the entrance and development of plant
diseases. Bordeaux mixture generally is used for this purpose,
though the plants may be dusted with copper-lime dust. When
bordeaux mixture is used one of the aphicides mentioned above
may be combined with it for controlling aphids when an infesta-
tion of these insects is present. It is not necessary to use a
spreader as the bordeaux mixture serves this function.
Cotton is frequently severely infested by the cotton aphid and
at times the plants are nearly or completely defoliated by it.
Very little work has been done in Florida toward controlling
aphids on this crop. Hamner(1), working in Mississippi, found
nicotine dust to be the most satisfactory insecticide for control-
ling aphids on cotton. A 2 percent dust is recommended, made by
mixing 1 pound of nicotine sulfate with 19 pounds of hydrated
lime. This dust should be applied at the rate of 10 pounds per
acre when the air is calm, with no dew on the plants and the tem-







Florida Agricultural Experiment Station


perature is above 70 degrees Fahrenheit. It is suggested that if
one wishes to control the boll weevil at the same time as the
aphids, one-half or all of the hydrated lime may be replaced by
calcium arsenate.
Citrus, though frequently attacked by the melon aphid, is
rarely injured to such an extent that artificial control is necessary.
If control should seem desirable dusting the trees with a 3 percent
nicotine sulfate dust will prove a very effective method of dealing
with the pest.
When hibiscus and other ornamental plants are infested with
the melon aphid treatment with a liquid spray usually will be
the most satisfactory method of attack. These sprays leave no
unsightly residue on the foliage and flowers such as follows the
application of nicotine sulfate dust.

SUMMARY
The melon aphid is the most serious insect pest of watermelons
in Florida and is frequently injurious to cucumbers, cantaloupes,
okra, peppers, eggplant and other vegetable crops.
From May 20, 1930, to May 20, 1931, life history studies were
carried out in an insectary approximating out door conditions.
A first-born and a last-born series of aphids were reared. Of the
first-born series 51 generations were born of which 47 completed
their life cycle, and of the last-born series 17 generations were
born of which 16 completed their life cycle. The average number
of completed generations for the year was 311/2. The nymphal
period varied from three to 20 days, with an average of 7.3 days;
the reproductive period from two to 31 days, with an average of
15.6 days; and the post-reproductive period from none to 21 days,
with an average of 5.3 days. The length of life varied from nine
to 64 days with an average of 28.4 days, the aphids living longest
during the coolest weather.
The number of young born in one day varied from one to 14,
the average number for the year being 4.3. All of the aphids
were viviparous females which produce an average of 67 young
each.
The most favorable temperature for the aphids seems to be
from 780 F. to 800 F. However, the aphids live and reproduce
throughout the winter on both wild and cultivated hosts, migrat-
ing to the young melon vines as they come up. This migration is,
of course, accomplished by the winged forms, which tend to de-






Bulletin 252, The Melon Aphid


velop in large numbers when the plants upon which the aphids are
feeding become unfavorable as food.
The aphids may be controlled by treating the infested plants
with nicotine sulfate dust or with one of the liquid aphicides con-
taining extracts of nicotine, pyrethrum or derris. The kind of
material used and the method of application will depend largely
on the habit of growth of the plants concerned, the state of the
weather, and the equipment available. A funnel to cover the
plants is very useful while the plants are small, making it possible
to dust regardless of the wind. On plants which grow more up-
right and spreading a liquid spray frequently will prove more
effective than dust.

LITERATURE CITED
1. HAMNER, A. L. Cotton Aphis Damage. Quar. Bul., Mississippi State
P1. Bd. 11:1-4. 1931.
2. HARNED, R. W. Annual Report of the Department of Zoology and
Entomology. Mississippi Sta. Rept. 41:23-29. 1928.
3. MILLER, R. L. The Biology and Control of the Green Citrus Aphid,
Aphis spiraecola Patch. Florida Agr. Exp. Sta. Bul. 203:431-476.
1929.
4. PATCH, EDITH M. The Melon Aphid. Maine Agr. Exp. Sta. Bul.
326:185-196. 1925.
5. PERGANDE, THEODOR. The Cotton or Melon Plant-louse. Insect Life.
7:309-315. 1895.
6. THOMPSON, W. L. The Seasonal and Ecological Distribution of the
Common Aphid Predators of Central Florida. Florida Entomologist.
11:49-52. 1928.
7. TISSOT, A. N. and W. L. THOMPSON. New Aphicides. Florida Ento-
mologist. 14:7-12. 1930.
8. WATSON, J. R. and E. W. BERGER. Citrus Insects and Their Control.
Florida Agr. Exp. Sta. Bul. 183:362-369. 1926.




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