Report of a trip to India and the Orient in search of the natural enemies of the citrus white fly

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U. S. DEPARTMENT OF AGRICULTURE,

BUREAU OF ENTOMOLOGY—BULLETIN No. 120.
L. O. HOWARD, Entomologist and Chief of Bureau.

REPORT OF A TRIP TO INDIA AND THE ORIENT
IN SEARCH OF THE-NATURAL ENEMIES
OF THE CITRUS WHITE FLY,

BY

RUSSELL S. WOGLUM,

Entomological Assistant.

Issurp Frsruary 28, 1913:

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WASHINGTON:
GOVERNMENT PRINTING OFFIGE.
1913.

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ee DEPARTMENT “OF ‘AGRICULTURE,

BUREAU OF ENTOMOLOGY—BULLETIN No. 120.
L.O. HOWARD, Entomologist and Chief of Bureau.

REPORT OF A TRIP TO INDIA AND THE ORIENT
IN SEARCH OF THE NATURAL ENEMIES
OF THE CITRUS WHITE FLY.

BY

RUSSELL S. WOGLUM,

Entomological Assistant.

IssuED Frpruary 28, 1913.

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WASHINGTON:
GOVERNMENT PRINTING OFFICE,
1913,

BUREAU OF ENTOMOLOGY.

L. O. Howarp, Entomologist and Chief of Bureau.
C. L. Martatr, Entomologist and Acting Chief in Absence of Chief.
R. 8. Curron, Executive Assistant.
W. F. Tastet, Chief Clerk.

F. H. Curtrenpen, in charge of truck crop and stored product insect investigations.
A. D. Hopxins, in charge of forest insect investigations.

W. D. Hunter, in charge of southern field crop insect investigations.
F, M. WessteEr, in charge of cereal and forage insect investigations.
A. L. QUAINTANEE, in charge of deciduous fruit insect investigations.
E. F. Pures, in charge of bee culture.

D. M. RoeeErs, in charge of preventing spread of moths, field work.
Routa P. Currie, in charge of editorial work.

MABEL CoxcorD, in charge of library.

Citrus Fruir Insect INVESTIGATIONS.
C. L. Maruatr, in charge.
R. S. Wocium, W. W. Yotuers, E. R. Sasscer, J. R. Horron, P. H. TrimBeR LAKE,
C. E. Pemperton, H. L. Sanrorp, entomological assistants.
J. G. SANDERS, collaborator.

2

D. OF D. |
MAR 17 1918

LETTER OF TRANSMITTAL.

Unitep Srates DEPARTMENT OF AGRICULTURE,
BurEAvu OF ENTOMOLOGY,
Washington, D. C., September 11, 1912.

Sir: I have the honor to transmit herewith an account of the trip
undertaken by Mr. Russell S. Woglum, a special agent of this bureau,
to India and the Orient in search of the natural enemies of the citrus
white fiy, which for many years has militated against the successful
commercial operation of the orange-growing industry in Florida and
elsewhere. , This paper is especially valuable in view of the fact that
Mr. Woglum not only has located many of the natural enemies of the
citrus white fly in their native habitat, but has, as well, demonstrated
the correct methods of procedure in the transshipping, alive, of
predaceous and parasitic material, which has heretofore rendered the
importation of natural enemies of our insect pests so precarious. I
recommend the publication of this manuscript as Bulletin No. 120
of this bureau.

Respectfully, L. O. Howarp,
Entomologist and Chief of Bureau.
Hon. JAMES WILSON,
Secretary of Agriculture.

CONTENTS.

POG Weis et eee eee ela sae Sot ne Dale amie clown te Mele
Ape EAU D UCR AIDE TEN, So cmines Oe cise ee rie cela es a ln ie aa hice S/S Cyne ee oleh wlaiaie SSE
VET ETAN Ne ol eh eh A Sa AS ee ES “ee ine

Lo PEGI E NS Cesc eg sally ag GI eh Ble eS aS SI gs
Distribution in the United States... ./-..2..202.22.---. nh she eT Paes oc ee

|S Eg eT ee ae 8 SR OE ey Ory SN oe
Methods oicontrol andthe efiiciency 8. a a SP ns oe
Conditions leading to demand for a search for natural enemies of the citrus white
1S SR A A ee i Ne gS IW Sencar Sth es ADI ON PL a
eemnban ions tor tie AOArCh sc. tao ce ae tee eee oily 2 Noh el oe a
LENORE Sy REreert a 9 ATE RTE U LB OT 11) © SPM Rm aed Pe pl et eae aR eg
Pirventieations In Cevlons oo Jac. coe c ee Se otek cietes sede we cece sneaks
Aiea e Hea pieenie Mata hte koe) Srete hte a eee ee ee as SRL CRUE Oe age Se
“CAST EE GN Gel co i la eg a Ate tae pa ene KAI 7 ee Sea eA SE A eG
PURER OLATeR CATO eNa GS. asl tan re ar SU oe ra elite bt AMUN
Discovery of the citrus white fly at Saharanpur..................-.....--
Discovery of Cryptognatha flavescens, the lady-beetle enemy of the citrus
MUNN EN s or cet cake Meee ea Mae cage te Ne,s Walla cities ea atata Nome ee
Discovery of the brown fungus, Atgerita webberi.............------------
rE VET Ere NS Hal bE Reve & ahs as AI PADD ag ea a OE EA er ROO en ge Oe Ree A AE
Discovery of Prospaltella lahorensis, the true internal parasite of the citrus
MURRELL PONS ec Nee Pet ee ng ia mans ang cate te SNA te es ces NRL Bade ah
Conclusions drawn from situation at Saharanpur and Lahore....-..........-

BAe apavareC E717) VAN EYL CUEA EN he yu, 8 et te ee oe 2 EL, fins sama A
Investigations in Burma, Java, southern China, and the Philippine Islands - . -
Piirthenaavesitoncions He lndis 6 = ae Poe ses el Ne Ne OY
Coneentration of efforts at Laltore..- 015.222 o.62 2 s ae Sse
Pincay cry anliwine parasivesc: cn. wrt wi Coenen a nL eden eee Vee
Considerations in collecting and transporting Prospaltella lahorensis.....- -
Destruction of young growth of citrus trees by insect pests......-...---..-
Notes on the life history of Aleyrodes citri in northern India. .........-.--
Number of broods) of the citrus’ white fly 2.20. 22252 222 222 vend ep 2o o8
The effects of temperature on white-fly development. ..........--.-.-.--
The effect of humidity on white-fly development.............------.----
Prospaltella lahorensis, the true internal parasite......................-.-.-
Infesting young orange trees with Aleyrodes citri......-....-..----+-------
Capea used in transporting parasites. 2c stay... ee ge eee
Cryptognatha flavescens, the predatory enemy of the citrus white fly....-.
Preparation of beneficial insects for shipment. ..-..........-.-........--

- Transporting the natural enemies of the citrus white fly from India to the
MEN CMU SEALER SSS el2 Sco ee Sa ove bo es aoe ne coe ee sia Dee
Condition of natural enemies on arrival at Orlando, Fla....................---

Conditions at Orlando, Fla., when the natural enemies arrived.............---
CRE OR eve Mba seIeROIER ee es LL Lh 2 ie a amet oe SD

6 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

Page.
Desirability of continuing the attempt to introduce these two natural enemies. 40
Feod plants ‘of the citrus white fy ee. eo... 2 eee ei 41
Probable native home of Aleyrodes etirps. 2: 0.20.2 < 25 eee ecient 44
Appendix A: “Citrus ironte im Imdiai noose. 2202s 2-6 --seee ete aes Sere eet 47
Appendix B. Insect pests of citrus trees seen by the writer during his investi-
gations In various foreign countries.......-..-..-:--2/2ss!-s- 49
Appendix C. Observations on Coccide and their natural enemies in Spain,
DGedl ye teeth ANG A Cha oa inline ete Rinse iene he 49
Appendix D. Coccinellide introduced from India.........--.--------------- 52
Appendix E. Fumigation of citrus trees in Spain ....-......-.-.------------- 52

PLATE fe

VOR

1h

TV:

V.
VI.

VII.

VIII.

. Orange production in India.

LELUST RATIONS.

PLATES.

Fig. 1.—Leaf showing pupa cases of the citrus white fly (Aley-
rodes citri); also a few pups and eggs. Fig. 2.—Underside of
orange leaf showing heavy infestation by citrus white fly.
Fig. 3.—Leaf showing pupa cases of the cloudy-winged white
fly (Aleyrodes nubifera), an insect prevalent on citrus plants in
Florida and very closely related to Aleyrodes citri............

Fig. 1.—Tender growth of citrus swarming with adults of the cit-
rus white fly. Fig. 2.—Leaf of same enlarged................

Fig. 1.—Orange covered with sooty mold ( Meliola sp.).
Leaf of orange coated with sooty mold................--.----

Orange production in India and Java. Fig. 1.—A native house
in eastern India with orange trees in the yard. Fig. 2.—How
Clan les Abe: PrawnuaD Jawa Assy eestor Sl ccs tamale 5

Scenes in the botanical gardens of India......................-

Traveling in India. Fig. 1—Country boat, utilized for travel-
ing in Assam. Fig. 2.—Traveling by horseback in the outer
ekg Lea yeas Pee har SASS 2 ert Ua A de ge 2 le

The leaf-miner Phyllocnistis citrella in India. Fig. 1—Young
citrus trees showing leaves of top shoots deformed by attacks
of a leaf-miner (Phyllocnistis citrella). Fig. 2.—Cloth cages
placed over young citrus to protect them from the ravages of
EUS SO AIew IMO Lone Veseer tases cera Mat aie uaa til whine as

An orange hedge in the Botanical Garden at Lahore, India. Figs.
1, 2, 3.—Method of protecting citrus from penetrating rays of
sun by utilizing cloth coverings... -.. falda Lata er ne Pee

. Transshipping the natural enemies of the citrus white fly. Fig.

1.-—The six Waydian cases containing the natural enemies of
the citrus white fly as they arrived at the laboratory at Orlando,
Fla. Fig. 2.—A Wardian case with the top removed........

. Fig. 1—The six Wardian cases containing natural enemies of the

citrus white fly leaving Lahore at the beginning of their long
journey to the United States. Figs. 2 and 3.—Native Hindu-
stani who rendered assistance to the writer in collecting the
natural enemies of the citrus white fly....................
Fig. 1.—Orange production in the
Khasia Hills of Assam. Fig. 2.—A native orange grower. ....

. Transporting oranges to market in the outer Himalayas. Fig. 1.—

Natives in the Province of Sikkim carrying oranges in baskets
to the bazaar. Fig. 2.—An orange bazaar in the outer Hima-

TEXT FIGURES.

Fig. 1. Map showing present known world distribution of the citrus white fly
ee URES) A oR PCa Li eae
2. Map showing localities in which the citrus white fly was found in India.

62800°—Bull. 120—13——2 7

Page.

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32

36

36

48

48

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REPORT OF A TRIP TO INDIA AND THE ORIENT IN
SEARCH OF THE NATURAL ENEMIES OF
THE CITRUS WHITE FLY.

INTRODUCTION.

This bulletin has been prepared with the idea of presenting some
of the more important phases, from a scientific standpoint, of a
journey made in search of parasitic and predatory enemies of the
citrus white fly (Aleyrodes citri R. and H.). The major portion of
the bulletin is devoted to a treatment of material bearing directly
on the citrus white fly, its enemies in Asiatic countries, and the
efforts toward their collection and introduction into the United States.
Supplementary to this is appended a consideration of other topics
with which the writer became familiarized during the expedition and
which have a more or less direct bearing on the culture of citrus fruits.

The information herein relative to life history, distribution, and
injury of the white fly in this country has been taken largely from
the results of the work of Drs. Morrill and Back in their investiga-
tions of the citrus white fly in Florida."

THE CITRUS WHITE FLY.
GENERAL.

The citrus white fly belongs to a group of insects popularly
known as the mealy-wings (Aleyrodide) and is closely related
to the scale insects (Coccide), numerous species of which are very
injurious to citrus fruit trees in all parts of the world. In fact,
entomologists of the earlier days classified the Aleyrodide as a division
of the Coccide. Subsequent investigators, however, have found
certain characteristics normal to the group sufficiently distinct to
call for its separation into a family of its own.

The first record of the white fly as a serious pest to citrus fruit
trees was from the State of Florida, and from the date of that record
to the present time its injury has continued as a menace to the most
profitable commercial citrus-fruit production. In 1885 the insect
was given the scientific name of Aleyrodes citri by Mr. Wm. H.
Ashmead ? in a local Florida paper and subsequently was fully de-
scribed by Riley and Howard, of the Division of Entomology, in
Insect Life.®

1 Bul. 92, Bur. Ent., U.S. Dept. Agr., 1911.
2 Florida Dispatch, n. ser., vol. 11, November, 1885.
= Ins, Life, vol. 5, no. 4, pp. 219-226, 1893.

10 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.
DESORIPTION.

Although the citrus white fly is known to attack several species
of plants, its special importance as a pest is owing to its injury of
citrus trees, in which the infestation is confined to the leaves. The
insect as commonly seen on trees is of the appearance of a small,
thin, transparent or greenish-white scale entirely devoid of wings.

In the earlier stages of development, as hatched from the egg, it
possesses three pairs of short, stubby legs and somewhat resembles
in general appearance a small louse or mite. So small is the insect
at this time and so transparent is it that only the closest observation
will reveal its presence to the naked eye. In fact, persons unac-
customed to close observation might easily examine an infested leaf
without discovering the presence of these young insects. This is
the only time in the life of the immature insect in which it is able to
move about the plant. After hatching from the egg the minute
larva crawls about the leaves until it finds a situation suitable to its
taste. This found, it inserts its elongate threadlike mouthparts into
the leaf and then settles down to remain in this position until full
grown. The juice of the leaf is extracted through this threadlike
mouth. To allow growth, the hard. outer skin of the young insect
is cast off from time to time. The legs are lost with the first molt,
so that in the later stages of development the insect is entirely without
the power of locomotion.

With the third molt the insect passes from the so-called larval con-
dition into the pupal stage (Pl. D. This is the last stage of develop-
ment and the one in which the insect is most commonly noticed. At
first thin and so pale green as to be almost transparent, it becomes
thickened and opaque on approaching maturity. When almost
mature a bright orange spot appears on the back and later two purple
spots toward the anterior end. The insect at this time is about one-
sixteenth of an inch long or practically the size of the head of a
pin. These purple spots are the eyes-of the adult and appear from
three to eight days before the same is fully mature. When fully de-
veloped the pupa case splits down the back, allowing the adult to
come out.

The adults are light orange-yellow in color and possess four wings,
which enable them to fly about the tree or from one tree to another _
‘y) 7~, This is the only stage in which the white fly possesses much

, and were it not for the winged adults the mechanical con-

tr this species would be quite easily accomplished. The eggs are

2d on the lower surface of the leaves. An individual female

wili average about 125 eggs during life. Usually many thousands of

eggs are deposited on a single leaf, the leaf presenting an appearance
as if sprinkled with grains of dust.

Bul. 120, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE I.

PUPA CASES OF THE CITRUS WHITE FLY.

Fig. 1—Leaf showing pupa cases of the citrus white fly (Aleyrodes citri); also a few pup and eggs

Fig. 2.—Underside of orange leaf, showing heavy infestation by citrus white fly. Fig. 3.—Leafshow-
ing pupa Cases of the cloudy-winged white fly (Aleyrodes n ubifera), an insect prevalent on citrus
plants in Florida, and very Closely related to Aleyrodes citri. (From Morrill and Back.)

Bul. 120, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE II.

ADULTS OF THE CITRUS WHITE FLY ON FOLIAGE OF ORANGE.
Fig. 2.—Leaf of same,

Fig. 1.—Tender growth of citrus swarming with adults of the citrus white fly.
enlarged. (From Morrill and Back.)

THE CITRUS WHITE FLY: INJURY. ry

DISTRIBUTION IN THE UNITED STATES.

The citrus white fly in the United States has been recorded as
existing under natural conditions in Florida, southern Georgia, South
Carolina, Alabama, Mississippi, Louisiana, and Texas. In 1907 it
was discovered in two localities in California, following which stren-
uous efforts were made toward its eradication. Recent reports!
state that the insect has reappeared in one of these districts. In
addition to the above citations the pest has long been known from
greenhouses in many northern States.

_ The importance of the white fly as a citrus fruit tree pest is shown
almost exclusively in those Gulf Coast States where citrus fruits are
‘produced commercially. Although oranges are being grown quite
extensively in Louisiana and Texas, and to some extent in Alabama,
it is in Florida that the orange-growing industry stands forth as a
ereat and most important one. The distribution of the white fly in
Florida has become so general that it has been reported by Morrill
and Back? as occurring to a greater or less extent in all but two of
the 17 important citrus fruit-growing counties. All important agi-
tation and efforts toward control have originated in this one State.
The close association of this insect pest with the orange and grape-
fruit industry of Florida has led to its frequently being called the
“Florida white fly’? when referred to in other parts of the United
States.

INJURY.

The white fly is the most serious enemy of citrus trees in the Gulf
Coast States. Considering the extent of its injury, together with the
difficulty experienced in its control, it stands as without doubt the
most serious pest to citrus-fruit production in the entire United
States. Injury from the white fly may be considered from two
standpoints—direct injury to the tree by loss of vitality through
removal of sap, or injury produced from the presence on the leaves,
branches, and fruit of the sooty-mold fungus which flourishes on the
honeydew secretions from the white fly. Although the injury due
to loss of sap is undoubtedly considerable, it is of small importance
compared with the injury directly or indirectly resulting from the
fungous growth, and were it not for this secondary consideration the
present fear to the citrus-fruit grower of white-fly infestation would
be largely eliminated. The sooty mold remains in a more or less
nascent period during the winter months and early spring, but later
develops rapidly, so that with the approach of summer it has heavily
coated those trees severely infested with the white fly.

The fungus naturally follows the distribution of the honeydew,
which is prevalent especially on the upper surface of the leaves and

1Monthly Bul. Cal. State Comm. Hort., vol. 1, no. 6, pp. 242-243, 1912.
2 Bul. 92, Bur. Ent., U. S. Dept. Agr., pp. 25-26, 1911.

12 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

the upper half of the fruit (Pl. IID. It is in these places that the
development of the sooty mold is greatest. The mold may also be
found to a greater or less extent on the branches and underside of the
leaves. The injurious effect resulting from fungous growth on the
leaves is due to the check which it places on the assimilative process
that takes place within the tissues, retarding the availability of a
normal food supply for the tree. The injury to fruit has been care-
fully worked out by Drs. Morrill and Back,! and the following state-
ment is based on their investigations: The greatest injury by the white
fly lies in the reduction of the number, size, and quality of fruit pro-
duced. Conservative estimates, based on extended observations, have
placed the average yield in different white-fly infested groves in
Florida as between 20 and 50 per cent below that of normal unin-
fested groves. In addition to this the packing size of oranges is re-
duced one or two grades, while the increased number of culls due to
retarded ripening and other causes materially lowers the market
value of the crop. Moreover, fruit coated with sooty mold must be
washed before marketing. It has been shown by Dr. G. Harold
Powell,? formerly of the Bureau of Plant Industry of this department,
that decay in shipment is greatly increased in washed fruit. Hence
the cost of washing, augmented by the additional loss from decay in
washed fruit over that which is unwashed, is an added loss from
white-fly infestation.

Summing up the whole situation after their experience, Drs.
Morrill and Back estimate that in the average infested grove the
total loss from the white fly may be placed at about 45 to 50 per cent
of the value of the orange crop. Considering that fully 45 per cent
of the citrus groves in Florida are infested by the white fly it has been
estimated that in money value this would amount to more than half
a million dollars annually.

Meruops oF CONTROL AND THEIR EFFICIENCY.

Greater effort has been devoted to the control of the white fly
than of any other pest in the Florida citrus belt. Agents of this
department commenced studying the white fly as early as the eighties,
and since 1906 this*bureau has retained a corps of investigators
continuously in the field testing the various possible methods toward
its successful control. Entomologists from the Florida State Experi-
ment Station have also been working along similar lines for many
years. The efforts of these different scientists have resulted in the
proposal of three distinct methods for control of the white fly: (1)
Fumigation with hydrocyanic-acid gas, (2) spraying with various
insecticides, and (3) the utilization of several fungous diseases of

1 Bul, 92, Bur. Ent., U. S. Dept. Agr., 1911.
3 Bul. 123, Bur. Plant Industry, U. S. Dept. Agr., 1908.

Bul. 120, Bureau of Entomology, U. S, Dept. of Agriculture. PLATE (II.

FIG. 1.—ORANGE COVERED WITH SOOTY MOLD (From Mor ind Back.)

FiG, 2.—LEAF OF ORANGE COATED WITH SOOTY MOLD (From Morrill and Back.)

CITRUS AND SOOTY MOLD

CONDITIONS LEADING TO DEMAND FOR SEARCH. 13

this insect already prevalent in certaim parts of Florida. As to the
comparative efficiency of these three methods authorities are not
universally agreed, but from an unbiased point of view it would
seem that each has its advantages over the others within certain
more or less restricted fields. A discussion of these restrictions is
unnecessary in this place. Suffice it to say that by 1909-10 results
of investigations had not established universally in the minds , of
Florida orange orchardists the absolute commercial efficacy of
mechanical-control methods."

CONDITIONS LEADING TO THE DEMAND FOR A SEARCH FOR
NATURAL ENEMIES OF THE CITRUS WHITE FLY.

The climate of Florida is, in general, very damp, a condition
especially suitable to the free development of fungous diseases.
Six different fungi have been recorded as attacking the citrus white fly,
and their resultant destruction in localities of much humidity appears
at times to total a high percentage.

Following a movement toward efficient organization of the citrus
industries of Florida, the extent of damage which results from white-
fly infestation, as well as its direct bearing on the market quality of
the fruit, was brought forward with renewed force. Considering
the failure at that time of the mechanical methods to meet ade-
quately the demands of the orchardists, coupled with the apparent
partial efficiency of fungous diseases, the time seemed ripe that the
popular idea of control by natural enemies should gain a devoted
following.

This theory of control by natural enemies, in brief, is that all life
in its native home is kept in check by other forms of life which prey
upon it; in other words, that all nature is in a state of equilibrium.
Chief among these natural factors of control in the case of insect
pests are other forms of insect life which are parasitic and preda-
tory on the noxious form. In recent years much attention has
been devoted to the discovery and subsequent introduction from
one country into another of beneficial insects for utilization in
attempted control of certain of our more important insect pests.
One of the earliest importations into America was that of a small
lady-beetle, Novius cardinalis Muls. For several years a large scale
insect called the cottony cushion scale (Icerya purchasi Mask.) had
been producing such extreme injury to the orange and lemon groves
of California that the industry was threatened with ruin. Mechani-
cal means of control proved ineffective. In the belief that the insect
had been introduced into the United States from Australia, Mr.
not met with genera} adoption, largely because of certain practical considerations which render it

unavailable economically under present conditions in Florida. However, recent results with special
oil sprays have placed the control of the white fly on a very satisfactory commercial basis.

14 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

Albert Koebele was sent by Prof.C.V. Riley, then chief of this office, to
that country in search of natural enemies. His discovery of Novius
cardinalis, its introduction into California in 1889, and its subse-
quent rapid development and spread soon resulted in such a com-
plete destruction of the cottony cushion scale that the insect has no
longer been a factor in citrus production in that State.

This remarkable work of Novius resulted in a great stimulus
to the efforts to bring about insect control by means of natural
enemies and has become an historical event in applied entomology. It
might be added that the universal success against the cottony cushion
scale by a single natural enemy has never since been duplicated in the
case of any other insect pest. From this most successful mtroduc-
tion to the present day many more or less successful attempts in the
utilization of natural enemies have been made. The most exten-
sive work of its kind ever undertaken is that now being carried on
under the direction of this bureau in New England against the gipsy
and brown-tail moths, which are highly destructive to forest, orchard,
and shade trees inthat region. These insects were accidental introduc-
tions from Europe, and on that continent are preyed upon by numer-
ous natural enemies. Extended efforts in importing all available
parasites and predatory insect enemies of these two pests and in
establishing them in New England have met with marked success.

Because of these facts and others of a like nature a demand devel-
oped in Florida for an exploration of foreign countries to discover if
possible the natural enemies of the white fly. Such exploration had
been heartily recommended by the various investigators of this bureau
who had been working on the white fly problem in Florida, and was
also supported by the Florida Experiment Station and by orange
growers. The partially effective control by the various fungous
enemies of the white fly was an additional argument for the introduc-
tion of the natural insect enemies to supplement the work of these
beneficial fungi.

As the result of these demands Congress set aside a special appro-
priation, in 1910, for the purpose of searching the world to discover
the native home of the citrus white fly and learning if it was there held
in check by natural enemies. If natural enemies could be found these
were to be collected, brought to this country, and, if possible, estab-
lished in Florida.

PREPAiATIONS FOR THE SEARCH.

The writer was asked by Dr. Howard, Chief of the Bureau of Ento-
mology, to undertake the mission of searching for the native home of
the white fly and of ascertaining if it was anywhere attacked by natural
enemies other than those already known in Florida. After bringing
to a satisfactory close an investigation of the use of hydrocyanic-acid

INVESTIGATIONS IN EUROPE. 15

gas for fumigation purposes in the destruction of scale-insect pests of
citrus-fruit trees in southern California—work which had been in
progress for three years—the writer proceeded to Washington to make
final arrangements for his departure on the mission.

Since the white fly is reported from the United States as being pri-
marily an enemy of citrus it was considered that its distribution
would be limited to those regions in which citrus trees occur, and nat-
urally it followed that these were the places to which travels should be
directed. It is well known that citrus trees are grown to a greater
or less extent in the semitropical and tropical zones throughout the
world. The most tenable supposition is that they originated in
southeastern Asia, whence their distribution, either directly or indi-
rectly, to those countries in which they are at present to be found.

In the collections of this bureau are specimens of the citrus white
fly which have been taken on orange trees in southern China and in
Japan. On his way eastward the writer passed through San Fran-
cisco on the day that Mr. George Compere, the well-known collector
of natural enemies of insects for the State of California, was return-
ing from the Orient with supposedly valuable introductions. An
examination of an orange tree which Mr. Compere had secured in
Japan revealed the presence of the citrus white iy, thus corroborat-
ing previous records from the Orient.

The collection of Aleyrodide of the late walinans Maskell of New
Zealand is now in the custody of this bureau. In examining type
material from this collection of a species named Aleyrodes aurantit
Mask., collected on orange in the northwestern Himalayas of India,
Prof. A. L. Quaintance, of this bureau, an authority on Aleyrodide,
decided that this Indian species was none other than the citrus white
fly of Florida, Aleyrodes citri. Having the above information at
hand it was at once evident that special attention should be devoted
to a search of that part of the Orient having a tropical or semi-
tropical climate.

The present known distribution of the citrus white fly throughout
the world is shown in figure 1.

r INVESTIGATIONS IN EUROPE.

On July 31, 1910, passage was taken on a steamer from New York
en route to Spain via Gibraltar. This first stop was made in response
to a request from the Minister of Agriculture of Spain that the writer
demonstrate before the orange growers of that country the procedure
of hydrocyanic-acid gas Geena ane in the destruction of scale-insect
pests of citrus trees. The orange and lemon trees of Spain are seri-
ously affected by several species of scale insects. Satisfactory con-
trol of these insects had never yet been accomplished, while many of
the orchardists were in despair lest their trees should be ruined.

62800°—Bull. 120—13—3

16 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

The month of August was spent in southern Spain, chiefly at Malaga
and Valencia in company with Comte de Montornes, Royal Commis-
sioner of Agriculture to the Province of Valencia, and Leopoldo Salas,
Agricultural Engineer to the Province of Malaga. During this time
the equipment essential in fumigation was acquired until a crew was
properly fitted for field work. Demonstration work was then carried
on in training the crew until it had become familiar with the general
procedure of fumigation. Meanwhile experimental work was being
carried on, the results of which furnished a basis for dosage against
the insects treated.

Abundant opportunity was found during this demonstration to
study the insect pests of citrus trees in different parts of the country.

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Fic. 1.—Map showing present known world distribution of the citrus white fly (Aleyrodes ciéri).
(Original.)
The citrus white fly, however, could not be found in Spain. From
Spain the writer continued to Italy and Sicily and these countries
were searched but failed to reveal the presence of Aleyrodes citri;
nor has this insect ever been found in European orchards. Thus
the great citrus belt of Europe, although beset with many injurious
insect pests, most of which are mentioned in the appendices of this
bulletin, has not yet become infested with this particular menace,
the citrus white fly, which has proven so discouraging to the orchard-

ists of Florida.
INVESTIGATIONS IN CEYLON.

Leaving Naples, direct passage was taken to Ceylon, which was
reached September 30. Citrus fruits are not grown commercially
in Ceylon, their production being confined to scattering trees, in
yards and gardens, and are grown for decorative purposes as well
as for fruit. Orange trees do not appear to grow with much vigor

—

INVESTIGATIONS IN INDIA. 17

on this island, and the fruit produced is inferior in size and quality.
When picked, the rind is perfectly green, although the flesh may be
fully matured. This failure of the fruit to color—a condition noticed
in other countries lying near the equator—is doubtless attributable
to the excessive dampness of a tropical climate.

The orange trees examined on this island were found entirely free
of the citrus white fly. Through the kindness of Dr. E. E. Green,
Government Entomologist, his extensive collection of Aleyrodide
from all parts of Ceylon was examined, but without evidence of

the citrus white fly. When we consider the above data it does not

seem at all likely that the citrus white fly occurs in Ceylon.

INVESTIGATIONS IN INDIA.
GENERAL.

The journey was continued from Ceylon to India, which was
entered at Tutveorin, the southernmost seaport of importance.
Thence the writer proceeded by rail to Calcutta, his object in visiting
this city being to obtain all possible information as to the distribu-
tion of citrus trees throughout the Indian Empire. Calcutta is the
one city which the naturalist seeking information about this country
will first desire to reach. In addition to the natural advantages
resulting from the fact that it has been the headquarters of the Gov-
ernment and that it is the largest city with very much the largest
white population of any Indian city, it contains the Indian Museum,
the largest if not the oldest institution of its kind in the Orient.
This building is especially rich in natural history material. Many
investigators are employed at this Government institution for research
work and to classify and bring to the notice of the public information
on the natural history and resources of this great yet little known
country.

Through the kindness of Dr. F. Anondale, Director of the Indian
Museum, access was had to the entomological collections contained
therein. An examination of material of the family Aleyrodide
brought to light some severely infested orange leaves which were
labeled as collected in the northwestern Himalayas about 1893, it
being stated on the label that duplicate material had been sent to
William Maskell, the late eminent entomologist of the New Zealand
Institute. It happened that about 1894-95 Maskell described a new
species of Aleyrodes as occurring on orange in the northwestern
Himalayas, calling it Aleyrodes aurantii. “Hence it was at once evi-
dent that the material found in the Indian Museum was identical
with the Aleyrodes aurantii of Maskell. Prof. Quaintance, of the
Bureau of Entomology, in examining the Maskell collection, came to the
conclusion that the Aleyrodes aurantii of Maskell was the same species
as Aleyrodes citri R. & H., the citrus white fly of Florida. The writer’s

18 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

examination of material in Calcutta corroborated Prof. Quaintance’s
determination that the citrus white fly occurs in India. Moreover,
infested orange leaves from a place in the northwest called Kulu were
also found in the museum, and this gave the writer a definite locality
for the white fly in India. Kulu is such a difficult place to reach that
it was decided to visit first other more available localities in the
northern part of the Empire.

During his stay in Calcutta the writer interviewed all available
authorities who had acquaintance with agricultural conditions in

different parts of that country, but little definite information rela-

tive to the distribution of citrus fruit trees was secured. It must be
considered that agriculture in India is for the most part in a very
primitive condition. Commercial orange growing, as we know it in
America, does not exist, but the production of fruit is confined
almost exclusively to individual or small patches of trees in yards
and native gardens, both on the plains and in the hills or lower
elevations of the mountains. (See PI. IV.) In the latter places they
are sometimes grown among the trees of the forest. However, occa-
sionally one sees larger plantings which in extreme instances might
reach 5 or even 10 acres in size.

THe BoTANICAL GARDENS.

The greatest aid to the writer in his searches for citrus fruit trees
were the Government botanical gardens which are situated in differ-
ent parts of the Empire. (See Pl. V.) The more important of
these gardens have European directors—men usually familiar with
agricultural conditions in their respective provinces. Then, too,
most of these gardens contain a large variety of fruit trees. The
largest and oldest one is situated near Calcutta. From interviews
with the authorities at this garden the writer learned that the oldest
garden in Upper India was situated at Saharanpur and also that
citrus trees are grown to some extent in this locality.

For this reason, as well as because this would be the most feasible
place in which to secure information relative to the distribution of
citrus trees in northern India, the writer proceeded to Saharanpur in
the latter part of October, 1910. This was a most fortunate move,
for in Mr. A. C. Hartless, the superintendent of the Saharanpur Bo-
tanical Garden, was found a most capable botanist, whose familiarity
with the conditions in India and wide acquaintance with botanists
and horticulturists, acquired during 25 years of continuous service in
different parts, opened to the writer a source of information pertain-
‘ing to this problem the equal of which was available im no other one
plade.

A large number of citrus trees of many varieties are grown in this
garden. Orange, lime, and grapefruit are also scattered throughout
the immediately surrounding region.

DISCOVERY OF CRYPTOGNATHA FLAVESCENS. 19

DISCOVERY OF THE CitRUS WuHirE FLY aT SAHARANPUR.

An examination of orange trees at Saharanpur soon led to the dis-
covery of the citrus white fly, and subsequent search revealed the
fact that it was of general distribution hereabouts. The insect at
this time had reached the pupal stage. Specimens of the fly could be
found on practically all trees examined, but the infestation was so
light that the insect was in no way a serious pest. Of the insects
infesting the leaves only a small percentage was living. The trees
containing the largest number of living insects were noted to be the
ones with the densest foliage and those protected by large over-
shadowing ornamental trees. In no instance was a tree affected by
“sooty mold’’ ( Meliola sp.).

DISCOVERY OF CRYPTOGNATHA FLAVESCENS, THE LADY-BEETLE
ENEMY OF THE Cirrus Waite Fry.

Closely following the discovery of the white fly, several minute
larve of a coccinellid were seen on fly-infested trees, and later it was
found that these were feeding on the young pup of the white fly.
This happy discovery proved conclusively that Aleyrodes citri is
attacked by a natural enemy in its native home, and thus one part
of the mission on which the writer had been sent was successfully
fulfilled. Later developments showed that the adults of this species
were small reddish-brown beetles, about one-tenth of an inch in
length.

Several days were spent in a careful and exhaustive search through-
out this region, with the result of finding about 200 specimens of the
lady-beetle. These were collected by placing large sheets of cloth
underneath the trees early in the morning before the insects had
become active and then beating the branches with sticks. In this
manner much ground could be covered in a short time.

About 100 specimens of the insect were placed in a small, specially.
made wooden box containing two chambers connected by an opening
about the size of a 50-cent piece. One of these chambers was loosely
filled with damp sphagnum moss, the other with dry fiber from a
palm tree. Such packing allowed the insects free movement and at
the same time reduced possible injury from rough usage to a mini-
mum. ‘The box was so constructed as to allow necessary aeration.

This box was forwarded to the American consul-general at Cal-
cutta, who placed the same in the personal charge of the captain of
a cargo steamer sailing direct from Calcutta to the United States.
All insects had died before their arrival in Florida.

A second sending made by letter mail also failed to come through
im good condition.

This beetle was identified by Mr. E. A. Schwarz, of the Bureau of
Entomology, as Cryptognatha flavescens Motsch.

20 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

DiIscoOVERY OF THE Brown FuNGUs, AUGERITA WEBBERI.

During this examination of the Saharanpur region the writer's
attention was frequently called to the presence of a brownish fungus
attacking the white fly on trees in well-shaded positions. It seemed
identical to all appearances with the Florida brown fungus (4gerita
webberv), yet in order to be certain in this determination a quantity
was sent to Prof. H. S. Fawcett, formerly of the Florida Agricultural
Experiment Station, an authority on fungous diseases of the white
fly. His identification of it as Mgerita webberi was conclusive in
showing that this fungus occurs in India as well as in Florida.

The writer failed to find this fungus except in the region about
Saharanpur. A great deal of exchanging of plants, especially of
citrus trees, between the botanical garden at this place and certain
nurserymen in Florida has been going on for many years, and it
seems quite likely that the brown fungus was introduced from
Florida into India through these exchanges.

SEARCHING AT LAHORE.

Leaving Saharanpur on November 10 the search was continued
northward into the Punjab, and Lahore, the principal city in this
Province, was made temporary headquarters. It is located toward
the center of a broad plain and is less than 500 feet above sea level,
although more than a thousand miles inland from the ocean. The
plain is bordered on the north and east by the gigantic Himalayas,
while it opens southward in an unbroken stretch to the sea. The
climate is generally dry, the temperature of the summer being exces-
sively hot, frequently reaching to between 115° and 120° F., while
the winters are comparatively cold, the minimum temperature
averaging between 35° and 50° F. It is very seldom that the tem-
perature falls below 35° F.

Orange trees are abundant at Lahore, being found in almost every
yard, as well as being the most common plant used for hedges. In
the vicinity of this city they are grown to a considerable extent for
commercial purposes. This consideration, coupled with the induce-
ment offered by the presence of a large botanical garden, led to the
decision that Lahore was the most suitable situation in the north for
continuing our efforts, and later developments resulted in demon-
strating it to be the most suitable locality in all India. Considering
the abundance of orange and lime trees as well as their diverse con-
ditions of cultivation, existing, as they did, from dense growths of
seedling trees, entirely uncared for, to well-cultivated orchards of
healthy budded stock, it seemed that if the white fly and natural
enemies were to be found anywhere in northern India this must
be the place.

“

Bul. 120, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE IV.

Fia. 1.—A NATIVE House IN EASTERN INDIA WITH ORANGE TREES
IN THE YARD. (ORIGINAL.)

Fic. 2.—How ORANGES ARE GROWN IN JAVA. (ORIGINAL.)

[To a large extent the production of oranges depends upon orange trees planted in gardens
and about native dwellings. The fruit is largely of the tangerine variety.]

ORANGE PRODUCTION IN INDIA AND JAVA.

Bul. 120, Bureau of Entomology, U.S. Dept. of Agriculture. PLATE V

Fia. 2.

Some of these gardens contain many citrus trees. In the one at Lahore, of which figure 1 is a
view, the citrus white fly was found attacked by two natural enemies. The living material
transported to the United States was largely collected in this garden. (Original.)

SCENES IN THE BOTANICAL GARDENS OF INDIA.

DISCOVERY OF PROSPALTELLA LAHORENSIS. oF

A careful search, covering several days, resulted in determining
that the white fly was of widespread distribution. The infestation
was quite similar to that already described as occurring at Saharan-
pur. Although of general distribution, the fly was in no place so
abundant as to be a serious pest. The smut so prevalent in white-
fly infestations of Florida was almost entirely absent. While it was
not a difficult matter to find large leaves in well-protected, densely
foliated trees that contained large numbers of white flies, few were in
a living condition. Those alive were in an early stage of pupation.

DiscovERY OF PROSPALTELLA LAHORENSIS, THE TRUE INTERNAL
PARASITE OF THE CiTRUS WHITE FLy.

During the investigation at Saharanpur a few pupa cases of the
citrus white fly were noticed to differ somewhat in appearance from
those of normal shape. Some of these contained very small holes which
were of such a character as could easily have been made by a lady-
beetle or some other biting insect. However, when large numbers of
these abnormally thickened pupa cases were found at Lahore, and
always with a small rounded hole in the exposed surface, it was very
apparent that this condition was the result of internal parasitism.
Considering the type of the host as well as the character of the open-
ing, one was at once led to infer that the parasite was of a hymen-
opterous species. The cold weather at this time of year had driven
almost all insect life into hibernation, so it was impossible to find
any living parasites. A large quantity of leaves containing insects
which had been parasitized was collected and sent to the Bureau of
Entomology in Washington. <A careful examination of this material
resulted in finding five dead specimens of a very minute insect, which
Dr. Howard, Chief of the Bureau of Entomology, determined as
belonging to the genus Prospaltella, of the hymenopterous subfamily
Aphelinine.

In stating the results of this examination Dr. Howard wrote:

The specimens on leaves sentin by Mr. Woglum have been examined with great care.
None of the full-grown larve or nymphs contained pupal parasites, but five specimens
of a very minute aphelinine of the genus Prospaltella were found dead and attached to
the orange leaves in the vicinity of perforated Aleyrodes. The size of these specimens
is such as to justify the conclusion that they had issued from aleyrodids, and their
juxtaposition and the known habits of the genus confirm this conclusion.

As the insect was new to science, it was described as follows by Dr.
Howard: }

Female —Length, 0.54 mm.; expanse, 1.42 mm.; greatest width of forewing, 0.25
mm. Antennz long, not clavate; scape long, slender; pedicel nearly as broad as
long; first funicle joint somewhat longer than second; second and third subequal;
club equal in length to second and third funicle joints together; terminal segment of

1 Journal of Economic Entomology, vol. 4, no. 1, p. 132, 1911.

22 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

club slightly longer than middle segment, basal segment again slightly shorter. Fore-
wings broad, with moderately long bordering cilia; disc uniformly covered with
minute cilia; stigmal vein rounded below, its anterior margin for a time parallel with
costa; marginal vein faintly indicated, its base joining stigmal in an acute angle. (In
this respect this species differs from all other known species of its genus.) General
color light yellow; all legs pallid; eyes dark; ocelli coral-red; antennal club jens
wings hyaline, wing veins dusky.

Male.—Of practically the same size and structure as the female, but differing in
color. The coloration closely resembles that of Aspidiotiphagus citrinus, to which-it
bears a superficial resemblance; pronotum brownish; mesonotum orange yellow;
metanotum and epimerum brownish; abdomen dark brown except at base and tip
where it is lighter; hind femora dusky at tips; wing veins distinctly fuscous, consid-
erably darker than in female.

CONCLUSIONS DRAWN FROM SITUATION AT SAHARANPUR AND LAHORE.

Our searches at Saharanpur and Lahore had resulted not only in
the discovery of the citrus white fly, but, what was especially impor-
tant, the discovery that it was being attacked by both a predatory
enemy and a true internal parasite. It was at once evident that our
next duty lay in attempting to collect and transport to Florida living
material of these beneficial sects. Unfortunately the season at this
time was so well advanced that practically all insect life was in a dor-
mant condition, so that the collecting of living material during the
next few months was impossible. Rather than remain inactive in
upper India until the following spring, it seemed best to continue the
search throughout India and into China with the hope of acquiring a
broad grasp of the white-fly situation throughout the Orient. Havy-
ing the situation thus in hand, we would know whether or not there
were other regions equally prolific in natural enemies of the white fly.
Such information would be of great value to all future work in this
particular field.

ALEYRODES CITRI IN INp1A.

With the exception of the lower part of the peninsula practically
all of India suitable to the growing of citrus fruit trees has been
searched. The writer has examined orange trees at Peshawur, the
frontier city in the northwest near the entrance to the Khyber Pass;
along the lower elevations of the Himalayas (PI. VI, fig. 2) at Dehra-
dun; in the United Provinces; in Sikkim below Thibet; and eastward
into the Khasia Hills of Assam (PI. VI, fig. 1). In the west the writer
has been among orange trees at Poona, in the Bombay Presidency, and
eastward at Nagpur, in the Central Province. Much of the interven-
ing territory between these dutposts of travel has been covered.

As a result of these travels it can be stated that in all places visited
in India, in which oranges were grown, infestations of the white fly
were to be found. This is equivalent to stating that this aleyrodid

Bul. 120, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE VI.

Fia. 1.—COUNTRY BOAT, UTILIZED FOR TRAVELING IN ASSAM.

It is so constructed as to afford protection from heat of sun during the day, and one may
also sleep within at night with some comfort. (Original.)

Fig. 2.—TRAVELING IN THE OUTER HIMALAYAS.

The traveling in this region was performed for the most part on horseback, with native
bearers for carrying provisions. (Original.)

TRAVELING IN INDIA.

INVESTIGATIONS IN BURMA, JAVA, ETC. 23

is distributed throughout India south of the Himalaya Mountains.
(See fig. 2.) i

Evidence of parasitism was seen in practically all localities infested
with the white fly.

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Fig. 2.—Map showing localities in which the citrus white fly (Aleyrodes citri) was found in India,
(Original. )

INVESTIGATIONS IN BURMA, JAVA, SOUTHERN CHINA, AND THE
PHILIPPINE ISLANDS.

Leaving Calcutta December 24, 1910, the writer continued the trip
to Burma with the idea of searching a large citrus section reported to
be in the vicinity of Moulmein, Lower Burma. A week’s search in
this region revealed about a half dozen dying orange trees which
were free of the white fly. Although reliable information was re-
ceived from an engineer in the Burmese public works department
that orange trees occurred wild some 50 miles to the east in the
mountains on the border between Lower Burma and Siam, as well

62800°—Bull. 120-—-13——-4

24 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

as far to the north in the Upper Shan States on the Chinese border,
the limited time at the writer’s disposal rendered it inadvisable to
explore these distant and very inaccessible regions. Instead return
was made to Rangoon, where a steamer was boarded en route to Java
via Penang and Singapore.

Batavia was reached on January 16 and a few days were spent
hereabouts in making short journeys into the surrounding country.
To the biologist visiting Java, the one place to which his attention is
particularly directed is Buitenzorg, the seat of the far-famed Botanical
Garden, which is situated about 60 miles from Batavia, the capital
and principal seaport of the island. After having acquired a knowl-
edge of Batavia and its surroundings, naturally the next move was to
proceed to Buitenzorg. Itself most beautiful and surrounded by
equally attractive country, this locality is a veritable tropical para-
dise. The garden is immediately adjacent to the city. Its great
variety of plants, beauty of arrangement, and size would place it in the
foremost rank of the botanical gardens of the Tropics, while the
extensive and well-equipped laboratories for research, as well as a
splendid museum, probably afford the investigating biologist a com-
bination of desiderata unsurpassed in the Tropical Zone.

Orange and grapefruit trees occur in the garden and are found
scattered throughout the surrounding country. A week was spent
in this locality, during which many trees were examined, yet without
evidence of the citrus white fly.

Through Mr. Max Wigman, botanist of the Buitenzorg Gardens,
detailed information was secured relative to the localities in Java in
which citrus trees were most prevalent. Utilizing this information
during the following two weeks the journey was continued through
the western half of the island. Orange and grapefruit occur through-
out this region, the plantings for the most part consisting of scat-
tered trees along the roads and paths or in gardens about the native
houses. .

At no time during the writer’s travels in western Java were there
seen as many as a hundred orange or grapefruit trees in a single
orchard.

The citrus fruit trees were attacked by a number of insect pests,
but no evidence of Aleyrodes citra could be found. So many trees
were examined in different parts of the island that it would seem a
safe conclusion that the citrus white fly does not occur in Java.

Leaving Java early in February (1911) a boat was taken to Singa-
pore, where transfer was made to a steamer sailing direct to Hong-
kong. On arrival at the latter port a cablegram was received from
Dr. Howard advising that a return trip be made to India and that
effort be made to secure living material of the two natural enemies

FURTHER INVESTIGATIONS IN INDIA. 25

of the white fly for transfer to Florida. It was decided to spend a
fortnight in southern China before taking return passage, as this
would enable the writer to gain some information on conditions in
that little-known country.

It was learned from Mr. Tutcher, superintendent of the Hongkong
Botanical Garden, that oranges were grown extensively over a broad
range of territory inland from Canton, and that a second large citrus-
fruit region was westward of the seaport of Swatow. As Mr. Tutcher
kindly consented to loan the services of one of his native collectors
who was familiar with the Canton region, arrangements were begun
for investigating that territory as,soon as passports were available.

Application for a passport into the interior was filed at Canton
with the American consul general, who stated that it would be about
10 days before the same could be prepared. After returning to
Hongkong the writer decided to utilize the delay occasioned by the
passport by a trip of inspection to the Philippines, which are about
two days by water from this British seaport. While awaiting the
sailing of a steamer for Manila a day was spent at Macau, a Portu-
guese settlement near Hongkong. Some orange trees infested with
Aleyrodes citri were seen here, thus giving a new and definite record of .
this insect in southern China.

Manila was reached on February 28. Through the assistance of
officials in the bureau of science a number of orange trees were found
in this city and carefully examined. No white flies were seen. From
information available it would seem that very few oranges are pro-
duced in the Philippine Islands. The only localities in which citrus
fruits are grown commercially are Santo Tomas and Tanauan, in the
Province of Batangas. These localities were examined, but no white
flies could be found.

While in the Philippines the writer was taken ill and confined to
the hospital throughout the month of March. This illness came at
a very critical period and delayed an early return to India. Hasten-
ing, as he did, from the hospital before having fully recovered, it
was nevertheless impossible to reach India until the last of April,
when the spring season was well advanced.

FURTHER INVESTIGATIONS IN INDIA.

Landing in Bombay on April 22, necessary paraphernalia and pro-
visions were at once collected and a native interpreter engaged pre-
paratory to starting inland.

CONCENTRATION OF EFFORTS AT LAHORE.

The writer’s objective point was Lahore, in the Punjab, about
1,200 miles inland from Bombay. Previous experience had shown
this locality to present the best field of any place in all India for

296 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

possible successful operations. Not only were there a great number
of citrus trees in this region, but the infestation of the white fly as
well as the percentage of parasitism exceeded that of any other place
visited. This was also one of the few places in India in which
young nursery trees were available in large numbers. Being also
the seat of a large botanical garden which contained many citrus
trees, it afforded excellent facilities for the purpose in hand, and
thus was the logical place in which to concentrate efforts.

A stop was made en route at Saharanpur, where success had been
achieved the previous year in the collection of Cryptognatha flavescens,
the predatory enemy of the white fly. Diligent search this time
revealed very few living Aleyrodes; so after employing from Mr.
Hartless, the superintendent of the garden, a ‘molle’”’ or gardener
who had assisted the writer the previous year, the journey was con-
tinued to Lahore.

A eareful canvass of the orange and lime trees of the Lahore
region was at once started in order to ascertain the prevalent condi-
tion of the white-fly infestation. Several days of laborious endeavor
covering much of this locality resulted in the finding of a very light or
scattering infestation of living Aleyrodes. The number was so
small as to be worthless for use in breeding or parasitic work.

Confronted with this discouraging outlook, a trip was made to
Gujranwala, about 50 miles north of Lahore and the greatest com-
mercial orange-producing center in northern India. The condition
of the white fly on citrus trees here was quite comparable with that
at Lahore. Few living insects could be found, although the number
of dead specimens on some trees was large. The previous autumn
a small garden of an ornamental bush (Jasminum sambae), whose
flowers are valuable for making perfumed oils, was found surrounded
by orange trees. These Jasminum bushes were severely infested
with Alcyrodes citri; in fact, it was the most severe infestation seen
in all India, so much so that the leaves were blackened with a crust
of sooty-mold fungus. As he felt confident that this garden would
furnish a splendid breeding ground for the white fly, the discourage-
ment of the writer can be well imagined when on examining this
garden it was found that the extreme temperature of the previous
winter had frozen back most of the bushes and almost eradicated the
fly. Returning to Lahore, a most careful search was continued, with
the ultimate result of discovering in one part of the botanical garden
a well-protected hedge which was well infested with the white fly.
This fortunate discovery constituted the basis of future operations.

DiscovERY OF Livina PARASITES.

{mmediate attention was next devoted toward the discovery of
the parasite Prospaltella lahorensis, which the work of the previous

YOUNG GROWTH OF CITRUS DESTROYED BY INSECTS. par

autumn had shown to occur throughout this region. Efforts soon
were rewarded with the finding of living parasites in very small
numbers on the more protected parts of the infested hedge.

CONSIDERATIONS IN COLLECTING AND TRANSPORTING PROSPALTELLA
LAHORENSIS.

As explained under the discussion of the citrus white fly, this
insect very shortly after hatching from the egg settles down on the
underside of the leaf to remain in a stationary position throughout
its life. If the leaf is removed from the tree, the insect dies when
nourishment is no longer available. Prospaltella lahorensis, being
a true internal parasite of the white fly, is dependent on the hving
condition of its host in order to attain maturity. From a consider-
ation of this situation it was at once evident that the only practicable
way of transporting the parasite to America in a living condition
was by means of healthy nursery trees infested with parasitized
Aleyrodes citri. Moreover, the journey from India to Florida occupies
between five and six weeks, while the entire life cycle of the parasite
at high temperatures is of about three weeks’ duration. This would
mean that even if the parasite left India in the egg stage a complete
cycle of development would take place and the adults emerge before
America was reached. This latter feature necessitated the presence
of living Aleyrodes throughout the journey so that the parasites
at time of their emergence would have material upon which to work.

As small nursery trees are alone practicable for transportation
over great distances, it was at once evident that the success of the
mission depended on obtaining young trees well infested with the
white fly. Young orange trees were available in sufficient quantities
at the Lahore garden, but all were free from living white flies. Young
fiy-infested trees had not been seen anywhere in that country. The
problem thus resolved itself into the artificial infestation of the trees.

DESTRUCTION OF YOUNG GROWTH OF CirTRUS TREES BY INSECT Prsts.

A large number of young orange trees from 1 to 4 feet tall were
dug and placed in earthenware pots. As these trees contained
no young growth, they were placed in a shady place and kept very
moist. It is well known that the adult white fly prefers tender
growth for oviposition. Young shoots soon developed, but no sooner
did the leaves begin to expand than they were immediately attacked
so severely by a lepidopterous leaf-miner, Phyllocnistis citrella Stainton
(Pl. VII, fig. 1) as well as by a bud-worm (Agonopteryz sp.), that the
young leaves of all the plants curled and shriveled before reaching
maturity, thus rendering the plants worthless for the purpose desired.

In order to avoid the destruction of young growth by these two
insect pests cloth houses were constructed and into these were placed

28 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

a second set of potted nursery trees (Pl. VII, fig. 2). The trees were
carefully examined before being introduced into the house in order to
destroy any of the pests that could be seen. This was not difficult
of accomplishment, as the pests pupated in the trees. Inspection
was continued every few days so that the plants were soon free of the
pests and in due time the development of young growth followed.

Notes oN THE Lire History or ALEYRODES CITRI IN NORTHERN
INDIA.

The following notes on the life history of Aleyrodes citri on citrus
were made at Lahore during 1911 and might be said to be typical
of this insect in the great plains of northern India. Observations
made at different times of the year in other parts of India would
tend toward the probability that the development recorded in the
northern part would also be more or less applicable to central India.

On May 1-4, 1911, the earliest dates of observation, the white
fly was in the egg and larval stages. Calculating on the basis of
the conclusions of Morrill and Back in their white-fly investigations
in Florida that during the spring the duration of the egg stage
averages somewhat less than two weeks, it would appear from the
stages of development existing at Lahore on May 1 that the first
brood of adult flies had emerged during the earlier part of April.
This conclusion was somewhat corroborated by information from a
native entomologist who stated that he had seen adult Aleyrodes in
ereat numbers during the first part of April about the citrus hedge
which the writer had found well infested and which he had selected
as a basis for operations in collecting. Circumstances prevented a
close observation of white-fly development between the middle of
May and June 11, but an examination on the latter date showed the
insects to be in the pupal stage. By June 24 the pupz were almost
fully matured and in a tew individuals the purple eyes of the adults
had commenced to be prominent. On June 25 a small number of
adults emerged and this emergence continued during the following
two or three days. Emergence had stopped and practically all
adults disappeared by June 29. From this time throughout July
and up to August 20, a period of about eight weeks, the insects appeared
to remain perfectly dormant. The last 10 days of August were a
period of great activity. Excretions of honeydew appearing on the
pupee between August 20 and 25 marked the first evidence of activity
following their dormancy during the hot,drysummer. From August
26 to 30 the pupe rapidly thickened and the purple eyes and whitish
wings of the adults became evident through the thin pupal cover-
ing. The first adults commenced to emerge on August 31, and within
a week or ten days the flight was as its height. By September 13
practically the entire brood had emerged. On September 20 very

Bul. 120, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE VII.

Fia. 1.—YOUNG CITRUS SHOWING LEAVES OF TOP SHOOTS DEFORMED BY
ATTACKS OF A LEAF-MINER (PHYLLOCNISTIS CITRELLA).

At certain times of the year in northern India practically all new growth on young trees is
atfected by this insect. (Original.)

Fia. 2.—CLOTH CAGES PLACED OVER YOUNG CITRUS TO PROTECT THEM FROM
THE RAVAGES OF THIS LEAF-MINER.

The destruction of young foliage on trees as soon as it appeared necessitated artificial
manipulation in order to avoid the leaf-miner (Phyllocnistis citrella). Two cloth cages
were constructed, and in these were placed potted plants. After several hand pickings
the plants were freed of the leaf-miners, and the cloth protection permitted the young
foliage to develop. (Original.)

THE LEAF-MINER PHYLLOCNISTIS CITRELLA IN_ INDIA.

EFFECTS OF TEMPERATURE ON WHITE FLY. 29

few adults remained in flight, while the first eggs deposited were
hatching. All eggs were hatched by October 5 and by October 20
many insects had reached the pupal stage.

Investigations at Rajpur and Saharanpur revealed conditions com-
parable with those at Lahore. Observations throughout northern
India in November of the previous year (1910) showed the insect
at that time to bein the pupal state. From a consideration of these
conditions found in two different years it is evident that the white
fly passes the winter in northern India as a pupa.

NuMBER oF Broops OF THE CITRUS WHITE Fry.

It has been stated by Morrill and Back that while there may be
in Florida from three to six generations, adult flies are found in
ereatest abundance only during three more or less distinct periods,
or generally speaking, there are three broods of white flies each year.
Strictly speaking, there is great irregularity of breeding and overlap-
ping of generations so that adult white flies may be found in varying
numbers at all times except during the colder periods of winter. In
all this irregularity, however, there stand out in prominence three
general broods—a spring, a summer, and an autumn one.

Turning to northern India we find a different condition. Here
there were two very distinct broods on citrus trees in 1911, adults
of the first emerging in early April and those of the second during the
first part of September. So far as the writer’s observations extended
these broods were sharply defined and without overlapping genera-
tions. In fact, so sharply defined were these two broods that no
adult flies were seen outside of the two normal periods of emergence
with the exception of a very few during three to four days in June.
The latter emergence was due.to a preceding period of high humidity
accompanied by slight rains.

THe Errects oF TEMPERATURE ON WHITE-FLY DEVELOPMENT.

The climatic conditions of the plains cf northern India are very
different from those of Florida, and the resultant effect on the devel-
opment of the white fly is equally apparent.

Whereas the winters in the Punjab of India average colder than in
Florida the summers are very much hotter. During the months of
July and August the average daily mean temperature in central
Florida is 82° F., while during the same period in 1911 at Lahore it
averaged 96° F., or 14° higher. The average daily mean tempera-
ture at Lahore for the months of May, June, July, and August was
94° F. and the average maximum temperature for the same period
was 107° F. Such high temperatures have naturally a deterrent
effect on insect development. Most of these days are bright and
sunshiny, and so penetrating is the direct action of the sun that

80 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

Europeans require heavy protection in order to withstand it. Then
frequently hot blasting winds blow with great violence, stirring up
the dust in dense clouds and rendering life doubly uncomfortable.

In the direct rays of the sun the temperature during this time
often exceeds 150° F. Failing rains cause vegetation to dry
up and insects develop with difficulty. The following instance shows
the effect of drought on the white fly:

In the Government Horticultural Garden at Lahore there is a very
large nursery containing small orange and lemon trees. These trees
were free of living Aleyrodes with the following exceptions: At
one side of the nursery there was a large, densely foliated deciduous
tree which overshadowed a number of orange trees. Some of
these trees which were more densely shaded contained a small number
of living white flies. Near the center of the nursery was a densely
foliated tree about 10 feet tall, against the base of which were two or
three small orange trees which were in shade throughout the day.
These trees contained some living white flies, whereas other trees
immediately surrounding but exposed to the sunshine contained
none. Moreover, it can be stated that at no place in India did the
writer find living Aleyrodes on small nursery trees except im situa-
tions that were well protected by shade.

The most severe and at the same time extensive infestation of the
white fly on citrus in India occurred on a large hedge at Lahore, and
this was utilized in the writer’s breeding and collecting work. A
part of this hedge was protected by a cloth awning and this protected
portion was infested on all parts. (See Pl. VIII.) On the part not
covered with awning the white fly occurred in abundance only where
the hedge was protected by densely foliated overhanging trees which
kept the direct rays of sunlight from the hedge plants throughout
the heat of the day. The side of the unprotected hedge exposed to
the direct rays of the afternoon sun was entirely free of living white
flies, whereas on the lower part of the opposite side, which was in
shade except for a very short period in early morning, living flies
could be found in considerable numbers.

In the case of large citrus trees the greatest number of living
insects was invariably found in those having the densest foliage. A
tree in which the foliage was light seldom contained living flies
except where protected by the shade of a large overhanging species.
Although the white flies appeared to prefer trees of the tangerine
variety, they were seldom able to multiply to any extent on these
because of the small leaves and the less dense foliage than that of
other varieties. In any species of citrus in which living specimens of
the white fly occurred the infestation was found almost invariably in the
shadiest part of the tree or the interior part near the main branches.

EFFECT OF HUMIDITY ON WHITE FLY. St

If large leaves grew in this part of the tree their examination was
usually certain to reveal living insects provided the latter were to be
found on the tree. In fact, after extended experience in the examina-
tion of citrus trees in India, examination of the larger leaves near the
trunk of a tree was found to be such a conclusive key to infestation
that the writer was able in most instances to ‘“‘size up”’ the infested
leaves before starting the inspection.

The statements previously made show the destructive action of
very high temperatures on the citrus white fly. The prolonged hot,
dry summer weather of the plains of northern India checks the
development of almost all terrestrial forms of insect life. During the
months of July and August, 1911, not only was the development of
the white fly at a standstill, but this condition was also noticeable
with other species of Aleyrodide as well as with all Coccide observed.
Insects on the wing were seldom seen. In fact, this extremely hot,
dry period appeared equally effective in checking the activity of
insect life as does a prolonged cold period, such as occurs during the
winter in central Florida or in the orange-growing parts of southern
California.

That vast numbers of msects are destroyed in these regions of
greatest heat is at once apparent to the entomologist who has spent
a summer in India. In summing up the writer’s experiences and
observations he is led to the belief that this hot, dry climate of the
Indian plains exerts a greater influence in holding the white fly in
commercial control than all other factors combined.

Tuer Errect or Humipiry oN Waitr-FLY DEVELOPMENT.

It has been stated by Morrill and Back?! that ‘‘while a normal
amount of humidity is necessary for emergence of the white fly
to occur, it is not so controlling a factor as temperature during
ordinary Florida weather.’ We have found that the above state-
ment will have to be modified if applied to the Punjab of India, and
this is not surprising when it is considered that the normal humidity
and temperature of these two countries are so essentially different.

Under normal conditions at Orlando, Fla., the relative humidity at
any season of the year rises to nearly or quite 100 per cent by 6 to 10
p. m., and remains at this degree of humidity until the following
morning. Rain falls throughout the year, but is lightest during the
winter months.

In the Punjab it was found that the humidity is comparatively
low throughout the year. With the exception of a few light falls of
rain in the winter the rainfall during a normal year is confined to the
so-called ‘‘monsoon period,” occurring in June, July, and August

1Bul. 92, Bur. Ent., U. S. Dept. Agr., 1911.

32 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

and averages about 15 inches. Taken as a whole the climate of the
Punjab is very comparable with that of portions of the arid south-
western United States.

The writer’s observations were confined almost entirely to the
year 1911, during which conditions were somewhat abnormal because
of the almost total failure of the rains during the monsoon in the
plains of northern India. The prevailing extremely high temperature
and low humidity throughout the summer (with the exception of two
periods of very light rainfall) gave excellent opportunity for observing
the effect of high temperature on the development of the white fly,
as well as the effect of humidity on its development and emergence.
Throughout the period between April and September the humidity
continued so low that at no time was foliage noticeably moistened by
dew except in a few instances following precipitation. Heavy dews
occur during the autumn and winter months, yet they are much
less heavy than in Florida.

With these considerations regarding Indian weather in mind, an
attempt will be made to specify its effect on the development of the
white fly durmg 1911. It is quite probable that the emergence of
the first brood at Lahore took place about the Ist of April. By May
1 it appeared that practically all eggs had hatched, while the insects
were in the earlier stages of development. The temperature during
the latter half of April averaged about 82° F. Development con-
tinued throughout May, and by June 11 the insects were mostly in
the thickened pupal condition or approaching maturity. As com-
pared with that of Florida, development thus far had been about
normal. The mean temperature from May 1 to June 11 was 93° F.
During the period, June 11 to 15, about 2 inches of rain fell, while
the humidity, which had averaged about 39 during the preceding six
weeks, now rose to an average of 74. This moisture apparently
hastened the development of the pupz. <A few of the more advanced
individuals changed to adults and emerged about 10 days after the
rain. Almost immediately following this period of precipitation the
temperature rose, while the humidity returned to normal. This
return to previous hot, dry conditions appeared suddenly to check
further development, but such pup as had already changed to
adults began emerging on June 25, 10 days after the last rain. A
very light shower of rain fell on June 26 and appeared to bring out all
adults ready for emergence. Within four days practically all adult
flies had disappeared from the hedge plants.

This hot, dry weather continued throughout July up to August 20.
Slight thunderstorms on July 13 and 14 moderated the temperature a
few degrees. The very dry, hot atmosphere immediately preceding
and following these rains, as well as the sunshine between showers,
almost immediately dissipated any marked change of the tempera-

Bul. 120, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE VIII.

FiGaace

These hedges were found well infested with A/leyrodes citri, and were protected from the rays
of the sun by cloth coverings. In all three figures is seen the method of covering, and in
figures 2 and 3 is shown the construction of a wooden platform alongside the hedge for holding
the potted orange trees. These potted plants were placed in this position so as to become
infested with the citrus white fly when the brood emerged on the hedge plants. (Original. )

AN ORANGE HEDGE IN THE BOTANICAL GARDEN AT LAHORE,
INDIA.

EFFECT OF HUMIDITY ON WHITE FLY. | 30

ture and relative humidity. The relative humidity as taken at
8 a.m. throughout the period of high temperatures and low humidity
between the middle of June and August 20 averaged 52 per cent.
The temperature during the same period ranged between an average
maximum of 106° F. and an average minimum of 84° ,F. The
average mean temperature was 95° F. So great was the effect of
this hot, dry weather on the pupe of the white fly that they remained
in a practically dormant condition throughout this interval, and
many were killed by the penetrating rays of the sun.

Lahore is situated in the plains about 50 to 100 miles from the
Himalaya Mountains. Heavy rains falling in the outer ranges
during the latter part of August affected the humidity of the sur-
rounding plains. By August 20 the effect of these rains began to
be felt at Lahore and was marked by a high rise in humidity over
that of the preceding weeks, while the dry atmosphere changed to one
of muggy oppressiveness. This humidity was accompanied by aslight
lowering of the temperature. This condition continued for several
days and on August 25 heavy showers fell. A very thorough examina-
tion of the infested plants on August 26 showed that a remarkable
change had taken place within the past few days. All living Aleyrodes
were active, as noticed by exudations of honeydew, a condition not
seen during the preceding several weeks of dry weather. The pupe
were also changing to adults. This humid weather, accompanied by
occasional showers, continued and by August 31 the first adult white
flies emerged. By September 2 they could be seen in great numbers.
The issuance of adult white flies was at its greatest height about
September 7 or 8, while by September 13 practically all adults had
emerged and eggs had been deposited very freely.

The foregoing observations show that when dealing with high
temperatures, such as in the Indian plains, humidity is the great
factor regulating emergence of adult Aleyrodes. Low humidity
coupled with high temperatures between the middle of June and the
middle of August kept the pupe in a dormant condition. The
approach of a humid atmosphere on August 20 and continuing into
September effected immediate development of the white fly and rapid
emergence followed.

The effect of humidity on other insects was equally apparent.
Several species of scale insects (Coccide) which had been in a dormant
condition throughout the summer commenced development with the
approach of the humid period during the last of August. The rapidity
of this development in the case of some species was most striking.
‘Trees which had contained a moderate infestation of inactive scales
during the summer months now became severely infested within a
fortnight following the first rain.

34 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.
PROSPALTELLA LAHORENSIS, THE TRUE INTERNAL PARASITE.

Tt has been stated in another part of this bulletin that the first
definite discovery of parasitic action on Aleyrodes citri was made at
Lahore, India. Also it was here that at a later date living material
of the parasite was first seen. While no special attempt was made to
work out the life history of this insect, numerous observations taken
during the summer of 1911 while preparing material for introduction
into Florida furnish some definite information on certain points of
value. "

Adult parasites could be found at any time between May and
November. They were most numerous during the months of May
and September. Although found in June, July, and August, they
were so scarce that it frequently required several minutes before a
single specimen could be located. Moreover, during this time of
ereat heat a large percentage of the parasites died within the host
before maturity. As no evidence of hyperparasitism was evident
and since this mortality occurred at all stages of parasite develop-
ment, the writer is inclined to attribute this mortality to the effects
of the hot dry climate. Observations would lead us to believe that
at no time did parasitism of the fly exceed 1 per cent.

The parasite prefers the larval stages of its host, but when necessary
will oviposit in the pupe. Parasitized larve and pupx develop a
much greater thickness than healthy ones. They also soon lose their
transparency, becoming opaque, and this renders them easy of detec-
tion. By the use of a lens the parasitic larvee, which are of a whitish
cast, can be seen within the white-fly host. On reaching the pupal
stage the parasite becomes very dark, almost black, so that at this
time parasitized white flies containing pupa cases appear very dark.
Having attained maturity the parasite eats a small hole in the dorsum
of the host and through this opening emerges into the open air.

Parasitized Aleyrodes are largely confined to the shadiest part of
the plant. The parasite is apparently distributed throughout the
citrus-growing region of the Indian Empire.

INFESTING YOUNG ORANGE TREES WITH ALEYRODES CITRI.

It has been stated under another paragraph that young trees
infested with living white flies were necessary for the safe trans-
mission of parasites from India to Florida. Since young trees infested
with the white fly were not available in that country, infestation was
secured in the following way: A large portion of the infested orange
hedge at Lahore had been protected by a heavy canvas awning.
(See Pl. VIII.) Under this awning immediately adjacent to the orange
hedge, and on the side away from the midday and afternoon sun, was
constructed a narrow platform for potted citrus trees. This platform

CASES USED IN TRANSPORTING PARASITES. oD

was of such height that the top of the young trees placed thereon
would approximate or slightly exceed the height of the hedge. (See
Pl. VIII, figs. 2, 3.)

Potted acne were arranged on this platform immediately preced-
ing the emergence of the brood of the white fly in September. The
awning was then so extended as completely to cover the hedge‘except
at the side on which the plants were placed. This procedure not only
protected the foliage from the sun but so shaded the hedge that when
the white flies became active in the morning and evening they would
come in contact with the potted trees, in their flight toward the light,
and thus be more likely to oviposit thereon than upon the hedge itself.
All fresh and tender foliage was removed from the hedge before
emergence of the white fly took place so as to render its foliage less
attractive than that of the potted plants. As a result the flies ovi-
posited freely on the young plants and a gross infestation was thereby
secured.

The plants were continued in this position after infestation in order
to afford natural conditions for the action of parasites. About the time
white-fly eggs commenced to hatch, parasites could be seen running
about the young plants, and later it was found that the percentage
of parasitism on the young trees was equally as great as had been
seen on the infested hedge at any period during the observations.

Jt was now the middle of October and, believing that all conditions
at that time were most opportune for success in carrying through the
parasite to America in good condition, the writer commenced boxing
the plants on October 18 preparatory to shipment.

Cases Usrep IN TRANSPORTING PARASITES.

When tender plants are shipped long distances, as from one country
to another, a specially made crate called a Wardian case has been
used with marked success. These cases much resemble miniature
greenhouses, being constructed of heavy wood throughout with the
exception of the top, which is made of glass. The cases are perfectly
tight except for two small holes at the top, which afford a slight ex-
change of air with the outside. Plants contained in these cases go
great distances without watering. The writer’s attention was called
to this case by Mr. C. L. Marlatt, assistant chief of this bureau, and
by Mr. David Fairchild, in charge of plant introductions in the Bureau
of Plant Industry of this department. Request for one of these cases
was made to the Government Botanical Garden, Calcutta, and in due
time a sample case was constructed and shipped to Lahore. These
Wardian cases are used for seedling plants, and consequently are low-
topped. It was found that in order to utilize this type of case for our
insect-infested plants it would be necessary to make a number of altera-
tions. This was done and the completed case as used for transporting

836 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

our material to this country is seen in Plate [X. The base measure-
ment of the cases was approximately 24 by 34 feet, while the height
varied from 4 to 5 feet. Three large holes were made in both ends of
the cases toward the top so as to allow a free exchange of air. These
holes were covered with fine brass gauze to prevent the escape of
insects. ‘Two small doors were made in each case to be used when
watering the plants. These doors were kept open in good weather
during the voyage and a specially made fine wire-gauze screen placed
in the opening. The glass portion of the case was divided into small
sections, six on either side. Thick glass was deep set in the heavy
frames so as to reduce to a minimum the possibility of breakage en
route.

A rack of half-inch boards rested on the bottom of the case, thus
keeping the plant jars from coming in direct contact with the bottom.
This helped to minimize the effect of sudden jolts as well as to allow
seepage of excess water when the plants were watered. Several auger
holes were bored in the bottom of each case. The earthenware jars

containing trees were tightly packed with a mixture of the fiber from

palm treesand sphagnum moss. Strips of boards were tacked over the
tops of the jars to keep them in place. The cases were made in sec-
tions held together by screws. They could be easily taken apart and
reassembled when needed.

CRYPTOGNATHA FLAVESCENS,’ THE PREDATORY KWEMY OF THE CITRUS
Waite Fty.

During the autumn of 1910 a small reddish-colored lady-beetle was
found destroying the white fly at Saharanpur, India, and two ship-
ments of this species were made at that time to America. All insects
were dead on their arrival.

When the writer was carrying on an inspection of citrus trees in-
fested by Aleyrodes, immediately following his return to Lahore in
May, 1911, his attention was soon directed to a very few larvee of this
coccinellid busily destroying the white fly. By May 9 the larve had
become fairly numerous on parts of the infested hedge about which
work was centered. Very few adults were seen at this time. During
the last ten days of May adults had become numerous, while larvee were

seldom seen, which would indicate that the latter had reached -

maturity. Careful observations were made June 11 to 14 and the
discovery was made that not only had all larve disappeared, but the
adults as well with the possible exception of an occasional straggler
and these too disappeared during the latter part of the month. No
Coccinellidee were seen during July, August, and September, but on
October 5 one adult and a few young larve were found on young

1This insect is mentioned in Indian Insects, by H. Maxwell-Lefroy, under the name Clanis soror, as
attacking Aleyrodes sp. on castor (Ricinus sp.).

Bul. 120, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE IX.

Fic. 1.—THE SIX WARDIAN CASES CONTAINING THE NATURAL ENEMIES OF THE CITRUS
WHITE FLY AS THEY ARRIVED AT THE LABORATORY AT ORLANDO, FLA., AFTER THEIR
LONG TRIP FROM INDIA. (ORIGINAL.)

Fia. 2.—A WARDIAN CASE WITH THE TOP REMOVED.

This top is tightly fitted on the glass case by means of screws. The elbowed funnel was used in wat ering
the orange trees through the small door at the end. (Original.)

TRANSSHIPPING THE NATURAL ENEMIES OF THE CITRUS WHITE FLY.

Bul. 120, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE X.

Fla. 1.—THE SIX WARDIAN CASES CONTAINING THE NATURAL ENEMIES OF THE CITRUS
WHITE FLY LEAVING LAHORE AT THE BEGINNING OF THEIR LONG JOURNEY TO THE
UNITED STATES. (ORIGINAL.)

Fia. 2.—NATIVE HINDUSTANI WHO RENDERED ASSISTANCE TO THE WRITER IN COLLECTING
THE NATURAL ENEMIES OF THE CITRUS WHITE FLY. (ORIGINAL.)

TRANSPORTING ENEMIES OF WHITE FLY TO UNITED STATES. 387

orange trees infested with larve of the white fly. By October 13
the coccinellid larve were in large number and a week later adults
had become numerous. ,

This coccinellid feeds upon the eggs and larve of the white fly. <A
few cases have been noted in which pup were attacked. They do
_ splendid work when the proper food is in abundance. The most
extreme instance of efficient performance by this lady-beetle was
observed on some young potted orange trees severely infested with the
white fly in the larval condition. About thirty of these trees were
grouped closely together in the shade of a large overhanging tree in the
Lahore Botanical Garden in order to secure infestation with parasites.
Within a period of 10 days these trees had become inhabited by so
many lady-beetle larvee that the white flies were largely destroyed and
the trees were rendered useless for the writer’s purpose. This insect
has been collected by the writer in the Hastern United Provinces
and the Punjab.

PREPARATION OF BENEFICIAL INSECTS FOR SHIPMENT.

The coming of the rains during the latter part of August, which
resulted in the emergence of the fall brood of the citrus white fly and
subsequent infestation of the young potted trees, marked the begin-
ning of a period of steady progress toward successful accomplishment
of our endeavors in India. Closely following the hatching of the first
white-fly eggs numerous specimens of Prospaltella lahorensis could be
seen walking around on the leaves of the infested young trees. By the
middle of October it was evident that many aleyrodid larvee had been
parasitized. Fortunately large numbers of the coccinellid Cryp-
tognatha jlavescens had appeared simultaneously with the imternal
parasite.

Believing it to be the ideal time for preparing the shipment, five
cases were packed on October 18 with aleyrodid-infested trees. Each
of the cases contained between 10 and 20 trees. Three cases were
filled with material parasitized by Prospaltella, while each of the other
two cases contained about 150 specimens of the lady-beetle Cryp-
tognatha. The lady-beetles were in both the larval and adult stages.

TRANSPORTING THE NATURAL ENEMIES OF THE CrtTRUS WHITE FLY
FROM INDIA TO THE UNITED STATES.

On October 20, 1911, the five cases of natural enemies of the white
fly, together with a sixth case, which contained several valuable
varieties of citrus fruit trees native to that country, were placed
aboard a train at Lahore and started on their long journey to America.
(Plate X.) At Bombay the shipment was placed aboard a vessel
bound for Europe. As there are no through steamers between
Bombay and New York, it was necessary to transship to other vessels

388 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

at Port Said and Naples. Careful prearrangements enabled good
connections to be made at both of these ports, so that little delay
was experienced throughout the voyage. New York was reached on
November 28, exactly one month out from Bombay.

The writer accompanied the shipment and gave it his personal
attention throughout the long voyage. The cases were kept on deck
except for the last three days out of New York when cold and stormy
weather necessitated their being placed below. a

CONDITION OF THE NATURAL ENEMIES ON ARRIVAL AT
ORLANDO, FLA.

The cases were shipped from New York to Florida by express,
arriving at Orlando on December 2, when they were immediately
taken to the Government laboratory. An examination of the con-
tents was at once instituted. The ultimate result was the recovery
of 28 active and healthy lady-beetles (Cryptognatha flavescens) and 8
adult Prospaltella lahorensis. A large number of living Prospaltella
in both the adult and pupal states were left in the cases.

This condition of the shipment was all that could be desired. A
sufficient number of both the predatory enemy and the true internal
parasite had arrived in a living condition for breeding purposes.
Thus it seemed to the writer that his mission had been successfully
terminated.

CONDITIONS AT ORLANDO, FLA., WHEN THE NATURAL ENEMIES
ARRIVED.

The writer’s return in December was unfortunate but unavoidable.
White flies in Florida at this time are in a practically dormant pupal
state and continue in this condition during the winter months.
Although the winter weather in central Florida causes such tender
insects as the white fly to remain inactive, the more resistant species,
such as the Coccinellide, are not completely driven into winter
quarters, but continue to be more or less active during many of the
warmest days.

Mr. R. Wooldridge, an agent of this bureau then stationed at
Orlando, had on hand a large number of young orange trees infested
with the white fly for use in feeding the natural enemies. All these
insects, however, were in the pupal stage and then not suitable as food
for either of the two introductions, which attack only the younger
stages of the white fly.

LOSS OF THE NATURAL ENEMIES.

Without any experience to act upon, it was not easy to determine
the best method of carrying these parasitic and predaceous enemies
through the winter. In view of the writer’s acquaintance with the

POSSIBLE EFFICIENCY OF ENEMIES IN FLORIDA. 39

conditions in India and from the fact, as he had there determined,
that both the parasitic and predaceous enemies of the white fly pass
through considerable periods of hibernation, both in the winter season
and in the dry season, it seemed to him that the best chance of success
was to allow the imported material to go through the winter in a nor-
mal condition of hibernation. The alternative was artificially to
force, throughout the winter, active breeding of these imported
insects and of the white flies as hosts.

With the exception of a small number of the more active specimens
of the lady-beetle enemy of the white fly, an attempt was made to
carry the imported insects through the winter in a state of hiberna-
tion, with the unfortunate result that none of the parasites or of the
lady-beetle enemy of the white fly survived.

The small number of more active ladybird beetles referred to were
removed from the Wardian cases in which they had been imported
and taken into the laboratory and placed on young trees infested with
white flies in the dormant, pupal stage. The white fly in this stage
was not well suited to them as food, which is by preference the egg
and early larval stages, and by the 1st of January all but two of the
beetles taken into the laboratory had perished. About the middle
of January eggs were obtained from white flies reared in the warm
room and the two remaining beetles were removed to a small potted
seedling orange tree stocked with such eggs. The feeding of these
beetles on the eggs was voracious and they remained alive through
the winter but as they were apparently of the same sex they died
without reproducing.

The loss of the parasites and the ladybird enemies of the white fly
is very regrettable. Possibly such loss can be avoided, if another
importation is made at the same period, by adopting the method of
keeping the insect enemies and host insects in active breeding through-
out the winter in a suitably constructed and well-stocked greenhouse.
Possibly an even better chance of success will come from importations
so timed as to arrive in early summer.

THE POSSIBLE EFFICIENCY OF THESE NATURAL ENEMIES IF
ESTABLISHED IN FLORIDA.

Considering the comparative weather conditions of Florida and the
parts of India infested with the white fly, the writer sees no reason
why Prospaltella lahorensis and Cryptognatha flavescens could not be
successfully established in this country.

It has already been stated that neither of the two natural enemies
of the white fly exerts any great effect in controlling the white fly in
India. The great natural enemy of the white fly in that country is
the excessive heat, and this very element which limits the injuriousness
of the white fly is, in the writer’s opinion, largely the one that keeps

40 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

down the natural enemies of this pest as well. Probably the adults of
Prospaltella never emerge from the majority of parasitized larve and
pupe of the fly, and this because of their destruction by heat previous
to the time for their exit. This same extreme weather which limits
the white fly to two distinct broods has both a direct and an indi-
rect effect on the lady-beetle. Since this insect destroys only the
younger stages of the white fly, the heat has an indirect effect by
limiting the breeding of the pest to two distinct broods, so that there
is only a very short time in the spring and in the fall during which
‘ food for the coccinellid is available. The direct effect is that the ex-
treme heat produces a deterrent influence on the lady-beetle’s activity.

It may be well to state what could be expected of these natural
enemies if established in Florida. At the very maximum of possible
efficiency the writer believes they would fall far short of commer-
cially controlling the white fly. In fact, it is very doubtful if its
commercial control by natural enemies alone is possible. Granting
that this high degree of control could not be expected, the writer’s
observations and experience lead him to believe that the introduction
of these natural enemies, especially the lady-beetle, is likely to result
in sufficiently beneficial results to be well worth the while. Espe-
cially would this be so when these natural enemies were working in
connection with the different fungous enemies of the fly now found
in Florida.

The elimination in this country of the checks to the development
of these natural enemies, which exist in India, would assuredly have a
beneficial effect. Whereas in India the white fly can be found on
citrus trees only in small quantities and is limited to two distinct
broods, the situation is entirely changed in Florida in that there are
several broods in a single year. The presence of an adequate food
supply throughout a large part of the year, in a climate in which the
most extreme day of summer is sufficiently mild to allow their free
activity, would seem to present such a favorable situation that these
natural enemies of the white fly must needs accomplish excellent
results after becoming thoroughly established.

DESIRABILITY OF CONTINUING THE ATTEMPT TO INTRODUCE
THESE TWO NATURAL ENEMIES.

It has been pointed out in the preceding discussion that conditions
in Florida appear favorable to splendid results from the establish-
ment of these natural enemies, especially the lady-beetle (Cryp-
tognatha flavescens). As previous experience has shown how best to
cope with the situation in order to carry it through to a successful
termination, the present would seem an inopportune time to termi-
nate endeavors in parasite introduction. We have detailed informa-
tion of localities in which to find the natural enemies, the proper

FOOD PLANTS OF CITRUS WHITE FLY. 4]

season of the year for their collection, the most successful methods to
be employed, manner of shipment, and all other factors regulating the
procedure. A greenhouse could be prepared in Florida, so that there
would be breeding Aleyrodes on hand at all times of the year.

As an outline of a second attempt at introducing the natural ene-
mies of the white fly, the writer would make the following suggestions
on the basis of his past experience: The work should be carried along
on a more extensive scale than previously and with the object of
continuity should the first attempt fail. Two men should be sent
abroad, to arrive in India by March 1. This would give time for
adequate preparations before the appearance of the first brood of the
white fly in April. Several cases such as were used by the writer in
his expedition should be filled with aleyrodid-infested trees and trans-
ported to India. This would insure a supply of Aleyrodes as well as
citrus trees should any difficulty be experienced in an attempt to
secure either on arrival in India. Having collected a supply of nat-
ural enemies, one of the two men could return with the same to America
while the second man remained in India carrying out preparations for
securing material from the second brood of the white fly. Then, if the
first shipment should prove a failure, no time would be lost in the
second attempt. Should the first shipment come through success-
fully, as soon as this was definitely known the agent in India could be
informed. He could then proceed to the great citrus-fruit-growing
regions of southern China and endeavor to find other natural enemies
of the white fly in this little-known region, in which it is quite possible
the Aleyrodes origmated. The writer is very strongly of the opinion
that in China there should be other natural enemies not found in India.

FOOD PLANTS OF THE CITRUS WHITE FLY.

The citrus white fly has attained its great economic importance in
the United States because of its injurious action to citrus fruit trees.
Specific consideration of this matter has been given on pages 11-12 of
this bulletin. It has been stated by Drs. Morrill and Back that in the
Gulf States oranges of the tangerine group are preferred hosts over
other varieties of citrus. This same preference was observed by the
writer in India. Similarly, other varieties of oranges are preferred
to grapefruit, which was always found highly infested or else free of
this insect. Lemons and limes appeared to stand intermediate in
point of infestation between oranges and grapefruit. Some varieties
of limes were quite as much preferred hosts as oranges. Although
living specimens of the white fly were usually found on the larger
leaves of infested plants, because of the greater protection from the
sun, it is a point of much interest that grapefruit trees were much
less severely infested than the orange, although in general their larger
leaves produced a more dense shade than those of the former.

42 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

The citrus white fly has other host plants than the varieties of
citrus, and below is given a list of its definitely known food plants
as taken from Bulletin 92 of this bureau, page 29:

Definitely known food plants of the citrus white fly (Aleyrodes citri).

Crass I. PREFERRED.
Introduced:

1. Citrus (all species cultivated in America).

. China tree (Melia azedarach).

. Umbrella China tree (Melia azedarach umbraculifera).
. Cape jessamine (Gardenia jasminoides).

. Privets (Ligustrum spp.).

. Japan persimmon (Diospyros kaki).

. Lilac (Syringa sp.).

. Coffee (Coffea arabica).

CcOmI mS Ore CC bo

9. Prickly ash (Xanthorylum clava-herculis).
10. Wild persimmon (Diospyros virginiana).
Ciass II. OccAsIOoNALLY INFESTED.

Introduced:

11. Allamanda (Allamanda neriifolia).

12. Cultivated pear (Pyrus spp.).

13. Banana shrub (Magnolia fuscatum).

14. Pomegranate (Punica granatum).
Native:

15. Smilax (Smilaz sp.).

16. Cherry laurel (Prunus laurocerasus).

17. Wild olive or devil wood (Osmanthus americanus).

18. Viburnum (Viburnum nudum.)

19. Green ash (Fraxinus lanceolata).

The bulletin just referred to goes on to say that in addition to those
of the foregoing list there are several species reported as food plants
of the white fly which, although probably true food plants, can not
consistently be included in the recognized list until the observations
have been repeated and the infesting species positively identified.

Authorities on the white-fly situation in ‘his country appear
agreed that the economic control of this insect necessitates proper
attention to different food plants. It can then be seen that in case
a citrus orchard was so treated that the fly was eradicated therefrom,
the presence of other species of infested food plants in the iramediate
neighborhood which might escape treatment would furnish a direct
source for its reinfestation. Knowledge of the different kinds of
food plants would readily enable the horticulturist to determine
before treatment whether or not his sole efforts could be devoted to
his orchard trees.

As the white fly is an introduced pest it has also been conceded
that knowledge of the different preferred food plants might essist
materially in the discovery of the original host plant as well as indi-
rectly the original home of the insect. Practically all investigators

FOOD PLANTS OF CITRUS WHITE FLY. 43

of the white-fly situation in the Gulf States agree that the China
and umbrella trees (Melia sp. and var.) are the greatest breeders of
the white fly of all known food plants including the citrus. In
speaking of the umbrella China tree Morrill and Back state:

First this insect shows in one respect a greater degree of adaptation to this food
plant than to citrus plants, as shown by the very low rate of mortality in immature
stages. The second important point is that adult citrus white flies are so strongly
attracted by growing leaves of umbrella trees that under certain conditions with
umbrella and citrus trees growing side by side more adults collect on three or four
umbrella leaves than are present on entire citrus trees of medium size.

From the preference shown in the white-fly region of this country
for the different China trees some entomologists have even ventured
to state that they believed these trees to be the original host plants.
It is known that China trees are native to Asia, and that certain
species occur wild in India. The writer found these trees common
in northern India, and many were examined. In no instance, how-
ever, was the white fly found on China trees in that country, although
in some cases the foliage of these trees came in contact with aleyrodid-
infested orange plants. -

JASMINUM SAMBAC.

Some of the most common bushes throughout India belong to the
genus Jasminum, and of these probably Jasminum sambac is the
most common species. This plant is used for ornamental purposes
in yards and gardens, but is of especial importance through culti-
vation for its very fragrant flowers, which are used in making scented
oil as well as in connection with various religious performances of
certain native sects. Patches of one-fourth, one-half, or even an
acre in size are common throughout northern India, and the writer
has seen the plant in every other part of this country in which he
has traveled. The special point of interest is that these bushes are
invariably infested with the white fly, and usually more or less
severely. The writer has seen patches of this plant in which almost
every leaf of each plant contained some living white flies. Bushes
were sometimes found to be very black with sooty mold, a condition
never seen in citrus trees. Not infrequently has the writer exam-
ined as many as a score of orange trees with the result of finding
living material on only one or two, whereas every Jasminum bush
in the immediate vicinity would contain much living material. In
the Central Provinces no white flies were seen on citrus trees, yet
in numerous instances Jasminum bushes planted between the trees,
in some cases even touching their trunks, contained many active
insects.

In conclusion, it might be stated that in all localities in which
Jasminum bushes were examined, which included northern and
central India, these were found infested with Aleyrodes citri, and

44 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

frequently somewhat severely. The white fly was found on citrus
trees throughout this region, with the exception of the Central
Provinces and the Bombay Presidency; in these places it was seen
only on Jasminum. Probably the majority of citrus trees examined
were entirely free of the white fly, and where this insect was present
it was entirely under control, barring two or three exceptions. On
the Jasminum, however, it was seldom that living material was not
present, and frequently infestation was more or less severe.

The Jasminum is a low, spreading bush with very dense foliage,
which remains on the plant throughout the year. The broods of
the white fly on this species are not distinct as on the citrus plants,
which was shown by the presence of adult white flies on Jasminum
at several different times between the months of May and October.

Enough has already been stated to show the preference, in many
instances in India, of the white fly for the Jasminum rather than
for citrus plants. The following additional evidence is in itself con-
clusive: During May, while adult flies were emerging in large num-
bers on a Jasminum bush, a number of small seedling orange trees
of very tender foliage were placed immediately about the plant, so
that the leaves of the orange trees were in contact with those of
the Jasminum. Very few flies settled on these orange trees, while
large numbers would be present on leaves of the Jasminum within
a few inches of the former. Even if the bush was so disturbed
that the flies in their flight would settle on the orange trees they
would ultimately desert these in order to go back to the original
food plant.-

In addition to citrus plants and Jasminum the only other host
of Aleyrodes citri seen in India was a large-leaved vine—Hvptage
mandalobata. The citrus white fly appears to be less parasitized on
these two hosts than on citrus trees.

PROBABLE NATIVE HOME OF ALEYRODES CITRI.

Authorities on citrus fruit trees are generally agreed that the
native home of this group of plants is southeastern Asia. The
writer’s observations in the Orient support this conclusion in all
respects. By far the most common variety of citrus fruit in the
Oriental region is the tangerine (Mandarin) orange, including other
forms so closely allied as evidently to belong to the same group.
Tangerines are found everywhere that citrus plants can be grown.
The writer has seen them throughout the Indian Empire, where
they form the bulk of the orange crop, in Ceylon, Java, and the
Philippines. In China they are extensively grown and are found
also in southern Japan. That oranges are not native to but have
been introduced from the mainland into the surrounding islands is

PROBABLE NATIVE HOME OF ALEYRODES CITRI. 45

very evident from observation of their present condition in the
latter places, even if we had no more conclusive evidence. Oranges
do very poorly owing to the great humidity of these tropical islands.
The trees for the most part are stunted, while the crop of fruit is inva-
riably very light, of small size, and usually ripens without the green-
ish skin changing to an orange color, as it does in more temperate
climates. In short, orange trees in the eastern Tropics appear to
be struggling under conditions so ill-suited to their best develop-
ment, whereas in a semitropical climate they flourish with great
prolificness, that it is very evident that they originated in the latter
regions. }

In India proper oranges do not occur wild. Although grown in
all parts of this large country their distribution has resulted after
introduction. In the Khasia Hills of Central Assam oranges occur in
a half wild state intermingled with the other trees of the forest.
They are grown in the extreme northeast of Assam where the Indian
Empire is adjacent to southern China. Information was received from’
an engineer in the Indian service who had traveled extensively along
the eastern border of the Empire to the effect that he had seen oranges
growing wild in the forests of the North Shan States of Upper Burma.
This latter region, which is contiguous with orange districts of China,
is only about 300 miles east of that part of Assam in which the writer
saw oranges in a half wild state. Oranges are known to occur in
southern China, Siam, and Indo-China. From this knowledge,
coupled with the writer’s own observations, it can be seen that
oranges are grown in a more or less scattered condition throughout
southern Asia, where climate allows. Eliminating the varieties found
i various botanical gardens and on the estates of wealthy natives,
and the limited amount of commercial production, the remaining trees
in all countries are for the most part seedlings of the tangerine group.
In the valleys along the southern slopes of the Himalayas as well
as in the Khasia Hills of Assam this is almost exclusively the case.
When it is considered that oranges in the eastern part of India are
almost exclusively tangerine seedlings, and that these are found grow-
ing about most of the native houses as well as being in a half wild state
in a part of this region—a condition that does not occur anywhere
to the westward—we feel safe in concluding that oranges were first -
introduced into India through Assam and thence have spread through-
out the rest of the Empire. The western region was later affected
by varieties introduced from Europe, for it is in this part of India,
including the northwest, that budded varieties of citrus trees pre-
dominate.

The writer has seen the white fly on citrus trees in the Khasia
Hills of Assam, in the lower parts of the Himalayas in Sikkim, and

46 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

westward throughout northwestern and north-central India. He has
also seen this insect at Macau, in southern China, while in the collec-
tion of this bureau in Washington is material on orange leaves col-
lected at Canton, southern China. These records are sufficient to lead
to the belief that the white fly occurs on citrus plants throughout
southern Asia. If citrus is the original food plant of this insect (but
we have no conclusive evidence that it is) it would then appear quite
probable that its original home was in that part of southeastern
Asia in which citrus plants originated and that it followed the dis-
tribution of the citrus through other parts of that continent.

In India the white fly prefers Jasminum as a host plant over citrus
trees. On this plant the insect was of much greater occurrence and
capable of withstanding climatic conditions better than on any other
host. Viewing the problem entirely from the standpoint as seen by
the writer in India, it would appear that Jasminum was the original
host rather than citrus. The most commonly cultivated species of
Jasminum, called sambac, is considered a native of India, but other
allied species are native to China. Various species are cultivated
throughout subtropical Asia. Hence it is quite probable that the
white fly infests this plant in China as well as in India.

The lhghtest infestation of the white fly occurs in the eastern part of
India while the most severe infestation is in the northwest. Consider-
ing climatit conditions one would expect the contrary, as the weather
of Assam is of greater humidity and less extreme temperature than
the upper country. Trees in the Khasia Hills at between 1,000 and
1,500 feet elevation and surrounded by forest trees so as to be abun-
dantly protected by shade were so lightly infested that only an occa-
sional insect could be found and most of these were parasitized.
Although the infestation in the northwest was so light that the insect
was in a satisfactory condition of control it could be generally stated
to be much more severe than in eastern India. This condition,
together with the fact that the only known reports of injury from the
white fly received in the Indian Museum came from the northwest
during the early nineties, leads the writer to believe that this insect is
of recent introduction into that region.

After all has been said and we know that citrus and Jasminum
are the present preferred food plants of Aleyrodes citri in southern
Asia, nobody is able to state definitely that either is the original host,
even though indications would tend to point that way. Nevertheless,
it is sufficiently certain as to be considered a fact that the citrus white
fly is a native of the semitropical part of continental Asia, andthe
strongest indications point toward the Indo-Chinese region as its
original home. ‘

CITRUS FRUITS IN INDIA. 47

APPENDIX A.
CITRUS FRUITS IN INDIA.

The climate of India is suitable to the production of citrus fruits
from the lower altitudes of the outer Himalayas southward through-
out the peninsula. Although many places throughout this vast
region are splendidly adapted to citrus fruit growing, the acreage at
present in commercial production is so limited as to fall far short of
meeting even the home demands. Pomelos and limes are of general
distribution and lemons are grown to a limited extent, but it is the
orange alone that attains commercial prominence.

The locations of supply most widely known and largely depended
upon are the Khasia Hills of Assam (PI. XI, fig. 1), the Nagpur dis-
trict in the Central Provinces (Pl. XI, fig. 2), Poona in the Bombay
Presidency, and Gujranwala in the Punjab. The Khasia Hills supply
much of the fruit used in the Calcutta and Assam markets. The chief
center of orange cultivation in these hills is a narrow strip of coun-
try bordering the south and west sides, which extends from the plains
up to an altitude of not more than 1,500 feet. The Khasia orange
gardens are seldom composed exclusively of orange trees, but have
them scattered through the forests with other trees, especially the
areca palm, from which the betel nut is derived. To the Ameri-
can, trees of such a character in a half-wild state would scarcely
be looked upon in the light of commercial production, but in India
they form the chief source of supply for the entire eastern part of
the Empire. These oranges are all seedlings and of the shape and
flavor of tangerines. They are inferior to American-grown tangerines
in both size and flavor.

The Nagpur orange is the most famous orange in India. The
supposed excellence of this fruit is so widespread that it has almost
developed into a tradition that in no place else can such excellent
oranges be grown as in this limited region. The writer is of the
opinion that this popular conception is largely a fallacy. Orange
growing at Nagpur has been known for many years, and doubtless at
present is carried on there with more care than in almost any other
place in India. The fruit almost exclusively produced in this region
is a very loose-jacketed tangerine, somewhat above the average size of
this orange. It is produced on budded trees, in the selection of which
some care was originally used. When it is considered that the bulk
of the oranges grown in India are from seedling tangerine trees, many
of which develop into unusual monstrosities through lack of selection,
it is easily understood that the competition of a large, loose-jacketed
fruit, with such an irregular assortment, would quickly place it in a
prominent position. The orange production about Nagpur is much
less than would be expected, as the total supply is probably taken
from far below 1,000 acres.

48 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

This so-called Nagpur orange can be grown in other sections with
equal success and is the orange largely produced about Poona in the
Bombay Presidency. In fact, the writer was informed on good
authority that the so-called Nagpur orange purchased in the Bombay
markets does not come from the Nagpur region, but rather from
Poona.

At Gujranwala, in the Punjab, the Malta orange is the principal
kind produced. The trees are budded and in general are in a well-
kept and healthy condition.

The normal time for gathering the fruit is November and December.
In the more southern and warmer parts of the country the fruit is
ready for market in November, but in the Punjab, as well as the outer
Himalayan tracts, it is not picked until December. About Nagpur
and Poona in the central Provinces two crops of fruit are gathered—
one in November, the other in April. The first crop comes at the
normal period of fruiting, while the second is produced artificially by
the well-known method of removing the dirt from a part of the root
system, the result of which is such a shock to the tree than an extra
period of blossoming is brought about. The roots are exposed during
the dry season in late spring. Irrigation is not practiced throughout
this period, which is of about a month’s duration. After exposure of
the roots for about one month they are heavily irrigated, and in a
short time after this treatment the blossoms are said to appear. The
maturity of this crop in April, which is an off-season period for
oranges, results in the fruit commanding a high price.

In the plains the fruit is carried loose in ox carts to themarket place
or bazaar, while in the mountainous districts it is first carried in
baskets by native bearers (PI. XII, fig. 1) to the nearest bazaar (Pl.
XII, fig. 2), from which it is shipped to the railroad either by coun-
try boat or ox cart. The price paid for fruit is variable. One grower
at Nagpur stated that he received 14 to 3 rupees (50 cents to $1) per
hundred for fruit at his orchard, while in one of the obscure bazaars
in the outer Himalayas, upon which the writer happened, the natives
brought oranges in baskets on their backs from pomts many miles
distant to sell at the’rate of about 600 for 1 rupee (82 cents).

Citrus trees in India are never pruned. Fertilization is practically
unknown except for a few instances in which a little manure is added.
The best orange groves are plowed frequently in order to keep down
the weeds. Irrigation is almost universally practiced in those places
where much fruit is produced. Many horticulturists irrigate every
week or 10 days during the warm, dry season. The common system
in practice is by means of a single furrow along the base of each row
of trees, so that the trees rise directly out of the furrow. Hence the
bases of the trees are always standing in water while the irrigation is
taking place.

Bul. 120, Bureau of Entomology, U. S. Dept. of Agriculture.

PLATE XI.

Fia. 2.—A NATIVE ORANGE GROWER, OWNER OF THE LARGEST

Fic. 1.—ORANGE PRODUCTION IN THE KHASIA HILLS OF ASSAM.

GROVES IN THE FAMOUS. NAGPUR DISTRICT OF CENTRAL

(ORIGINAL. )

INDIA.

go
5

ORANGE PRODUCTION

aching

c

ry for re

ardens the orange trees are intermingled with

Long bamboo ladders are necess

(Original. )

trees of the forest.

In many of the Khasia g
the fruit.

INDIA.

IN

Bul. 120, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XII.

Fic. 1.—NATIVES IN THE PROVINCE OF SIKKIM CARRYING ORANGES IN BASKETS

TO THE BAZAAR, WHERE THEY ARE PURCHASED BY BUYERS FROM THE LARGE
CITIES.

At this bazaar the oranges were brought through the mountains by native carriers from

distances as great as 10 to 15 miles and sold at the rate of 600 for 1 rupee (32 cents).
(Original. )

Oranges are here purchased from the natives and transported to the railroad in oxcarts.
(Original. )

TRANSPORTING ORANGES TO MARKET IN THE OUTER HIMALAYAS.

/
j
:
|
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:
/
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Fic. 2.—AN ORANGE BAZAAR IN THE OUTER HIMALAYAS.

COCCIDA AND THEIR ENEMIES ABROAD. 49

APPENDIX B.

| INSECT PESTS OF CITRUS TREES SEEN BY THE WRITER DURING
HIS INVESTIGATIONS IN VARIOUS FOREIGN COUNTRIES.

SPAIN. INDIA.
Chrysomphalus dictiospermi (Morg.). Chrysomphalus aurantii (Mask.).
Parlatoria zizyphus (Lucas). Chrysomphalus aonidum (1..).
Pseudococcus citri (Risso). Erium sp.
Lepidosaphes beckit (Newm.). Monophlebus dalbergie Green.
Lepidosaphes glovert (Packard). Pseudococcus citri (Risso).
Aspidiotus hedere (Vall.). Aspidiotus lataniz Sign.
Saissetia olex (Bern.). Lepidosaphes beckii (Newm.).
Coccus hesperidum (L.). Lepidosaphes lasianthi (Green).

Coccus hesperidum (I,.).

RN A Fiorinia thee Green.

Chrysomphalus dictiospermi (Morg.). Vinsonia stellifera (Westw.).
Parlatoria zizyphus (Lucas). Aleyrodes citri R. & H.

Lepidosaphes beckii (Newm.). Aleyrodes, 3 species (undetermined).
Pseudococcus citri (Risso). Papilio demoleus L.

Aspidiotus hederx (Vall.). Phyllocnistis citrella Stainton.
Saissetia olex (Bern.). Bud moth (Agonopteryz sp.).

Coccus hesperidum (L.). Borer.

The determination of almost all the Coccide included in these lists
has been made by Mr. E. R. Sasscer, of this bureau. The scale
insects have been arranged in order of economic importance in so
far as was possible from the observations of the author and informa-
tion available. Without doubt the most serious insect pest in India
is Phyllocnistis citrella, a leaf-mining lepidopteron. It is especially
destructive to young nursery stock. While the infestation of indi-
vidual trees by other of the Indian citrus pests is occasionally some-
what severe, these infestations are not so general:as to be of com-
mercial importance.

APPENDIX C.

OBSERVATIONS ON COCCIDZ AND THEIR NATURAL ENEMIES
IN SPAIN, ITALY, SICILY, AND INDIA.

Most species of Coccide and Aleyrodide seen during the writer’s
travels in tropical and semitropical regions were parasitized to a
greater or less extent. Some species appeared to be attacked by a
single natural enemy while other species were affected by several.
It might be safely stated that the combination of climatic conditions
with natural enemies keeps all scale and aleyrodid enemies of citrus
trees in India under commercial control except for occasional spo-
radic outbreaks. In Spain, Italy, and Sicily also climate and natural
enemies have proved of great efficiency against numerous citrus-tree
scale pests.

50 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

The following specific treatment will be largely confined to pests
observed during the writer’s travels abroad, which are of economic
importance in the United States.

Spatn, ITaty, AND SICILY.

Chrysomphalus dictiospermi is the most destructive pest of citrus
trees in these three countries. According to Prof. Silvestri, the emi-
nent Italian entomologist, this species was first noticed in Italy and
Sicily in 1909. Fortunately the infestations of this insect are of a
localized nature in these countries. In Spain it is widely distributed
and undoubtedly was present here many years before its appearance
inltaly. The species is attacked by numerous natural enemies, both
parasites and predators, in all three European countries.

Parlatoria zizyphus, the pest which ranks in point of injuriousness
next to Ch. dictiospermi in these three Mediterranean countries, does
not occur in citrus groves in the United States. It can thus be seen
that the citrus groves of this country are free of the two pests most
injurious to the same plants in southern Europe. Chrysomphalus
dictiospermi has been reported in greenhouses from most parts of the
United States, but no record of the definite establishment of Parla-
toria zizyphus is at present known.

Lepidosaphes beckii, Saissetia olex, and Pseudococcus citri, namely,
the purple and black scales of California and the citrus mealy bug,
which are very serious pests in our own country, produce very little
serious injury in the Mediterranean region. It should be of the
greatest interest to the citrus fruit growers of California, who spend
so many hundreds of thousands of dollars annually in combating these
pests, to know that in the chief citrus-fruit producing countries of
southern Europe these same pests, though present, are for the most
part under natural control so that artificial effort is seldom necessary
for their subjugation. To quote from a communication respecting
this subject received from Prof. Silvestri:

The other species of citrus pests (which include the purple and black scales and the
mealy bug) produce here and there some injury, but not continually nor so great that
the cultivator has any interest in attempting to control them with insecticides. Only
occasionally does an outbreak occur of such serious nature as to require artificial means
of control.

Lepidosaphes beckii, the purple scale, was observed in Spain but
only in such slight infestations, so far as the writer’s observations
extended, that it may be said to be under commercial control. Mr.
L. Salas, the agricultural engineer of the Province of Malaga, in-
formed the writer that the purple scale was once very severe in parts
of that Province, but for some unknown reason had suddenly disap-
peared in recent years. A similar report was heard from another
authority in that Province. In Italy and Sicily the purple scale is

COCCIDZ AND THEIR ENEMIES ABROAD. 51

generally distributed, but is serious only by sporadic outbreaks as
stated by Prof. Silvestri. This species is attacked by Coccinellide of
the genera Chilocorus and Exochomus. Silvestri states that some
Acari (mites) eat the eggs.

Saissetia olex, the black scale, is another pest generally distributed
through Spain, Italy, and Sicily, but is in such perfect control in
these countries as to be of no special economic importance. Wherever
it was seen the writer always found Scutellista cyanea Motsch., the
internal parasite, attacking it. Prof. Silvestri states that the black
scale is attacked in Italy and Sicily by Scutellista cyanea, Coccophagus
flavoscutellum Ashm\~ Jrastria scitula Ramb., and Coccinellide of the
genera Chilocorus and Exochomus.

Pseudococcus citri is the species of insect which is of the greatest
interest to many citrus fruit growers in this country. The purple
and black scales can be easily controlled by artificial means, espe-
cially fumigation, but these methods have thus far proven unsuc-
cessful against the citrus mealy bug. In certain parts of southern
California Pseudococcus citri is a very serious pest. However, in
Italy and Sicily as well as to a large extent in Spain it is in such per-
fect control as to be of little commercial importance. Only one grove
in Spain was seen by the writer to be at all severely infested by this
pest, and in this many larve and pupe of a dipterous parasite were
observed among the masses of mealy bugs. A second species of
parasitic insect, probably a dipteron, was observed in another part
of that country.

The mealy bug was seen in many groves in Sicily, but always to
such a limited extent as to do no injury to the trees. Practically
every mass of insects examined showed evidence of parasitism. A
dipterous species appeared most common. Prof. Silvestri informed
the writer that Pseudococcus citri is attacked in that country by two
species of Chalcidide, by two to three species of Neuroptera, by a
species of Leucopis, and by Coccinellide of the genera Chilocorus and
Exochomus.

Since the citrus mealy bug is so well under control in Italy and
Sicily as well as to a great extent in Spain, it is at once evident that
this region should prove a fertile field for study in an endeavor to
overcome the mealy-bug pest on citrus trees in America. That
natural enemies take a leading part in this natural control of the
citrus mealy bug in southern Europe must be admitted by anyone
who has care*illy examined the prevailing conditions there. The
writer is of the opinion that a thorough investigation of the citrus
districts of the Mediterranean by a competent entomologist, including
extended shipments to this country of the different available natural
enemies of such citrus pests as Pseudococcus, Saissetia, and Lepido-
saphes, especially the former, would prove a very profitable economic
investment for the citrus fruit growers of America.

52 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.
INDIA.

The main portion of this bulletin is devoted to a treatment of two
natural enemies of Aleyrodes citri, so no further mention of these
species is necessary. Chrysomphalus aurantii, the red scale so inju-
rious to citrus fruits in California, occurs throughout India, but
in such slight quantities as to produce little injury. Sometimes
individual trees in shady situations are severely infested, but such
instances are very infrequent. The scale on such trees is invariably
found to be heavily parasitized by a species of the hymenopterous
genus Aphelinus. Chilocorus nigritus Fab., an oriental coccinellid,
also attacks this scale. Pseudococcus citri, the citrus mealy bug, was
very seldom seen in India and in those instances observed was under
perfect control. It is quite probable that the species is attacked by
natural enemies.

APPENDIX D.

COCCINELLIDE INTRODUCED FROM INDIA.

Several species of ladybirds of economic value were included with
the shipments of the natural enemies of the white fly. All have failed
to develop with the exception of two species, Chilocorus nigritus Fab.,
which preys on various species of Coccide, and Chilomenes sermacula-
tus Fab., which preys upon aphides.

Chilocorus nigritus did admirable work against Chrysomphalus
aurantii in certain parts of India and was introduced in the hope that
it might prove of economic value if established in this country. It
is at present being successfully reared in California and Florida.

Chilomenes sexmaculatus feeds on various species of Aphidide. It
is a rapid breeder. One female in captivity has deposited over a
thousand eggs. Vast numbers of this species have been reared and
liberated in both California and Florida.

APPENDIX E.
FUMIGATION OF CITRUS TREES IN SPAIN.

When the writer stopped in Spain in 1910, while en route to India,
no fumigation had ever been practiced. Chrysomphalus dictiospermi
and Parlatoria zizyphus were such serious pests as to have become a
menace to profitable orange production in certain parts of the country.
The growers affected were eager for some method to control these
insects even as were the orchardists of California when the cottony
cushion scale was such a pest before Novius cardinalis had been
introduced.

The writer spent the month of August, 1910, in Spain in an attempt
to demonstrate the efficiency of fumigation with hydrocyanic-acid

FUMIGATION IN SPAIN. 53

gas against these insects. Compte de Montornes, the Royal Com-
missioner of Agriculture from Valencia, and Leopoldo Salas, Agri-
cultural Engineer of Malaga, had been appointed by the Minister of
Agriculture to supervise such demonstration experiments as were
necessary. Through the aid of these gentlemen paraphernalia essen-
tial for the equipment of a field fumigation crew such as the writer has
used in California ' were acquired so far as was possible. Intelligent
men were selected and drilled in the procedure, so that before leaving
Spain a crew competent to carry on field fumigation under the direc-
tion of the two eminent Spanish authorities had been established.
Dosage tables of the character used by the writer in California were
introduced into Spain.

The initial procedure of 1910 has developed very rapidly. In a
letter recently received from the Compte de Montornes he stated
that now there are 10 complete outfits of 30 tents each, as well as
several smaller ones in different parts of Spain. Six of these outfits
belong to the Government, the remainder to societies and private
individuals. The results everywhere were said to be very satisfac-
tory, and as the success of the process is becoming known to the grow-
ers it is producing a great demand for more extended operations.

1 Bul. 90, Part I, Bur. Ent., U.S. Dept. Agr., 1911.

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Page.
Acari, enemies of Lepidosaphes beckw in Italy ...-.--..-.......--.----.--+--- 51
Aigerita webberi, discovery in Saharanpur region of India.....-.........-.--- 20
Agonopteryx sp. feeding on young growth of orange. ..-....---.-.----------- 27-28
POC AWCEIN bsp 274 APRN eee a SC ArT 49
Peele S UIT — Aer OC CRIER IL, = aha. 2 oie oi jo) aia) eins wn nn = clone w= o uyiie a Bye oo 15, 17-18
citri (see also White fly, citrus).
WETTER TER OG: Sh 6110) 4 Re ee ase 15, 16-18
pil sie ch area eth ght cgr tem Bra I pala une ss ae ene NEEL gm A 49
sii Wd rae bE: ee eRe S See ey RON centages enti et eM Nig ate 22-23, 28-29
SOUTER CRAM Ay eal Pe eS oles orate ot lae cise Senn a ale Gls: a= 25
nie history an\nortkerm, Undid. Motes Se. 2 ye aol te on a aren, ain eno, 28-29
method of securing infestation of potted orange trees. .....-...- 34-35
Hrobable Mabive Ome 32 sie 2 so cle eral kis Claire cia ue etal boleh aye atk 4446
BP. ON CASTOR GRRCUNIRISD )n clot apogee sia a a ute ec keys oe ac oid salsa aap 36
prey of Clanis soror (Cryptognatha flavescens).........-.--------- 36-37
three undetermined species on citrus in India................-.--. 49
Allamanda. (See Allamanda neriifolia. )
millamanda neriifolia, food plant of Aleyrodes citrt.. ..'.,2--------- +2252 -222 6s 42
Ash, green. (See Frazxinus lanceolata.) p
prickly. (See Xanthoxylum clava-herculis.)
Aspidiotus hederx on, citrus in Spain, Italy, and Sicily ..................----- 49
Gitar OnACiIsAMUIROIA iets Soci aes ase tense scence es 49
Banana shrub. (See Magnolia fuscatum.)
LEME STA CONINETT A TTS IT BE MARIO RA ARO SS AGRE rae On ae ea te 49
Botanical garden at Buitenzorg, Java, citrus fruit trees therein - cae 24
gardens of India, aid therefrom in searches for citrus frat me CON Scie os 18
Cases used in transporting parasites of citrus white fly to United States from
ASP Nahe acs aN CER aoe ae Hamam Las mists bite einisias @ 35-36
Caster hacimus:sp.). 1000 plant ol Aleyrodes sp.) 2). 5-24. -~ sa seee 5-2 sees 36
Chalcidid parasites of Pseudococcus citri in Italy and Sicily............-.-. me 51
Cherry laurel. (See Prunus laurocerasus.)
Chilocorus, enemies of Lepidosaphes beckii in Spain, Italy, and Sicily ....-.-... 51
Pseudococcus citri in. Italy and Sicily......-....-.-...- 51
Saisselig.olee in Taly and Sicily. o2 2 ee 00h selec 2 cee 51
Chilocorus nigritus, enemy of Chrysomphalus aurantii in India, introduction
CMM MRLOC STATCS cic ee Ace sa a a clad an. § oe SON te wd gn Oe 52
Chilomenes sexmaculatus, enemy of aphides in India, introduction into United
PSUS cst IN A eR ea oP = ary a SACRO MET Wi EUR tey SY oR aL UR PSE 52
China tree. (See Melia azedarach.)
umbrella. (See Melia azedarach umbraculifera.)
Chrysomphalus aonidum on citrus in India..................-.-2---+-0--- we 49
aurantin, host of Aphelinusisp. im India. :..52.5...25-e25-<235 4 52
On ertrus in, [agias ee oe ae hee 49
prey of Chilocorus nigritus in India............------ 52
dictiospermi and its natural enemies in Spain, Italy, and Sicily. - 50
on citrus in Spain, Italy, and Sicily .........---.- 49, 52

56 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

Page.
Citrus, destruction of young growth by insect pests at Lahore, India.......... 27-98
food plarits.of Aleyrodes cing 2000 2 os. RS a en we 42°
Erdit in India’: «<i. .oceeeeeee cere 6. Lo eide ete ee eee ee 47-48
injury by citrus white fly (Aleyrodes citri)..........-...2...2.-+-- 11-12
trees in botanical gardens at Buitenzorg, Java.................... 24
of Indiavet a vat. a 18
probable mative home. .......:.25. Bosses eee ee 44-46
insect pests seen by R. 8. Woglum in Spain, Italy, Sicily, and India. . 49
white fly. (See White fly, citrus.)
enemies, natural. (See Enemies of citrus white fly.)
Clanis soror, name used for Cryptognatha flavescens..........-...2------+-+---- 36
Coccide and their natural enemies in Spain, Italy, Sicily, and India. ........ 49-52
Coccinellide introduced into United States from India......................-. 52
Coccophagus flavoscutellum, parasite of Saissetia olex in Italy and Sicily....... 51
Coccus hesperidum on citrus in Spain, Italy, Sicily, and India. ............... 49
Coyesa arabica, food plant of Aleyrodes citrt..25.- 2222. 0.2 eee ee eee 42
Coffee. (See Coffea arabica.)
Cryptognatha flavescens (see also Enemies of citrus white fly).
enemy of citrus white fly, discovery........ a Due 19
observations on habia ae 36-37
first shipments to United States from India............ 19
later shipments to United States from India............ 37-38
Devil wood. (See Osmanthus americanus.)
Diospyros. kaki, food plant of Aleyrodes citric. oo. es ee ees eee eee 42
virginiana, food plant of Aleyrodes citri.. stg AMEE RS a i 42
Dipterous parasites of Pseudococcus citri in Spain, Tely, ond Sisily. Bree hiemte (| 51
Enemies of citrus white fly (see also Cryptognatha flavescens and Prospaltella
lahorensis).
cases used in transportation to America from India. 35-36
condition on arrival at Orlando, Fla., from India. . 38
conditions at Orlando, Fla., on arrival from India... 38
desirability of continuing attempt to introduce
THOM. 2) os deel je acces tee Ca oe eee ee 40-41
discovery of living parasites at Lahore, India...... 26-27
loss of introduced specimens through lack of green-
ROWSE! - seas cigs ss oaks aheie sayy ein eo ee eee 89
possible efficiency if established in Florida........ 39-40
preparation for shipment from India to America... 37
search ‘at Lahore, Todia..4oeas- = 22 sels sc eee 20-21
concentration of efforts at Lahore, India.... 25-26
conclusions drawn from situation at Saharan-
pur and Lahore: ........ 2, eee ee ee 22
conditions leading to demand therefor...... 13-14
investigations in Burma, Java, southern
China, and Philippines:coe...----....2202 23-25
investigations in Ceylon.................-.. 16-17
Biitope.-.-....-.) |. soe
Tne (1910). -- SS eee 17-23
leary: ee 25-38
preparations therefor.................----- 14-15
transportation from India to United States.......- 37-38
Erastria scitula, enemy of Saissetia olex in Italy and Sicily..........--------- 51

Brum spon citrusiin India. - 2.0 Ss ado mee nesses cic seis ble os arte eee eee 49

; INDEX. 57

Page.
Exochomus, enemies of Lepidosaphes beckii in Spain, Italy, and Sicily. ....... 51
Pseudococcus citri in Italy and Sicily................. 51
Saissetia olex in Italy and Sicily..................... 51
CBenmrtsa hese ON): GILPUA AT IMIG cee Pe he bs ke cs cee 49
Fraxinus lanceolata, food plant of Aleyrodes citri.........-.-.2........22202-0- 42
Fumigation against citrus white fly, efficiency. ..............-.............- 12-13
UNC RITIS LEGER TIA PANT Cee ee BPRS
Fungous diseases against citrus white fly, efficiency. ........................ 12-13
Fungus, brown. (See Ageriia webberi.)
sooty mold. (See Sooty mold.)
Gardenia jasminotdes, food plant of Aleyrodes citri. ..........-..22.2.-2------- 42
Hiptage mandalobata, food plant of Aleyrodes citri.............-..--22-22.---- 44
Humidity, effect on white-fly development in northern India vs. Florida... .. 31-33
Hydrocyanic-acid gas. (See Fumigation.)
Icerya purchasi, control through introduction of natural enemy................ 13-14
Jasminum sambac, food plant of Aleyrodes citri..........----.---------- 26, 43-44, 46
Jessamine, Cape. (See Gardenia jasminoides.)
Lady-beetle, Novius cardinalis, importation into United States..............-- 13-14
Laurel, cherry. (See Prunus laurocerasus.)
Lepidosaphes beckvi and its enemies in Spain, Italy, and Sicily................- 50-51
on citrus in Spain, Italy, Sicily, and India................. 49
lever GR Cleric uN AIT a 2. ee a eae a gt Se 49
PORTER Et OW) ClUPUR EM LGR Oe eo aes th ia te Ue 49
Leucopis sp., enemy of Pseudococcus citri in Italy and Sicily.....-...2....-.-.-- 51
Tigustrum spp., food plants of Aleyrodes citri.....-.-...---- age! ASE is aera AT 42
Lilac. (See Syringa sp.)
Magnolia fuscatum, food plant of Aleyrodes citri........----------.---+-++----- 42
Mecha azedorach, food) plant of Aleyrodes ctiri.. 2.22. 5.2.2.0 sooo on Fen mane ne 42
umbraculifera, food plant of Aleyrodes cilri.......-----.------- 42
Meliola sp. (See Sooty mold.)
Monophlebus dalbergiz on citrus in India....-.......-.- SSE eee 49
Pe RETIOLROR Eels a wisest ciel pane oto OA ee UM od eo ee Sale 47, 48
Neuropterous enemies of Pseudococcus citri in Italy and Sicily............--.-- 51
Novius cardinalis, enemy of cottony cushion scale (Jcerya purchasi), importa-
OSTEO TEDE) J0 Sie Care) SE SSR eC ne CNY 13-14
Olive, wild. (See Osmanthus americanus.)
Orange. too plan’ eb Agonapieryt Sin se Sele hee ALL ev Sawin eS oe 27-28
TR OEILSLLS CULV CULE 2 orn 5 Shared se Seay eget eR ah ae 27-28
trees at ahiors. Smita sl eee pa ak eae Been be Vez 20-21
potted, method of securing infestation with Lipa citri in
Teas A eee ete oe me peta Cm 34-35
Osmanthus americanus, food plant of Aleyrodes citri.......-.....-.--.------+--- 42
RemeReTOleUs Of: C1ITUS In) TadIa. ee oe So eae SS 49
Parasites of citrus white fly. (See Enemies of citrus white fly.)
Parlatoria zizyphus on citrus in Spain, Italy, and Sicily......-.......-..-- 49, 50, 52
Pear. (See Pyrus spp.)
Persimmon, Japan. (See Diospyros kaki.)
wild. (See Diospyros virginiana.)
Phyllocnistis citrella feeding on young growth of orange. .....-.----.--------- 27-28
Giverteus in. Tae. 25): See sees ne gone dines = 28 49

Pomegranate. (See Punica granatum.)
Prickly ash. (See Xanthoxylum clava-herculis.)

58 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY.

Privets. (See Ligustrum spp.)

Prospalteila lahorensis (see also Enemies of citrus white fly). Page.
considerations in collection and transportation... .. one 27
copy: of origmal description) 02) 02 0.2. 7 ey 21-22
observations on habits and life history.................. 34
parasite of citrus white fly, discovery in India......... 21-22
shipment to United States from India. ................ 37-38
Prunus laurocerasus, food plant of Aleyrodes citri............-....------------ 42
Pseudococcus citri and its enemies in Spain, Italy, and Sicily................. 50, 51
on citrus in Spain, Italy, Sicily, and India.................. 49,52
Punsca granaium,; food plant of Aleyrodes ctiry.2 202052. 77222 oe ee 42
Pyras spp. 100d plants or Aleyrades ciirt....2 20-2 = - 22 eke eee 42
Ricinus sp., food plant of Aleyrodes sp.............--22-.202220-ceeeeecceeeee 36
Saissetia oleex and its enemies in Spain, Italy, and Sicily..............-...-.- 50, 51
on citrus in Spain, Haly,and Bitily-. 22.5.5. -2 2.22.2 see 2 vee 49

Scale, cottony cushion. (See Jcerya purchasi.)
Scutellista cyanea, parasite of Saissetia olex in Spain, Italy, and Sicily......... 51

Smilax. (See Smilaz sp.)

Smee sp:, food plant of Aleyrodes curt... 52-22 ote ean te eee ac ee a eee 42
Sooty mold, injury to citrus accompanying work of citrus white fly........... 11-12
Spraying against citrus white Hy, efficiency --!...2-2220 222. 2222 ee 12-13
Syringa-sp-; food plant ot Aleyrodes etire: (010.2 cl occ... ssndceneds 6 passes 42

Temperature, effects on white-fly development in northern India vs. Florida.. 29-31
Umbrella china tree. (See Melia azedarach umbraculifera.)
Viburnum. (See Viburnum nudum.)

Viburnum nudum, food plant of Aleyrodes ctiri....0.. 22.22.22 eee eee eee 42
Vinsonia steliifera on citrus in India... ... 2.252.220.2222 2 eee ee ee aes ra eee 49
Wardian cases, use in transporting living parasites of citrus white fly from India |
ROMUMIRC CE SEAbeR 5 ets Soo COUT mice ce ace ct ne ere etevone 9 ore Oise oie ace 35-36
White fly, citrus (see also Aleyrodes citri).
description. and development. -..25 4.5 34.-- koe ose sees 10
development as affected by humidity in northern India vs.
Florida 2/72 Sco eee nae 31-33
temperature, northern India vs
Biorida 225.2 2ee eee Reenter 29-31
discovery ai Saharanpur, Tndiat2s 02502 eee 19
distribution in United States.........- 2 heat enh uae 11
enemies. (See Enemies of citrus wine ee a
food plants. . Sete SUSE ES eo eens Sees on oe ee
general ee eis UU Oa gee ee eee Ser 9
TDIULY cso. scanners sees y Se Soe a aie Cee ene oe en eee a 11-12
methods of control and their efficiency.................--.--. 12-18
number of broods in northern India vs. Florida. Bis har ile ahd a of 29
Xanthorylum clava-herculis, food plant of Aleyrodes citri.........--.-------+-- 42

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