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Introduction . . . .« «© «© © e we « «

Common Names... ..« «ec « « «

Origin’. 3. 6) Ss
Distribution ....

Source of Hawaiian Infestation. . .

Conditions Favorable to Establishment in

the Hawaiian Islands

' Climatic Conditions . . ....

Host Conditions
Economic Importance

UNITED STATES DEPARTMENT OF AGRICULTURE
BULLETIN No. 536

Contribution from Bureau of Entomology
L. O. HOWARD, Chief

PROFESSIONAL PAPER

THE MEDITERRANEAN FRUIT FLY
IN HAWAII

E. A. BACK, Entomologist, and C. E. PEMBERTON,
Assistant Entomologist, Mediterranean and
other Fruit-Fly Investigations

CONTENTS

WASHINGTON .

By

January 26, 1918

lhtfie ye soe Galea a: Go be Ove A oes
Methods of Spread ......-. » 18
18 (YS 5d UG oO caer Gobet BO Ce 21
Fruits Erroneously Listed as Hosts. 22
Proven Hosts in Hawaii. ... . 24.
Life History and Description. . .. . 49
Seasonal History .... - Boe ite Wek tea teen
Natural Control . . .. =.=... -« eae (Tf
Artificial Control . . . « »« «© © «= e 101

Summary’ . 2s « « 0 « © » « « 0,116

GOVERNMENT PRINTING OFFICE

1918

UNITED STATES DEPARTMENT OF AGRICULTURE

4%, BULLETIN No. 536 §

f Contribution from the Bureau of Entomology
Sw Yet. L. O. HOWARD, Chief

. Washington, D. C. PROFESSIONAL PAPER January 26, 1918

THE MEDITERRANEAN FRUIT FLY IN HAWATI.

By HE. A. Back, Entomologist, and C. E. PemBerron, Assistant Entomologist,
Mediterranean and Other Fruit-fly Investigations.

CONTENTS.!
Page Page
NRO MUGLOME eee ate: ce eee ae eeic a Sas 1a ie baby 2s oa ahaa CORB Sone Geo o Orato sar mraae 16
(Commonnamesmeas Aes soe oe See cles os 2m eMethodsronispreadie: on. -se cee eee eee eee 18
Omitting er cons cosa ieee eae aa necurener 2 | ELLOS tHMULGS Peers sae asi Se oe so nvAelseerons foe Ses oe 21
Distr Wt Ones ce ete Saal nee ebe ene 3 Fruits erroneously listed as hosts..-...-. 22
Source of Hawaiian infestation. ............. 8 Rrovenshostsimebawalls =. se2s.--.. 5 - 24
Conditions favorable to establishment in the Life history and description.............. ae 49
awallanelslan dGaresee = ser eee eceere seis OF miScasonalelnistomyees essa see eee = eae 75
Climatic conditions in Honolulu ........ One Nea tunalicombtnro leases eyo eel ea eles iae 77
Es h CoOmGWiNOISs S--sehogce ssc ouosssosede ie eAtinietalkcontnolesessceeias- = eee seein eee ae 101
WCOnOMICIMPpPOLlANCe asta eee sees i1s5." || SbbMII AVES Sec cneeods so cusedoee coat nsoereere 116
INTRODUCTION.

The Mediterranean fruit fly (Ceratitis capitata Wied.) (fig. 1; Pl. 1,
fig. 1) since its discovery in the Hawaiian Islands in 1910 has caused a
serious and permanent check upon horticultural pursuits in these
islands. The history of this pest shows that it has been gradually
spreading to all tropical and subtropical countries. The frequency
with which infested fruits from Hawaii are being discovered and con-
demned at California ports by representatives of the Federal Hor-
ticultural Board indicates that this fruit fly might have become es-
tablished in parts of California and in our more Southern States and
might now be doing untold injury to fruit interests but for the effi-
cient quarantine maintained on the Pacific coast by State and Fed-
eral authorities. It is feared, however, that the Mediterranean fruit
fly ultimately will be able to find some unavoidable weakness in the
quarantine work and eventually become established on the main-
land of North America.

The investigations reported in this publication have been carried
on by the Bureau of Entomology, United States Department of Agri-

1 It has been found necessary to omit a bibliography consisting of about 350 references accompanied by
brief résumé material. Reference should be made to Silvestri, EXO are No. 3, Hawaiian Bd. Agr. and
Forestry, for the most complete printed bibliography.

81340°—18—B ull 536 -——1

2 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

culture, under the immediate supervision of Mr. Charles L. Marlatt,
assistant chief of the bureau and chief of the Division of Tropical and
Subtropical Fruit-Insect Investigations. This work was undertaken
during September, 1912, primarily to make available for mainland
fruit-growing interests information that will prove of imestimable
value in determining the extent of the possible distribution of this
pest and the factors of control which will be most important in eradi-
cating newly discovered outbreaks.

The senior writer wishes to acknowledge his obligations to Mr.
Marlatt, who has greatly aided these investigations by his direction,
and to express his appreciation of the assistance rendered by his
associates, Messrs. C. E.. Pemberton and H. F. Willard.

Fic. 1.—The Mediterranean fruit fly (Ceratitis capitata): a, Adult female; 6, head of same from front; c,spatula-
like hair from face of male; d, antenna; e, larva; /, anal segment of same; g, head of same. a and e,
Enlarged; 6, 9,/, greatly enlarged; c, d, still more greatly enlarged. (Howard.)

COMMON NAMES.

The common name “Mediterranean fruit fly’? was first used by
Frogatt in 1899 to distinguish Ceratitis capitata from other fruit flies
found in Australia. At the present time this name is the most widely
used and most satisfactory of the common names by which this pest
has been known and will be used by the writers. Other common names
found in literature are ‘the fruit fly,” “the maggot,” “peach fly,”
“peach maggot,’ “fruit grub,’ “apricot worm,” “trypeta fly,”
“West Australian fruit fly,” “orange fly,” and “orange fly trypeta.”

ORIGIN.

Although Wiedemann first described Ceratitis capitata from speci-
mens collected by Daldorf, supposedly in the East Indies, the failure of
subsequent entomological exploration in the Indo-Malayan region to

MEDITERRANEAN FRUIT FLY IN HAWAII. 3

locate this species, except where it is known beyond question to have
been introduced; has led entomologists to seek its original home else-
where. Known facts concerning the artificial spread of this pest
narrow its probable origin to the African continental area. According
to Bezzi, the genus Ceratitis is of African origin. Information gained
by various writers indicates that southern Europe is not its native
home, although it has been recorded from this region for many years.
Leonardi states that the Mediterranean fruit fly was not recorded as a
pest in southern Italy until 1863, nor in Sicily until1878. Hadit been
a native of Italy its ravages, as were those of the olive fruit fly (Dacus
oleae Rossi), would have attracted the attention of writers prior to
this time. While De Bréme first records specimens reared in southern
Spain in 1842, it is easier, in the light of more recent investigation,
to believe Spain to be an adopted rather than the original home.
Compere states that in 1903 there was living at Carcagente, Valencia
County, Spain, an aged priest who could well remember the time in
his childhood that peaches in that part of Spain were free from fruit-
fly attack. Compere is also authority for the statement that com-
mission merchants at Seville found that the pest was spreading
farther inland to the north every season, even as late as 1903. The
work of Graham (1910) and Silvestri (1912) has proved that C.
capitata is present in the little-developed West African countries of
Nigeria, Dahomey, and the Kongo, and Gowdy found the species
already established in Uganda as early in the development of that
country as 1909. These records, coupled with the information by
the South African entomologists regarding its spread into the south-
ern part of the African Continent, lend color to the statement of
Silvestri that the natural habitat of Ceratitis capitata is “certainly
tropical Africa south of 8° N. latitude.” Silvestri, however, is of the
opinion that one can not state whether the whole of this region should
be considered as the natural habitat, or only the western portion,
until careful studies have been made in French Equatorial Africa
and British East Africa. Further exploration of the west coast of
Africa north of 8° north latitude is very likely to establish new rec-
-ords of distribution and extend somewhat these limits of origin to
include more semitropical territory.

DISTRIBUTION.

The Mediterranean fruit fly is at present established on every
continent except that of North America. It has been recorded
from the following regions:

Europe: Spain, France, southern Italy, Sicily, Greece, and Malta.

Asia: Asiatic Turkey (Beirut, Jerusalem, Jaffa.)

Africa: Egypt (Cairo and Kafir el Zayet), Tunis, Algeria, the Azores, Madeira
Islands, Canary Islands, Cape Verde Islands, Dahomey, southern Nigeria,
the Kongo, Cape Colony, Natal, Delagoa Bay, southern Rhodesia, British
East Africa, Uganda Protectorate, Mauritius, and Madagascar.

4 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

Australasia: Western Australia, New South Wales, Victoria, and Queensland,
northern New Zealand, and Tasmania.

South America: Brazil and Argentina (Buenos Aires).

North America: Bermuda Islands.

Hawaiian Islands.

MEDITERRANEAN REGIONS.

The dates of the first discovery of the Mediterranean fruit fly in
the countries bordering on the Mediterranean can not be used with
precision in establishing a chronology of dispersion, since the pest
may have been present many years prior to the first entomological
observations recorded unless statements to the contrary are made
in literature. Aside from our first record of establishment in Mau-
ritius by Latreille in 1817, the earlier records refer to damage in the
Mediterranean region. According to Macleay this pest was well
established in the Azores, Cape Verde, and Madeira Islands as early
as 1829, and was the source of much injury to oranges arriving at
London from these islands. It was first recorded from Spain in
1842, from Algeria in 1859, and from Tunis in 1885. Compere gives
us our first records of its presence in Egypt at Port Said and in
Asiatic Turkey at Beirut, Jaffa, and Jerusalem in 1904. During
the same year, Cartwright records the infestation of oranges at
Kafir el Zayet (Egypt) and four years later Froggatt found many
infested oranges in the Cairo (Egypt) markets. Literature does not
record the presence of this pest in Malta until 1890, although it was
known to have become established there about 1875. In France the
Mediterranean fruit fly was reared from apricots at Courbevoie, in
the environs of Paris, in 1900, and by 1904 the fruit industry around
Maritimes was ruined, according to Hooper. in 1916 the citrus
crops in Attica (Greece) and Epirus (Southern Albania) were reported

infested.
AFRICA.

Very little is known regarding the general distribution of the
Mediterranean fruit fly throughout the great central portion of the
African continent. While it is known to be a serious pest along the
Mediterranean shores and to have spread into the southern portion,
too few entomological observations have been made to warrant state-
ments concerning spread throughout the more tropical regions.
Graham in 1910 and Silvestri in 1913 state that it occurs in Dahomey,
southern Nigeria, and the Kongo. Gowdey’s records from Uganda in
1909 are the first from tropical East Africa, although Anderson states
in 1914 that he had found C. capitata infesting coffee cherries in Brit-
ish East Africa. In 1912 Jack lists C. camitata as abundant through-
out southern Rhodesia, but Morstatt states definitely that the pest
did not occur in coffee cherries in German East Africa during 1913
and 1914.

The first record of injury caused by the Mediterranean fruit fly in
South Africa was made by Miss Ormerod in 1889; but, as Mally states

Bul. 536, U. S. Dept. of Agriculture. PLATE |.

THE MEDITERRANEAN FRUIT FLY.

Fic. 1.—Three adults of the Mediterranean fruit fly ( Ceratitis capitata) about
natural size, attempting to oviposit in an orange; note the relative size of
flies and fruit. Fic, 2——Ripe apple showing many punctures in the skin
made by C. capitata in confinement. (Original.)

MEDITERRANEAN FRUIT FLY IN HAWAII. - 5

in 1904, it was introduced many years before. In 1893 Bairstow
writes that he was familiar with C. capitata in South Africa in 1880, -
and that the Rt. Rev. Bishop Richards remembered damage done as
far in the past as 40 years. In 1903-4 Fuller records C. capitata
as one of the newly observed pests among the Natal orchards. It is
not known whether the introduction in South Africa was by infested
fruit from the Madeiras or by the gradual spread overland along the
coastal regions, although the Madeiras seem the more probable source.

C. capitata was first recorded from Madagascar during 1914, when
it was found seriously injuring the peach crop.

AUSTRALASIA.

Western Australia.—The Mediterranean fruit fly was first recorded
in literature as a pest in Australia in 1897 by Fuller, who states that
it had been known to have been established in western Australia for
about two years in Claremont and Perth and along the Swan River,
especially at Guildford. According to Despeissis, the first report of
injury in Australia was made to the Bureau of Western Australia in
1894, which was, in his opinion, about one or two years after the date
of its actual introduction. The pest has since been recorded from
as far north as Geraldton and Northampton and as far south as
Bunbury.

New South Wales.—In New South Wales the Mediterranean fruit
fly was first reared in 1898. French found that peaches imported into
Victoria from Sydney were infested and notified Froggatt. Within
a few days Froggatt was able to verify this record by rearings of
his own from fruit supposed to have been infested by the Queens-
land fruit fly (Bactrocera tryon Froggatt). As Froggatt had been
on the watch for C. capitata, it is probable that it became estab-
lished about Sydney during 1898, although Rose, in 1897, states that
in the northern part of New South Wales, at Warialda, peaches
and nectarines had been nearly all destroyed in 1897 by a fruit fly
first appearing about 1895 and identified by Froggatt as probably
C. capitata. According to Froggatt, the pest has spread through-
out all the citrus orchards of New South Wales to a greater or less
extent.

Victoria.—Editorial comment in 1907 states that serious infesta-
tion of C. capitata had been recently discovered in the orchards in
Goulburn Valley and farther west at Bendigo and at Horsham, and
Froggatt is authority for its establishment at Albury and for the
statement that it is present throughout the northern half of Victoria.

Queensland.—There are very few references to the presence of C.
capitata in Queensland. Froggatt states, in 1909, that for a long
time it was believed that it was not to be found in this part of Aus-
tralia, but that, while it might not be abundant, he had specimens

6 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE,

from Brisbane. Voller, in 1903, mentions Brisbane, Toowoomba,
and Warwick as places especially subject to C. capitata attack.

Tasmanva.—The Mediterranean fruit fly became established in
Tasmania about Launceston during the early part of 1899 and, ac-
cording to Lea, attacked apples, pears, and peaches. As the result
of a meeting of the Tasmania Council of Agriculture, held on June 1,
to discuss correspondence regarding establishment and methods of
eradication, a vigorous clean-culture campaign was authorized, which
apparently was responsible for the eradication of the pest. No cases
of infestation have since been observed in Tasmania fruit.

New Zealand.—Kirk states in 1901 that the Mediterranean fruit
fly had not, up to that time, appeared in any New Zealand fruit-
growing district. Two outbreaks were later recorded, at Blenheim
and at Napier, respectively, but were reported to have been quickly
stamped out by the destruction of the fruit and treatment of the soil.
A third instance of temporary establishment in New Zealand was
recorded in 1908 at Davenport. At present the Mediterranean fruit
fly is not known to exist in New Zealand.

Islands about Australia.—In 1904 Kirk states that he had never
reared C. capitata from fruits received in New Zealand from the
islands of Suva, Nukualofa, Vavau, Rarotonga, Mangaia, Heratine,
and Samoa.

BERMUDA ISLANDS.

The Mediterranean fruit fly was not recorded from the Bermuda
Islands until 1890, when specimens of infested peaches were sent
Dr. C. V. Riley. It was known as a pest in Bermuda during the
25 years previous, and is supposed to have become established about
1865, when a.vessel carrying a cargo of fruit from the Mediterranean
region, bound for New York, was forced by severe storms to discharge
her cargo in Bermuda.

WEST INDIES.

’ There are no known records of the presence of Ceratitis capitata in
the West Indies. The fact that the Jamaica Botanical Department
in 1900 published a bulletin on orange culture and diseases, by Borg,
in which reference is made to C. capitata as a pest of the orange, has
led some to believe that the Mediterranean fruit fly has become
established in Jamaica. The subject-matter of this bulletin was
originally presented before the Malta Archeological and Scientific
Society and contains nothmg to warrant the conclusion that the
author was dealing with the subject except in a most general way,
particularly as he speaks of the fly occurring only about the Mediter-
ranean.

Ballou, in an article published in 1913 on the prevalence of some
pests and diseases in the West Indies during 1912, states that ‘‘fruit-
fly’ attacks were not so general in Dominica as in former years.
The editor of the Review of Applied Entomology erroneously iden-

4 /
TIS AL

MEDITERRANEAN FRUIT FLY IN HAWAII. 7

tified the ‘‘fruit fly’ as ‘C. capitata.’”’ Ballou has since denied in
correspondence that C. capitata was the insect in question.

SOUTH AMERICA.

Dr. L. O. Howard first identified the Mediterranean fruit fly from
South America from specimens reared from peaches sent him by
Dr. H. von Ihermg in 1901. Compere, in 1904, and Lounsbury, in
1905, found the pest in the States of Sao Paulo and Rio de Janeiro.
In 1906 Hempel states that C. capitata was the most common of the
fruit flies attacking peaches in Sao Paulo.

In writing of fruit culture in Argentina in 1905, Lounsbury states
that peaches near Buenos Aires were badly affected by an unde-
termined species of fruit fly which he thought likely to be Ceratitis
capitata. Silvestri definitely records C. capitaia from Buenos Aires,
_ presumably as a result of this statement of Lounsbury.

HAWAIIAN ISLANDS.

The Mediterranean fruit fly was first observed in- the Hawaiian
Islands by Mr. D. T. Fullaway, who captured a living adult in the
insectary at the U.S. Department of Agriculture Experiment Station
on June 21, 1910. During the followmg September another adult
- was captured by Terry and Perkins on the laboratory windows of
the Hawaiian Sugar Planters’ Association. Observations made in
the field during September by Terry showed that the pest was already
established in the Punchbowl] district of Honolulu on oranges and
limes, and from that time new records of infestation were rapidly
brought to light. By October, 1911, the pest had already become
established on the island of Kauai, and was known to exist on Molokai
at least by January, 1912, when it was first recorded from the Kohala
district of the island of Hawaii. During March, 1912, specimens of
infested coffee cherries were reported from the Kona district of
Hawaii. The first records of éstablishment in the Puna district of
Hawaii were made during March, 1913, when infested oranges and
peaches were found at Naalehu and Hilea. Peaches were not
reported infested in the Hilo district of Hawaii until the spring of
1914, but soon after infestations were found throughout the Hilo
and Hamakua districts. The fruit fly was found established on the
Island of Maui by May, 1912. By July, 1914, the Mediterranean
fruit fly had spread to every important island of the Hawaiian group,
and at present is well established in every village and wild guava
scrub examined by the writers. Judging from the rapidity with
which this pest has svoread throughout new districts in Hawaii, the
writers agree with Ehrhorn that the pest secured its first foothold
in Hawaii at Honolulu about 1907, although there are several well-
informed horticulturists in Honolulu who believe establishment
occurred even one or two years earlier.

“AY WMI] Weouvs1IEI poy,
ol} JO MOLNIISIP OY} UL LoYJOUR OUO OF UOT}e[oI MOY} PUL UOT}TSOd OAT}LIOI LOY} SULMOYS ‘SpULIS] UeIeMeT oY} Jo dew;—'Z “oI

:

UDS

FAIS
yn .

SOURCE OF HAWAIIAN INFESTATION.
little doubt that the Mediterranean fruit fly was carried

SGNV ISI NVIIVAVIL

BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

IV OW HES

DIQGVUUY

Ss

There is

8

Before this fruit

fly was known to have become established about Honolulu, Compere,
as a traveler between Australia and Honolulu, observed C. capitata

larve emerging from host fruits stored on the deck of his vessel and

plying between the ports of these two countries.

MEDITERRANEAN FRUIT FLY IN HAWAII. 9

pupating in the corners of the fruit containers and in secluded spots ©
about the deck. It would have been quite possible for larve thus
emerging to have completed their development during the days re-
quired for the voyage between Sydney and Honolulu and emerged as
adults while the ship lay at anchor at Honolulu within several hun-
dred yards of host fruit trees. As the Mediterranean fruit fly did not
become established about Sydney and. the eastern portion of Aus-
tralia until 1898-1907, its establishment about Honolulu between
1907 and 1908 came as a natural sequence. This is most forcibly
brought to the attention of those interested in horticultural devel-
opment when they appreciate the frequency with which this pest has
attempted to bridge the Pacific between Honolulu and San Francisco
since its establishment at Honolulu, as indicated by the interception
of infested fruit at San Francisco by officers of the Federal Horti-
cultural Board.

CONDITIONS FAVORABLE TO ESTABLISHMENT IN THE HAWAITIAN.
ISLANDS.

CLIMATIC CONDITIONS IN HONOLULU.

The climate of the littoral regions of Hawaii, and up tc an elevation
of 1,500 feet, is most favorable to the establishment and rapid increase
of C. cayitata. At Honolulu the temperature very rarely drops as
low as 58° F., and then only for a few hours during one or two nights
in the year. The data in Table I, taken from the monthly meteoro-
logical summaries of the U.S. Weather Bureau at Honolulu for 1914,
are given as a fairly reliable guide to the ranges in temperature
throughout littoral Hawaii.

TaBLE I.—Temperature and relatwe humidity at Honolulu during 1914.

| Relative hu-
Temperature. midity.
|
Daily range. Mean at 1 \Mean
Month. Lor |
Maxi-| Mini- mas"! Maxi-| Mini-
mum Mean.
mum MUI. vaxi-| Mini-| Aver-| 6a. | 2p. | 9p. | and [UU™ mum.
mum.jmum.| age.| m. | m. | m. | Min |
jmum
|
COR SIRE Sa Sak SIA SIG] TARO TA MST PE Fal Be (oh real Sno (Gis Pl BS (Bic
January. Se at AS ae eh oe Mp 78 60 18 6 | 10 67.4 | 74.0 | 68.9 |269.1 83 50 | 66.4
Mebroaine © ni. . ee 81 61 14 8 | 11.4 | 66.2 | 72:4 | 68.3 | 71.4 82 52 | 70.9
IManchietas 2. soe ae Pak Ss 80 57 15 7 | 10.5 | 67.5 | 74.8 | 89.6 | 70.9 86 53 | 68.6
Jey 0y tl bee epee ye ieee eee ae 82 60 15 7 | 10.7 | 68.6 | 75.8 | 70.9 | 72.5 81 52 | 68.7
INA see So REE Oe a) 83 66 14 6| 9.4 | 72.6 | 79.9 | 74.6 | 74.3 82 56 | 70.1
AEE De Stipes So Bae sel Seger 83 69 12 6| 9.1 | 74.0 | 80.4 | 76.0 | 76.6 80 58 | 68.8
Selliye Sete ee eS 85 70 15 6| 9.2 | 75.2} 81.5 | 76.3 | 78.4 81 62 | 69.6
PAIS hes gee rte So 86 71 12 5 | 9.1 | 76.0) 81.4 | 76.8 | 79.0 80 58 | 69.2
Heptemberts-earsess 222 Sk 87 70 12 6 | 8.1] 75.9 | 80.6 | 77.0 | 78.7 85 62 | 71.4
WMELODEI pm ces see 83 67 14 Tale Oeaa ia56.| TOs tale tole | aia O 74 60 | 68.0
INOVem bet 2-8 2. cee: 83 65 13 Bed OuDs|iwied fone-oep foso | 146 8518452) |. 7085
Wecembers-..5 2... +.) 280 61 14 lel On val Gi. Oilod4s OuO9..7 alr dled 89 | 60 | 72.7

1 Compiled from 1914 and 1915 data, taken from the 1916 Hawaiian Annual.
2 The normal mean for January is 71.1° F

a ae

10 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

It will be observed that the daily range is very small, averaging £
between 8 and 11 degrees, and that the normal monthly mean tem- —
peratures range between 70.9° and 79° F. In Table II are given the
monthly and yearly means, together with the yearly maximum and —
minimum temperatures, recorded at different places on the islands of —
-Hawaii, Maui, and Oahu, which, at their-respective elevations, repre- _
sent the variations in range of temperature from that in Honolulu, to _
be found at points in Hawai where host fruits are grown.

TaBLe II.—Monthly and annual mean and maximum and minimum temperatures of —
representative localities in Hawai where host fruits of the Mediterranean fruit fly may be

7

grown. F
:
Monthly mean temperatures. Annual.° :
a |3 M
| B.3/Sd i
3 | A0/aod |
Locality. | is ; aevise
a BS S S| & 23iso am
aS) S bat a a 7 Te} ESD ola
= H Ss : e g oO | _ |e Blas & f
S |e) pias : Seen aed 0\20 |
p |B Sizlelsi/elalel|sl2)sisssca
2 \|sleo|Sl/als|sl[s|/s/2 s/s] s]s wees &
ASI ls#l ls els (6 /alalola\i/aljsae wp
|= =< 2a sierra r
Island of Oahu: Heet.:| ° Fe) OB) OB) 2 FOULS BE O oF Oo Be |e Hall och cuales eles Maal ored bonnie
Honolulu =e eee eee 111)70. 0/69. 7|71. 4/73. 3|74. 3/75. 3/76. 4178. 1/76. 875. 2174. 7/72. 4|74.0} 85) 58
Waal ery Mia eee eee 30/70. 4/68. 7/71. 0/72. 7/73. 4\74. 4/75. 8)77. 0/75. ie 9172-8170. 5/73. 0) 91) 55
Wialanaece es. poe ee ese 6|71. 370. 4|71. 9/73. 8\74. 8)77. 3/79. 2 80. 0,79. 3/75. 5|74. 8/73. 275.1] 91) 52 ef
Schofield Barracks. -.-....--- 990/66. 6 65. 8/67. 4/68. 9/69. 8/71. 0/73. 0|74. 0)73. 271. 2/66. 4/68. 1/69.6] 89) 51
Tantalus Heights. ....-..-- | 1, 300/63. 6 64. 1/66. 3/67. 2/68. 0|67. 7|69. 3/70. 4/69. 1/68. 5/67. 4/65. 6/67. 3} 84) 54 ?
Island of Maui: | ;.
Kaanapaliz es oases 12/70. 2.70. 4/71. 4|74. 0/76. 077. 3/79. 3\80. 0/79. 4/76. 5/75. 2/73. 0/75. 2) 92) 57 z
Wiailuku eee eee: 250!68. 8 69. 2/69. 8'72. 2/73. 074. 1)75. 5/77. Al75, 8)74. 0172. 8/70. 9)72. 8] 89! 56
Haiti < Se Se ae ee ee | 700/67. 2/67. 2/68. 6/69. 6|70. 7\70. 7/72. 8/74. 2/72. 4/71. 8/70. 4/68. 7|70.4| 83] 57 ;
Island of Hawaii:

Tost) Sees eee ee ee 100|68. 4/68. 7/69. 470. 8|71. 3/72. 4/74. 0/74. 6/73. 8)73. 0/71. 4|69. 6\71.4| 88] 55
HOnOkaat ae apes eres 470/67. 6/67. 8/70. 1/71. 0\72. 3/72. 6/73. 4|74. 6:72. 8/72. 4/71. 2/69. 0/71. 2) 90) 53
HOA aes a ee 1, 350/67. 0/66. 6/66. 7/68. 8)68. 3,69. 4/70. 8,71. 2/70. 8/69. 4/68. 266. 2.68.6} 84) 51
Puen ul ets :is eer oases ee 2, 000/65. 2/65. 4/66. 4'68. 3/68. 6/70. 1/72. 6,73. 371. 7/69. 8/68. 8/66. 8.68.9] 87] 50
Pahalaves seer eee nee 850/68. 6/68. 4/68. 7/71. 2/71, 2/72. 1/74. 0/75. 2/74. 9/73. 0/72. 4/72. 0\71. 8) 91) 53
On al aVial ee ere eae 270/68. 4/67. 9/69. 7/70. 9]72. 2|72. 6|74. 2\75. 2/74. 2/73.1)71.7|70.271.7| 86] 54
Wallin ea 2 2 eae eee 2, 720/58. 6)60. 4/62. 0.61. 9/61. 9 61. 8.63. 6 65. 1/68. 7)64. 2/61. 7/60.4.62.1} 80] 44 ;
WoleanovEHouse) sass 4, 00057. 8/58. 6/59. 0/59. 6/59. 2 60. 1/60. Hee si 3/61. 0/60. 8,60. pe 6} 72} 42 ;

|

Biological work has shown that even the lowest monthly means of
localities up to 1,500 feet elevation have little effect upon C. capitata
other than to retard development somewhat. It is never cold enough
throughout littoral Hawaii to render either the adults or the larve
inactive. Asaresult there are no periods of the year at any Hawaiian
port when the climatic conditions are unfavorable for the establish-
ment or increase of this pest. Data presented later in the text indicate
that a continuous temperature ranging between 58° and 62° F-., or the
lowest range of temperature usually experienced in littoral Hawai,
does not increase the normal mortality among the immature stages of
the fruit fly, and that these stages withstand for short periods, with-
out injury, temperatures lower than any recorded in Table Il. The
two stations, Holualoa and Huehue, at about 1,350 and 2,000 feet
elevation, respectively, may be taken as fair examples of altitudes
above which host fruits are only scatteringly grown, but at which the’
fruit fly has demonstrated its capacity to injure fruits seriously.

:
:

ee) lt me.

MEDITERRANEAN FRUIT FLY IN HAWATITI. 1]

HOST CONDITIONS.

Favorable as are the climatic conditions for the establishment and
increase of the Mediterranean fruit fly in Hawaii, the host conditions
are even more so. Mr. H. J. Quayle, who has studied fruit-fly con-
ditions throughout southern Europe, and Mr. J. C. Bridwell, who has
had similar opportunities in western and southern Africa and in Aus-
tralia, have stated to the writers that nowhere have they found host
conditions so favorable for establishment and rapid increase as in
littoral Hawaii, especially about Honolulu and Hilo. Under the sub-
ject of host fruits, on page 24, the writers record 72 species of fruits
growing in Honolulu that are subject to attack by C. capitata. The
discussion of their susceptibility to attack, however, throws little light
upon their numerical abundance or upon the seasons of the year
during which their fruit is available for fruit-fly infestation. During
the clean-culture campaign waged against this pest m Honolulu
during 1913, data were secured which forcibly demonstrate the ideal
host conditions found in Honolulu, making possible extraordinary
increase and excessive infestations. The residents of Honolulu are
justly proud of their magnificent vegetation and have taken great
pleasure in growing an unusually large assortment of trees and
shrubs upon their town properties. An inventory of such trees and
shrubs, that bear fruits subject to infestation, growing upon 60 blocks
in that portion of Honolulu bounded by Liliha, Punchbowl, Beretania,
and School streets, is given in Table III.

TaBLE IIIT.— Number of host trees and shrubs of the Mediterranean fruit fly growing during
1918 in that portion of Honolulu bounded by Liltha, Punchbowl, Beretania, and School
streets.

Lots | Trees Lots | Trees | Lots | Trees Lots | Trees
Block. in in Block. in in || Block. in in Block. in in
block. | block. block. | block. | block. | block. block. | block.
— | =
1 19 81 16 18 90 31 7 19 46 9 160
2 10 64 17 6 13 32 10 62 47 4 51
3 10 105 18 5 20 33 5 10 || 48 15 217
4 3 19 23 101 | 34 5 22 49 23 167
5 16 137 20 12 48 | 35 5 9 50 6 111
6 9 28 pak 18 118 | 36 8 51 51 16 112
7 9 64 22 | 7 59 37 14 134 52 9 41
8 4 59 23 | 3 0 38 13 | 108 53 5 65
9 6 18 24 | 14 75 | 39 41 115 54 14 83
10 9 124 25 3 8 | 40 12 74 55 23 112
11 28 132 26 7 25 | 41 36 135 56 | 26 158
12 6 163 27 4 7 | 42 17 76 57 12 37
13 9 66 28 4 15 | 43 18 208 58 | 4 0
14 9 66 29 9 42 | 44 24 144 59 j 3 124
15 25 86 30 2 39 | 45 9 54 60} 12 98
J

Total number of lots in 60 blocks, 712; total number of trees, 4,610; average number of trees per lot, 6.5;
average number of trees per block, 76.8.

From this it will be seen that there was a total of 4,610 trees and
shrubs on the 712 lots under consideration, or an average of 6.5 trees
per dooryard capable of supporting the fruit fly. In Table IV are
given data indicating the relative abundance of different hosts.

1 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

Taste 1V.—Number and specees of host trees of the Mediterranean fruit fly growing in
that portion of Honolulu covered by Table IIT.

ASpriCole. crc Lj Wig cp orsas ek ao ceee 201 | Mandarin........- 28 | Rose apple..-...... 25
INVOCROWeepaaeoase 653 | Guava, common... O45 | Mangos coc -- -sesa- 1164 | "Sapodilia s55-=ee= 5
Breadfruit .......- 58 | Guava, strawberry 73 | Mangosteen.....-- G\eSap0tarre =e eeerse 30
Carambala........ 48 | Java plum........ 80 | Mountain appie..-. 40) SSOUTSOD=s=- sense 57
Chinese inkberry. 6 | Kamani, ball. .... 4 | Mock orange....--. 33 | Spanish cherry... 1
Chinese orange.-.. 148 | Kamani, winged-. 13 | Orange, sweet.... 3/2] Starapple-.__-..- 4
Cofiee . s245 Sees 298 | Kumquat........- 4, Papaya jo: ae 687 | Surinam cherry... 63
Coffee, Liberian... 3) |, JUSTO NSS Soeee sess on Rea hen eee 69) Wik eee 19
Cottone2eeeee ee TM Walcot Divelalere seg ae rare 40 | Pear, Bartlett..... 2| Waiawal.......... 60
Custard apple..-... Tilly Tagan ey Bea Ay Sea ear 10 | Pomegranate..... 128 ——
Damson plum.... Ae WOgQuateseessceaee 33) | ;bomelozeces..2esee 15 | Totalza--ee 4,610

In Hilo, island of Hawaii, host conditions are quite as favorable for
fruit-fly development as in Honolulu. Thus the folowing numbers of
host trees and shrubs were found in certain yards of Hilo during
March, 1914:

YARD 1. YARD 2. YARD 3. YARD 4,

1 Rose apple.! 2 Surinam cherry. 11 Rose apple. 4 Peach.

4Surinam cherry. 2 Papaya. 2 Mango. 6 Mango.

2 Japanese plum 1 Thevetia. 3 Thevetia. 1 Loquat.

6 Mountainapple. 2 Orange. 1 Avocado. 3 Winged kamani.

1 Star apple. 2 Strawberry guava. 2 Surinam cherry.
34 Coffee trees. 14 Coffee. ; 1 Strawberry guava.
20 Common guava. Bananas.
15 Brazilian banana. 2 Avocado.

4 Avocado. 1 Peach.

3 Mango 3 Fig.

2 Papaya. 2 Mountain apple.

5 Orange 2 Lichee nut.

1 Peach. 3 Common guava.

1 Grape.

1 Winged kamani.
- 1 Mangosteen.

1 Fig.

1 Mimusops.

There is no time in Hawaii when fruits are entirely out of season.
The fact that several hosts, such as the Chinese orange (Citrus
japonica), Surmam cherry (Lugena michel), and mock orange
(Murraya exotica), bear several crops a year, while others, such as
certain specimens of ball kamani (Calophyllum inophyllum) (Pl. VI)
and winged kamani (Terminala catappa) (Pl. XTX), appear to be sel-
dom entirely free from ripening fruits, assures food for the fruit fly the
year round. |

The succession of fruits is also increased by the individuality of
trees of the same species, or even of certain branches of a single tree,
which results in a very uneven ripening of the fruit. While the data
in Table V do not indicate the seasonal abundance of host fruits,
they have been summarized from the collections of clean-culture
inspectors made during 1913 to show the remarkable succession of
host fruits found ripening in greater or less quantities throughout

1 For scientific names of fruits see section on host fruits, p. 24.

Bul. 536, U. S. Dept. of Agriculture. PLATE ll.

RELATION OF FLORA OF HAWAIIAN ISLANDS TO THE MEDITERRANEAN FRUIT FLY.

Fic. 1.—Men grubbing out a guava scrub which has taken possession of pasture land. Many
thousands of acres are thus overrun in Hawaii and furnish excellent breeding grounds for
the fruit fly. The ripening fruits fall into the dense grass and the larvee within them develop
unmolested by the heat of thesun. Fia. 2.—Thickets of guava bushes often crowd upon
the country roads and ripen tons of fruit. This fruitis gathered by pedestrians and autoists
and carried to all parts oi the islands, thus becoming a medium for the wide dissemination
ofthe pest. (Original.)

PLATE III

. of Agriculture.

. Dept

Bul. 536, U.S

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Pest, 2

pees

| Bul. 536, U. S. Dept. of Agriculture. PLATE IV.

THE MEDITERRANEAN FRUIT FLY.

Fie. 1.—A dense forest growth of the mountain apple (Jambosa malaccensis) near Hilo, which
illustrates one of the many strongholds in Hawaii that the fruit fly found favorable to its
thorough entrenchment. Fic. 2.—Rose apple trees (Hugenia jambos). While the fruit of this
tree ripens chiefly during the months of March to May, afew may be found beneath trees at
any time. Fruits of both the mountain apple and the rose apple are among a Class of host
fruits that are carelessly taken on board ships by tourists, in whose possession they have
Cork oe by the officers of the Federal Horticultural Board at San Francisco.

riginal.

Bul. 536, U. S. Dept. of Agriculture. PLATE V.

THE MEDITERRANEAN FRUIT FLY AND THE COFFEE INDUSTRY.

Fia. 1.—Coffee plantation on the Kona slopes of Hawaii. Fie. 2.—A fruiting branch.
Fia.3.—Low type of coffee tree. Fic. 4.—Coffee cherry cut to show the two large
beans which are of-commercial value, and the very thin outer pulp. This pulp is the
only portion of the cherry eaten by the fruit-fly larve. Note that the well-grown
larvee illustrated feed so close to the papery epidermis that parasites have no difficulty
in ovipositing in them. Thousands of acres are densely planted to coffee on the island
of Hawaii and offer food for the fruit fly the year round. (Original.)

MEDITERRANEAN FRUIT FLY IN HAWAII. 13

the year in Honolulu. The presence of so much ripening fruit,
coupled with the favorable climatic conditions and the hardiness cf
the fruit fly itself, has made the establishment of C. capitata and its
multiplication a most easy problem within the city limits.

While the fruit fly finds host conditions most favorable within the
city limits, because of the large number of host trees and shrubs,
some of which are bearing at all seasons of the year, it has been able
to establish itself and multiply in the country, often miles from towns,
in some one or more of its hosts which have escaped cultivation,
and to have spread over uncultivated and uncultivable areas. Of
such hosts, the, common guava (Psidium guayava) is the most
abundant. It has taken possession of the roadsides, pastures (PI. II),
vacant town lots, mountain gulches and hillsides, and even crevices
in precipices, from sea level up to 1,500 feet elevation.1 So easily
does this plant grow from seed, and so thoroughly distributed are
its seeds by cattle, birds, and man, that it is seldom that a bush can
not be found within a stone’s throw. In the lowland pastures and
mountain gulches up to an elevation of at least 1,300 feet, particularly
when sheltered from strong winds and well watered, the guava may
become very treelike and form dense thickets (Pl. II]). At higher
altitudes, and in wind-swept or arid areas, it may remain a low,
scrubby bush. While the guava fruits most heavily during the
spring and fall months, the bushes are continually blooming
and ripening a sufficient number of fruits to support the fruit fly
every month in the year. The writers are depending upon the illus-
trations to acquaint the reader, as words can not, with the well-
nigh universal distribution of this host and the wonderful oppor-
tunities it offers C. capitata for easy establishment and thorough
intrenchment.

Second to the guava as a host occurring in wild, uncultivated areas
is the prickly-pear cactus (Opuntia vulgaris) (Pl. XVII). While the
fruits of this plant are not preferred by the Mediterranean fruit fly,
they are sufficiently infested in the absence of more favored hosts to
serve as food, and, as in the case of the guava, there is almost no
time during the year when a few ripe fruits may not be found in any
cactus scrub.

Other host fruits, wild or escaped, are not so universally distrib-
uted. As a few of the many examples, there may be mentioned a
grove of ball kamani trees in an isolated valley on the island of
Molokai, gulches overgrown with the passion vine (Passzjlora sp.)
and the damson plum (Chrysophyllum oliviforme) on the island of
Maw, the thickets of winged kamani growing along the windward
shores of the island of Oahu, and the wild coffee and mountain apple
(Pl. IV, fig. 1) in the forests of Oahu and Hawan.

1 Stunted bushes have been observed at 4,000 feet elevation.

14

in Honolulu collected various fruits infested by the

.

re campaign

Mediterranean fruit fly.

TasLeE V.—Data indicating the seasons of the year when inspectors of the clean-cultu

BULLETIN 536,

U. S. DEPARTMENT OF AGRICULTURE.

1 This table is not intended to indicate the seasonal abundance of host fruits.

"T8-€6 00 | KKH SK UK KKK KKK MM KM K KKK OK K KKK
"IZ-OT 00 | KKK fH tM OK K HK OM KKK OOK KM OK TK MK
"71-600 | HHH SM IKK MMM IMM KM OM OIKM DR MMM:
‘LG 00d | KKK tH IKK KKH KKM KK KKK ORR OK MRK Ee
“ORGS "AON | SHH fh CM MMMM 8 8 SM Si le SMM es
“EC-RTCAON | SHH fh CMM IMM UKM MMMM oe bt fee Speke os
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‘T*AON-Z°900 | tHM TM IK OK MMMM DKK IMM iM DD oR KKH OD
"7-06 100 | HK “HR SRR Cee eae eae
"SI-€1 100 | th HM TK EM EMM DK EM FoR EK RK KK
T1-9°900 | :hH th IMM KM MK KS OM OK 8 te COMM MM
"6400-60 '3deg | KKM KK IK IKK KKM tM KKK OOK HK IKK MMR
"1-66 9d9g | KKK Kh IKK IM KKH DEM ERK DRM IMM KM
0c-ST-3deg | HHH WMH ik S SoM KR De SMe SOM CRM MK :
"eI-g-ydog | MMH KK IMM CMM KM fh tuk CMM DKK MMM
"9-1 -4dog |- MKH Sh IMM EMH SS OM K ORK KKM SKM HR :
"0G-G2"SNV | KMK fh tM SEK K 8 SM SMa 8 OM tf CK MK MK
“ee-e1 any | HHH KK Shhh Ke Mk eee een:
‘LI shy | MMH RH PHM OMe OM hh Dee OM RMR
“6p Sty | Wie alts She el ee 2 paid Oe ba) oe ei
‘gsny-9¢ 4p | MH IM IMM MMM DM DK ODM MH IMM DMM
“9¢-1Z ANE. | KwMM 8H OK oth OK SK BM eM Oe OM MH:
“61-71 Aqne | KHIR 8h OK TKK TSR Rh KKM RH ORR
“GEL AqUue |, Pals ied) Wes ae stpaia ts eaipalice bali ipal pails pa esaeipa eae tates
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| SENG I Ook ean ia wid ent cap aep aid cpa peenl hig RAR oie i
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"OI-G ACW | StH TKK KKK HM DMM MK MMR
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| QZ-1S "Idy | 3: tH ft HM MH OK KKM HMR OM MMR
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| "S-e°qoq | iM tHMMH IKRM ORM ME MMM MH Se SH beh ci:
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“CC-0G UCL | THK TKK MMM MMMM MMM tee ta te
| ‘gL-el Utl| fH IMM MK MMMM MMM MMMM OM MM
‘TI-Tauee | thw TKK KK KKM OM KKH OOK KEK fb bw MK
igSlighiiliiilii@iibiiiibiiigs
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2 i259 TES ig eg lida Li igge tig ese
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| SREDEEES [PRERE CoSEE SS RE 2 ne Se BEBE
| 4500 SAGMOOMMA SS SOR MMA mama ss Mae

MEDITERRANEAN FRUIT FLY IN HAWAII. 15

In addition to the wild fruits in country places, the fruit fly finds
_ strongholds in the many, and often very isolated, native-home sites
scattered throughout the littoral regions. About these may be
growing the mango (PI. XII), rose apple (PI. IV, fig. 2), orange, peach,
avocado, ball and winged kamanis, etc. In the Kona district of the
island of Hawaii there are large areas containing thousands of acres
of coffee under cultivation (PI. V) in which the fruit fly finds food in
the pulp of the ripening cherries at all seasons of the year because of
the irregularity in blooming and the long harvesting season due to
the varying altitudes at which coffee is grown.

ECONOMIC IMPORTANCE.

The economic importance of the Mediterranean fruit fly as a pest
of fruits varies with the climate of its habitat. Thus in France,
near Paris, where it has been known to attack apricots, pears, and
peaches, it has not become a serious pest because of climatic checks,
and such checks to the severity of its attack have been noted in
portions of Australia and South Africa and would be operative in
_ continental United States, except in parts of California and of the
Southern States. On the other hand, in tropical and semitropical
climates this fruit fly is capable of becoming a pest of prime impor-
tance and, as in the Hawatan Islands, may be classed as the most
important insect check to horticultural development. <A study of
the fruits infested by this world-wide pest shows that practically
every fruit crop of value to man is subject to attack. Not only is
the Mediterranean fruit fly of importance as a destroyer of fruit, but
it is the cause of numerous stringent quarantines which cost the State
and Federal governments much money to make effective, and rob
countries of good or prospective markets for their fruit. Fortunately
it has been found that the Chinese banana (Musa cavendishiz) and the —
pineapple (Ananas sativus), the two most valuable species of fresh fruits
formerly exported from Hawaii, offer so little danger as carriers of the
Mediterranean fruit fly when they are packed for shipment that this
part of Hawai’s export trade with the coast may still be carried on,
provided the inspections of the Federal Horticultural Board now in
_ force are continued. The necessary quarantine against all other host
fruits, however, particularly against such fruits as the avocado and
mango, two fruits which can be grown very well in Hawaii, has had,
and will continue to have, a serious effect upon horticultural pursuits
and the development of the small farmer.

At the present time the infestation of edible fruits in littoral
Hawaii is general and about as severe as could be expected. Aided
by the melon fly (Bactrocera cucurbitae Coq.), the Mediterranean fruit
_ fly has effected a most serious and permanent check upon the horti-

cultural development of the Hawaiian Islands unless a successful

16 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

method for combating it is developed. In the Bermuda Islands the
peach industry has been a ruined one for many years. MacLeay
and Westwood wrote, during the early part of the nineteenth century,
of the increased cost to the inhabitants of London of citrus fruits
imported from the Azores as a result of fruit-fly attack. Lounsbury
and Mally, of South Africa, consider C@. capitata one of the greatest
drawbacks to the development of the fruit industry in Cape Colony,
and have stated that during certain favorable seasons large areas
of apricots, figs, pears, plums, apples, and quinces were almost
all affected. Hooper, writing from Southern France, states in 1904
that, as a result of fruit-fly attack, what was once an important and_
lucrative industry was at that time little more than a haphe ‘ard
traffic in fruit casually produced. In 1903 Compere found that peach
growing about Barcelona, Spain, had been so demoralized by fruit-fly —
attack that few trees were being grown and that the market was
supplied by fruit from the Balearic Islands, while at Cadiz the fruit
merchants no longer cared to handle peaches owing to the fact that
they were badly infested. At Malaga, according to Compere, the
bitter Seville oranges are seriously affected. Wickens, writing in
1913 in Western Australia, states that the fruit industry there was
suffering not only directly as a result of the actual loss of fruit in-
fested, but indirectly through the restricted plantings in districts
where the fruit fly was abundant.* About Perth, where late peaches
can be grown to perfection, very few are being cultivated; instead,
many trees have been cut down. Other instances of damage caused
to citrus crops in southern Europe, South America, Africa, and
Australia might be added which would impress one, unfamiliar with
the ravages of C. capitata, that it is a very serious pest. Its economic
importance is so great that every effort should be taken to prevent
its establishment in new territory.

INJURY.

NATURE OF INJURY.

The injury caused by the Mediterranean fruit fly is confined to the
fruits of the hosts attacked. The foliage, stems, and roots are not
attacked so far as investigators have been able to determine. No
better idea of the nature of the injury caused by the fruit fly can be
gained than from an examination of the illustrations. The larve
hatching from the eggs deposited just beneath the epidermis burrow
their way throughout the pulp and, as they develop, cause by their feed-
ing, and through the development of fungi and bacteria, decayed areas
which vary in extent according to the age and number of the larve
and the ripeness of the host. Since the larve most frequently burrow
at once to the pit or core of the fruit, they are able to feed for some
time before their work is evident from the surface; thus peaches and

MEDITERRANEAN FRUIT FLY IN HAWAII. 17

oranges may be quite thoroughly devoured within and yet maintain
a fairly normal appearance externally. In rapidly growing fruits,
or those oviposited in while they are still too green to support larval
growth, slight deformities are developed which injure the appearance
of the fruit. In lemons, oranges, and grapefruit which have been
provided so well by nature to withstand fruit-fly attack, the rmd may
become badly infested with eggs and young larve, while the pulp
remains edible. The breaks in the skin made by the female fly in de-
positing eggs, however, affect the shipping qualities of such citrus fruits
and, from this commercial aspect, may cause an injury the nature of
which is quite as serious as is any to the pulp.

EXTERNAL EVIDENCES OF INJURY.

There are always external evidences of infestation, but these are
often so inconspicuous that they are overlooked by the average
person. The eggs are deposited by the adult through a break, no
larger than a pin prick, made in the skin. While these punctures
are readily discernible under the hand lens as soon as made, there is
nothing about them to attract attention. Soon after oviposition,
however, the tissues about the egg cavity begin to wither and
there develops about the puncture a discolored or sunken area in the
skin. In certain hosts the immediate area about the puncture may
remain green long after the remainder of the fruit has turned yellow,
as in the loquat (Eriobotrya japonica), or red, as in the strawberry
guava (Psidium catileyanum). In green oranges the fruit may turn
yellow about the puncture while the rest of the fruit remains green.
Such tender-fleshed fruits as the ripening Surinam cherry (Hugenia
michelit) may develop sunken areas without discolorations. Often
filaments of clear gummy excretions exude from punctures made in
peaches, lemons, and grapefruit. Punctures made in green star
apples (Chrysophyllum cainito) are usually marked by exuding white
latex which dries about and over the puncture. Punctures made in
quite green winged kamani nuts (Terminalia catappa), in which no de-
velopment of larvz occurs, are marked by depressions in the flesh due
to permanently arrested development at the punctured point.
Oviposition or attempted oviposition in bananas and partially ripe
mangoes is followed by exudations which run down the sides of the
fruit and dry as a dark stain. The evidences of early infestation
such as have just been mentioned are too numerous to warrant de-
scription. No one host responds to infestation exactly the same
each time; much depends on the degree of ripeness at the time of
attack. There may be no gummy exudations from peaches or citrus
fruits, and there may be no development of discolored areas in any
of the host fruits. Avocados seldom give evidence of infestation by
any external mark except the puncture in the skin. Fruits already

81340°—18—Bull. 536——2

18 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

ripened when infested show none of the usual signs of attack ur’
the larve have begun to work. It is due to this failure of fruit:
record their infestation by some external sign, other than the r
spicuous puncture, that so much fruit is purchased as sound
markets, or shipped from orchards, or taken on board ships

As the larve hatch and begin their work of destruction v>
host, the signs of infestation increase rapidly. The suns S
about the punctures of tender-fleshed fruits may increase untu «ie
entire fruit has a collapsed appearance. J

In all fruits well infested within there is a ‘‘give”’ to the area be-
neath the puncture, indicating destroyed tissues beneath. In hard-
fleshed fruits such as some varieties of apples (PI. XI, fig. 2), pears,

and quinces there may be no external evidence of larval work except —

a ring of dark decay about the puncture, and yet the outer portion of
the pulp alone may be unaffected. Peaches are often thoroughly
infested within and still maintain their normal shape and give evi-
dence of infestation only by a dull and slightly darkened color of the
skin. A hole in the rind, no larger than the lead of a pencil, from
which juice exudes when the fruit is compressed, may be the only
indication of infestation in oranges and grapefruit, although rings of
decay usually develop in infested citrus fruits containing numerous
larve. Fruits of the elengi tree (Jémusops elengi), which have an
orange shell-like exterior (Pl. VIII, fig. 2), may appear normal, but
on being broken open are found to be literally packed with well-
erown larve. It is never possible for the average man to examine
casually any host fruit and state conclusively that it is not infested.

METHODS OF SPREAD.

There are numerous records on file which demonstrate clearly

the methods by which the Mediterranean fruit fly is spread, not only

between widely separated countries, but about land areas. The
development of rapid transit and cold storage and the increase in
tourist travel have been the greatest factors in dissemination in more
recent times.. Geographical. isolation is no longer a protection
against introduction, as has been proved almost monthly by the
interception of fruit flies at the ports of entry of the United States
by the agents of the Federal Horticultural Board.

SHIPS.

The unrestricted consignments of fruit and ships’ stores have
been responsible for much of the spread of C. capitata between coun-
tries. MacLeay, as early as 1829, records the importation at
London of cargoes of oranges from the Azores that contained larve,
and Middleton, in 1914, states that in the same city hundreds of
larve and pupe are imported every year from Spain and destroyed

Ria

MEDITERRANEAN FRUIT FLY IN HAWAII. 19

in the manufacture of marmalade. The establishment of C. capitata ©
in both the eastern and western parts of the Australian continent
is traceable to the development of cold storage and rapid ocean
transportation which made possible the large exports of citrus fruits
from the Mediterranean region to Australia. Kirk records the —
receipt at Auckland, New Zealand, of a case of peaches from Cape
Colony which contained living larve, although they had been en route
in cool storage for four weeks. The same writer intercepted 47 cases
of infested apples at Wellington, New Zealand, imported from New
South Wales. Lea, in 1908, states that larve of C. capitata were
seen in numbers every year in fruit imported into Tasmania from
Sydney. The establishment of this pest in the Bermudas and South
America is beyond doubt the result of the importation of infested
fruit from Mediterranean regions. Increased knowledge of fruit
flies and the quarantines in force in several countries now make the
introduction of this pest in consignments of fruits less likely.

The vigilant work of the quarantine officials at the Pacific ports of
the United States, however, demonstrates the grave danger that still
exists of introducing the Mediterranean fruit fly in ships’ stores.
Instances of the discovery and destruction of the pest in fruits in
ships’ stores on vessels entering the port of San Francisco during the
past four years are recorded in the reports of Frederick Maskew,
chief quarantine officer of the California Horticultural Commission
and collaborator of the Federal Horticultural Board.

TOURISTS.

The desire on the part of tourists to carry to their friends at home
specimens of exotic fruits is at the present time the most likely
avenue for the introduction of this fruit fly into California as well as
the southern United States. This has been clearly proved not only
by the large variety of host fruits offered for inspection at Honolulu,
but by the interceptions at the California ports. To the quarantine
officer the tourist is a difficult problem. Fruits carried in containers
are easily observed, but smaller fruits are found with difficulty.
Strong, in 1918, discovered in the overcoat pocket of a tourist landing
at San Francisco infested nuts of the winged kamani (Terminalia
catappa), which were intended for planting in southern California.
In like manner infested coffee cherries were found at Honolulu in the
pocket of a gentleman about to sail during February, 1916, from
Honolulu direct to San Pedro, Cal.

DISSEMINATION GN LAND BY PUBLIC AND PRIVATE CONVEYANCES.

On land, railroads, automobiles, hawkers’ carts, carriages, etc.,
are all responsible for much spread. The fact that host fruits only
slightly infested appear normal to the average man leads to the pur-

20 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

chase by the traveling public of much fruit which later, when found
to be infested, is discarded, often many miles from the point of origin.
Bairstow as long ago as 1893 records the selling of infested apricots
by native girls to passengers on trains about to leave for interior
points of South Africa. The spread of the pest in Australia has
been most rapid along the-railroads. French, in 1896, states that
peaches imported by rail into Victoria from Sydney were infested
and Newman states that in Western Australia many instances have
come under his observation in which infested fruits thrown from the
windows of coaches of both suburban and country trains were re-
sponsible for introductions into districts previously free from attack.

In the Hawaiian Islands the spread from village to village and from
island to island unquestionably has been hastened by the habit of the
poorer population of carrying small lots of fruit in their travels, either
for food while en route or as presents for their friends. Much of this
fruit is more or less infested, and when an attempt to eat it proves the
interior to be infested and unpalatable, it is discarded either along
the road or at the point of destination. The inspection service of the
Hawaiian Board of Agriculture has shown that even the most stringent
regulations have not prevented the movement of infested fruits
from point to point by man in automobiles, in carriages, or on foot.

POSTAL AND EXPRESS PACKAGES.

The interception at Washington, D. C., by officers of the Federal
Horticultural Board of a package from Mexico containing a living
pupa of the papaya fruit fly ( Toxotrypana curvicauda Gerst.) attached
to an unknown vine, and of a living adult of the olive fruit fly (Dacus
oleae Rossi) and a dead adult of another species of fruit fly, apparently
Dacus semispharens Becker, in a package of olive seed, 28 days after
it had been mailed in South Africa, indicates the possibilities for
spread by means of parcel post. The persistency with which unin-
formed persons insist upon including among bananas and pineapples
intended for shipment by express from Hawaii to the mainland
United States small contraband host fruits has demonstrated fully
the danger of express packages as carriers of. C. capitata.

NURSERY STOCK.

A fruit-fly pupa (species unknown) was found at Auckland, New
Zealand, in the soil about the roots of a plant imported from Australia.
Newman has called attention to the danger of spreading the fruit fly
in the pupa stage, in the soil about the roots of nursery stock grown
beneath host fruit trees. |

PACKING MATERIALS.

Larve developing in fruits packed in wooden crates or in bags

often pupate against the sides of such contaimers. Second-hand

~

MEDITERRANEAN FRUIT FLY IN HAWAII. DAL

packing crates and old burlap, etc., recently used as containers are |
_ apt to carry the pest and should be guarded against until experience
for the locality and temperature concerned has proved that the
adults have emerged. Certain instances of spread in western Aus-
tralia are believed to have occurred through carelessness in the use
of second-hand packing cases. In Hawaii, Hilo grass (Paspalum
conjugatum), gathered from beneath guava bushes (PI. XIV, fig. 1, in-
sert), was discontinued as a packing material for bananas for fear
pupe of the fruit fly attached to it might reach California.

COLD STORAGE.

While cold-storage temperatures may be used to render fruits free
from danger as transporters of the fruit fly (see p. 108), the use of
temperatures fluctuating above 38° F. may be one of the greatest aids
in prolonging the duration of fruit-fly life within host fruits.

WIND.

That adult males of the Mediterranean fruit fly can be carried by
the wind distances varying from one-fourth to 14 miles from points
of liberation has been demonstrated by Severin, who states further
that in all probability some of the flies which he had set free at the
head of Manoa Valley “were caught up and carried far into the city
of Honolulu, or even away beyond into the sea, miles away from the
points of liberation.” The writers agree with Severin as to the
ability of winds to carry adults considerable distances. The dis-
covery by Mr. H. T. Osborn of an adult upon the summit of Kona-
huanui (elevation 3,105 feet), the highest peak of the range separating
the windward and leeward sides of the island of Oahu, and at a con-
siderable distance above the highest range of host plants, makes it
easier for the writers to believe that the few adults which they
captured in traps in the scant vegetation on the leeward shore line,
and at considerable distances from known sources of infestation,
during very windy weather, were specimens caught on the windward
side in strong ascending air currents and carried entirely across
Oahu. There is no doubt that the adult on Konahuanui observed
by Osborn was transported thus from the lower windward levels.

HOST FRUITS.

The writers know of no edible fruit commonly grown in the
Hawaiian Islands, except the pineapple, that is not subject to attack
by the Mediterranean fruit fly. From a practical trade standpoint
the banana should not be considered a host when grown and shipped
in accordance with the regulations of the Federal Horticultural
Board. :

22, BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.
FRUITS ERRONEOUSLY LISTED AS HOSTS.

No infestation has been found in pineapples (Ananas sativus),
banyan (Ficus indica), pride of India or chinaberry (Melia azedarach),
noni (Morinda citrifolia), jujube (Zizyphus jujuba), mulberry (Morus
nigra), tamarind pods (Tamarindus indica), wine palm (Caryota
ureus), Ixora coccinea, Canarium commune, Sideroxylon sanduichensis,
mammee apple (Mammea americana), durion (Durio zibethinus),
Cape gooseberry or poha (Physalis peruviana), ohelo berry (Vaccinium
reticulatum), kukui nut or candlenut tree (Aleurites moluccana),
night-blooming cereus (Cereus triangularis), and jack fruit (Artocarpus
integrifolia).

PINEAPPLE.

The pineapple (Ananas sativus) is not a host fruit of the Mediter-
ranean fruit fly in Hawai. Negative data are given here because -
of the persistent reports that this fruit is subject to fruit-fly attack.
Ilingsworth reared the pineapple fruit fly (Dacus xanthodes Broun)
from pineapples in Fiji in 1913. In 1904 Kirk states that he had
reared only the Queensland fruit fly (Dacus tryona Frogg.) from pine-
apples exported from Queensland into New Zealand. In 1908 Kirk
again states that Dacus zanthodes was commonly found in pineapples
and oranges froui Fiji and Rarotonga entering New Zealand.
Gowdey, in 1913, reports rearmg C. capitata from pineapples in
Uganda, British East Africa. So far as the writers are aware no
data have ever been published from careful experiments to determine
the true status of the pineapple as a host fruit, and the writers know
of no positive evidence that C. capitata has ever been reared from this
fruit.

It is certain that during a period of over three years not one of
seven entomologists in Honolulu has succeeded in rearing adults
from this fruit. Fullaway, of the United States Experiment Station,
obtained negative results from fruits placed in a large cage. The
market and plantation inspectors of the Federal Horticultural Board
have brought to the office during the past three years many partially
decayed fruits, but no fruit flies were reared from them, although
many decay flies were. Although pineapples are grown profitably
- only under the best horticultural conditions (Pl. III), none of the
developing fruits are sufficiently isolated from other varieties of host
fruits affected to warrant the belief that adult fruit flies are not
present in large enough numbers to infest each fruit were the pine-
apple susceptible to infestation.

In an attempt to force an infestation within the laboratory, 50 ripe
pineapples were placed either singly or by twos in large glass jars con-
taining from 300 to 500 adult flies in a mature egg-laying condition,
and allowed to remain with the flies from 2 to 4 days. The pineapples
were then removed and placed over sand in covered jars. No flies

MEDITERRANEAN FRUIT FLY IN HAWAII. 23

were reared from the fruits. The flies readily deposited eggs in apples _
placed with them both before and after exposure of the pineapples.
A record of the time each of the 50 fruits was exposed is as follows:

TaBLE VI.—Nonsusceptibility of pineapples to the attack of the Mediterranean fruit fly.

Number of

Number of

fruits patos oFes ausire to fruit flies

exposed. : reared.
913.

Deiat oss OchiT4ts ae a

1 DiS eee ea Octslielee ==

nL era aes eek TOS92 VEL Is Dee

DESI 2 ae Cia232 74 eee

Gin a None.
110i Oct. 30-Nov. 22. =
| Dae ere INOW OS(s oes eee
ioe eee INOW gO id reece =

During July 18-20, 1913, a very ripe pineapple was hung in a jar
containing flies. An examination of the fruit after this two-day
exposure revealed 2 punctures in the pulp containing respectively

16 and 11 eggs. One puncture had been made in a slight abrasion;

the other in normal tissue between the eyes. Seven other batches of
eggs, containing 9, 5, 8, 7, 4, 5, and 4 eggs, respectively, had been
deposited on the surface of the fruit, but in the creases between the
eyes.

In experimental work the writers have had no difficulty in trans-
ferring larve from one favored host fruit to another. Experiments
in transferring first, second, and third stage larve to pineapple
invariably resulted in the death of the larva. A total of 925 larve
were transferred, as follows: 7

TaBLeE VIl.—Failure of larve of the Mediterranean fruit fly to develop in the pulp of ripe

pineapples.
Number =
Date of transfer. larvee duster y 8 Results.
transferred. eeu.

INDUS 22 oe see ee eee we 150 EB SOCON Cte ese ene All Ged by Apr. 26.
AGO) Shey 2 eee eae a aE 200] | See dose asa s-
ADR oo et see eee LOO: SRATS Glee see - 5 All died by Apr. 24

IDO reas Zon SCCONC se sm aes 19 dead by Apr. 25; 6 dead by Apr. 26.

DOs seas See 15 OW Svounesthindis === a" All dead by Apr. 25.
NDT Zoe oe es SN 150, eee Ose ate ey eet Do.
ANT Doma eee et a 150 | Well grow WW HOUIKG leer | Do.

While the experiments above reported indicate that under forced
laboratory conditions a few eggs may be deposited within the pulp of
very ripe pineapples, the failure of all stages of the larve to survive
in a medium of fresh ripe pineapple pulp is conclusive evidence that
the pineapple should be dropped from lists of host fruits of the Med-
iterranean fruit fly.

BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

PROVEN HOSTS IN HAWAII.

Adults of the Mediterranean fruit fly have been reared from the
fruits of the trees, shrubs, and vegetables in the following list. The
hosts are arranged alphabetically according to scientific name, and not
according to the preferences shown by the fruit fly. The numbers in
parentheses refer to the degree of preference for each fruit as a host.
Fruits that are heavily or generally infested are marked (1), those that
serve occasionally as hosts or of which many escape infestation are
marked (2), while those rarely infested are marked (8). The writers
appreciate that differences of opinion may arise over any classification
of hosts according to degree of infestation, and realize that in colder
climates than Hawaii some of the fruits classed as (2) would fall into
class 3, or even might not be recorded as hosts at all. The list
following represents conditions in littoral Hawaii, particularly about

Honolulu:
Hosts of Mediterranean fruit fly in Hawaii.

Scientific name. Common name. | Scientific name. Common name.

|
1, Achras sapota (3)........-- Sapodilla. 38. Garcinia mangostana (2). ..| Mangosteen.
2. Acordia sp. (3) =z. 23-2 2- Acordia. 39. Garcinia ranthochymus (2) -| Mangosteen.
3. Anona muricata (2)........ Sour sop: 40. Gossypium spp. (2)...----- Cultivated cotton.
4, Arenga saccharifera (3)....- Sugar pel 41. Jambosa malaccensis (2)...| Mountain apple.
5. Artocarpus incisa (3)..--.--- Breadfruit. 42. Latania l6ddigesii (3)..-.---- Blue palm.
6. Averrhoa carambola (2)... ..| Carambola. 43. Lycopersicum esculentum | Tomato.
7. Calophyllum inophyllum (1)| Ball kamani. 2).
8. Capsicum annuum var. | Bell pepper. 44, Litchi chinensis (3).......-- Lichee nut.
grossum (2). 45. Mangifera indica (1)......- Mango.
9. Carica papaya (2)........-- Papaya. 46. Mimusops elengi (1)-..-..-.-- Elengi tree.
10. Carica quercifolia (2)..-..--- Dwarf papaya. 47. Murraya exotica (1)....-.--- Mock orange.
11. Carissa arduina (2).....--. Carissa. AS = Mise Sppsi(3) = <-ta- e Banana. |
12. Casimiroa edulis (1)......-- Sapota. 49. Noronhia emarginata (3). --| Noronhia.
13: (Cestrum:sp. (8)s-2 52252. -2 Chinese inkberry. 50. Ochrosia elliptica (2).--..--- Ochrosia.
14. Chrysophyllum cainito (1)-.-| Star apple. 51. Opuntia vulgaris (2).......-| Prickly pear.
15. Chrysophyllum oliviforme | Damson plum. 52. Passiflora coerulea (3).-..--- Passion Vine.
(1). 53. Persea gratissima (2)......- Avocado.
16. Chrysophyllum polynecium | 54. Phoenix dactylifera (3)....-- Date palm.
(1). 55. Psidiwm cattleyanum (1)..-| Strawberry guava.
17. Citrus japonica (1)......--- Chinese orange. 56. Psidium guayava (1)...-..- Sweet red and
18. Citrus japonica (1).-......-- Kumquat. white lemon gua-
19. Citrus nobilis (1).......---- Tangerine. vas.
QO ROLTUS MOULLESICL) eee Mandarin. 57. Psidium guayava pomi- | Common guava.
21. Citrus medica limetta (1).-..| Lime. Jerum (1).
22. Citrus medica limonum (1) -.| Lemon. 58. Psidium guayava pyriferum | Waiawi.
23. Citrus decumana (1).....-- Grapefruit. (3). j
24. Citrus decumana (1)...--.- Shaddock. 59. Prunus persica (1)..-..----- | Peach.
25. Citrus aurantium (1).......| Orange. 60. Prunus persica var. necta- | Nectarine.
26. Citrus aurantium var. | Sour orange. rina (1).
amara (1). 61. Prunus armeniaca (1)..---.- | Apricot.
27. Clausena wampi (3).....--.| Wampi. 62. -Prunissppacl) <6 2 Plum.
28. Coffea arabica (1).-.......- offee. 63. Punica granatum (3)... ---- | Pomegranate.
29. Coffea liberica (1)..-.-.-.-.-- Liberian coffee. GAS PaTus Sppa(h)= 22s s2<ceseee Apple.
30. , Cydonia vulgaris (1)......-- Quince. 65.0 PYTEs Spa Gliese eee Pear.
31, vane yios decandra (1)...-.- Persimmon. 66. Santalum freycinetianum(’).| Sandalwood.
32. Eriobotrya japonica (1)...-- Loquat. 67. Solanum melongena (3)..--| Eggplant.
33. Eugenia brasiliensis (1)....- Brazilian plum or || 68. Spondias dulcis (3)....-....- Wi.
Spanish cherry. 69. Terminalia chebula (1) .....- Natal plum.
34. Eugenia jambos (1)....-.--- Rose apple. 70. Terminalia catappa (1)...-| Tropicalalmond or
35. Hugenia michelii (1)........| Surinam cherry. winged kamani.
36. Eugenia uniflora (1).....-- French cherry. 71. Thevetia neriifolia (1)....-.-.| Bestill.
37s ictus carica\(L) 22225 522222 Fig. | 72. Vides labrusca, (3)-2522 2 o2-2- Grape.

1. Sapoprua (Achras sapota).

The sapodilla or naseberry (Achras sapota) is not a preferred host of C’. capitata in
Honolulu. A large percentage of the fruits ripen without becoming infested. In-
festations are slight. Only 3 adults were reared from 1 fruit.

<

Bul. 536, U. S. Dept. of Agriculture. PLATE VI.

HOST FRUITS OF THE MEDITERRANEAN FRUIT FLY.

Fic. 1.—A grove of large ball kamani trees ( Calophyllum inophyllum) producing shade for a country
home on windward Oahu. Fruits from these trees are badly infested and are falling through-
out the year. Fic. 2—The inedible fruit consists of a round seed, covered by a thin fibrous
pulp in which the larve of the fruit fly work. (Original.)

Bul. 536, U. S. Dept. of Agriculture. PLATE VII.

ZL

Host FRUITS OF THE MEDITERRANEAN FRUIT FLY.

Fig. 1.— Carissa arduina. Typical of a class of fruits which are protected from infestation until
they are practically ripe by a copious flow of white sticky sap from punctures in the skin made
by theadult fly. Note this dried white sap covering punctures on fruits. Fie. 2.—Bartlett
pear (Pyrus sp.). Fruit-fly larvee may eat out the entire center of a pear and yet the fruit
(On ary attached to the tree and shrivel up after the larye have fallen to the ground.

riginal.

Bul. 536, U. S. Dept. of Agriculture. PLaTE VIII.

Four FAVoRITE Host FRUITS OF THE MEDITERRANEAN FRUuIT FLY.

Fic. 1.—Rose apple ( Eugenia jambos) sectioned to show the large hollow interior on the
surface of which larve prefer to feed. Fic. 2.— Mimusops elengi; fruit of an ornamental
tree which sheds its infested fruit throughout a3 to 4 month period. Fie.3.—Adult C.
capitata captured in sticky exudations of solidified sap about punctures in Chryso-
phyllum oliviforme. Fic. 4.—A handful of mock-orange ( Murraya exotica) berries. The
mock orange fruits several times each year and the berries falling become hidden in
the grass. (Original.)

MEDITERRANEAN FRUIT FLY IN HAWAII. 25

2. ACORDIA sp.

The fruit of an Acordia with white fleshy pulp was found infested in Bermuda dur-
ing December, 1913, by the senior writer. The fruit of the Acordia in Honolulu,
which is a different species and more woody, is not infested.

3. Sour Sor (Anona muricata).

The sour sop (Anona muricata) is a fruit which is not ordinarily infested until well
grown and is found in the markets in season in perfect condition. Under certain
conditions it may become heavily infested. Of 6 overripe fruits, 5 yielded 95, 67,
132, 87, and 2 adults.

4. Sucar Patm (Arenga saccharifera).

A single adult fly was reared from the fruit of the sugar palm (Arenga saccharifera)
during May, 1912, by the Hawaiian Board of Agriculture and Forestry. From a lot
of 14 fruits gathered March 17, 1914, only 3 yielded adults. From these 3 fruits, 1, 4,
and 2 flies were reared.

5. Breaprruit (Artocarpus incisa).

There are no definite records of infestations of the breadfruit (Artocarpus incisa).
No adults were reared from 100 very much overripe fruits taken from the ground
during August, 1914, and placed over sand in jars. Three larve were found in one
partially decayed fruit, but they were the only ones ever seen by the writers in bread-
truit during a three-year period.

6. CARAMBOLA (Averrhoa carambola).

The carambola (Averrhoa carambola) becomes infested usually only as it ripens, in
spite of the fact that it is fragrant and thin skinned. Many fruits escape infestation
even in badly infested districts. Of 40 very ripe fruits collected during September,
10 yielded no adults. The other 30 yielded 172 adults, 5 fruits yielding 2, 6, 11, 15,
and 20 adults. Only 22 of 62 ripe fruits gathered during August produced adults;
from these a total of 289 adults were reared.

7. Batt Kamant (Calophyllum wnophyllum).

The ball kamani (Calophyllum inophyllum) is badly infested at times (Pl. VI).
The adults oviposit very abundantly in the thin, stringy pulp covering the huge
seed, as the fruit ripens, but successful larval development often depends largely upon
whether the fruit in falling lodges in a place where it remains moist. The fruits on
separate trees differ in regard to infestation. On certain trees the pulp may be largely
consumed and the larve well grown when the fruit falls. Generally speaking, the
larvee in ball kamani are apt to be underfed, their pupe unusually small, and the
adults so depauperized that they may be undeveloped sexually. In a few instances
where fruits have fallen in grass on the windward island areas the larve have developed
to normal size. As many as 120 larve have been reared in onefruit. In April, 1913,
7 {fruits taken from the ground in Honolulu contained 39, 86, 0, 27,6, 82,and 115 larve.
From 104 fruits picked from a tree at Waikiki during April, 1913, 927 larvee emerged.
Of 20 fruits taken from a second tree 11 yielded no adults; the remaining 9 yielded
77 adults, 19 being the largest number from any one fruit. Of 20 fruits of a thick-
skinned variety picked from the tree, only 1 yielded adults; a single adult was reared
from thisfruit. From 1,555 fruits collected during December, 1915, 4,213 larvee were
reared.

8. PEPPERS (Capsicum annuum var. grossum).

Peppers (Capsicum annuum var. grossum) grown in market gardens and generally
known as “‘bell”’ or “green sweet’? peppers, and used uncooked in salads, are fre-
quently, although not generally, infested. Five pounds of peppers gathered August 1

26 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE. :
at Waikiki, containing very green as well as overripe fruit, yielded no adults when
placed over sand in jars. Of 221 ripe peppers gathered at the same place during.
November, 1915, 213 were not infested; the 8 infested fruits contained from 1 to 5
larvee each, or a total of 19 larve. Thirty-five adults were reared during December,
1913, from 100ripe peppers, whilefrom 13 pepperscollected on March 25, 1913, 14adults
were reared. The fruit fly was first reared from peppers in Honolulu by E. M. Ehr-
horn, who reared 6 adults from peppers collected at Kaimuki. While there are
reports that all peppers are infested, the writers have never known a. to
exceed 5 per cent of the fruits examined.

Chile peppers (Capsicum spp.) have never been found infested by the writers,
although many fruits have been under observation.

9,10. Papaya (Carica papaya and C. quercifolia).

The papaya (Carica papaya) is one of the commonest plants about Honolulu and its
fruit is the universal breakfast fruit, yet the writers have never seen a fruit sufficiently
ripe and fit for eating purposes infested with larve. Only fruits too ripe for the table
or those having decayed spots are found infested. Sound fruits cut from the tree
several days before they soften, a practice which is customary among fruit dealers,
are always free from infestation. The milky juice which exudes copiously from cuts
in the skin of the fruit contains a digestive principle said to be similar to pepsin. The
hands of horticulturists working with the papaya soon become sore if exposed to this
juice. It has been shown by Knab and Yothers that the larve of the papaya fruit
fly (Toxotrypana curvicauda) can not live-in the pulp of papayas still green, because
of this juice. This is true also in the case of C. capitata until the fruits are ripe,
although several of about 500 eggs introduced artificially into well-grown but still
ereen-colored papayas attached to the tree were able to hatch; the larve died. It
has been stated in Honolulu that fruits were infested while still green, but the writers
have never been able to verify this and all evidence would appear to disprove it.

During January, 1914, an adult female was observed ovipositing in a perfectly
sound fruit that was just beginning to turn color. Much juice had exuded around
the ovipositor and had formed a gummy semisolid globule. After about 3 minutes
the fly withdrew her ovipositor with comparative ease, but the mass of solidified
juice remained fast to the tip of the abdomen. The fly freed herself from this mass
with considerable difficulty. Seven eggs were found within the puncture, but they
failed to develop.

During the winter months very ripe fruits are more heavily infested, as a rule,
because of the relative scarcity of other hosts. From 2 fruits picked from the tree
on January 18, 1914, 205 and 67 adults, respectively, were reared. Thirty-eight
adults were reared from a decayed area in a fruit picked July, 1913. From 6 fruits
gathered during May and June, 1913, 27, 13, 49, 2, 30, and 61 adults, respectively,
were reared. From one lot of 7 overripe iruits gathered during May only 1 wasinfested.

The dwarf papaya (Carica quercifolia) serves also as a host fruit of C. capitata.

11. Carissa arduina.

The fruits of Carissa arduina are often found generally infested. Even at as late a
period in development as that when the fruit has turned deep red, slight abrasions
in the thin skin are followed by exudations of white sap which dries about the punc-
tures, as illustrated in Plate VII, figure 1. Every fruit becoming fully ripe on one
hedge was found, during February, to be well infested and as many as 30 adults were
reared from single fruits.

12. Sapota (Casimiroa edulis).

The white sapota (Casimiroa edulis) is quite generally infested about the time it
ripens.. Practically every ripe fruit falling to the ground is variously infested. As
many as 40 adults have been reared from a fruit 2 inches in diameter. While green
the fruits are protected by white sap which exudes copiously from skin abrasions.

MEDITERRANEAN FRUIT FLY IN HAWAII, 27

13. CHINESE INKBERRY (Cestrum sp.).

The Chinese inkberry (Cesirum sp.) is seldom infested, although the trees produce
an abundance of fruit. Samples of several hundred fruits, each taken from the ground
among badly infested coffee trees, have yielded no adults. In one instance 3 adults
were reared from fruits collected by the Hawaiian Board of Agriculture in Manoa
Valley in November, 1911.

14. Star APPLE (Chrysophyllum cainito).

The star apple (Chrysophyllum cainito) is a preferred host and is always grossly
infested. The writers have not observed a single mature fruit during the past three
years that was uninfested. The milky, sticky juice exudes from abrasions in the skin
until the fruit is overripe. Often, as is the case with other species of Chrysophyllum,
this juice solidifies so rapidly that the female fruit fly is caught by the ovipositor and
held captive until death. From four very ripe fruits collected at Haleiwa, May 30,
1913, 188, 110, 105, and 5 adults, respectively, were reared. Five fruits from the
same tree, picked May 27, 1914, yielded 18, 96, 54, 105, and 44 adults, respectively.

15. Damson Puiu (Chrysophyllum oliviforme).

The small plum Chrysophyllum oliviforme is one of the preferred hosts of C. capitata.
Like its relative, the star apple (Chrysophyllum cainito), it is well protected by the
white sticky juice which exudes rapidly from breaks made in its skin until quite
well grown. (Pl. VIII, fig. 3.) Although larvee develop to a very large size in this
fruit and scarcely a fruit ripens uninfested, the average number of larve per fruit is
small. Ofasample of 48 fruits collected during February, 18 produced no adult flies.
From the remaining 30 fruits an average of 2.4 adults resulted, 14 being the largest
number of adults reared from a single fruit.

16. Chrysophyllum polynecium.

This fruit, which is round and about half an inch in diameter, is congeneric with the
star apple (Chrysophyllum cainito) and the Damson plum (Chrysophyllum oliviforme).
Like them it is a preferred host and always grossly infested. From two lots of 500
fruits each gathered from the ground during May, 1914, 1,584 and 1,140 adult flies were

reared.
17-26. Cirrus FRuvIts.

In a previously published paper! on the susceptibility of citrus fruits, the writers
present data secured under Hawaiian conditions which show_why such thin-skinned
fruits as the tangerine, mandarin, Chinese orange, and kumquats are readily infested,
and why oranges, lemons, and grapefruit resist infestation of the pulp with such remark-
able success. All varieties of citrus have been found in Hawaii containing well-grown
larvee of C. capitata in their pulp and first-instar larvee transferred to the sourest, and
even half-grown lemons have been reared to the adult stage, so there is no question as
to the correctness of classifying all citrus fruits among the hosts of C. capitata. While
it seems evident that the acidity of partially ripe lemons has a detrimental effect upon
larval growth, it has been proved experimentally and by field observation, both by
Quayle and the writers, that no fruit is too acid for larval development. Savastano,
in 1914, giving the results of experimental work carried on in Italy, exaggerates the
part played by the acidity of citrus fruits in protecting them from C. capitata attack.
In Hawaii his conclusions have not been borne out by the results of investigations by

_the writers. The data in Table VIII are presented in detail because of the difference
of opinion existing between investigators as to the cause of egg and larval mortality in
thecitrus groups. The conclusions of the writers, based upon extensive examinations,

1 Back, E. A., and Pemberton, C. E., Susceptibility of citrus fruits to the attack of the Mediterranean
fruit fly. Jour. Agr. Research, v. 3, no. 4, Jan. 15, 1915.

98 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

are that, in Hawaii at least, citrus fruits resist fruit-fly infestation of their pulp in pro-
portion to the thickness and texture of the rag underlying the rind, the quantity
of oil liberated from the oil celis during the process of oviposition, and their ability to
develop quickly about the egg cavity the gall-like tissues which so often make of the
cavity a prison for the larve that hatch. The datain Table VIII emphasize the large
numbers of eggs deposited in the skin of Citrus spp., and the relatively small number
of these that produce larve able to reach and _ enter the pulp except in the Chinese
oranges, limes, and tangerines. Larve that succeed in entering the rag from the egg
cavity in the rind are unable to reach the pulp except in astonishingly small numbers
because of the imperviousness of the rag. It is the persistent attack of successive lots
of larvee hatching from different batches of eggs, laid very often in the same puncture,
that finally breaks down the barrier between the young larve and the pulp. If the
types of mortality among eggs and larve in the rind of oranges, grapefruit, and lemons
protect those fruits so well under Hawaiian conditions, where the weather is so warm
that the adult flies can deposit their eggs every day in the year, they should constitute
a valuable factor in control when supplemented by climatic cultural conditions more
adverse to the development of C. capitata in other countries.

TaBLeE VIII.—IJnfestation of citrus by the Mediterranean fruit fly.

Larve.
Eggs, appear-
Punctures. ance:
Alive. Dead.
Fruit.
|
aa In In |
Not Nor- | Abnor- In : ees beck
Empty.|empty.| mal. | mal. aol In rag-) pulp eee In Tag | pulp

Chinese orange:
1h else as See 0 2 TB A es eer (Biers Reel fe ae iE eer ae eee es | RY
DS NSF aie 0 TOR) ORES Lite aL PATOL, RRR Qt, Mes SE Rite Se
See ae eee 0 1 aS Sea ors ater ye) Fed Speke, fare Raa Sls cere ee eae ee emer S
Ls Vogal or ead eee 0 2 2 il eee LA 5 a a ed es Sere 5 rp ake a 4
Bits: Sek F4Se Se 0 1 RE Fd Ace Ana tee Se gh eee Oghya. 2 Sipe Saaeea ee
(eee ven a EAs 0 ih eres DG3| So ee ele ee | etis bate Seu eae eee adits
is Shee Soe oe 0 DA) 3 AS Ae essen al eee ee ee | Cyst is So Pa Te ae ee
Se ee | Dre ee Salah tel eyed ences rane, Se erl| 19? en 2s. eee eee
Oe Mesias pyar ear 0 1 Wi ese Pease eee ae [Pane eee | 33 See ee ee eee
1) ess ee ae ee 0 | 1A SSIES ls SOR RA AS eae ee ol ee ee 1 i ee ed 6
We eens sees 0 Ws ae 2 sees Se ays rhea] teers ete Bere cre Eee ee | eevee 6: | sees
DPE see a ee 0 4 Pores Sse. eS ee 1s ee ae fee leur ree leans
TG prieteeriea! seat oe 0 in | see gee TI Nepieee set aaa ta (i testa) Paes | Lace
paces Te ee. F523) 0 je epee. i aa a eee ee oo) DO 9 ae Si eee ee erey a exe
(een aera | 0 do Sees nahgeis-w alae site [bape Sy ae aee sas es

Lime: | |
ibe trae. th FS SEES. 10 Oy etc SES SEE SEE es eee Sse ees eR Ee L3rigScbass
DG De | 6 5 | 1 53G| oAEI cea Ps cat t legieletl when t| Siege
ee see 7 4 Fo sal (eater) rage eS 6 el (A PS © ed 2 4 Ca eran kat aS
(Se Re ar 4 Gil Ses eS epee | ea oll by eee Pe ree tee 10 StH eee
eae ea aneaatias 1 5 53 hy Pesca! Of he Fab, Cas beaten ths ieeeses
GESe EPG EL 6 OF 22 Ae 1 Let oee ye eee [ste a a eel a Sees s = 20 TS et ess
(hop aera e Oe | 0 7 Co Fd [eee | a a Le ae eae 9 5 ie eres ace
te PPE Woe sun tes, ap AN 3 Sal 80 Opa Sad oe ay See ee eae Ss Stones 9 eee
OF sensttgs Bh doc, | 3 1 ee nap re 8) for vee) Same ie eee See ee eaten See
ROSA een oe eee 8 id Na es Toon eal emo ene eres | 56 | ON ee ae
TA ee Ae er 0 Q) bach £4 3a SLRS pee eal eee pee | ree lye Sep beet eee AQit - E serere a!
LI Se aa te 6 5 61 77g See aa EE prt endrce 6 3 | Sea oe
Nia aay eS Be 4 Dae Sa Sc PPETES SEA Bh tp ball Ree pet kal Rae TWse SSUES
1 a poe Bre ee 9 Dal eon no) LL Pees, eo ee eee myer Boer 7B) ee ea Ot Se De
pees 3 henna 7 Fh meee esa a nl pp Babel AR ee 9 17 eee
GEAR! Sree eee 5 Ofer. Se] es es pee erie es ee ae ee ie eee
| ly ARE ee eR Op 11 Ooo eee coe] eso Me Sl ee 2 ee | ee | renee ne ee eke ee Rag Eke
TBP s Re re Ye 5 iL eee 142) BES. HOE Dae eee 14 STIeaaee
Cr ies ae fo 7 Gal ee cl er kc eae one Me ee BEST) 12, eee
Fs copeeital ea 5 i ape Weasel ad io Bagg oes (or ee ee

Grapefruit:

| Ser ee eae: 7 25 83 Bia | Cy etn soemecn | sate ae | 19 Pe ton Soh
Nis SR aah a ee 1 12 369 a4 Bl AS ee ee 1G eee he? ORE | 26 Assi eke
Dawa orapecto ccd 0 3 17 16 HA Scereesesocal ec ie 1 U8 Wh Pe [Se a 8
eo) 2 A es 2 3 Alo. Raise cda heehee Ome eae © ame Ne cea etme oe Di [eee aes
Sy Sree ae 5 6 42 Oech aero all ects e cee fy ) Soa ocean ne seit
Gh Se eS 7 14 43 203 CTE CIE Re 13 45 J RGAE

: MEDITERRANEAN FRUIT FLY IN HAWAII. 29

Taste VIII.—IJnfestation of citrus by the Mediterranean fruit fly—Continued.

Larve.
Eggs, appear-
Punctures. eas
+ Alive. | Dead.
Fruit.
Empty Not | Nor- | Abnor- an c- | Inrag In aa c- | In rag In
empty.| mal. mal. Ae pulp ane pulp
Grapefruit—Contd. |
(ee oie | 8 DAE | eee | AB Arkin eee a ae eevee tops eee 17 iis |bis SOs ee
a ee EN Cai 4 19 9 G0GH| Pe eecec a eeser a loasces - 10 UA eee ere
es Re SIS eves 2 (al ea GOn ee ae (See ese see 59 Oleseaa=
Use oases 5 7 het etree AQ Arle Fees pene eal oe ceste ailtene cette So SOM eee eae
ees cee aes 1 1 hae 2328 |= Seles See ea we ee Del Reber See |e
i Drees re EN 14 8 32 75 Sileb as seo Sess aker His Ss csartenta Seria Seen
NBS ae eee eres 0 27 5 S8De |i ee ee esse sel eeontoset: Saye eee ee |e pte ert
UAC re seep eie a Oe a 0 18 88 PAV] Wis at Sr EI Ss Sa os Ae 4 OF ae
IE eae ere see oe 0 Duleaceeos: 86 Sr Retees alleen Sage Woe hab ael acres eer mee
1G a ee es ees ee 0 11 8 DG By es cp orale ios re lve es ee 19 Wl Geos ese
eR Sere es Nee Wat 0 GE eet syess! 42 toe fechas Ske ean ears GHEPEceeeel pias
1 cst Be Sener a ri 0 ASN ieee 2a ee TM Nerc rape clears cris yeas rere Sera larsye spree nec Sicrall Sea ag
iO ee eld setae 0 LOM sss 2: Bl corstcan GaShoan boda tets EA Nee eee) aaccelcers eae
QOS Freese eek 0 1 Bel Sotee se SP A0)d Se OHeb oe lacie GSte a aonore 7a ell Sere | be Re
Lemon
1 ree ey ee 3 4 PR Ssnosac SPA) Nee ay oye ec Ai lees ene ee tte
FA Bee sa poner Beak 0 2 UG Gees See aso ss eee a ees (meer aeee | DS aR eye eee as
Sie eee 5 On Ez aes ey es ead Se eles cpanel | Kine ase leoee opal eeoodcor aoast see
Ae Aen ee 4 LP Sore C7 RRS Bex Gl Ee ie see gees Paced Borla repel Veet dee neal acre
Dea Cea ee 14 4 1 USE | teens eee ere Sl Ween sm eae ee | 1S sae rete ee
Geet t ese 2 2 By epee ation! Bese MoS Abas seeel Seema ilsacaeced eesawnes
ee Went Cee Sees 3 2 Dr eee ees rare rays. eorermall lacs) oe aes Aral egetc termes rs | eto ace
cha eRe Saisie 4 Oy Seas beg some ee seinl a orate sete ments es ol | ME Sey (ee ees |fejcerecet ac aie. ©
Ole cmus awe: Be 28 12 47 US wee Soca een oe Gel ebeae ae ON ees eercee
Ona ro oe: 8 3 15 De | erage ea] So reso | aes as olla peers estate va|Ner Bros 2
ila be San Reso 6 10 129 Sl oate ers [ea eee ie eee DAA Ss ace Sel lee Be
Nes eee ee 11 5 39 ial ee 2 as ed eo 1 cee Wee
Aer er ee eae 9 5 38 PO Gece heel seta acu sll ies nora ee cia enema Aaa cease
Aes oot es as ee 15 1 MOD eee See [SESE oe teens a See | Steeneoeee Pes pers bees eee
Uy in cra yee 4 ON eee eel Cehecesse ee Fe peret Saeses beeede as ee cel [ee ce fee eee ots shee Gee beaeae
UGE re eres 2 168| S225 2 GA icra Sere ata ie Se Be le aeheernee Bisley
IE Rrcso eases Goee 8 2 NO ee eSucec |e. ssteiae Shtepsees at ere ae [hfeeteata seal sjah-ie Aer eee Bi
AG eee elects 1 Qriece Cassa tee ees gre ele ei [ee geeg sal | es ida lr eh a te Ihe Steel ae
Ie eres oe ee 7 Cel eectences Srl Renee cae tees ich es I esl (gen Bekele Pars ae Fe eel
20 ae ess 12 15 19 Ghidlosocuon aed een al lscoesess | Buenas eel | eee!
TOE eS AR SARA ee 30 3h, MLD) eRe | Sefer een a ets st or pace lle earn a | SepetatepanMe sie eae sie
Daa esti Seber see 53 10 23 7A ES Sse es occ es Ges Are | OB eeeyeet se lems
23 ee ene tis 12 Suen sez ee I fe PS ast Se ae Ts lees eee 209|E Seer ees te
pe 24 es een ee 11 iS aereMsine zd oceeraetine eee es |e ee 1 aber opesllaooe shee
PD ete Shee ee 5 ell evens Bae idl eee Sala hegceesee tie oar Seer eeae eee as
VAs See ae Bee ee 5 Ou ae eee el iets crs ae [fvek tse Nessa eateries WEEP INOS Sy leks pererlen ie ae a
DI GR are 2 4 14 TRS ate era He eo | aa ee 4 TQ) ol iets ee
Gis ce tele a eee 6 22 0 (lg earee sl eet Omar ee 2 [bss o0s ta eRe sis
DOr cha ae 2 1 Ageless SS pea pleas te Pete a lb eon | hare (ets areas
S0St ees 4 8 62 Da eae stent el (ae pe eas eseeeaeee
SISA ee ee 4 1 0 Uaioe Boden epee ee ce AUR ee Nada | Se ec | er cee eee
Ooo teeta NEL Saetae Sale see ae ice seers ee ha es Sh hale a MEPS IND SE aire se Wee Sate
oo See eee 6 12 67 Ol Were Saar et eee ieee NOWE Sees [esieeee =
SY bee cor aa re femles 4 TSE SAS SS Ge ree | Seeessresipa persis vars [tence (iN We es jpadHsnss
Sar ere Meer eee 4 2 l6get es. eneor reer Deca ae te Belge Preceys| sae
Sweet orange: 2 | |
beretey Ah Pete 2 Wee ees tas eee SIE rsh kee ey ea eed 41 10h |Es-2233-
Dee eee ona 13 TELS? es eles sea neg els Renee yf es et |e 42 Me egees a5
Deets circ ae 0 Dial eaten ces eee caerale ats ee cine Soe el oeeeae ae eee cys oe DOF semeoes
ES See eae ae tee 2 By | ses Sesame dll: een liegl Mey! Bape all otek now 30 15 BG ere Serie
Soe anne eee 2 By ee Oe ee Oe eee GS ee See ee eee 14 Bill Meer
Gone 28 4 0 eee oe) se gM GCs eee eae hs eee me ces Gate tees
SS aes Sr ee 0 TDuleepetsce) oremu acta eect als yore (Gr Si 4: 17 Aa eres
Sess SpE ey ae 5 HS Sees lee ela eee a Aen cel cee Sees i ene 83 OM eeSees se
OSS Staseeee ers - 1 dices Seas oe Ae Ato pe aii coal ao ceae no ema aE acl |aaeous apo aba ss
Ose ee pens = 2 oH at he Fria AB tah INE nie eer a ae a 37 Pf NOE eae
tees Se a0 Deiat eee Sons NE ED AE ek PRESET Y TEE LIDS SELENE Sees
LORS: 2 Rene eae 2 Gye eee a ae Ke Bic LN ee oot ee UR 19 | 265) ee oe
GS eke een 1 Bl Peeereaer hes sha 5 suai les A ica) a 36 | I Dh uk busses
aS se eae ar 1 Bh lss. Seer etal ek Spek pee} rele ley anaes (2 35 13 I PN Gees ete
tS eee ee 1 9 Dives aces ae Ce ak eee ete 6 G4) ee
pret Say fe 7 sia ae aa pong a estas OR 1s 1 ul Nteae toad EL B75 5Si| eae

1 These 29 newly hatched larvez were feeble and appeared to be about ready to die. ;

2 Fruits of sweet oranges 1 to 13 picked Mar. 7, examined Mar. 10, 1914; 14 to 20 picked Feb. 24, examined
Mar. 6 and 7, 1914; 21 to 25 picked Sept. 10, examined Sept. 16, 1913; 27 to 29 picked Sept. 10, examined
Sept. 18, 1913; 30 picked Sept. 4, examined Sept. 15, 1913.

$ Third-instar larve in pulp; orange not decayed.

30 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

TaBLe VIII.—Infestation of citrus by the Mediterranean fruit fly—Continued.

Larve.
Eggs, appear-
Punctures. . 88 a | :
| Alive. Dead.
Fruit. |
In In
Not Nor- | Abnor- In | In
Empty-| ompty.| mal. | mal. aw In rag. | pulp le | In rag-| pulp.
Sweet orange—Con. | |
hee ee 0 Ss ce eee [2 oc Soars gees a see eae ea es 0 Ly eae hots.
1 Ro tees Seer eee Ue 2 16 en eae eres ee ee ee ee eee TH Steines?
it See: eeesaee 6 | ON ea eae ie ee ane bee ee eS Ce oe 3 PAs eee
OV ae Sea eames 5 Gs ees eS 9S aS elen See 112 19 TO" Sees
7A ae ier hea 7 20 3 204s cee SS3 | ee shea eee ee 107 63. eee
DIN ee SUR AES SE 15 18 7 DA Glo BOS Cees | a enca 66 51S See ae
FS eis CSOES ee ae 8 Os eae Soups aeelE ES See Ste 7 pS paps ns a
FF at NT ag tb et 29 16 12 685 hoc ees = Bee ee 18 BY dy eae Pe
DES ae ee 4 13 14 BES a See er etal eee 48 G5<| sateen
PORE REE aan 2 3 AQ Meee 77 al ees caper pes ate el [ee ee 35 (et ae
Die eae ao ees 4 9 40 SOR Shes Soe Soe es lees 27 ol pees ae ee
Dot Soh seep se 10 12 25 Ve Pease PA oc AS Sieg 1 ae a Bee sate
Tala Se OES | a BS nang 13 Up Saeed Perea aren enor 52 ce Bee epee
2X1) ee ee See | 12 11 150 BOWS. skal s Seco See |e eee ae ol a eres eters oer
Sour orange:2

Pees Sec eee 5 5 li 1 Yi) ees es Os eee See ee ee 1) ee

jaro Sete eres ee 2 6 0 Qa tae | eae eae 3b lou See eee

Sc ia ss 3 8 19 To) |ascrers aoe eee etree gee cecal a

det eS a 2 8 30 Bp a tee ie valeat oP Ue Lint ee ere:

Ey iraae Siaas oan ay oe aes 0 8 12 1h Sees <a ee BE Sele ee ee SU (aves Se ees

Glee sae 3 10 “75 D5 [eS rete ey cae 32 14 oe

(Saves See Vea 2 8 4 TAG Sea icles Bed Seon oe Se ES 24 Tlesetccs

bo eae Depseee ee eae 1 7 7 hae cole see| eee 59 ay Reet re Fee Ge a

Asa ea ea alee 1 7 0 4 nC eee ee 7 23 10, eee
NOR eae a en wer 4 9 10 ABS. So Stree eerste ae ch eae ee ie
1 Uy Faas ee Seoee if 27 12 tos Weegee es al aN Py Soe 28 Ble | Sots ees Sees
OEE anes osene 1 12 36 1 We Baers ieee) ae bese 5 iol bape iis eae va,
WS ee ee = eee 1 5 0 25 Ul (Ste eae ea oe | eee 16 (8 esas
Uf bicexe Saree ei sears IP 2 2 10 Ie: Sp [esr ties Meee Se 25. PS. sap ccaleee aed 1
lets see ato SF 0 2 0 tS ey ees Aes =) Ss ae SOs te. Sle ee ee ee
(Ce Ui isang (Caen (Ente A sey Pre ett) ae ins SS Sa oe Gl eae San thi Ss [ae
jg (ae eee ene ett a yee ee See eee bee Ae ees ec eS Ras ees ae eee WT Se ee Saale
US eee Se ee 2 1 5h (Rel (pee emer i i oat ee ole ae es hee ce ele co csece
1G aes. eo ee 4 | 4 57 del ees ee NEE ee Panans s = eee bal eet aes bow Se eae
SRR ORT ES hee 1| 2 0 A4 Mh ers eS ek [2s2-255 nore e ee eee

| |

i Third-instar larve in pulp beneath soft but undecayed spot in rind.

2 Fruit of sour oranges, 1 to 16 picked Mar.3, examined Mar. 10 and 11, 1914; 17 to 20 picked Sept. 4, exam-
ined Sept. 5, 1913.

3 Very badly decayed.

17-21. Crrrus Fruits Eastry INFESTED IN HAwalt.

The varieties of Citrus japonica in Hawaii known as the Chinese orange and the
kumquats (‘“‘testa di turco”’ of the Italians), of Citrus nobilis, known as the mandarin
and tangerine, and of Citrus medica limetta, or lime, are easily infested by C. capttata.
The data of Table VIII on the infestation of Chinese oranges and Hawaiian limes are
introduced as examples of infestation for the varieties of C. japonica and C. nobilis. The
rind of the Chinese orange and of many limes, mandarins and tangerines is so thin
that the adult fly is able to deposit eggs either directly within the pulp or between the
rind and the skin covering the pulp, but parallel with the rind and at a‘slight distance
away from the ruptured oil cells where they more often escape the fatal action of the
oil or hindrances in the form of a dense rag. Of 609 eggs deposited between the rind
and the pulp in Chinese oranges, 98.5 per cent hatched and the larve, unhindered by
the presence of an impervious rag, entered the pulp. The infestation of the pulp of
limes, tangerines and mandarins isin inverse proportion tothe thickness of therind. It
is interesting to note that eggs in the Kusaie limes, the rind of which is sufficiently thick
so that the eggs are usually deposited directly beneath the puncture, die with great
regularity, while the eggs in Hawaiian limes, the rind of which may be sufficiently
thin to permit the eggs being deposited as in Chinese oranges, or so thick (according to

Settee ki a

MEDITERRANEAN FRUIT FLY IN HAWAII. 31

the individual tree) that the eggs are laid either in the cavity in the rind, or between
the rind and pulp but directly beneath the puncture, suffer a degree of mortality
between that of eggs deposited in Chinese oranges and Kusaie limes. Mandarins and
tangerines in Hawaii usually are infested if allowed to ripen thoroughly upon the tree.
The Satsuma orange is a fruit that easily becomes infested because of the looseness of
the rind and lack of well-developed rag.

22. LEMON.

Because of the danger of introducing the Mediterranean fruit fly from the Mediter-
ranean regions in lemons, the importance of this fruit as a host has been thoroughly
investigated at the request of Mr. C. L. Marlatt, chairman of the Federal Horticultural
Board. The observations of Martelli and Savastano in Italy have led them to definite
statements as to the immunity of commercial lemons to C. capitata in Italy. H. J.
Quayle, who conducted an investigation during 1913 in the Mediterranean citrus
regions under the direction of the Federal Horticultural Board, found less than 15
lemons with infested pulp during a search of eight weeks throughout commercial
lemon orchards in Italy and Sicily. It is interesting to record that of the 15 fruits
containing larve within the pulp, all had the appearance of having been injured,
either mechanically or by fungi, and in all but two instances they were found in an
overripe and overdeveloped condition on the ground beneath the trees. The two
fruits found infested while still attached to the tree were partly decayed on one side.
These instances of infestation recorded by Quayle, who is thoroughly competent to
judge from long experience with citrus in California, refute the argument that lemons
are too acid to support C. capitata larve, although the small number of lemons found
infested, of the thousands examined during the eight-week period, strengthens the
argument set forth by the Italian entomologists, as well as by the writers, that lemons,
commercially grown and cured, will not support the fruit fly if they are not first
subjected to some mechanical or other injury while still attached to the tree.

In Hawaii, where climatic and host conditions are so favorable to C. capitata activity
and where every host is subjected to the severest tests, the writers have never found
a lemon of either the commercial or the rough-skinned type showing infestation of the
pulp unless it had first received mechanical injuries. Although there are compara-
tively few lemon trees in Hawaii, those known to the writers have seldom been found
infested. By “infested” is meant, in this instance, an infestation by C. capitata
larve in the pulp. Out of 235 well-grown and for the most part ripe lemons of the
commercial type, picked from the tree, only one eventually developed adults, three
in number, and this fruit when picked was partially decayed as the result of a thorn
prick. Out of 161 lemons of the same variety taken from the ground in a very much
overripe condition, only two developed larvze, 1 and 5, respectively. No larvee devel-
oped in 434 ripe, rough-skinned, but badly punctured lemons picked from the tree. One
partially decayed rough-skinned lemon picked from the ground produced 12 larve.
These instances of infestation of the pulp, taking place in the field, are the only ones
which have come to the attention of the writers during the past four years in Hawaii.

The recording of so small a number of lemons with larvee developing in their pulp
should not be interpreted as meaning that lemons are particularly free from attack in
Hawaii. The data of Table VIII prove that, in reality, lemons of the commercial
type grown in Hawaii are very attractive to adult C. capitata as host fruit. The many.
fruits listed above from Hawaii from which no adults were reared were as heavily
infested in the peel as those recorded in Table VIII. Particular attention is drawn to
this point since it is the contention of the writers that the immunity of lemons, other-

wise uninjured, is due not so much to the acidity of the pulp as it is to the impervious-

ness of the rag. It seems incredible that lemons heavily oviposited in should be able
to resist successfully infestation of their pulp, yet this is true. Examination of 5
lemons showed that 73 of 79 egg cavities or punctures had been made between the

32 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

oil-cells, hence the immunity of lemons is due chiefly to the imperviousness of the rag
and the gall-like developments about the egg cavity which make it difficult for the
hatching larvee to leave the cavity.

In the laboratory a comparison was made between the infestation of the rind of
cured California lemons and well-grown fruits picked fresh, both green and yellow
in color, from the trees. About the egg cavities in freshly picked fruits infested by
adults in the laboratory, a hard, more or less gall-like condition of the walls and ad-
joining tissues develops rapidly. In the well-cured fruits no such gall-like harden-
ings were detected following infestation, and after hatching the larve had little
difficulty in working their way out of the puncture into the rag. Thus six California-
grown lemons such as are found on the markets were exposed between April 3 and
5, 1915, in large glass jars containing each about 200 flies. After removal they were
held until April 12, when an examination showed them to have been oviposited in
16, 26, 31, 29, 39, and 20 places, respectively. Of the 161 punctures, only 8 had been
made in, or through, an oil-cell and in these the C. capitata (numbering, respectively,
2,1,1,3,0,2,5, and 8) weredead. From the remaining 153 punctures, made between
the oil-cells, 441 larvee had escaped into the rag beneath, where, without exception,
they were found dead. Other well-grown but greenish colored lemons were gathered
from the trees and immediately exposed to adults within similar glass jars between
April 14 and 16, 1915. These fruits were examined April 19-20. Before being
exposed in the jars all punctures in the rind, made previously in the field, were
covered with gummed paper. The results of the examination of two of these fruits

are given here as typical:
Fruit No. 1.

Puncture 1. One dead larva in puncture located between oil-cells.

. One unhatched egg in puncture in oil-cell.

. Three unhatched eggs in puncture between oil-cells.

. Six unhatched eggs in puncture between oil-cells.

. T-wo larve barely alive in rag beneath puncture made between oil-cells.

. Five unhatched eggs in puncture between oil-cells.

. Seven unhatched eggs in puncture between oil-cells.

. Four unhatched eggs in p incture between oil-cells.

. Six dead larve in puncture between two oif-cells.

. One cess larva in punctu*s between two oil-cells and one dead in rag
close by.

11-19. These nine punctures were shallow and contained nothing.

co
SO CONT SO OT > Co LO

—

Fruit No. 2.

Puncture 1. Nine dead larve in rag beneath puncture between oil-cells.

1

2. One dead larva in puncture made between oil-cells.

3. Four dead larve in puncture made between oil-cells.

4. Three unhatched eggs in puncture made between oil-cells.

5. One dead first-instar larva in rag beneath puncture made between oil-
cells.

These data indicate the way citrus fruits are protected from infestation of the
pulp, and they supplement previously published data on the development of larvee

within lemons.
23. GRAPEFRUIT. ts

The ordinary types of grapefruit which have come under the observation of the
writers have been particularly resistant to attack up to the time when they are fit
for table use as indicated by the data of Table VIII. These data were secured dur-
ing September. Many fruits from these trees in Manoa Valley, Honolulu, which
were sufficiently ripe to fall to the ground, have been held over sand in the labora-
tory but yielded no adult flies. The writers have found other trees bearing fruits
with rinds of a looser texture from which they have reared adults, and in certain
instances have found fruits still attached to the trees, which, though much overripe,
were badly infested. It seems very probable, therefore, that should the fly reach the
citrus regions of the mainland, certain thin-skinned varieties of grapefruit might

Bul. 536, U. S. Dept. of Agriculture. PLATE IX.

GRAPEFRUIT AS A HOST OF THE MEDITERRANEAN FRUIT FLY.

Two types of infestation. Fie. 1.—Larve have eaten out a portion of the fruit
while the rest remains unaffected. Fie. 2.—Infestation extending throughout
the pulp. Note that the rind shows evidence of infestation of the pulp only at
the decayed spot on the lower side. (Original.)

Bul. 536, U. S. Dept. of Agriculture. PLATE X.

THE ORANGE AS A HOST FRUIT OF THE MEDITERRANEAN FRUIT FLY.

Fic. 1.—Orange infested with larve of the Mediterranean fruit fly. Note that
the fruit looks sound, except about the irregular hole, through which a few
well-grown larve have already left the fruit. Fic. 2.—Orange infested with
larve of the Mediterranean fruit fly showing two breathing holes of the larve
in the decayed area. (Author’s illustration.)

MEDITERRANEAN FRUIT FLY IN HAWAII, 30

become seriously iniested unless gathered and sold early. Three grapefruit out of
five dropping from the tree in an overripe condition, two months after they had been
marked as sufficiently ripe for eating, produced four, two, and four adults. It is
interesting to record that when these five fruits were marked they already had been
oviposited in. E. M. Ehrhorn reared 16 adults from an overripe grapefruit grown in
the Punahou district of Honolulu during November, 1911. The grapefruit grown at
ex-Gov. Frear’s city and mountain residences have been found infested when much
overripe. The fruits used as illustrations (Plate IX) were taken from Tantalus during
a particularly wet season when it appeared to the writers that the action of numerous
showers had aided the larve in breaking down the protective rag of the rind.

The exudation of gum from punctures does not always occur, although at times it
may be very excessive in Hawaii.

24. SHADDOCK.

The lage, very thick-rinded shaddocks are not infested successfully until they are
very much overripe. During March, 1914, fruits were gathered from a tree in Hilo,
Hawaii, from which fruits had been taken for the table during the months of January
and February. During those months no infestation of the pulp had been noted by
the owner. Examinations made of the fag end of the crop showed that larve had
successfully penetrated the pulp and had been able to burrow about through the
loose-textured rag. Instances were found in which the larve had completed their
entire development within the rag. As many as 22, 17, 9, 17, 16, 25, 19, 8, 1, and 18
living larvee were found in the rag of 10 fruits. Of these 10 fruits only four possessed
27, 13, 3, and 12 living larve in the pulp. On examination, made at the same time,
of equally ripe fruits of another shaddock tree that possessed a firmer rag, there were
found 6 normal and 39 abnormal appearing eggs; 5, 2, and 3 living larve in the punc-
tures, rag, and pulp, respectively; and 405, 696, and 1 dead larve in the punctures,
rag, and pulp, respectively.

25. SWEET ORANGES.

Oranges are subject to severe attack from the time they are nearly grown until they
fall to the ground or are picked. (See Pl. X.) Ten oranges just beginning to turn
color, collected in Honolulu in November, 1915, had 14, 33, 74, 4, 22, 13, 99, 11, 20,
and 14 punctures, respectively, in their rind; 10 others of another crop gathered dur-
ing June, 1913, had 29, 17, 34, 14, 11, 17, 33, 17, 18, and 17 punctures, respectively.
Ten ripe fruits picked in the same general locality as these 20 fruits during October,
1915, had 21, 2, 17, 10, 10, 3, 2, 46, 9, and 3 punctures, respectively. In spite of the
fact that 39 oranges picked in September when they were just becoming well yellowed
had an average of 32 punctures per fruit, none of them developed larve within the
pulp. But of 784 oranges gathered during March, 1914, when very much overripe,
254 produced 2,272 larve, or an average of 9 larvee to the fruit. Such data as these,
coupled with the more detailed data of Table VIII, throw much light on the wonder-
fully resistant power of oranges to fruit-fly attack. Were oranges not so well equipped
by nature to withstand attack they would be ruined long before any of them could
ripen. Considering the number of eggs deposited, very few adults emerge even from
fruits that become infested in the pulp. Thus, only 5, 13, 4, 1, 6, 12, 6, 30, 8, 4, 1, 1,
14, 26, 1, 12, 31, and 2 adults were reared from 18 fruits picked because they appeared
to be badly infested.

26. SouR ORANGES.

The ordinary sour orange commonly found in Florida groves is as severely attacked
as is the sweet orange, but on account of the looseness of the rind and rag it becomes
infested in the pulp more easily. A larger percentage of fruits become infested in the
pulp when well ripened than of sweet oranges. (See Table VIII for data on infest-
ation. )

81340°—18—Bull. 536——3

34 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

27. Wampr (Clausena wampi).

The wampi (Clausena wampt) is a native of China. While a large percentage of the
fruit produced by a tree growing at Beretania and Punahou Streets, Honolulu, was —
found free from attack during June, 1914, certain overripe fruits contained larvz of
C. capitata. From 200 fruits gathered during July, 1913, only four adults were reared.

28, 29. COFFEE.

Coffee cherries (Coffea arabica and C. liberica) are favorite hosts of the Mediterranean
- fruit fly. Coffea arabica is grown in various portions of the Hawaiian Islands, but
commercially, at the present time, only on the island of Hawaii. (Pl. V.) During
the fiscal year ended June 30, 1915, there were exported from the islands 4,363,606
pounds of raw coffee beans valued at $651,907, besides the coffee locally consumed.
Fortunately for the coffee growers in Brazil and Africa, as well as in Hawaii, the
larvee of the fruit fly attack only the pulp of the cherry surrounding the beans or seeds
and in no way affect the value of the latter. The chemical analyses of Miss A. R.
Thompson, formerly of the United States experiment station at Honolulu, have proved
that beans from infested cherries do not differ chemically from those from uninfested
cherries, and tasting tests of coffee made from roasted beans by Messrs. L. Macfarlane
and Robert Wallace, coffee growers of Hawaii, Mr. H. L. Lang, of the office of Home
Economics of the United States Department of Agriculture, Dr. E. V. Wilcox, for-
merly director of the Hawaii Federal Experiment Station, and the writers have failed
to discover differences in either the flavor or the aroma.

The unrestricted development of larve within coffee cherries does, however, bring
about certain losses to the growers and mill owners that are apt to be overlooked
except by those best informed. Before the introduction of parasites into the coffee
districts cherries were infested, often as soon as they began to turn white from green,
in the final ripening process. The larve, numbering from 2 to 8, were able to become
nearly full grown by the time the cherries had turned red. An examination of the
coffee cherries as illustrated (Pl. V, fig. 4) shows that the beans occupy the larger
portion of the fruit. The pulp itself, with its thin, easily punctured epidermis, varies
in thickness from 0.04 to 0.14 inch, or is scarcely thicker than a well-grown larva of
the fruit fly. Therefore, by the time the cherry would ordinarily be ready for har-
vesting the larve have devoured practically all the pulp, leaving the seeds hanging
more or less loosely within a sack composed of the thin epidermis. If the weather
happens to be dry, the epidermis shrivels and hardens about the beans and the cherry
remains on the branch indefinitely, resembling closely those killed by disease. How-
ever, should the harvesting season be rainy, the epidermis decays rapidly and under
the weight of the beans the cherry falls to the ground. The writers have been in
certain coffee fields where a slight jar to the tree would cause many cherries to fall
to the ground, where they are lost. This type of loss necessitates extra pickings and
greater cost of labor. Since the successful introduction of parasites the fruit fly has
been so reduced, as discussed on page 99, that while cherries are infested in about the
same proportion as formerly, the infestation occurs so late in the ripening process that
extra pickings now are not necessary and the cherries on reaching the mills during
the height of the harvesting season contain chiefly eggs or young larve which have
not had an opportunity to reduce the pulp. Whether these improved conditions of
1914 and 1915 will continue remains to be seen.

For some time after the advent of the fruit fly into the coffee districts, prices for
coffee in the cherry delivered at the pulping mills remained the same per pound.
During 1912 and 1913 when the fly attack was severe it was difficult to find at the
mills cherries which were normally bright red and sound. Practically every cherry
that was red was badly infested and its pulp had been consumed, and the floors about
the delivery platforms were well strewn with emerging larve. As the pulp only had
been destroyed, a pound of coffee cherries badly infested contained in reality many

MEDITERRANEAN FRUIT FLY IN HAWAITI. 35

more coffee beans, or of that portion of the cherry that had any commercial value.
Counts made of samples of badly infested cherries, and of those in which the infesta-
tion had not progressed sufficiently far to affect the weight, were made and the loss
both in numbers and percentage of cherries is given in Table IX.

TABLE IX.—Loss of weight and pulping quality of coffee cherries due to infestation by
Mediterranean fruat fly.

: Loss due to infes- Cherries failing Cherries partly
Number of cherries. areas to pulp. pulped.
Weight of sample. = - = a
Badly | j.cent | berot.| Lyper |. Badly |qacnt |~Badly. |. paen
ght ber of : bright |: bright
infested ad cherries. | centage. infested. ant. infested. ari
BIPOUNAS oe 3, 060 1, 980 1,080 54.5 692 0 334 25
AO OUNGS Ss ee2 oe 3, 675 2, 892 783 27.1 833 11 699 227
4 pounds. .<<0 aoc: 1,828 1, 277 551 43.1 274 3 357 274
Spounds 2. oss: 1,171 736 435 DOr ime ee! ene | ee eet ee
10 pounds............ 3, 562 2,561 1,001 BO een eter cle carl els 27. El 25 eet

1 Attention is called to the fact that differences in the size and succulency of coffee cherries is responsible
for the differences in the number of cherries per pound in the different samples. While several ordinary
weighing machines were used in securing data in Tables IX and X, the uninfested and infested cherries
or beans of the same sample were weighed on the same machine.

It will be noted that loss in the number of coffee cherries due to heavy infestation,
when the cherry is sold by the pound at prices paid before the advent of the fly,
ranged in the particular examples taken from 27.1 to 59.1 per cent. In practice,
however, this loss is considerably reduced by the addition of half-ripe fruits in the
fields. This loss has been appreciated by the small Japanese coffee growers and
has been responsible, in the opinion of the writers, for the erection of many small
puiping mills throughout the Kona coffee district. It has also encouraged coffee
renters who deliver their crop at the large mills to put in their sacks a high percent-
age of ‘‘too-green” cherries which will not pulp and are therefore lost.

Badly infested cherrtes do not pulp as easily as do sound fruits, as shown in the data
of Table IX. Thus in 6, 10, and 4 pounds of badly infested cherries, run through a
gasoline pulping mill, 692, 833, and 274 failed to pulp, whereas in three samples of
the same weight of unaffected cherries, 0, 11, and 3 cherries failed to pulp. The
number of badly infested cherries that only partly pulped is also much larger than
that of unaffected cherries.

To determine whether the beans from infested and noninfested cherries differed
in weight after they had been dried and sacked for several months the beans of 1,000
cherries were weighed separately with the results given in Table X.

‘TaBLe X.—Relative weights of thoroughly dried beans from badly infested and uninfested
coffee cherries.

Weight of sample of dried beans from 1,000 cherries.

Not in- Not in-
Lot. Infested. fested. Lot. Infested. rested?
Ounces. | Ounces. Ounces Ounces
1 11 3 10 10
1 Lae be il 2B ee peed erg come 10.5 10.5
10.5 11 12 12
9.5 10 11.5 11 g
10 10 Li Syst eng 11 1 bes)
Dee ge ee 9.5 10 12 12
9.5
9.5

ij

36 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

The data indicate that the weight of the bean is not affected by infestation.

In experimental work coffee cherries should be avoided, if possible, as a source of
fruit-fly larve unless one is working close to coffee fields. While from 2 to 8 larve
may mature in each fruit if the fruit remains attached to the tree, the fruit heats and
decays so rapidly after being picked and placed in containers that only a relatively
small number of adults can be reared. Only 427 adults were reared from 1,500 ripe
infested cherries placed over sand in lots of 25. If these cherries had been allowed to
remain on the tree they would have produced at least 6,000 adults.

30. QuINcE (Cydonia vulgaris).

The quince (Cydonia vulgaris) is not grown in Hawaii, but fruits obtained from the
mainland were readily infested. The quince is frequently infested in Australia,
South Africa, and Spain.

31. PErRsmmMon (Diospyros decandra).

The brown persimmon (Diospyros decandra) is the only Diospyros grown in Hawaii.
Mr. G. P. Wilder has grown fruits a few of which have become infested on reaching
maturity. From one ripe fruit 57 adults were reared during December, 1911, by the
Hawaiian Board of Agriculture. The persimmon has been reported infested from
Algeria, South Africa, and Australia.

32. Loquat (Hriobotrya japonica).

The loquat (Eriobotrya japonica) is badly infested in Hawaii, and appears to be a
favored host. Infested loquats often hang on the tree and shrivel up after the larve
have become full grown and dropped to the ground. When punctured before the
_ fruits are ripe, the areas about the punctures remain green after the rest of the fruit
turns yellow, thus making these infestations very evident. As many as 1] punctures
have been counted in a single fruit. From lots of 200 and 150 fruits each, 1,261 and
990 adults, respectively, were reared. From one cluster of 17 fruits 458 adults, or an |
average of about 27 flies per fruit, were reared. )

In Bermuda the loquats are badly infested and serve as a host by means of which
large numbers of flies pass the wirzter and spring months.

33. BRAZILIAN PLUM OR SPANISH CHERRY (Eugenia brasiliensis).

The Brazilian plum or Spanish cherry (Hugenia brasiliensis) is easily and badly
infested. Itis doubtful ifa single fruit comes to maturity in Honolulu without becom-
ing at least partially infested. The larve develop well in this fruit and often as
many as 20 adults may be reared from a single fruit slightly over one-half inch

in diameter.
34. RosE APPLE (Eugenia jambos).

The rose apple (Eugenia jambos) (PI. IV, fig. 2, and Pl. VIII, fig. 1) is a preferred
host and is everywhere generally and badly infested about Honolulu. From 36 fruits
gathered during July, 1913, in Manoa Valley there emerged a total of 1,688 adulis,
or an average of about 47 per fruit. Each fruit yielded adults, 10 fruits yielding 53,
6, 91, 36, 44, 58, 1, 18, 56, and 92, respectively. A total of 1,395 adults, or an average
of 19.6, were reared from 75 fruits collected in Nuuanu Valley during March, 1914.
One fruit from Kalihi Valley in July, 1913, yielded 20 adults.

35, 36. SuRINAM CHERRY (Eugenia micheli?) AND FRENCH CHERRY (Eugenia uniflora).

The Surinam cherry (Eugenia micheliz) and the French cherry (Eugenia uniflora),
known in Spanish countries by the general term ‘“‘pitangas,’’ are fruits very generally
infested, and although they never yield many adult flies in proportion to their size,
very few fruits escape attack. In Bermuda the former was found to be one of the
principal hosts of C. capifata. From 437 supposedly badly infested fruits gathered

a4

Bul. 536, U. S. Dept. of Agriculture. PLATE XI.

HOSTS OF THE MEDITERRANEAN FRuIT FLY.

Fic. 1.—The Mediterranean fruit fly attacks cotton bolls about the
time they are nearly fullgrown. This attack, however, appears
to be of a secondary nature and follows that of the pink bollworm
(Pectinophora gossipiella). AS many as 10 well-grown larve have
beenremovedfromasingleboll. Fre. 2.—Cross section of an apple
(Pyrus malus) showing the destruction caused by feeding larve
of the Mediterranean fruit fly. (Original.)

Bul. 536, U. S. Dept, of Agriculture. PLATE XII.

THE MANGO AS A Host FRUIT OF THE MEDITERRANEAN FRUIT FLY.

Mango trees may become very large (fig. 1) and bear enormous crops of f ruit (fig. 2), which, when
ripening and falling, present impossible conditions for the fruit-fly inspector. (Original.)

Bul. 536, U. S. Dept. of Agriculture. PLATE XIII.

THE MANGO AS A HOST FRUIT OF THE MEDITERRANEAN FRUIT FLY.
Fic. 2.—

No matter how diligently clean-culture inspectors gather fruit during the mango season, each
day finds the ground beneath the trees well strewn with fallen infested fruits. Fic. 3.—In-
fested fruit about natural size. Note large cavity in upper right side containing several hun-
dred whiteeggs. (Fig. 1, from Severin; figs. 2 and 3, original.)

Fic. 1.—Larve of the Mediterranean fruit fly, about natural size, in infested mango.

MEDITERRANEAN FRUIT FLY IN HAWAII. St

during July, 1913, only 191 adults were reared. Of 45 fruits gathered during Febru-
ary, 1916, only 29 were infested. These 29 fruits yielded 55 adults, or an average of
about 2 per fruit. Seven is the largest number of adults reared from any one of 16
infested fruits during April, 1913.

37. Fie (Ficus carica). si

The fig (Ficus carica) is very generally infested. Because of the white, sticky sap
which exudes copiously from abrasions made in its skin it does not become infested
until the fruits are sufficiently ripe for the market. The larve are very small, as a
rule, when the fruits are offered for sale and because of the interior structure of the
fruit are easily overlooked. Only 6 out of 24 very ripe figs purchased in the market
during July produced a total of 9 adult flies. Of ripe fruits purchased during March,
6 out of 22 produced 34 adults. From 12 apparently perfect figs, purchased during
June, 36 adults were reared. Of 44 figs sufficiently ripe that little sap ran when they
were gathered from trees in Manoa Valley, 10 proved to be uninfested. From the
remaining 34 fruits 430 adults were reared, 12, 25, 28, 32, 44, and 48 adults being reared
from 5 individual fruits. Kirk records rearing 241 adults from 7 figs imported into
New Zealand from Australia.

38, 39. MANGOSTEENS (Garcinia mangostana and Garcinia xanthochymus).

The mangosteens (Garcinia mangostana and G. xanthochymus) do not become in-
fested until ripe. They are not preferred hosts under Hawaiian conditions. The
writers have never reared more than an average of 2 adults from infested fruits. A
large percentage of the fruits are uninfested.

40. Corton (Gossypium spp.). -

The Mediterranean fruit fly was first reared from cotton bolls (Pl. XI, fig. 1) on
October 19, 1911, by E. M. Ehrhorn from bolls collected by D. B. Kuhns from trees
erowing on King Street, Honolulu. Numerous flies were reared during June, 1915,
by August Busck from bolls collected on the U. 8. Experiment Station grounds in
Honolulu and at Kaneohe, Oahu. During the same month the writers found 10 out
of 201 and 6 out of 174 bolls infested. In 10 bolls 32 larve were found, 10 larve
being in one boll. In all cases infestation by C. capitata was secondary to attack by
the pink bollworm, Pectinophora gossypiella (Saunders), and the larve of the fruit fly
appeared to be feeding only upon the affected portions of the bolls rather than upon
the cotton fiber itself.

41. Mountain APPLE (Jambosa malaccensis).

The mountain apple, or ‘‘ohia ai”’ of the Hawaiians ( Jambosa malaccensis), is a wild
tree thriving well up to 1,800 feet elevation. The trees frequently are found growing
in forests (Pl. IV, fig. 1). The fruits maturing in the forests do not appear to be more
than slightly, and often not at all, infested. Fruits ripening on trees within the
city of Honolulu are often badly infested. All the fruits ripening during August,
1914, on a tree growing in Pauoa Valley were infested. Ehrhorn reared adult flies
from fruits from Kalihi Valley during August, 1911. Asa rule, the fruits from the
mountains, offered for sale in Honolulu, are free from infestation.

While none of three varieties of water apples (Jambosa spp.), of which there are a few
trees in Honolulu, have been found infested, there is no reason why they should not
be infested, as they are similar in texture to Jambosa malaccensis.

42. Biue Pam (Latania loddigesit).

One nut of 12 collected from a tree growing on Keeamaku Street, Honolulu, was
found infested. Two adult flies were reared. Prof. O. H. Swezey has also reared
adults irom the overripe nuts of this palm.

38 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

43. Tomato (Lycopersicum esculentum).

The ordinary cultivated tomato (Lycopersicum esculentum) is not generally infested
by C. capitata, although many adults of Bactrocera cucurbitae and certain decay flies
(Drosophilidae) are reared. Thus 270 ripe fruits gathered promiscuously from the
market gardens of Waikiki during June, 1916, yielded no adult flies when held over
sand in jars. Sixteen ripe fruits gathered from the market gardens of Moiliili on March
25, 1913, yielded the melon fly (B. curcubitae). Itis interesting to note that of seven lots
of tomatoes collected during 1911 and early 1912 by the Hawaiian Board of Agriculture,
none produced adults of C. capitata. That C. capitata may be reared in numbers from

tomatoes under field conditions has been demonstrated by the ease with which adults

oviposit in both ripe and green, although well-grown, fruits in the laboratory under
forced conditions. Of4ripe tomatoes placed singly for 7 hours in jars containing about
200 adults, only one yielded 3 adults, although all 4 were oviposited in and contained
on removal from the jars an average of 13 punctures. One fruit yielding no adults
contained 42 punctures. From one green but well-grown fruit exposed in a jar for 7
hours with 200 adults, only 5 adults were reared. From six other ripe fruits similarly
exposed in two lots of 3 each, there emerged only 16 adults; and only 5 adults de-
veloped in one lot of 3 fruits containing 29 punctures in the skin.

The currant tomato (Solanum pimpinellifolium), the grape tomato (Solanum lyco-
persicum), and the “‘popolo” tomato (Solanum nodiflorum) have never been found
infested. Newman writes that C. capitata has often been reported infesting tomatoes
and other Solanum species, but that he had never reared from them any fly in Western
Australia but Lonchaea splendida Loew, the tomato fruit fly—a fly which does not

occur in Hawaii.
44. JacHEE Not (Intchi chinensis).

The lichee nut (Litchi chinensis) is not infested so long as the fruits remain perfect.
The shell-like covering of the fruits often splits as the fruit reaches maturity, and in the
pulp thus exposed the adult can, and has been known to, deposit eggs. Several split
fruits were found infested during September, 1913. One depauperized adult was
reared by the Hawaiian Board of Agriculture from a split fruit during July, 1912.
It is possible for infestation to occur in fruits infested by the tortricid Cryptophlebia
illepida Btl. Seven ripe fruits, freshly picked and sound in every way, were hung in
jars of adult flies for a two-day period during June, 1915. An examination of them
after their removal proved that the flies had not been able to puncture the shell.

45. Maneo (Plates XII, XIII).

The mango ( Mangifera indica) is a favorite host of the fruit fly. In Hawaii the
common seedling varieties are so badly attacked that many owners are willing to have
the crops removed and destroyed before they ripen. Twelve fruits picked from the
ground in upper Manoa Valley yielded 313 adults, 95 adults emerging from one fruit.
Of a total of 47 fruits from the same locality taken from the ground on July 27, 25
yielded 423 adults. Sixteen of 33 fruits taken from the ground at the Hawaiian
Church, Manoa Valley, yielded no adults, but 502 were reared from the remaining 17
fruits. Of fruits taken from the ground on the Cooper estate, Manoa Valley, 26 of 35
yielded 527 adults during August. These records are fair samples of the infestation
of seedling sweet mangoes in the outlying districts of Honolulu, where there are many
wild guavas bushes.

The mango is one of the fruits subject to attack which becomes infested only as it
ripens. Up to that time it is quite well protected from attack by the copious exuda-
tions of distasteful sap which follow attempts at oviposition.. Often where the com-
bined attack of the mango weevil (Cryptorhynchus mangiferae Fab.) and fruit-fly adults
is severe the fruits are well stained with the exuded sap. It has been the experience
of the writers that very few adults can be reared from hard well-grown fruits picked
from or beneath trees on which many fruits are ripening and falling to the ground,

MEDITERRANEAN FRUIT FLY IN HAWAII.

39

even where they show many indications of attempted oviposition. Thus from a total
of 292 such fruits representing 12 lots collected from the ground in Pauoa Valley,
Moanalua Gardens, and Nuuanuu Valley, during July and August, only 6 adults were
reared. The thicker the skin of the fruit the more difficulty does the adult have

in ovipositing successfully.

TABLE XI.— Varietal susceptibility of mangoes to the attack of the Mediterranean fruit fly
under forced conditions.!

Combination
of varieties.

Common mango
Cambodiana....
Brinda Bani....

Brinda Bani..--..

Common mango

Wood chutney 2

Samoan chut-
MOY 2ooeae essen

Common mango
Cambodiana....
Wooten chut-

Common mango

Cambodiana
(hard) eo sencsc

Cambodiana....

Common mango
Strawberry.--.-
Brinda Bani....

Strawberry.....

Seedling
1928 Sta sece te

Wooten chut-

Ne ysis sae
Brinda Bani....
Divaners-.-s--=

Wooten chut-
MC Yssoee sae oo

Number of—
’ Punc-
tures. Eggs.
48 327
8 61
0 0
3 42
0 0
0 0
8 73
60 584
12 138
5 52
9 86
10 115
40 293
0 0
18 182
15 111
8 91
0 0
15 206
3 32
0 0
0 0
44); 314
0 0
1 68
0 0
0 0
6 27
4 28
8 93

Combination
of varieties.

Strawberry...--
Wood chutney...
Brinda Bani..--

Common mango
ain Sea

NOM1928 23.2222
Samoan chut-

Common mango
Wooten chut-

Wood chutney..-

Piri(hard)......
Piri (slightly
SOlD) Reeeeee

Strawberry...-..

Jamshedi.......

Strawberry 3....
No. 1928... ..--
Brinda Bani....-

Common man-

Common mango
Wooten chut-

Number of—
Punc-
tures. | P88s:
16 139
11 129
0 0
14 129
23 249
0 0
3 18
29 291
0 0
20 223
25 403
7 43
e
0 0
0 0
8 112
2 11
21 196
0 0
1 3
0 0
14 132
4 42
0 0
4 35
5 38
7 40
5 60
24 272
0 0

Combination
of varieties.

Oe eee

Divine 4 ......--

Alphonse......-
Brinda Bani....

Common mango
Oahte- 2227-22

Common mango
Strawberry >....
Brinda Bani....

Wooten chut-
NGYEeoe ee eee
Wooten chut-

Common mango
Cambodiana....
Brinda Bani....

Common man-
043555 ee:

Strawberry %...-

Common man-

Oe eee
Cambodiana?...
Wooten chut-

Brinda Bante

Number of—

Punc-

tures.

bo
© 0100 (=)

Ne
Oo

|
}

Eggs.

ooo

ond

1 Unless otherwise noted, the fruits used in each experiment were equally hard, though fully matured
and from trees on which fruits had already begun toripen.
2 Less hard than the common mango.

3 Soft.

While the common thin-skinned sweet mangoes are badly infested when they ripen,
many chutney mangoes and certain highly developed horticultural varieties of eating
mangoes are less susceptible to attack, owing, in the one instance, apparently to a
greater amount of ‘‘turpentine” in the skin, and, in the other, to a much thicker skin.
Under forced conditions adults will oviposit heavily in chutney mangoes which,
ripening on the tree, escape infestation. Three fruits of a ‘‘Chinese” chutney variety!

1 For purpose of future identification it may be stated that one tree of this variety is grown by Mr. G. P.
Wilder, of Honolulu.

40 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

said to be iree from attack were exposed to adults in the laboratory and 219, 285, and
222 eggs, respectively, were laid in them. To determine whether the confinement of
different varieties of improved mangoes would throw any light upon their varie-
tal susceptibility, the various combinations indicated in Table XI were placed
in jars of ovipositing adults and allowed to remain 24 hours. This experiment
was made possible by the gift by the Federal Experiment Station at Honolulu of
fruits which had been protected from fruit-fly attack by paper bags. The extent of
infestation under these forced conditions shows that the Piri, Brinda Bani, and Divine
were least affected. The Divine and Brinda Bani are varieties so little attacked in
the open that they are not protected by paper bags during development. It is inter-
esting to note that the Piri, which is one of the very best eating varieties of mangoes
grown in Honolulu, is the least susceptible to attack of the varieties used in the ex-
periments with the exception of the Brinda Baniand Divine. The Black Alfonse and
Cowasjee Patel grown at the Moanalua Gardens &ppear equally resistant with the Piri,
and from these gardens Mr. 8. M. Damon has sent out many superb fruits of these three
varieties, which reach maturity uninfested and unprotected.

46. ELencI TREE (Mimusops elengi).

The fruits of Mimusops elengi grown in Hawaii appear to belong to two varieties.
Both are infested as they become fully ripe, but the glabrous variety supports many
more larve than the pubescent variety (Pl. VIII, fig. 2). The fruits of both have a
tough, firm outer shell, a mealy pulp, a proportionally large central stone, and are
about three-fourths of aninch long. Of 34 fruits of the glabrous variety gathered from
the ground during February only 7 yielded no adults. From the remaining 27 fruits,
355 adults, or an average of about 13 adults per fruit, were reared. Of# 15 fruits of the
pubescent variety gathered from the ground at the same time, 8 yielded no adults,
and 7 yielded 27 adults. From 10 fruits of the glabrous variety 17, 15, 13, 19, 7, 30, 21,
22,19, and 2 adults were reared.

47. Mock ORANGE ( Murraya exotica).

The small fruits of the mock orange or orange jessamine ( Murraya exotica) are pre-
ferred hosts (Pl. VIII, fig. 4). From 1 to 3 larve only are able to mature in a single
fruit. Of 111 fruits gathered during March, 1914, 26 were not infested. From the
remaining 85 fruits 148 adults were reared; 10 fruits yielding, respectively, 1, 1, 2, 3,
2,1, 1,2, 1, and 3 adults. .

48. Banana (PI. XIV, XV, XVI).

The banana export trade of the Hawaiian Islands amounted to 256,319 bunches
during the year ended June 30,1915. For the most part, the shipments were composed
of the chief commercial variety of Hawaii, the Chinese banana ( Musa cavendishii),
although a small number of Bluefields ( Musa sapientum) entered into the shipments.
With the appearance of C. capitata in Hawaii, it became imperative, therefore. to
determine to what extent, if any, this established trade jeopardized the mainland
fruit interests. Previous to the experimental work in Hawaii, the banana had been
classed among the host fruits of C. capitata by officials of the Australian Common-
wealth and by Gowdey ! of British East Africa without modifying statements.

A critical review of the Australian literature seems to indicate that the positive
references to the presence of C. capitata in bananas should be questioned, as it is more
than probable that the similarity in the appearance of fruit-fly larve has led to a con-

1 Tn a letter to the writers dated July, 1916, Gowdey writes that his previously reported rearing of C.
capitata from bananas was made under abnormal or laboratory conditions. Hesucceeded inrearing adults
from overripe bananas infestedin the laboratory. He was not attempting to prove the immunity, or
otherwise, of this fruit when green, although sufficiently ripe for the trade, and makes no claim that under
field conditions the bananais a hostfruit of this fly.

Bul. 536, U. S. Dept. of Agriculture. PLATE XIV.

REGULATING MEDITERRANEAN FRUIT-FLY CONDITIONS.

As a result of the regulation of the Federal Horticultural Board the unsanitary fruit-fly conditions
about banana plantations have been corrected. Fic. 1.—A small Chinese banana plantation.
At present, such guava bushesas areshown, and all other host plants about or in plantation from
which fruit is shipped, are cut sufficiently often to prevent fruiting, thus removing the oppor-
tunity for fruit-fly larvee emerging from fallen fruit (see insert) to become attached as pup& to
wrapping material and be transported to California. Fic. 2.—General surroundings of small
banana plantations in Kalihi Valley, Oahu, from which fruit is shipped to California, The
fruit fly is thoroughly entrenched on all the mountain slopes. (Original.)

Bul. 536, U. S. Dept. of Agriculture. PLATE XV.

THE MEDITERRANEAN FRUIT FLY AND THE BANANA INDUSTRY.

Fig. 1.—Typical Chinese house and packing shed at small banana plantations. The rice straw
and dried banana leaves used for wrapping all export fruit are stored in open sheds similar to
one illustrated to left of view. Fia. 2—In a bluefield banana plantation at Hilo. Note the
dead dried leaves hanging to the trees; when these are thoroughly dry they are cut and stored
for wrapping export fruits. (Original.)

Bul. 536, U. S. Dept. of Agriculture. PLATE XVI.

THE MEDITERRANEAN FRUiT FLY AND THE BANANA INDUSTRY.

Fic. 1.—Rice straw stacked in the open to be used as wrapping material for export
bananas. Fic. 2.—Chinese bananas cut and cleaned, waiting inspection by oflicer
of Federal Horticultural Board. Fic. 3.—Chinamen remove all split, overripe, and
bruised fruits as the bananas are brought to the packing shedsfrom the field. Each
bunch is thus cleaned previous to inspection as a safeguard to mainland interests.

(Original. )

Bul. 536, U. S. Dept. of Agriculture. PLATE XVII.

THE PRICKLY PEAR ASA Host FRUIT OF THE MEDITERRANEAN FRuIT FLY.

Fic. 1.—Heavily fruiting plant growing on dry arid and waste lands of the Island of Hawaii.
In many places this wild host, with the spiny Acacia, forms dense thickets in which the
fruit fly can breed. Fic. 2.—A sample of dense growth of prickly pear along the road
near Kailua, Hawaii. The seed pods of the algaroba tree (Prosopis juliflora) are not

infested. (Original.)

Bul. 536, U. S. Dept. of Agriculture. PLATE XVIII.

THE AVOCADO OR ALLIGATOR PEAR AS A HOST OF THE MEDITERRANEAN FRUIT FLY.

Cross section of improved fruit. Noteslight infestation at stem and blossom ends. In-
festation is not always general and usually does not interfere with local consumption.
The slight infestations, however, have forced this fruit_into the quarantine list,
thereby ruining a profitable and growing export trade. (Original.)

MEDITERRANEAN FRUIT FLY IN HAWAII. 41

fusion of other fruit-fly species. known definitely to attack bananas, with C. capitata. —
Illingworth, in 1913, reared the banana fruit fly (Dacus curvipennis Frogg.) from
larvee taken in Sydney from bananas imported from Suva. Lea, in Tasmania in 1908,
thoroughly familiar with the Mediterranean fruit fly as a result of the campaign for its
~ eradication about Launceston, states that the Queensland fruit fly (Dacus tryoni Frogg.)
only was found in bananas imported into Tasmania, and does not list this fruit among
the host fruits of C. capitata. Broun states that, in 1906, Dacus tryoni was the only
fruit fly reared from bananas imported during February and March into New Zealand
from Fiji and Rarotonga. In the report oi the biologist of Western Australia in 1898
we read that a consignment of 50 cases of bananas supposed to have originated in
Fiji, but more likely having been transhipped to Sydney from an original source in
Queensland, had been destroyed at Freemantle because found infested by the Queens-
land fruit fly. Quinn, in 1907, writes ‘‘after seven years experience with bananas
* * * we have not yet found the maggots in green bananas. If green when arriv-
ing here (South Australia), how very green indeed must they have been when cut from
the trees about three weeks previous.’’ French, of Victoria, appears to be the only
person in Australia who definitely makes the statement that he has reared C. capitata
from bananas exported from Queensland into Victoria. Yet Tryon, of Queensland,
in a conversation with the senior writer in 1913, stated that C. capitata had never been
taken in the banana fields of Queensland. The inclusion of the banana among the
fruits infested by C. capitata and intercepted at the entry ports of New Zealand by
Kirk seems to have been an editorial error, as already pointed out in the paper on the
banana as a host referred to below. From the foregoing references, it is possible to
assume that the results obtained by the writers in Hawaii, where fruit-fly attack is as
severe as anywhere, will be verified when opportunity is presented for such careful
experiments in other countries as the commercial value of this fruit warrants. Because
of the controversial statements of French and Severin it is desirable that Australian
entomologists publish data secured in field experiments.

Those particularly interested in the status of the banana as a host fruit are referred
to a paper! already published by the writers, giving experimental data from which the
following conclusions were drawn:

Since the Mediterranean fruit fly (Ceratitis capitata Wied.) as not been found
infesting the Chinese banana ( Musa cavendishi) or the Bluefield banana ( Musa sp.)
during the three years that the Federal Government has had charge of the inspec-
tion of export bananas in the Hawaiian Islands, it is evident that some reason exists
for this practicalimmunity. Thisis the more apparent since adult flies of both sexes
have been found present in all parts of banana plantations, and surrounding fruits
known to be hosts have been heavily infested.

This immunity is shown to be due to the fact that neither the egg nor the nearly
hatched larva oi the fruit fly can survive in the tannin-laden peel of green, though
mature, fruit. In fact, the copious and sudden flow of sap from egg punctures made
by fruit flies in unripe bananas renders the successful deposition of eggs in such fruits
difficult and rare.

The fact that not 1 of 1,044 fruits of the Chinese banana ripening singly and pre-
maturely among bunches growing in the field, and upon which, as in the case of
other host fruits, one might expect gravid females to concentrate their attention for
the purpose of oviposition, has been found to be infested, leads to the conclusion
that even ripe bananas are not desired as host fruits by adult fruit flies under Hawaiian
conditions. On the other hand, the rearing of flies from the ripe and yellow fruits of
the thin-skinned Popoulu variety, as well as from ripe fruits of other varieties under
forced and unnatural conditions, leads to the equally acknowledged fact that ripe
bananas in the field may serve as hosts and should therefore be properly guarded
against in all quarantine work.

From the facts stated, the writers believe that bunches of any variety of bananas?
now growing in the Hawaiian Islands, when properly inspected for the removal of

i Back, E.A.,and Pemberton,C. E. Banana asa host fruit of the Mediterranean fruit fly. Jour.
Agr. Research, v.5, p. 793-804. 1916. 7

2 As an added precaution against the spread of C. capitata to the mainland, cooking bananas of all
types are excluded from the trade.

49, BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

prematurely ripe, cracked, or partially decayed fruits, offer no danger as carriers of
‘the Mediterranean fruit fly, provided they are wrapped and shipped in accordance
with the demands of the trade and the Federal regulations.

In addition to the data already presented by the writers, on the immunity of bananas
during a 10-day period after the fruit is sufficiently mature for shipment during the
summer months, other experimental work has been carried out by H. F. Willard
under the writer’s direction. This experimental work in detail emphasizes so well
the immunity of well-grown bananas still attached to the tree but green in color,
although many fruits on the same bunch have either cracked or ripened, that por-
tions of the data are given herewith. The hands of fruit are numbered from the
stem end of the bunch.

On November 30, 1915, 14 bunches of Chinese bananas marked in the field at Moiliili
for shipment within two days to California were requisitioned and held uncut for
experimental work to determine how long during the winter months the bunches
could hang after they were sufficiently ripe for the export trade and still ward off
attack. A wire-screen cage containing 300 adult flies was placed over one bunch
December 13-15, and three days after its removal an examination of the 131 fruits
on the bunch, all green in color, showed 108 fruits to be free from attack. Of
those attacked 20, 1, and 1 had respectively,3, 1, and 4 punctures, all of which con-
tained no eggs and were more or less superficial; a single puncture in the remaining
fruit contained two living first-stage larve which later died.

A second bunch from which there had been cut on December 22 1 sound yellow
fruit, on December 27, 2 sound and 2 cracked yellow fruits, and on December 29, 3
cracked yellow fruits, was caged on the last date with 300 adults. On December 31,
or one month after the fruit was sufficiently ripe for shipment, the cage was removed
and on January 3 examined with the following results:

Hand 1: 13 fruits; 7 green and puncture free. Six yellow, 2 puncture free;
1, 1, and 2 had, respectively, 4, 2, and 1 empty punctures.

Hand 2: 15 fruits; 10 green and puncture free. Five yellow, 2, 1, 1, and 1
had 0, 2, 1, and 9 punctures. Punctures empty but ones which con-
tained 2 first stage larve that soon died.

Hand 3: 15 green puncture-tree fruits.

Hand 4: 14 green fruits; 12 puncture free, 2 had 1 empty puncture each.

Hand 5: 9 green fruits; 7 puncture free, 2 had.1 empty puncture each.

Hand 6: 12 green fruits; 11 puncture free, 1 had 1 empty puncture.

Hand 7: 14 green fruits; 13 puncture free. One fruit had been bruised, so that
it was yellow and had begun to decay on one side; it had 7 punctures, of
which 2, 2, 1, and 2 contained 6, 1, 4, and 0 eggs, respectively. From this
fruit 4 adult flies were reared. . :

Hand 8: 7 green fruits; 5 puncture free, 1 with 3 empty punctures, and 1 with
1 empty and 3 dead and 1 living first-instar larve. Living larve died in
puncture.

A third of the bunches marked November 10 was caged with 300 adults on January
5, after 43 yellow bananas had been cut from the bunch. On January 7 the cage was
removed and the bunch cut. An examination made on January 11 gave the follow-
ing results:

Hands 1 and 2: Fruits had ripened and been cut before caging.

Hand 3: 4 yellow fruits, 3 puncture free. Remaining fruit had 2 punctures
with eggs and eggshells. No adults were reared though the fruit was held
over sand.

Hand 4: 8 yellow fruits, 5 puncture free; 1, 1, and 1 fruits had 3, 1, and 1 empty
punctures.

Hand 5: 12 yellow fruits, 9 puncture free; 1, 1, and 1 had 3, 2, and 1 empty
punctures, respectively.

Hand 6: 13 fruits, 12 green and 1 yellow; no punctures.

Hand 7: 12 green fruits, 11 puncture free; 1 had 2 empty punctures.

Hand 8: 11 green fruits, 9 puncture free; 2 had 1 empty puncture each.

MEDITERRANEAN FRUIT FLY IN HAWAII. 43

The results of the foregoing experiments, together with others on file, strengthen
the conclusions quoted above that bananas cut, wrapped, and shipped according to
trade and Federal regulations are not a source of danger as carriers of C. capitata.
Particular attention is called to the very slight infestation secured under forced con-
ditions, even among fruits actually turning yellow on the tree. Many hundred adults
would have been reared from favored host fruits similarly caged with adults.

49. Noronhia emarginata.

Noronhia emarginata is a native fruit of Madagascar and Mauritius. The writers
have never found it infested, but Mr. E. M. Ehrhorn reared 24 adults from a sample
of fruit during July, 1912. Mr. Ehrhorn is also authority for the rearing of adults

from fruits grown on Kauai.
50. Ochrosia elliptica.

The shrub Ochrosia elliptica is grown because of the ornamental value of its scarlet
fruits. These are occasionally infested. Thirty adult flies were reared from one lot
of 12 fruits maturing in the Punahou district of Honolulu, and 8 from one fruit grown
at Waikiki.

51. Prickty Prar (Opuntia vulgaris).

Although the prickly pear (Opuntia vulgaris) grows wild (Pl. XVII) on waste arid
lands in Hawaii, it is not a preferred host. From 23 overripe fruits taken from the
ground during August, 1912, on Punchbowl, only 15 flies were reared, while no flies
were reared from 28 similar fruits gathered at the same time. No flies were reared
from 29 lots totaling 254 fruits collected in Pauoa, Palola, Makiki, Moanalua, and
Kalauao during September—December, 1912. These fruits were all ripe, many too
ripe to remain erect on the plant, and some had fallen to the ground. From 8 fruits
ripe, but erect on the plant, cut from plants on Punchbowl close to the Federal Experi-
ment Station, 8 flies were reared; 10 fruits taken from the ground near the top of
Punchbowl at the same time (September, 1912) yielding only 1 fly. Of 8 lots of ripe
fruits gathered from plants during December, 1914, from Ewa, Fort Shafter, Kalauao,
Red Hill, Salt Lake Road, upper and lower Palolo and Manoa Valleys, totaling 118
fruits, only 1 lot of 5 fruits from Ewa yielded 2 adults.

Compere reports the prickly pear about Malaga, Spain, to be infested by C. capitata.

52. Passion VINE (Passiflora coerulea).

The fruits of only one species (Passiflora coerulea) of passion vines have been found
infested by C. capitata in Hawaii. Infestation is by no means severe. At Haiku,
island af Maui, a search among several hundred ripe fruits proved only two fruits to
have been infested, and from these six adults were reared. While numerous fruits of
different sizes have been found deformed by punctures on Oahu no adult flies have
been reared. It is doubtful if this passion vine supports C. capitata except when
growing luxuriantly in shaded localities.

Fruits of Passiflora quadrangularis, edulis, laurifolia, alata and foetida have not been
found infested. The common water lemon (P. laurvfolia) found upon the markets of
Hawaii is impervious to attack when ripe, as proved by hanging fruits in jars of adult

flies.
53. Avocano (Persea gratissima).

The avocado (Persea gratissima), palta, or alligator pear asit is sometimes called (PI.
XVIII), is one of the host fruits of C. capitata that become infested, if at all, late in
their development. In fact, the nature of its infestation for most horticultural varie-
ties is so obscure that the general belief prevails that avocados are free from attack.
Previous to the introduction of C. capitata in Hawaii a small and growing export trade
was being developed and, because of the excellence of the improved Hawaiian avocado,

44 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

it promised to become a financial asset to the islands. Even since the quarantines of
the Federal Horticultural Board stopped shipments of avocados to the mainland of
the United States shipments have been made to the Philippine Islands in cold
storage. The following data are the first ever published on the infestation of avocados
and are given here to refute arguments for reestablishing the avocado trade on its
former basis:

There are many horticultural varieties of the avocado growing in Hawaii, but there
appears to be little difference in their degree of susceptibility to attack. The nutmeg
or Guatemala variety is the only one free from attack when growing uninjured. Under
forced laboratory conditions adults can not oviposit through its unusually thick rind.
The skin of all other varieties of avocados, whether very thin or of usual toughness, can
be punctured by the adult fly, as proved by the examination of many fruits. The
avocado, like the ordinary pear, is best if picked when still hard and allowed to ripen
in storage.

If left on the tree too long, the fruits drop and soften on the ground. With most
varieties it is not until the fruits are mature enough for gathering or dropping that
adults ovipositin them. As they are sufficiently soft for eating purposes within two
to four days after being cut from the tree, the larve are still very young, if not just_
hatched, and are to be found feeding close to the tough leathery rind. Their presence,
therefore, is seldom observed by those eating avocados served whole or cut in half to be
eaten with a spoon. When served cut in small pieces, with mayonnaise, the paring
process usually crushes the small larval burrows on the outer surface of the pulp and
the larve go to the table unobserved. As thousands of larve are thus consumed
yearly in Honolulu alone, it may be well to state that they do no harm.' Fruits in
which the larve have become well grown are usually too soft for eating purposes.

Several thousand fruits have been examined carefully by the removal of the skin.
Of 1,027 fruits thus examined, picked from the trees at Wahiawa and representing 10
separate lots of fruit, 173, or 16.8 per cent, were found to contain eggs or larvee; of 384,
representing six lots of fruit picked from the ground at Wahiawa, 57 fruits, or 14.8 per
cent, were infested. Notes on certain uninfested fruits show that of the green varie-
ties 354 were thick skinned and 75 were thin skinned; of the purple varieties, 254 were
thick skinned and 101 were thin skinned. Of 120 infested fruits, 42 and 12 were green
varieties with thick and thin skins, respectively, while of the purple varieties, 32 and
34 were thick skinned and thin skinned, respectively. The considerably larger pro-
portion of thin-skinned purple fruits found infested agrees in the main with observa-
tions on similar fruits found on the markets. Eleven purple fruits of an early thin-
skinned variety picked from the tree in the Makiki district of Honolulu had an average
of over 41 punctures in the skin, no fruit having less than 12 or more than 119 punc-
tures. A fruit of a second thin-skinned purple variety grown by Mr. G. P. Wilder, of
Honolulu, known to be generally infested if the fruits are allowed to remain on the tree
too long, was hung in a jar of adult flies for about 18 hours beside a fruit similar in
appearance and degree of ripeness, taken from another tree. An examination after ~
removal of the fruits showed 7 eggs to have been deposited in 1 puncture in 1 fruit
while in the, Wilder fruit 487 eggs had been deposited in 56 punctures. In a green
fruit with a hard, tough skin exposed to adults for 5 hours, 32 eggs were deposited in 14
punctures. One lot of 863 fruits of all varieties gathered by a fruit dealer from trees
in upper Manoa Valley and the Punahou district of Honolulu were not infested, but
these were picked several days earlier than they might have been picked. Avocados
shipped rather green from the islands of Hawaii and Kauai to Honolulu (Oahu) were
not found infested, but their freedom from infestation was due to the earliness of their
gathering. Ten thin-skinned purple fruits grown at Waikiki and purchased in the
market had an average of over 9 punctures per fruit, 1 fruit having 33 punctures and

1 The writers have personally conducted experiments in which it is estimated persons have eaten 2,000
eggs and young larvae in plums without injurious results.

MEDITERRANEAN FRUIT FLY IN HAWAITI, 45

only 1 being puncture free. Ten thick-skinned green fruits in the market from —
Kalauao had an average of 6.2 punctures, with no fruit puncture free; 4 of 6 thin-
skinned purple fruits taken from the market were puncture free, the remaining 2
fruits having 1 and 3 punctures, respectively. One thick-skinned green fruit picked
by the owner and brought to the laboratory as an example ofa fine fly-proof variety was
found when examined in his presence to contain 230 eggs in 18 punctures. The
details of the examinations of many hundred individual fruits are on file and open to
those desiring further information on the infestation of avocados at the time they are
offered for sale.

In spite of the frequency of infestation as indicated above, the avocado does not
appear to be a very satisfactory host for C. capitata when one considers its relatively
large size and the number of adult flies that can be reared from it. The larval
mortality is greater than in many preferred hosts. From thin-skinned purple fruits
containing 119, 41, 29, 19, and 37 punctures, 4, 7,39, 6, and 0 adults were reared. Only
36 adults were reared from a green-skinned variety known to have contained 230 eggs.
From 1 fruit that had begun to wither on the tree, an unusual occurrence, 16 adults
were reared. Forty-eight is the largest number of adults ever reared from a single
fruit by the writers. Of 81 fruits of all varieties known to have been infested when
placed separately in jars over sand, 39 produced no adults, while from the remaining
42 fruits 570 adults were reared. No adults were reared from 427 fruits gathered pro-
miscuously and placed in jars without examination to prove them infested.

~

54. Date Pawn (Phoenix dactylifera).

Although thousands of fruits of the unimproved date palm (Phoenix dactylifera)
ripen each year in Hawaii, the writers have found only one instance of infestation.
Thirty-five green, but well-grown, dates collected August 11, 1913, at Ainahau,
Waikiki, which appeared to have been affected by some disease that rendered them
abnormally moist, yielded 2 adults of C. capitata. This was probably a chance

infestation.
55. STRAWBERRY Guava (Psidium cattleyanum).

The strawberry guava (Psidium cattleyanwm) is a preferred host, and the fruits are
usually badly infested. From 96 out of 145 fruits picked March 16, 1913, 364 adults
were reared, or an average of 3.8 perfruit. No fruit yielded more than 8 adults.. From
500 fruits an average of 4.1 adults were reared during April, 1913. From 90 fruits
collected during February, 1916, an average of 4.8 adults per fruit were reared; 15
fruits yielding 1, 3, 2, 11, 7, 7, 6, 5, 9, 7, 6, 2, 8, 6, and 18 adults, respectively.

56-58. GUAVAS.

The common guavas of Hawaii (Psidium guayava, P. guayava pomiferum and P.
guayava pyriferum) are subject to general infestation. While the guava grows wild
up to 4,000 feet elevation and forms dense thickets on the lower levels, even many
miles from habitations (Pls. II, III), and isan ever-present source of adult flies, many
statements previously published exaggerate the degree of infestation of individual
fruits. The writers have never been able to collect samples of 25 miscellaneous
fruits without finding some infestation; 14, 18, 15, 17, 10, 10, 10, 24, 7, 6, 6, and 6
fruits collected at 14 places on the windward and leeward sides of Oahu on Sep-
tember 9, 1914, yielded respectively 60, 46, 46, 107, 119, 11, 19, 4, 41, 1, and 2 adults.
Each of 62 fruits, except 7, picked ripe from bushes at points along the Tantalus
Road yielded adults; from 55 fruits 307 adults were reared. During January, 1916,
75 per cent of all fruits examined along the same road were found infested. From
18 fruits collected May 30, 1913, from bushes near the Libby, McNeil, and Libby
Cannery, windward Oahu, at sea level, 423 adults, or an average of 23.5 flies per
fruit, were reared. Nine fruits collected between Wahiawa and Haleiwa, Oahu, on
January 21, 1912, yielded 96 adults. The writers have never reared more than 34 -
adults from a single fruit.

46 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

That it may be appreciated that, contrary to the belief of many, the wild guavas

in the mountains back of Honolulu are a continual source of adult flies, particularly
in midwinter, the following records were made:

21 fruits picked on and near the top of Round Top, Tantalus, 1,100 feet eleva-
tion, December 19, 1913, yielded 63 adults.

24 ee Pauoa Flats, 1,100 feet elevation, December 22, 1913, yielded
69 adults.

42 fruits from rim of Palolo Crater during December, 1913, yielded 362 adults.

22 ae from top of east ridge, Manoa Valley, 1,000 feet elevation, yielded 100
adults.

50 fruits from head of Palolo Valley, 1,000 feet elevation, on January 2, 1914,
yielded 84 adults.

59. Prac (Prunus persica).

The peach (Prunus persica) is the most preferred of all host fruits grown in Hawaii
and in other countries (fig. 3). While excellent peaches have been grown in the
islands, at the present time scarcely a peach matures on the lower levels, and usually
the fruits are utterly destroyed before they are more than half to three-fourths grown.
From 128 fruits, about three-fourths
grown, picked from the ground during
April, 1913, 2,929 adults, or an average of
about 23 adults per fruit, were reared.
From 10 of these fruits 34, 12, 25, 8, 49,
78, 64, 17, 6, and 54 adults, respectively,
were reared. As many as 90 larve have
been taken from a single fruit.

The writers have on file data secured
during experimental work on the infesta-
tions of several thousand individual
fruits, but they throw no additional light
on the severity of peach infestation.

60-62. NECcTARINE (Prunus persica var.
nectarina), Apricot (Prunus armeni-
aca), and Puum (Prunus spp.).

Fig. 3.—Cross section of peach, showing the gen-
eral shriveling of the walls of the egg cavity and
the separation of the eggs. Drawing made 1}
days after oviposition. (Authors’ illustration.)

Varieties of Prunus spp. known as
plums, apricots (fig. 4), and nectarines are
reported well infested where grown in infested regions. These fruits are imported
in season to Hawaii from California and have been easily infested under forced
laboratory conditions. It seems probable that they will serve best as hosts when
partially grown, as the excessive moisture content of the well-ripened fruits, par-
ticularly of such varieties as the Japanese plums, causes a high mortality among
young larvee. .

63. PoMEGRANATE (Punica granatum).

The writers have never reared C. capitata from pomegranate. Mr. O. H. Swezey,
of Honolulu, reared an adult identified by the senior writer as C. capitata from a fruit
partially decayed. The writers have examined many perfect and split fruits with-
out detecting evidences of infestation. Compere records finding infested fruits in
Asia Minor, and Trabut in 1901 reports infestation in Algeria.

64. APPLE (Pyrus spp.).

Only a few apple trees (Pyrus malus) are found growing in those regions of Hawaii
sufficiently warm for C. capitata, hence the writers can offer no observations on the
infestation of this fruit occurring in the field. Apples have been found infested in

,
4
.

MEDITERRANEAN FRUIT FLY IN HAWAII. 47

South Africa and Australia by other investigators. Gurney, of New South Wales, lists
the apple among host fruits occasionally infested. Wickens, in 1914, in western Aus-
tralia, writes that ‘“‘the apple growers who have been hoping that they would not
suffer so severely as growers of soft fruits are now becoming seriously alarmed at the
presence of fruit-fly punctures and larve in their export varieties of apples. For-
tunately the two apple-producing centers of the State (Bridgetown and Mount Baker)
are free from the pest.’’ Lounsbury, in South Africa, writes that ‘‘ordinarily only
peaches, nectarines, and pears are severely infested, but last year apricots, figs, pears,
plums, apples, and quinces were almost all attacked.’’ Newman states that in
western Australia eggs deposited in undeveloped apples and pears rarely hatch and
that if they do the larve die. The senior writer found apples grown throughout
eastern and southern Spain quite generally infested during 1916.

The writers have used apples extensively in
their experimental work and have found
them an excellent fruit for securing large
numbers of larve and eggs for temperature
studies.. The firmer apples, if not overinfested,
serve better than any fruit as a medium for car-
rying the pest along within the laboratory
for considerable periods. Some fruits become
too moist and these are not satisfactory. For
one type of infestation see Plate I, figure 2,
and Plate XI, figure 2.

65. Pear (Pyrus spp.). Fie. 4.—Small apricot, natural size, show-
; RIG 5 : 5 ing eggs of the Mediterranean fruit fly
There are few pear trees grown in yards in donotied aint Avae places (Oriemal)

Honolulu. The fruits are generally and badly

infested, the interior often becoming badly eaten out by larvee while the exterior
appearsunaffected. Often fruits, entirely destroyed, may dry up and remain attached
to the tree. Such a fruit is illustrated in Plate VII, figure 2.

66. SANDALWOOD (Santalum freycinetianum var. littorale).

Adults of C. capitata were reared during the summer of 1916 from the fruits of the
native sandalwood by Messrs. O. H. Swezy and J. C. Bridwell. The infested material
was taken from a tree growing about 50 feet above sea level at Waianae, Island of Oahu.

67. Eaapiant (Solanum melongena).

The eggplant (Solanum melongena) has been found infested only once during four
_ years by the writers. One hundred and fifteen fruits of all ages gathered from the
vines in the Moiliil market garden during April 26-30, 1914, showed no infestation
when examined May 2 to 5 by the removal of the skin. One thousand fruits in all
conditions of soundness were examined by the junior writer during November, 1915,
by carefully removing the skin from each fruit. In only one fruit were larve found.
These were well grown, several in number, and in tunnels immediately beneath the
skin. Adults of C. caprtata were reared from these larvee. The senior writer has ~
personally examined many fields superficially, but has never seen infestation due to
either C. capitata or Bactrocera cucurbitae.

68. Wi (Spondias dulcis).

The ‘‘wi” (Spondias dulcis), a native tree of the Society Islands but common to
the tropics of both hemispheres, is common in Honolulu and bears heavily. Its
fruits are only slightly infested by C. capiteta. From 200 very ripe fruits gathered on

48 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

October 2, 1913, only 7 adults were reared. Four adults were reared from 33 ripe fruits
in which many eggs were laid under forced laboratory conditions during December,
1915, and January, 1916. The fruits usually ripen uninfested.

69. Natat Pium (Termanalia chebula).

The Natal plum (Terminalia chebula) is well infested as the fruits ripen and has
proved an excellent source of larve for experimental work. From two lots of fruit
of 12 pounds each, 2,761 and 2,655 adults, respectively, were reared during October-
November, 1915.

70. TRopiIcAL ALMOND OR WINGED Kamant (Terminalia catappa).

The tropical almond or winged kamani (Terminalia catappa) is a preferred host.
It is one of the most reliable sources for fruit-fly material in the Hawaiian Islands.
The pulp, upon which the larve feed as the fruit ripens, is scarcely three-eighths of
an inck thick. (See Pl. XIX.) Severin obtained from 25 fruits 1,380 larvee; 98
larvee from one fruit. The writers have reared many thousands of larvee for experi-
mental work. From 16 lots of fruit from different Honolulu localities collected dur-
ing October, 1915, totaling 1,531 fruits, 10,005 larvee developed. From 3,902 fruits
collected from 28 localities during November and December, 1915, only 11,481 larvze
developed. It remains to be seen whether the scarcity of larve in the fruits develop-
ing during late 1915 was due to the work of parasites or to other causes.

71. Brestinyi ( Thevetia neriifolia).

The bestill or yellow oleander ( Thevetia nerwfolva) is never infested until it begins
to turn black when ripening. Until then it is excellently protected by its white
sticky sap which exudes rapidly from any slight abrasions in. the epidermis. The
pulp is quite dry and pithy and often escapes infestation, particularly during dry
spells. When the fruits ripen very slowly during colder weather and fall to damp
shaded spots, as many as 38 adults may be reared from a single fruit. In Bermuda,
in the absence of an abundance of other hosts, the Thevetia was found very badly
infested with unusually large larve during December. In Honolulu many fruits

ripen uninfested.
72. GRAPE ( Votis labrusca).

The Isabella grape (Vitis labrusca) is the only grape grown in any quantity in
Hawaii. The fruits mature and are sold on the markets and appear to be entirely
free from fruit-fly attack. This variety of grape is, however, subject to slight attack.
One fruit inspector detailed to collect suspicious-appearing fruits brought to the office
978 berries as the result of a 4-day search. A careful examination by H. F. Willard
of these with a hand lens revealed five well-grown larve in two lots of fruit totaling |
201 berries. Two of the larve died, but the other three developed into adults identi-
fied as C. capitata.

Newman, in western Australia, states, in 1912, that he found C. capitata frequently
in grapes, yet in 1914 he writes that at Crawley little or no sound fruit had been picked
for years except grapes. Lounsbury, in 1907, states that he found grapes only slightly
infested in South Africa. Whatever the degree of infestation is elsewhere, in the
Hawaiian Islands it is so slight that it is never noticed in the vineyards where fruit is
grown for the production of wine or where fruits are ripening for table purposes oa
isolated vines growing in badly infested districts of Honolulu. Excellent bunches oi
grapes are picked within a few feet of badly infested peaches.

Bul. 536, U. S. Dept. of Agriculture. . PLATE XIX.

A Host FRUIT OF THE MEDITERRANEAN FRUIT FLY.

Fiq. 1.—A large winged kamanitree (Terminalia catappa) with a 6-foot man standing be-
neath for comparison. The fruits of this species are badly infested and, because they
ripen and fall in large or small numbers during the entire year, greatly interfere with
successful clean-culture work. Fic. 2.—The nuts are from 2 to 2.5 inches long; the
fruit-fly larvee feed only on the thin pulp covering the nut. (Original.)

MEDITERRANEAN FRUIT FLY IN HAWAII, : 49

LIFE HISTORY AND DESCRIPTION.
THE EGG.

DESCRIPTION.

The eggs (figs. 3-6) are glistening white, about 0.945 mm. long,
elongate elliptical, and often more convex on the dorsal side.

DURATION OF EGG STAGE.

Martelli gives the duration of the egg stages at Portici, Italy, as
2 days in August and from 4 to 5 days in October. Newman states
that in Western Australia eggs hatch in from
2 to 4 days during summer and in from 14 to
19 days during winter. Mally, in South Africa,
found the egg stage to be from 2 to 4 days in
midsummer. Other data have been published
but give no additional information and, being
unaccompanied by temperature records, may
be omitted. Newman appears to be the only
investigator who has made an effort to secure
data for the winter period.

In Honolulu, or littoral Hawaii in general,
the length of the egg stage is very short, and
agrees with the minimum periods indicated by
writers in other countries. In Table XII are
recorded data on observations on 4,066 eggs
secured at Honolulu, which indicate that the
largest number of eggs hatch in from 2 to
3 days after deposition during the hottest yg. 5—section of grapefruit

weather. Atamean temperature of 79° F.,208 tind, showing two egg cavi-
h h a - ties, one in cross section.
eggs atched in Drawing made one week after

from 49 to 5] _ fruit was picked. Note coni-
cal elevation about the egg

h Ours a f ter cavities left by the withering
1¢+7 of the rind; also the thick-

d 2 aN SL 0200 2 ened walls of the egg cavity
w hil € Jy and the single larval channel

hatched in in the rag. (Authors’ illus-
5 tration.)
Fic. 6.—Cross section of peach, showing egg from 52 to 53
cavity of the Mediterranean fruit fly with hours, and 3 in from 53 to 54 hours. |
eggs. Drawing made directly after oviposi- At a mean temperature of 78.9° F.
tion. . (Authors’ illustration.) as 2
134 eggs hatched between 49 and 54
hours after deposition, although 12 eggs deposited at the same time
did not hatch until from 66 to .72 hours later. Ata mean of 71° F.,
695 eges hatched within 72-hours, while 3 hatched in from 120 to
144 hours, or about 6 days after deposition. At a mean of 70.5° F.,
437 eges hatched in from 77 to 83 hours after deposition and 227
after a period of 83 to 91 hours had elapsed. Ata mean of 69.8° F.,
81340°—18—Bull. 536-4

SS

50 - BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

356 eggs hatched after a period of from 84 to 91 hours, 216 after 91

to 92 hours, 127 after 92 to 93 hours, 33 after 93 to 94 hours, 8 after

94 to 95 hours, 5 after 95 to 96 hours, and 3 after 104 to 106 hours.

Kighty-eight eggs hatched between 4 and 4.5 days after deposition

at a mean temperature of 68.7° F.

TaBLE XII.—Duration of the egg stage of the Mediterranean fruit fly at Honolulu under
normal conditions.

2

Average
of eggs
anaee Eggs deposited. Eggs hatched. one
per-
observa- bare
tion
SH
88 | Jan. 21-22,4 p.m.tol0a.m.......... Jans 26) Gia. WG Ols Dye eres eee eee 68.7
3502\ Mar 910jaym: to 12)ms e+ eee Mar. 12-13, 4.30 p.m.to8a.m-.-.......... 70.2
102 | Mar. 27, asm. (GO| ps Mpes ceases ee Mar. 30) an 2% i 4; St ae Sees re 71
695 |---.- LON eee UR Jaen oe eee ear Mar.305a. m,, to Mars iva. esa eee 71
GA News Gove 2 Ns Su aay begga Mar. 31-Apr. 1,9a.m.to 8a.m-.......... Freeyd
b Yel ce se COG epee 2 a ams es Nai As da a INOS NYP OS TG OOS NSA. So sos cuacedsce= 71
176.2 Maye 12-13) 3) ps mato 12pm ss: Peer May 15, apineccts fe teee eters ees ee 75
DASE ae £6 3) Ree SS CS en A May 15- =16,:2 p-\l. LOS as ee ee eee 75
447\June’s8. 1230 tos. 30 p. Mei. - 252 sees June) 20-21. Gsp MIAO; aant! «ees esse eee aa
90 June 19, 1) 5 1001, WON, Ue Se aes bodes June 21- 22, Gaps OLSia eee 76.6
77 | June 20,9a.m.to4p.m-.-.....-....-... June 22- 23. 6pom. tog. 30 asm: <2) ese 77
63 | June 24; 1-300 4:30. p. me... 2.2.2... June 26-27, 4.30 p.m. to6a.m-............ 77
194.) July 25; 3:30,t0)}4-30 p. Tyseeeas- 5. yo 2 Julliyal:7444730 760 Gl aes eee 78.9
IZB Mee CO HES ig U ee Gre a A otra JULY: 17,6: UO|S Pik ac meses cess ea eee 78.9
Of) ewes e GUO BE as A SM ae re ey earns ret July AO to 10 pymesa: sas see eee eee 78.9
1A eee ee (OK) es SOMES Spa Na eres ela delay Oey Tome HOLY, Wo shs Leb ene! 78.3
208) Aug. 241 0'30:t0)t1:30 a. marae as: - a5 2 AUes265 11-30 asim eto lap am! ee ee eee 79
Wales CLO) era oS So Cahn cee eee Aug. 26, TCO; Zips Ms Ss ese eee eee 79
Se iSeseese Coe eee es es eee. 2 Peg ase AUS 2652 COs. Mm Ayvoss . eRe Sees eee gt 379
AT. -SODtsO 4s LOmepenliNe 2m 5-22 oS ee cise Sept. 11, 30:0 pa ee 79.7
101 | Nov. 13-14,4 p.m. to9a.m-.........-- Nove 16:2 to'6 anim stress. 6 ee 1525
LOS eee KO ope uate CS a er Nov. 16, GGomMWa pM sos eee eres 75.5
356.| "Decals; Mita mitow p: mice. pe ess Dec. 18-19, 11 prim, to 6jasml 4 ee ee 69.8
ZUG ee ae 6 Ka YR REN Decs19) 607-8. (ses sees ee ee 69.8
AQ es GO! SEEN SSeS. coke ee ake Dee. 19:4 toiSiarmso2 22s -c ee. eee 69.8
330 Beare GO as cee se ciara eeiein ae Dec 19-8 ¢o as Ws ssa aoe eee sees 69.8
Seles COs ees ov. See ee oe Dec 19s 10 towsk aan: Cheese eae 69.8
Duleeeae CLO is ue a ares aroereraie ayers IDG, IT ian GO Ta Bases So oee Se ess ek 69.8
SHE eaige - COs cee ss eee eae Dec-19<8itoslO pamiar S22 eter eeee 69.8
As (al eDecelG lira ms COMED Ets] = seer ee =e Deczl9 4 COA Opa a aaa 76.5
IPN Nessa (0 Co eee tees RSS ers rae See oe Dees 19-205 10) ps meitoGias miss ee eee 70
4,066

While eggs hatch in from 2 to 6 days after deposition in any fruit-
growing section in the Hawaiian Islands, they may require a much
longer period for development under colder weather conditions. In
the course of experimental work, the writers have secured data
showing that under varying conditions of temperature the duration
of the egg stage may be extended to at least 25 days. In Table XIII
data of special interest, as indicating how dependent embryonic
development is upon temperature, are recorded.

All of 131 eggs one day old when placed at Puulehua, where the
temperature ranged between 39° and 89° F., with a mean of about
52° F., were still unhatched after 16 days at Puulehua, after which
they were taken to Kealakekua, where they hatched the following
day, or when 18 days old.

Twenty-three eggs deposited in apples at Kealakekua, Kona,
Hawau, at about 1,100 feet elevation, on February 9-10, 1915, and
taken on February 11 to the summit of Hualalai, 8,250 feet eleva-

MEDITERRANEAN FRUIT FLY IN HAWAII. 51

tion, where the temperature ranged between 30° and 62° F., with a
mean of 46° F. for the period of observation, were still unhatched
after exposure for 14 days. After 14 days on Hualalai eggs were
carried in their host to Kealakekua and there hatched on February
27, or 17 to 18 days after they were deposited.

Additional information on the duration of the egg stage has been
secured under cold-storage conditions. Eggs hatch in refrigeration
at temperatures ranging between 54° and 62° F. Five eggs depos-
ited August 15-16 and placed in a refrigerator at 54° to 57° F. on
August 16 hatched within the refrigerator on August 23, or in from
7 to 8 days after deposition; 19 eggs deposited at the same time
| were removed unhatched on August 23 but hatched on the 24th,
| outside the refrigerator, or 8 or 9 days after deposition. A single

egg also deposited on August 15-16 and similarly placed at 54° to

57° F. had not hatched by August 30, when it was removed to nor-
mal temperature, where it hatched within 24 hours, or 14 or 15 days
after deposition. Thirty-two eggs deposited on July 15-16 and
placed on July 16 at 58° to 62° F. hatched in the refrigerator on July

20 or in from 4 to 5 days after being deposited, whereas 6 eggs of the

same lot were unhatched in storage on July 24, after which they

were removed to normal temperatures where they hatched on July

25, or 7 to 8 days after deposition. Eggs deposited on February

11-12, and placed at 48° to 52° F. on February 12, failed to hatch at

this temperature, but 20 removed after 14 days hatched within 16

to 17 days after deposition; 11 removed after 19 days hatched within

21 to 22 days after deposition; while 1 removed after 22 days of

refrigeration hatched on March 8, or 24 to 25 days after deposition.

The examination of a second lot of fruit containing 1,853 eggs, de-

posited during a 24-hour period before they were placed at a tem-

perature of 48° to 53° F., showed that one egg hatched in storage 18

days after the inward date and after 24 and 27 days of refrigeration

64 and 56 first-instar larve had hatched and died in the punctures.

Of these 1,853 eggs, 1,014 removed after refrigeration for 18 to 27 days

were dead; of 115 removed to normal temperatures after refrigera-
tion for 16 days, 35, 25, and 9 hatched in 17, 18, and 19 days, re-

spectively, after deposition. Eggs deposited during a 4-hour period
were placed immediately at 49° to 56° F.; after refrigeration for 21
days, 1 living and 7 recently dead first-instar larvee and 51 unhatched
egos were found. Of other eggs deposited at the same time but
held at normal temperatures for from 44 to 47 hours before being
placed in storage, 8, 12, and 48 had hatched after refrigeration for

16, 19, and 21 days. One egg, two days after deposition, was held

in storage at a temperature of from 40° to 45° F. for 20 days (June

27 to July 17), when it was removed to normal temperatures where
it hatched three days later, or 25 days after deposition. One egg

52 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

placed in storage at 26° to 30° F. when one day old, and held at this
temperature for 7 days, hatched three days after removal, or 11
days after deposition.

TaBLeE XIII.—Duration of the egg stage of the Mediterranean fruit fly under low tem-
perature conditions.

Cold-storage dates. Temperatures.
Num-
Number of Length
: Dates of | ber of
eggs under Eggs deposited. : . ofeg
Ghervatin. hatching.|days in Staer Hamre Mea
Inward. |Outward. storage. © in outside
storage. | storage.
& aN Oe sae Ze
10f | -Julyi6; 913i 2223: July 7|July 8/July 9 1 3 26-30 78
Ageess2 dO 22S see: |= 2d0x. | July 9] July 10 2 4 26-30 78
i peer does 2o2C 06:53. | 2.002.222) July 12 2 6 26-30 78
2A eae GoM eee eae do. | ul yaS= eno see 1 6 26-30 78
388 | Nov. 3, 1914....... Nov. 4] Nov. 8 | Nov. 10 = 7 26-30 76.5
6 | June 30, 1913. ....- July 2) July 8] July 6 9 26-30 kh
1 | Nov. 3, 1914...._.. Nov. 4] Nov. 11 | Nov. 14 cf il 26-30 76.5
520 | Sept. 25, 1914...... Sept. 26 | Sept. 28 | Sept. 29 2 a 32 77.6
PAN pee ee dos eee do.....| Sept. 30 | Oct. 2 = 7 32° 77.6
yl ae Co Ree ao see bane dozss.2 O¢t.-75:b0ek. 1.7 9 12 32 77.5
21 | Sept. 7, 1914....... Sept. 9 | Sept. 17 | Sept. 19 8 12 33-34 79.5
ZO | ORS ation aE nee dOz.<5< OFad Sept. 21 8 14 33-34 78.9
242 | Nov. 16, 1914...__. Nov. 17 | Nov. 25 } Nov. 28 8 12 36 69.5
bee Oe Pa ae Sol ye dOs2.c- Nov. 27 | Dec. 1 10 15 36 70.4
5 | July 4, 1913 .2225-2.| Pauly “5-) Jaly =8-) July? 9 3 5 33-38 17:2
io ee C8 (TR are ese el (eae dos...| July. 9 | July7i2 4 8 33-38 77.4
(sy) ame Goyns sits Se| 522 do.....| July 16 | July 18 11 14 33-38 “FERED
4) dulyj7, 1913... July 18 | Aug. 1| Aug. 4 14 18 33-38 78.9
Ao) Sune 25 1913-22582 June 27 | June 30 | June 30 3 5 38-45 77.8
See ng eee Oe do... 4|=..dos2e. July 2 3 7 38-45 77.6
role eee do. Lean et dt. July 5|July 6 8 11 38-45 77.3
ie Sees dos ee | Gos.2:4 July 8!July 10 11 15 38-45 77.4
Giese. dol StS | 22 dow 25. July i4 | July 15 17 20 38-45 77.7
te eetee 0 (aera er dos July 17 | July 1&8 20 23 38-45 77.9
ete. t dol tetas! do.....|...do.....] July 20; 20 25) 38-45 77.8
20 | Feb. 11-12, 1915...} Feb. 12 | Feb. 26 | Feb. 28 14 16-17 48-53 69.8
ia 8 geeks doris. StL NA de27.it Mar. 3 | Mar. 15 19 21-22 48-53 70.5
cI) CG (Bes ae ee Pa do.....; Mar. 6 | Mar. 8 22 24-25 48-53 70.6
19 | Aug. 15-16, 1914...} Aug. 16 | Aug. 23 } Aug. 24 7 8-9 54-57 79.1
Sole Osemesocacen eb soe 0:5 é Aug. 23 7 7-8 54-57 79. 1
aA est ae GON 28. RSE do.....| Aug. 30 | Atig. 31 14 14-15 54-57 79.1
32 | July 15-16, 1914....| July 16 (4) July 20 4 4-5 99-62 79.5
oe aes d0s.5.. a ae dos. July 23 | July 24 7 7-8 59-62 79.5
172 | Sept.9, 11 a.m. to | Sept. 9, (4) Sept. 16 7 7 60-64 79. 2
2p. m. 3p.m.
23 | Feb. 9-10, 1915....| 2Feb.11 | Feb. 25 | Feb. 27 |.....-.-. 17-18 430-62 69. 4
131 | Feb. 20, 1915..._-. SBOD: LU? Sse Fe Mart “6425225. - 14 539-89 67.8
1,720
'

1 Fruit not removed. Eggs hatched in storage.
ts Not placed in cold storage, but exposed to normal tmperatures at summit of Mount Hualalai, 8,200 feet
elevation.
3 Not placed in cold storage, but exposed to normal temperature at Puulehua, about 4,500 feet elevation.
4 Mean temperature about 46° F. y
5 Mean temperature about 70° F.

These data, together with those recorded in Table XIII, demon-
strate the great variation, from a fruit-fly standpoint, in the duration
of the egg stage.

THE LARVA.

DESCRIPTION.

A clear idea of the general shape of the larva or maggot of the
Mediterranean fruit fly can be gained by reference to text figures 7
and 8, and Plate XIII, figure 1. When first hatched from the egg,
the larva is about 1 mm. long but increases in size to from 7-8 mm.
long when full grown. Each larva passes through three well-defined

te Bee

MEDITERRANEAN FRUIT FLY IN HAWAII. 53

instars. While normally white in color, it may appear creamy yel-
low, pink, or with colorations of red or black, according to the nature
of its food, which shows through the semitransparent body walls.
First larval instar (fig. 8)—Length about 1mm. The first-instar larva is so small
that it is seldom observed. Aside from its size, it is most easily distinguished from

the succeeding instars by the absence of anterior spiracles. The tracheal system in
this instar opens to the exterior only at the posterior spiracles, and consists of two main

b Cc
Fic. 7.—Third-instar larva of the Mediterranean fruit fly: 2, Lateral view of entire larva; 6, dorsal view of
anterior portion; c, lateral view ofsame; d, ventral view. (Original.)

trunks extending the full length of the body. The posterior stigmatic plates, the
outer edges of which are about 0.061 mm. apart, have two instead of three slits, as
illustrated in figure 9, a. The mandibles or mouth hooks are not conspicuous and are
of the shape indicated in figure 10, a.

Second larval instar —In size the second larval instar is sufficiently large to be dis-
tinct from the first instar, but not from undersized third-instar larve. It may, how-
ever, be easily distinguished from the third instar by the shape of the anterior spiracles

Fie. 8.—First-instar larva of the Mediterranean fruit fly, showing one of the two main tracheal systems
opening at the posterior spiracles. (Original.)

(fig. 11, a), the mandibles (fig. 10, 6), and posterior spiracles (fig. 9, 6). The distance
between the outer edges of the stigmal plates is about 0.13 mm.

Third larval instar —The third-instar larva, which is about 7 to 8 mm. long, may
be distinguished when well grown from the two preceding instars by its jumping
habit when removed from its host, by the well-defined mandibles or mouth hooks
(fig. 10, c), and by the prominence of the posterior spiracles. The anterior spiracles
possess from 9 to 10 lobes (fig. 11, 6) and are borne on the second segment as in the
preceding stage. The posterior stigmal plates each bear three slits arranged as illus-
trated and are armed with four batches of delicate inconspicuous hairs (fig. 12).

54 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

The dotted lines of figure 12, indicate the general shape of the terminal chambers of the
tracheal system. The body is composed of 12 distinct segments, the last of which bears
the posterior stigmata upon the upper distal portion and the anus before the center
of the venter in the middle of a rounded tubercle (fig. 7, a). The head when viewed
eens from above or below is bilobed; each lobe bear-

: E ; *s. ingadistinct antennal protuberance; the dorsal

\ ; » : and more distal one terminating in a short incon-

. c: s ey / spicuous arista; the more ventral one less anten-
é Ae ace nalike and without a terminal arista (fig. 7, 6, c,
ai d). Mouth hooks sheathed (fig. 7, d). Body
armed only with inconspicuous spicules ar-
ranged in broken bands forming fusiform areas
on the venter of the 4-12 segments; portions of
the head and an irregular rind upon the anterior

“.

spicules. There are no distinct fusiform lateral
areas of spicules.

DURATION OF LARVA STAGE.

Fic. 9.—Posterior spiracles of larve of the : d
Mediterranean fruit fly: a, First-instar lar- The duration of the larval instars has

vee; b, second-instar larvee. (Original.) b een vari ously giv en by many writ ers.
Martelli found that larval development at Portici, Italy, required
from 9 to 10 days during summer, 11 to 12 days during early autumn,
and 15 days during November and December. Severin found that
larvee matured in the winged kamani (Terminalia catappa) in from 8

portion of segments 2 and 3 armed with similar — i

to 17 days. Newman states that from 14 to 16 days during summer

and 25 to 45 days during winter in Western Australia are the periods
required for development. Other data might be given but they add

Fic. 10.—Mandibles of larva of the Mediterranean fruit fly: a, First-instar larva; b, second-instar larva; c,
third-instar larva. (Original.)

nothing new to the foregoinginformation. No records previously pub-
lished except by the writers have been accompanied by temperature
data, hence they can not be satisfactorily interpreted.

In Honolulu larval life! is completed within 5.1 to 26 days. The
data in Table XIV indicate the variation found in the developmental

1 Back, E. A., and Pemberton, C. E. Life history of the Mediterranean fruit fly from the standpoint of
parasite introduction. Jour. Agr. Research, v. 3, no. 5, 1915, p. 363-374.

}

MEDITERRANEAN FRUIT FLY IN HAWAII. 55

period. During June when the mean temperature was 77.6° F. two
larve completed their entire development in 5.1 and 5.5 days, respect-
ively, but they were transferred daily
to fresh pieces of ripe papaya and thus
were surrounded by the best of condi-
tions. However, other larvee equally
well cared for and similarly fed and
transferred did not reach maturity
and pupate until 6.7, 12, and 14 days. :
Ordinarily larve complete their devel-
opment in from 6 to 10 days at an aver-
age mean temperature of 76° to 79° F.
During the cooler part of the year,
when the average mean temperature
is about 69.6° F., larve transferred
daily to fresh ripe papaya did not be-
come fully grown until 9, 10, and 14
day Ss old, while at about the same tem- yg. 11.—Anterior spiracles of larva of the
perature 18, 12, and 1 larvae required ‘Mediterranean fruit Wy: & Femina
10, 11, and 15 days for development at
in a green half-grown peach. Atamean temperature of about 70° to
71° F., 12, 14, 3, 1, and 1 larve pupated 14, 16, 19, 22, and 26 days,
respectively, after hatching. Larve hatching during December 25 to

Fig. 12.—Posterior spiracles of third-instar larva of the Mediterranean fuit fly. (Original.)

VAs

Jerse ae ise

(

26 in a very firm textured apple required 19, 25, and 35 days for
development when the mean temperature averaged about 68° F.
Four and 3 larve became full grown in 6 and 7 days, respectively, in
a ripe soft peach at a mean temperature of from 77° to 78° F., whereds

56 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

under identical conditions 6 larve required 9.5 days mm aripe but still
hard peach.

All data secured by the writers indicate that durmg the warmest
portions of the year larval development progresses rapidly and fairly
uniformly. With the approach of colder weather larval life is not
only lengthened but subject to considerable and entirely unexplainable
variation, even with larve hatching at the same time in the same
fruit, especially if the host fruit happens not to be in the best condi-
tion to support larval life. The three larve requiring 19, 25, and 35
days for development in a very hard apple furnish a good example.
In Table XV are recorded data showing the ability of cold weather
greatly to increase larval life.

The data in Table XIV indicate that under favorable conditions as
regards temperature and host the first larval instar is passed in from
26 to 48 hours, the second in 24 to 48 hours, and the third in 48 to 265
hours. It is profitable, therefore, to compare these and other data in
Table XIV with the data of Table XV.

At an elevation of 8,250 feet, on the summit of Mauna Hualalai,
Hawaii, where the temperature ranged between 27° and 73° F.,
but averaged for the period about 48° F., the first larval instar was
found to range up to 57 days. EHighty-nine larve in apples were
found still in the first instar after 30 days, 3 after 46 days, 7 after 54 days,
and 1 afterexposure for57 days. Thirty-three larvein the second instar
placed on Hualalai were still in this instar after 32 days, and 1 after 54
days. At Strawberry, Hawaii, a ranch station, where the temperature
ranged from 39° to 79° F., 49 first-instar larvee were found still in
this instar after 27 days and 19 after 29 days. At Kealakekua,
where the temperature ranged between 58° and 80° F., with a mean
of about 68° F., three larve in apples required 28, 58, and 74 days to
become fully oe and to leave the fruit to pupate.

In cold storage under what may be called artificial conditions,
larval life may be variously prolonged. ‘Thus one second-instar io
and one third-instar larva in peaches placed in storage at temperatures
varying from 40° to 45° F. were found still in those instars at the
end of 29 and 45 days, respectively, while check larve at the labora-
tory in the same species of host fruit completed their entire develop-
ment in from 6 to 9 days. Three third-instar larve in apples placed
in a refrigerator at temperatures varying from 48° to 52° F. were
still active after 60 days and one was alive after 79 days. In a
second refrigerator at temperatures ranging from 58° to 62° F.,
larve completed their development and pupated in 24, 36, 40, 44,
and 50 days.

MEDITERRANEAN FRUIT FLY IN HAWATI, af

TaBLeE XIV.—Duration of the larva stage of the Mediterranean fruit fly in Honolulu.

Num- Temperature
ber of of cover ots
pens De et: Larva Molted into | Molted into Larva Length| Monta ase.
Host fruit. aes hatched. | second stage. | third stage. pupated. eee
pose Range. |Mean.
Sune O70,
Papaya...- 3 | Dec. 19,9 to | Dec. 21, 10} Dec. 28, 4 | Dec. 28,12m. 9 61-78 | 69.6
10 a. m. a. m. to 2 p.m.
p.m.
Done ee TR |Bee oe Gone ease gee Govzeeee |) Dees 23) 10s Decya28,, 4 9 61-78 | 69.6
a. m. to 2 a.m.
: p. m.
DO Gee id Rees GOL Ae ees COR ys | DEC 2344. FON eee dots 9 61-78 | 69.6
10 p.m.
Does: ae Ties Gosse epee do........| Dec. 23, 10 |) Dec. 28, 12m. 9 61-78 | 69.6
a. m. to 2
p. m.
Monee TSE eee OR etal do........| Dec. 23, 4 to | Dec. 28, 10 9 61-78 | 69.6
10 p. m. a.m
1D) Oe Dbl ea Goss ee a leeees GOs 22 =| Deer 23,245 Deeoe 98, 11 9 61-78 | 69.6
p.m. a.m.
DONS ee aN bee es (0 Ko esis a eer a Coe ease ED eC 235 40 tonleae ne Goes ee 9 61-78 | 69.6
10 p.m.
DOM Lee alee (B Koyama tie ay es Cosas eeaed ore. yee) Dec. 28, 12 m 9 61-78 | 69.6
IDS AB bre se GOs Somesecl sees GOs OSeel ees ROO. eS Dec. 29, 4 10 61-78 | 69.6
a.m.
Doves Te) Se dopey Dec. 21, 2 to | Dec. 23-24,10 | Dec. 29, 3 10 61-78 | 69.6
; 4p.m. p. m. to 6 p.m.
a.m.
Doeere: 2 Ae eae Gores ee Pal Ch HOy Sec do........| Dec. 29,12m.| 10 61-78 | 69.6
p.m.
DD Oe see ae es aes dOss85 Deck 21-310) secs dors Jane2s ip.mie|n, 14 61-79 | 70
a. m. to 2
p. m.
IDOs366605 2 | June 12,a.m.| June 14,a.m.} June 16,a.m.| June 18, a.m. 5.1] 71-83} 77.6
IDOssdeese 3) June 12. p.m. | so. Goze ee hess GO eee Eke donne 5.5 | 71-83 | 77.6
DYES SESE 1 | June 19,a.m.| June 20-21, 4 | June 21-22, 4 | July 1, a. m..| 12 72-83 | 77
p.m to 8 1De 00's to 8
a.m. a.m.
ID Orie ees 1b Aes GO ee (G10) ae eel eyes Goss se: July 3,a.m..| 14 72-83 | 77.1
DOee ees Tiaee Osea sale umMes20> tuto) |eeeee do........| June 25, p.m. 6 72-83 | 76.4
4p.m
IDORAGaae Wile See do........| June 20-26, cl ae COsesa carers MOscece sas 6 72-83 | 76.4
p. m. to 8
Dore 1 7 72-83 | 76.6
Pigen peach 10 72-83 | 77.2
Be ep il 72-83 | 77.2
Ripe hard 9.5 | 72-83 | 77.4
peach.
Ripe soft 6 72-83 | 77.8
peac
DOs ess 7 72-83 | 77.7
Green peach 10 61-77 | 69.6
1D Oe sei (Oye g fate, alte apscha se eR eae a eRe oa ud Apr 11 61-77 | 69.8
Dogs t28 15 61-82 | 71.0
Commercial 14 57-80 | 70.2
lemon.

Gust: 16 57-80 | 70.3
Wore ioe tise se idoe Sit | PSAs eds ee A as Apr 19 57-80 | 70.5
DO Lss: re: ees 22 57-80 | 70.4
Woes. 22 pr. 26 57-80 | 70.4

Apple...... Jan. 13, 1915. 19 67-81 71.6
DOR See ee Jan. 19, 1915. 25 67-81 | 71.1
DOs es Jan. 30, 1915. 35 67-81 | 70

The data recorded in Table XV only indicate the possibilities in
lengthening larval life. Except at temperatures from 58° to 62° F.,
none of the larve would have been able to mature had they eon
kept at the temperatures recorded. The data merely bring out the
fact that upon the examination of the host fruits after so many days
the larve recorded were found alive. A very large percentage of the
larvee within the same fruits were dead, but this mortality, due to
exposure to cold for prolonged periods, is discussed elsewhere.

58

BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

TABLE XV.—Showing ability of low temperatures to lengthen larval life of the Mediter-

ranean fruit fly.

Temperature.
sone 7 Peete’ |Lengtnot
EES der ob. | Zustar. Locality. ; instar or
servation. Range., Mean. instars.

2 my ie Days.

1 2 poor eas 15
z Gold storages sss. ees cee wee oe ee cae ee eee ree SacBee: x
1 3 40=45 || eet has 45
12 3 . 48-54 50 24
: 3 Refrigerator INO: 52k see oe eee see eo earce eee ree = a
1 3 48-54 50 79
1 1,2,3 58-62 60 24
1 19534) 58-62 60 36
1 1523 ReirigeratonNo: dacisacs uese coe ce ee lace eee see eeaee eee 60 40
il 1523 58-62 60 44
3 12.3 58-62 60 50
1 1983 58-80 69 28
1 1 2: Sig pealakekuaire yas co ee sole delet oper ceneae an ace ooree 69 58
1 1ST 3 : 58-80 69 74
41 eats | 27-73 48 12
1 1 | 27-73 48 26
89 1 | 27-73 48 30
1 ite 27-73 48 45
2 PalPpHuUalalar: soc siscc oc coe oe ameue wie ee on maec eset cee eeeeee gras 48 46
1 7-7 48 54

1 1 27-73 48 57
33 2 27-73 48 32
1 2 27-73 48 54
133 1 | eee te ee ae hee AON ee ise se ee. Mol |) ete Sif ee 54
a ID PPI Globe ese Goes Gade so seoaoca sooodcabds scécosecee 55) \oestos = BEES cee 17
4 i | (arene te ae adios ts eee eemence Fa ye rennet reel pes Pr mer ae |e el a Se 36
49 1 é 39-79" 8.32 27
19 1 = Derry .--.------+--22-2- 2-2-2 2s 2222 ee en ees eee s- i 26°70) | ee 29

1 In securing these data apples were used as host fruits in all but the first four records for cold storage,
for which peaches were used.

In spite of the ability of cold temperatures to prolong larval life
greatly beyond the usual period required for development during
warm Hawaiian weather, it is interesting to record that individual
larvee whose development has been slowed down, or even practically
suspended, will continue their development normally when returned
to warmer temperatures. Thus one second-instar larva which had
been held for 54 days on Hualalai on being taken to Kealakekua on
March 26, where the mean temperature was about 66.8° F., and then
to Honolulu on March 29, molted into the third instar on March 30.
A second larva placed on Hualalai just after hatchmg and kept there
until March 17, or 45 days, on being taken to Kealakekua molted
into the second instar on March 21, into the third instar on March
24, pupated March 28, was taken to Honolulu on March 29, and
emerged as an adult on April 10.

PUPA.
DESCRIPTION OF PUPARIUM.

Puparium (Fig. 18, a, b, c).—Puparium elliptical in general shape; a little more
convex on the dorsal side; length about 4 to4.5mm. The sizeand color of puparium
vary and depend upon the amountand nature of larval food. Puparia formed by larve
feeding on coffee cherries dull white; the usual color light or dark testaceous. There
are only 11 distinct segments, the first being composed of the first and second larval

MEDITERRANEAN FRUIT FLY IN HAWATLI, 59

segments, and therefore bearing indications of the mouth opening and anterior spira-
cles of latter; last segment likewise bearing the remains of anal and stigmatal openings
of larva ;

DURATION OF PUPA STAGE.

Mally has found in South Africa, at Grahamstown, that the dura-
tion of the pupa stage may be as long as 35 days in a rearing box
kept ‘‘at the ordinary seasonal temperature.”’ Martelli states that in
southern Italy the pupa stage varies with the progress of the season;
that it may be from 10 to 11 days durmg summer (August), 18 to 20
days during autumn (October), or 30 or more days during the winter.
Newman found in Western Australia the periods to be from 12 to
14 days during summer and 25 to 50 days during winter. Nearly
all writers have offered data on the duration of this stage, but, unac-
companied by temperature or
humidity records as they are,
they add nothing new to the
foregoing information.

In a previous paper the
writers give data, accompanied
by temperature records, on ob-
servations including about
2,000 pup developing under
Honolulu conditions. From
these it would appear that the
minimum length of pupal life
is about 6 days when the
: mean temperatures range be-

ie tween about 76° and 79° F.
Fig. 13.—Pupa of the Mediterranean fruit fly:a, Dorsal During the warmest Honolulu
view; b, ventral view; c, posterior end, showing anal weather the largest proportion

sear and spiracles. (Original.) é

of any lot of pupzx require
from 9 to 11 days before yielding adults. Thus at a mean of
about 76° F. 5, 14, 101, 160, 7, and 3 pups yielded adults 6, 9, 10,
11, 12, and 13 days, respectively, after the formation of the puparium.

The pupa stage may be increased to at least 19 days when the
daily means drop to about 69° to 71° F. The data in Table XVI
covering observations on 7,000 pup are given in corroboration of
this statement. At a mean temperature of about 66.8° F., pupz
required from 20 to 28 days to complete their development at
Kealakekua, Kona, Hawaii. In Table XVI are given a large number
of records covering the coldest portions of the year in the usual
fruit-growing sections of the islands. These records, together with
many others on file, given in Table XXV in connection with parasite
work, indicate that there occurs no dormancy among pup at these
temperatures. In other words, while development is considerably
retarded, there is no yielding of adults by a few pup while others

60 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE,

yield adults after a period of dormancy for several months as has
been found to be true of the parasites Diachasma tryoni and Diachasma
fullawayt.

TaBLE XVI.—Duration of the pupa stage of the Mediterranean fruit fly in Hawaii
(7,000 pup).

Date of | Date of | Number| Length | Mean Date of | Date of | Number} Length | Mean
upation,| ©™erg- | adults pupa | tempera-|| ation. | °mers- | adults pupa _ | tempera-
ae ence. |emerging.| stage. ture. || PUP ‘| ence. |emerging.| stage. ture.
Days. oF ES Days. 2 LS
Feb. 31] Feb. 23 9 20 66.8 || Dec. 18-20) Jan. 1 167 | . 12-14 72.9
Dorsss Feb. 24 3 21 66.8 Dor 42- Janeen 12 466 13-15 72.8
Dole Feb. 25 82 22 66.8 Dose: Janine 152 14-16 72.7
Do..... Feb. 26 69 23 66.8 Dow Jan. 4 3 15-17 (25
Dose Feb. 27 1 24 66.8 DOr ke Jan. 5 2 16-18 72.4
Dope cee Mar. 3 1 28 66.8 Dot 262. Jan. 6 1 17-19 (Pe
Feb. 272] Mar. 13 7 14 70.4 || Dec. 22-29} Jan. 4 27 11-13 72.4
Doss. Mar. 14 40 15 70.3 WOse Jans 528 12-14 72.3
DORE Mar. 15 15 16 70. 4 Doses Jan. 6 541 13-15 72.1
Do..... Mar. 17 17 18 70.9 DOs. diy 7 804 14-15 71.9
DOs Mar. 18 3 19 70.9 DOse<e2 Jan. 8 57 15-17 71.5
Dec. 1] Dec. 12 8 11 73.2 IDWss655 Jan. 10 1 17-19 es
Dose: Dee. 13 279 12 73.1 )| June 101! June 16 5 6 76.4
Dose Dec. 14 269 13 73.1 IDO SS5cc June 19 14 9 76.3
IDOE Dec. 15 116 14 13.2 DOR nee June 20 101 10 76.3
Moz 3st Dec. 16 29 15 73.4 DOvscas June 21 160 11 76.2
Dec. 8-10 | Dec. 19 2 9-11 UB DOeaee. June 22 a 12 76.1
IDS 556 Dec. 20 1 10-12 73 Dose: June 23 3 13 16.3
ID seo6e Dec. 21 98 11-13 73.1 || wy 13) July 20 1 7 79.2
Dols 2 Dec. 22 478 12-14 (B57? IDO ASE July 21 3 8 79.2
Do..... Dec. 23 189 13-15 73.2 Docs July 22 39 9 79.2
DO-f... Dec. 24 2 14-16 73.2 Do..... July 23 43 10 79.1
Dec.16-18| Dec. 27 24 9-11 Taso DORAeu: July 24 3 ll 79
IDO Re aee Dec. 28 96 10-12 73.1 || June 8] July 16 2 8 76.2
IDX sS506 Dee. 29 654 11-13 73.2 DON July 17 15 9 76.2
Dow. Dec. 30 712 12-14 (ane Doras July 18 28 10 76.1
DOs Ak Dee. 31 72 13-15 73.2 Dorie: July 19 53 11 76.1
Dec.18-20| Dec. 29 4 9-11 (ey 2) Dox 86 July 20 53 12 76.1
DOM e8 Dec. 30 41 10-12 73.1 Dov July 21 5 13 76.1
Dorr Dec. 31 415 11-13 73
1 At Kealakekua, Kona, Hawaii. 2 At Honolulu.

While it is probable that the duration of the pupa stage in any
fruit-growing section in Hawaii is never more than 20 to 28 days
(average mean temperature 66.8° F’.) the writers have shown that it
may be much longer under cooler conditions. As a contribution
toward what the maximum duration may be, the following data are
presented.

In a glass refrigerator of the usual type for displaying fruits and vegetables, which
was kept at a temperature of from 58 to 62° F., the duration of pupal life was found to
range between 23 and 38 days when the pupe were placed within storage within half
a day after the formation of the puparium. Thus 4, 12, 9, 16, 44, 367, 1,217, 159, 25,
11, 5, 1, and 1 adults emerged in the refrigerator after 23, 24, 25, 26, 27, 28, 29, 30, 31,
32, 33, 34, and 38 days, respectively, of refrigeration. One pupa 8 days old was held
in storage at from 40 to 45° F. for 27 days and yielded an adult 2 days after removal
to normal temperature, or 37 days after pupation. One hundred pup placed in a
refrigerator when one-half day old and held continuously at a temperature of from 54
to 57° F. for 24 days, on removal to normal temperatures produced 2, 27, and 5 adults
in 4, 5, and 6 days, respectively, after removal, or 28, 29, and 30 days after pupation.
A second lot of 100 pupz, placed at 54 to 57° F. when 1 day old, produced 3, 16, 9, 3,
2,4, and 2 adults in refrigeration in 31, 32, 33, 34, 35, 36, 37, and 38 days, respectively,
after pupation.

MEDITERRANEAN FRUIT FLY IN HAWAII. 61

Pup formed by larve pupating within a refrigerator held at 52 to 56° F. yielded
2 and 1 adults within storage after refrigeration for 38 and 52 days, respectively. Out
of 39,500 pupz held in like manner at from 49 to 51° F. only 1, 2, 2, 3, and 1 pupe
yielded adults in storage after 20, 23, 44, 46, and 47 days, respectively, of refrigeration.
These 9 pupz yielding adults were 5 days old when placed in cool storage; hence they
were 25, 28, 49, 51, and 52 days old when they yielded adults. One 3-day-old pupa
held at an even temperature of 32° F. for 9 days, on removal to normal temperature
produced an adult on November 14, 10 days later, or when 23 days old. Two 1-day-
old pupe refrigerated for 19 days and then removed to normal temperatures yielded
adults in 29 and 30 days, respectively, after pupation. Investigators working in
countries where the temperature falls for short periods to or slightly below freezing
are referred for other data to a previous paper by the writers! in which are given
data on the effects of 32°, 33° to 34°, 33° to 36°, 28° to 40°, 38° to 40°, 40° to 45°,
49° to 51°, 52° to 56°, and 54° to 57° F. upon 173, 318 pupe.

During J anuary-March, 1915, the writers secured data on the effect upon the dura-
tion of pupal life of out-of-door temperatures at elevations of about 3,700 feet at Straw-
berry, at 5,000 feet at Puulehua, and on Mauna Hualalai at 8,250 feet. Pups formed
at Honolulu on January 31, shipped to Kealakekua on February 9-10, and placed at
Strawberry on February 11, were found to have produced 1, 72, 392, 4, and 6 adults
on February 24, 25, 27,and March3. The temperature at Strawberry for these periods
ranged from 42 to 69° F. with a mean of about 56° F. Other pup formed at Honolulu
on February 8, shipped to Kealakekua February 9-10, and placed at Strawberry
February 11, were found to have yielded 3, 307, 503, and 13 adults on March 11, 17,
20, and 25, respectively. Pups formed at Honolulu on February 6, shipped to
Kealakekua February 9-10, placed at Puulekua February 11, where the temperature
between February 11 and March 26 ranged from 38° F. to 72° F., with a mean of 53°
to 54° F., were found to have yielded 2, 10, 108, 126, and 13 adults on March 9, 17,
20, 25, and 26, respectively. The pupz yielding adults on March 26 were 48 days
old. Other pupz formed at Kealakekua on January 26 and taken the same day to
Puulehua yielded no adults before March 25, when they were removed to Kealakekua,
where the temperature ranged during March 24-27 between 60 and 84° F. At
Kealakekua 2 and 16 pupz yielded adults on March 26 and 27, respectively, or when
59 and 60 days old. Pupz formed at Honolulu February 12, shipped to ‘Kealakekua
February 17, and placed at Puulehua February 24, were proud to have yielded 4, 96,
and 1 adults on March 9, 17, and 20, waqneehvel ye Pupz formed at Kealakekua
January 27, taken to Hualalai January 31, and removed to Kealakekua March 26, pro-
duced no adults, and on examination appeared not to have been able actually to
pupate. The temperature on Hualalai for the period ranged between 31° and 70° F.
Pupee formed at Honolulu February 9, placed on Hualalai February 12, and removed
to Kealakekua March 2, yielded 10 adults between March 17 and 20, or when 36 to 39
daysofage. Pupe formed at Honolulu February 5and taken to Hualalai February 11
were found to have yielded 51 adults between March 23 and 26. On March 26 they were
removed to Kealakekua, where 17 and 2 yielded adults on March 27 and 28, respec-
tively, or 50 and 51 days after pupation. Of this lot of pups, 1,820 did not survive
the Hualalai temperature. Pups formed at Honolulu February 7, placed on Hualalai
February 12, and removed to Kealakekua March 26, yielded 52 adults on March 31,
or 52 days after pupation, but 1,506 failed to survive.

The data presented are of particular interest in bringing out the ability of pupee to
survive various climatic conditions apt to be experienced in countries harboring fruit
flies. It will be noted that 60 days is the longest period obtained by the writers for
pupal development.

1 Back, E. A., and Pemberton, C. E. Effect of cold-storage temperatures upon the pupae of the Medi-
terranean fruit fly. Jour. Agr. Research, v. 6, no. 7, 1916, p. 251-260,

62 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

THE ADULT.

DESCRIPTION.

A general idea of the relative size and coloration of the adult of the
Mediterranean fruit fly may be gained by an examination of text
figures 1 and 14, and Plate I figure 1, and Plate VIII figure 3. The
adults vary from 3.5 to 5 mm. in length. The description by
Froggatt is as follows:

Size 4 to 5 mm. about the size of an average house-fly, but looking somewhat smaller
when dead, because the body shrinks up beneath the thorax. General color, ocherous
yellow, lighter on the sides of thorax and basal joints of the antennae. The eyes of
the usual reddish purple tint, with a blackish blotch in the center of the forehead,
from which spring two stout black bristles, a fine fringe of similar bristles round the

Fic. 14.—The Mediterranean fruit fly ( Ceratitis capitata): Adult male. Greatly enlarged. (Original.)

hind margin of the head, with some coarser ones curving round in front of the head
between the eyes. The thickened basal joints of the antennae pale yellow, the termi-
nal segments black to the tips. The dorsal surface of the thorax convex, raised, and
broadly rounded with the scutellum, the ground color creamy white to yellow, marbled
with shiny black blotches forming an irregular mosaic pattern, the lighter portions
clothed with very fine white bristles. These light-colored bristles more lightly
scattered over the dark areas, and the whole bearing large stout black bristles thickest
on the black surface. In many of the pictures of this insect the black areas are drawn
as if they were projecting bosses or knobs, but this is incorrect; the whole forms a
regular rounded surface.

The wings are broad, semiopaque, with the extreme base blotched with ocherous
or brownish yellow, with the rest of the basal area curiously marked with black, form-
ing dark lines of the radiating nervures, with dark lines and spots between; beyond
this is a broad irregular transverse ocherous band, slightly lined with black, blotched
at the extremity; another similar shaped and colored blotch runs along inside but

&

dk Cebit ae

MEDITERRANEAN FRUIT FLY IN HAWAII. 63

not in contact with the costal nervure, also blotched towards the extremity in the
angular space. Between these bands is another shorter black band running parallel
with the first transverse band.

The oval abdomen is clothed on the upper surface with fine, scattered black bristles,
and has two rather broad transverse silvery white bands on the basal half of the body.
The male differs from the female in being furnished with a pair of stalked appendages
standing out in front of the head in a line with the front margin of the eyes, the ex-
tremities of which filaments are produced in spatulate appendages, black, finely
striated, and diamond shaped.

The living fly is an active little creature, running about over the foliage or fruit on
the trees, with its wings drooping down on the sides of the body. When disturbed it
has a short flight, seldom flying more than a few yards at the most, and it often returns
to the same spot.

EMERGENCE.

The adults of the Mediterranean fruit fly emerge in largest numbers
early in the morning during the warmer portions of the Hawaiian
year, but more scatteringly during the cooler portions. During the
summer the larger proportion of adults emerge between 5 and 8 a. m.
On December 31, 1914, when the temperature ranged from 66° to
78° F. and the mean relative humidity was 72 per cent, 55, 58, 125,
and 16 adults emerged between the hours 6 to 8-a. m., 8 to 10 a. m.,
10 a.m. to 1 p. m., and 1 to 4 p. m.,- respectively. On January 2,
1915, when the temperature ranged from 68° to 76° F. and the rela-
tive humidity was 58 per cent, 141, 159, 28, and 12 adults emerged
between the hours 6 and 8 a.m., 8 and 10 a.m., 10 a.m. and 12 m.,
and 12 m. and 2 p. m., respectively.

The adult when issuing from the puparium seems invariably to
cause a fairly regular split from the cephalic tip of the puparium
straight back along each side to near the middle of the fourth segment
and then upward over the dorsum, following a line fairly well in the
center of the fourth segment, and often splitting entirely around the
center of this segment. Thus the upper half of the first three seg-
ments and the upper anterior half of the fourth segment of the pu-
‘parium are usually broken away by the pressure of the ptiimum, and
often the entire anterior portion of the puparium is broken off back
to the middle of the fourth segment during the emergence of the

adult. :

Once out of the puparium, the adult forces its way to the surface of
the soil or out of other confinement, with the aid of the ptilinum.
Before the natural coloration appears and while the chitin: of the
_ body is still pliable, the adults are able to force their way through
meredibly small openings or cracks, through loose cotton stoppers,
and sometimes beneath rubber bands. Often the united efforts of a
few adults will force an exit in places from which single adults unaided
could not escape.

64 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

DURATION OF ADULT LIFE.

WITHOUT FOOD.

If adults have no opportunity to feed after emergence they die
within 4 days. Ninety adults issuing on March 15 and kept under
starvation conditions were all dead by the end of the third day. On
the second and third days, 68 and 22 adults, respectively, died, and
at 9 a. m. on the third day only 4 were barely alive, and these were
dead by5 p.m. Of 50 adults emerging on March 14, 1, 48, and 1 died
on 1, 3, and 4 days later. French states that he found that adults
died in Australia within 4 days if kept without food. The writers
have handled many thousands of adults during the past 3 years and
have never had flies live longer.

Tf given only water, life is shghtly prolonged. Of 300 adults emerg-
ing on October 17, 250 had died by the end of the second day, while
the remaining 50 were dead by the end of the third day. Of 42 adults
emerging May 20, 12, 25, 4, and 1 died after 2, 3, 4, and 5 days.

WITH FOOD.

In 1899, Lounsbury in South Africa confined adult flies In a wire ©

cage out of doors to determine the length of adult life. By the use of
apples as food, 1 female out of an original number of 60 was kept
alive from March 30 to July 19, or about 16 weeks. French states
that adults live to be 25 days old during March in Victoria, Australia.
Gurney found that in confinement adults live from a few days to
three weeks. Newman states that he has found that flies live usually

6 weeks, but when no suitable food is available for oviposition, they.

may live from 8 to 10 weeks. Later the same writer gives the length
of adult life in western Australia as ranging from 28 to 40 days in
summer and from 28 to 65 days in winter.

The writers have found that even when given the best of care many
adults die very young. In every lot confined in jars about 50 per
cent may be expected to die during the first 2 months. The early
death of many flies does not seem to be caused always by overcrowd-
ing, for frequently single adults given the best of care in separate jars
die at all ages from 1 to 2 days on. The greatest interest in connec-
tion with the longevity of adults must center in the minority that live
for long periods.

In a preliminary paper the writers record 1 adult that ied from
December 31, 1913, to May 11, 1914, or 131 days, and others emerg-
ing on February 28, 1914, that were still alive on August 1, or 5 chonthe
after emergence. Additional data have since been secured. One
female emerging on the same date died on September 4, or at the
age of 5 months; another female emerging on the same date died on
September 30. About 500 adults emerging on June 28 were placed

in large glass jars; on August 14 only 40 were still living. The last.

two of these 40 adults died on October 2, at the age of 97 days. The

MEDITERRANEAN FRUIT FLY IN HAWAII. 65

rate of mortality for the 40 is as follows: On August 14, 28; Septem-
ber 4, 9, 12, 15, 17, 19, 21, 23, 24, and October 2 and 3, there were
alive 40, 30, 17, 12, 11, 10, 10, 7, 5, 4, 2, 2, 0 adults. Two hundred
and twenty-five adults which emerged on December 31, 1913, were
placed in a large glass jar and fed daily. The last fly which died lived
to be 131 days old. A general idea of the mortality of these flies may
be had from the fact that when examinations were made on March 9,
13, 18, 22, 26, 31, April 1, 6, 13, 15, 17, 18, 19, 26, 27, 28, 30, May 1,
3,5, 7,9, 10, and 11, there were living 225, 214, 202, 171, 139, 94, 59,
APES ORE Om 18 16 BG Kor 254! 3609) and cit
respectively.

One female emerging on February 28, 1914, died on August 3; two
males emerging on the same date died on October 5 (7 months, 5 days),
and on October 15 (7 months, 15 days), respectively. One female
emerging on March 3, 1914, died on September 8 (6 months, 3 days).
The death rate among 95 males and 58 females, the only survivors on
July 3 of a lot of 800 adults emerging on February 28, 1914, is given
in Table XVII. The oldest fly lived 230 days, or 7 months and 10
days.

TaBLE XVII.—Data on longevity of adults of the Mediterranean fruit fly emerging on
Feb. 28, 1914, which had survived until July 8.

Adults still alive.

Adults still alive. Adults still alive.
Date. Date. Date.
Male. Female. Male. Female. Male. Female.
July 3 95 58 Aug. 15 19 Pe Sept. 11 5 0.
July 9 © 80 38 Aug. 18 14 2 Sept. 12 3 0
y 13 58 Aug. 22 11 2 Sept. 18 2 0
July 18 48 20 Aug. 25 10 2 Oct. 1 0
July 25 41 12 Aug. 29 9 2 Oct. 16 1 0
Aug. 1 35 6 Sept. 1 8 2 Oct. 17 0 0
Aug. 8 26 3 Sept. 8 6 0

One female, emerging May 22, 1914, and kept continuously in a
well-lighted glass refrigerator at 58°-62° F., lived until April 1, 1915,
315 days, or 10 months and 10 days. The rate of mortality of the
flies still living of this lot on December 4 is recorded in Table XVIII.

TaBLeE XVIII.—Data on longevity of adults of the Mediterranean fruit itty emerging on
: May 22, 1914, and kept in a glass refrigerator at 58°-62°

Adults still alive. Adults still alive. Adults still alive. |

Date. Date. Date.

Male. | Female. | Male. | Female. Male. | Female. |

| : |

Dec. 4 43 62 Jan. 5 17 32 Feb. 4 4 10 |

Dec. 15 31 55 Jan. 16 30 Feb. 10 1 6 |
Dec. 19 26 51 Jan. 13 14 28 Feb. 13 1 4
Dec. 23 24 48 Jan. 18 14 24 Feb. 17 1 3
Dec. 26 24 43 Jan. 26 9 20 Mar. 6 0 2
Dec. 29 24 37 Jan. 29 | 7 16 FADES uaa 0 1
Jan. 2 21 36 Feb. 1 | 4 12 Apr. 2 0 0

81340°—18—Bull. 536——5

66 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

Of the adults kept at 58-62° F. the majority died after the sixth
month of life, beng caught by the wings in moisture gathering
on the sides of the containing jars. . Under more favorable conditions
the writers believe that adult life may be extended to cover a full
eee MATING.

Martelli first described the mating process. He says that when the
male desires to copulate he ‘‘seeks to attract the female by curving
up and raising the last abdominal segment, then bending the extrem-
ity, swelling it to the form of a pinhead, while the venter is drawn

back half its length and the abdomen is puffed out laterally, etc.”
These evidences of sexual stimulation have been verified by the
writers. In addition to the dorso-ventral contraction and lateral
expansion of the abdomen, the male may vibrate his wings rapidly
for periods of 10 to 15 seconds, at the same time that he extrudes the
rectum (?) to form the white bulbous structure which is held almost
perpendicularly over the tip of the abdomen.

Often the female will move toward the head of the male from the opposite direction
to be greeted when within an inch of the male by a violent fanning of the wings of the
latter. When the female is within half an inch of the male, the male moves forward
in a halting fashion until the heads of each almost touch, when the male springs for-
ward and endeavors to clasp the female, but is often repulsed. One pair were ob-
served to go through this process five times in 30 minutes before copulation occurred.
Having once placed himself, the male makes vigorous efforts to bring the tip of his
abdomen in contact with the tip of the ovipositor, trying at the same time to grasp
the very tip of the ovipositor with the strong chitinized claspers situated on the
seventh sternite. The female need only extend the tip of the ovipositor to but a very
slight degree from within the last abdominal segment and the male will quickly clasp
it and draw it out to a considerable length. The operation of clasping the ovipositor
and drawing it out usually takes from 10 to 20 seconds. At the end of 15 to 20 seconds,
or even sooner, the long narrow ribbonlike chitinized copulatory organ begins slowly
to uncoil from its position. It extends up over either the left or right side of the sixth
and seventh abdominal segments and makes one, or sometimes two, loops about the
distal fourth with the tip resting under the posterior edge of the fifth tergite. From
this position the penis uncoils until the tip comes to a position almost between the
claspers, where it enters the vaginal opening.

Both males and females mate frequently throughout life. One male
was observed mating between 3 and 4 p.m., February 3, 1915, and
between 11 a. m. and 12 m. and 1 and 3 p.m., February 4. Males
observed mating on February 4, 1914, mated again on February 5, 6,
7,and 8. Individual females kept for oviposition records have been
observed to mate frequently with the males accompanying them.
Such data indicate that mating is frequent. Such frequent mating is,
however, unnecessary for egg fertility, inasmuch as one female emerg-
ing August 12 and observed mating September 8 (probably not for the
first time) was isolated on that date and placed with fruit. She
deposited 139 eggs between September 16 and November 25, and all

MEDITERRANEAN FRUIT FLY IN HAWAII. 67

hatched normally. Records on file show that the eggs deposited
by 12 other females isolated after mating on September 8 hatched
normally.

SEXUAL SMELL.

The writers have found that the males of the Mediterranean fruit
fly emit a peculiar odor by which they may be recognized. <A segre-
gation of the sexes proved that the females do not emit this odor,
or at least that no odor can be detected. That given off by the males
is very evident and, while difficult of description, resembles somewhat
that of stale mucus. No odor can be detected until the males begin
courting the females, but from that time on it is sufficiently strong
so that during calm weather a person sitting as far as 4 feet from jars
containing adults is able to state whether the flies within are Ceratitis
capitata or Bactrocera cucurbitae. Thelatterspecies emitsno odor. The
writers have attempted to make use of the odor emitted by the males
to trap the females in the laboratory and field, but in no instance
were females attracted to jars containing males, although the odor
eminating from the latter was pronounced. Males kept at 58° to 62°
F. neither courted the females nor gave off their characteristic odor.

AGE AT WHICH MATING AND OVIPOSITION BEGIN.

Adults, upon emerging from the pupa, must feed for several days
before they show evidences of sexual activities or begin oviposition.
Berlese, in Italy in 1905, published the first data bearing on this
subject. He states that the female does not oviposit until 10 to 12
days after emergence. Severin states that in Honolulu no fully
developed eggs were present in the ovaries of 3 females 8 days after
emergence. Although from the eighth day on he made daily dissec-
tions of 3 females, he found no mature eggs until the fourteenth day,
with the exception of a few in the ovaries of a single female 11 days
after emergence. The most careful observations appear to have been
made by Martelli, who states that females do not oviposit until
from 4 to 7 days after emergence during summer, or 10 to 12 days
during the autumn. Aside from Martelli’s general reference to the
season, no writer has published along with his statements data on
temperatures, which the writers have found to be an important factor.

The age at which the first eggs are deposited varies with the tem-
perature. During late July and early August, 1913, when the daily
temperatures at Honolulu ranged between 74° and 86° F., with a mean
for the period of 79° to 80° F., males began to show sexual activity
within 3 days, while mating and egg laying took place within 4 to 5
days. In securing infestation of fruits it was found that while few
eges were deposited within 4 to 5 days after emergence, 1t was not
until 7 to 10 days after emergence that any lot of females seemed to
reach their full egg-laying capacity. These observations are based

68 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

on work with over 20,000 adults. During the period May 21 to 28,
1913, when the daily temperatures ranged between 69° and 82° F.,
with a mean temperature for the period of 76° F., and with a mean
relative humidity about 66 per cent, many Females were not observed —
mating until 7 to 9 days.

During the period December 14 to 24, 1914, when the weather was
unusually cool for Honolulu, with the daily temperatures ranging
between 61° and 78° F. (a mean for the
period about 69.8° F.), and the mean relative
humidity about 72 per cent, 1 male was ob-
served giving the usual evidences of sexual
maturity 8 days after emergence, and several
others after 9 days. The first eggs, 3 in
number, from about 150 females were ob-
tained 8 days after emergence, while 10 and
38 eggs, respec- |
tively, were se-
cured after 9 and
10 days. Adults
emerging on Jan-

uary 3, 1916, did
Fig. 15.—Egg tubes of female jot eontain well-
Mediterranean fruit fly: a,
At time of emergence; b, 3-5 developed eggs
dye ate enargnes! rie until 10 dayslater,
as shown by daily
dissections. The temperature during this
period ranged between 60° and 75° F.,
with a mean of 68.7° F. The general
process of egg formation as it takes place
in the egg tubes is shown in figures 15 and
16, representing the development of the
eggs 1,3, 8, and 10 days after emergence.

PORTIONS OF PLANT SELECTED.

Adults of the Mediterranean fruit fly :
oviposit only in the fruit of the host. The 16. 16.—Egg tubes of female Medi-
terranean fruit fly: a, Development
female appears to have no preference for after 10 days; b, after 8 days; during
any particular area in the epidermis of ‘J2uary, 1916, at Honolulu. (Origr
very soft fruits, such as the strawberry nit
guava, mock orange, coffee, peach, sapota, or eugenia, as egg punc-
tures are to be found on all portions of the fruit. , But even in these
fruits adults oviposit most freely in prematurely ripened areas. In
the case of other fruits, the epidermis of which the fly has greater
difficulty in puncturing, females are apt to take advantage of previ-
ously made abrasions caused by thorn pricks, fungus attack, old egg
punctures, etc. Thus the females often deposit eggs in large numbers

MEDITERRANEAN FRUIT FLY IN HAWAII. : 69

only in a single break made by the mango weevil or fungus attack
on the skin of a large choice Indian mango. In cotton bolls eggs
appear to be deposited only in breaks made by the larve of the pink
bollworm (Pechinophora gossypiella Saund.). In some varieties of
avocados eggs are most often deposited, in certain localities, in the
eracks made by fungi, although other varieties with thinner skins
are freely oviposited in at all points.

DAILY RATE OF OVIPOSITION. .

No data on the daily rate of oviposition have ever been published
except by the writers. In a preliminary paper they record the daily
rate of oviposition during the first 18 weeks after emergence. In
Table XIX these data have been continued to include the ovipo-
sition records of the same females throughout life. For the daily
rate of oviposition for old females see Table XX. It will be noted
that there is considerable variation in the frequency of oviposition
among those specimens seemingly less hardy, but that those living
longest, and apparently the most normal, oviposited with great
regularity a few eggs nearly every day. The 9 females, the ovipo-
sition records of which appear in Table XIX, emerged on April 4,
1914, and were placed with fruit April 14.

The best record in Table XIX is that of fly No. 5, which oviposited
with great regularity from April 16 to September 2. During life
this fly oviposited on 106 days of 153. Of the 47 days on which she
laid no eggs, 20 were the first 20 days of her life and 13 of these 20
were evidently consumed in reaching sexual maturity. Hence, after
she began ovipositing with regularity she failed to oviposit on only
27 of 133 days. Fly No. 8, which lived 147 days, oviposited on 80
days. Fly No. 9, which lived 65 days, deposited only 3 eggs on
May 4 and 5. Had it been possible to secure oviposition data on
many individuals it is probable that the record of fly No. 5 would
have been exceeded and that many gradations would have been
secured between the records of flies Nos. 5 and 9. This is probable,
inasmuch as other females recorded under the subject of longevity
lived to be over 10 months old, and there is no evidence that ovipo-
sition necessarily ceases before death. It is not likely, however,
that the actual number of eggs deposited on individual days would
have been found greater than those recorded in Table XIX. This
actual number of eggs deposited on individual days was found to
vary from 1 to 22. The average numbers of eggs deposited by the
9 females, taking into consideration only the days on which ovipo-
sition occurred, are 6.6, 3.1, 5.7, 7.5, 5.9, 6.1, 5.9, 5.2, and 1.5. Flies
Nos. 5 and 8, which lived the longest, deposited, respectively, an
average of 5.9 and 5.2 eggs.

70

July

BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

TaBLE XIX.—Daily rate of oviposition of the Mediterranean fruit fly in 1914.

[Females emerged on Apr. 4, 1914, and were placed with fruit on Apr. 14, 1914.]

Date of oviposition .1

So Oooo OO omer o ooo c:|

ee air ad |

Number of eggs deposited.

Fly Fly Fly Fly Fly Fly Fly
No. 1. | No. 2. | No.3. | No. 4. | No. 5. | No. 6. | No. 7.
| 0 0 0
1 1 19 14 0
0 0 5 |
0 0 0
1 13 0 14
1 16 15 0
17 16 23
25 19 19
2. 12
0
19 1

_

ra
SCOCCOCMNO SCOR GSS OCCUR OMNONWNDOODDKH HP AIOOOONMNOCOOFOCCOF WwW
BROOCOoorOoroOoCcCoooooooONnsNoo-co

\

—

bo
OnmnonmnocoocococoooooooooooooOownNtioro&

—

—
BRoomoccowoocooowccocooo

_

=

_

—

i _
NOOO WOPfP1WNOCWWONOWOOF DOF OOOO

—

p=) ee

—_

—
SOoMWOWOOBPMUCSOOCSCHOHFOCOCOCOOCK-10O

—

J —
PONONCOF DOD OANN BAVA DH AWWNUIWAOWWOONWOUNADUOIWORMONO-10-10

—

s

—

14

—

_

NOCH DWE OR ONIWOOW EHH OWWWWOOMDORHOONFrNWOO

—

SAIN WOOF NATE WH HOR OOO EF DOW DE OIONWEHOON DOWKR AON DE WHAIWNOO

1
1
i 2
1 \
1
1 1
1
1 1
1 9
3
7
1
7
5
0
0
3
1 0°
0)
0
(°) 9
geese sae 12
Leite 3
PETE 0 |
Supe 7
Bee See 12
ele a 0
eae ae 6
AES ose 2
BEETS Tee 7 |
a Abet eee 3
£9 SPE 8 |
SN 2 |
SRE eS 4)

1 Dates on which none of the flies oviposited are omitted from the table.
2 Died on this date; 30 eggs present in abdomen.

3 Escaped on

this date.

4 Died on this date.
® Died on this date; 15 eggs present in abdomen.

Fly
No. 8

ws

—

_

_
SOO Fe WONWNWWNHODAON OM NWOTON DOD TE WWW ODMH ODOR KFOODOOSCOWONOOWOOCONOSOS

12

oooceocoococoocorvocococococococococ“ooc“eooowmooooccocc[co

MEDITERRANEAN FRUIT FLY IN HAWAII.

fe!

TaBLE XIX.—Daily rate of oviposition of the Mediterranean fruit fly in 1914—Contd. -

Number of eggs deposited.

Date of oviposition.

Fl Fly Fly Fly Fly Fly Fl Fl Fl

No. 1. | No. 2. | No. 3. | No. 4. | No. 5. | No. 6. No.7. No.8. No.9
RET Wild crars ete Stas ets oa ee ceive eral as icte os ae 0 QSpaOwes ook: 0 Q: aaeessas
eT ee tek LAE se SEG OS ACR et oo on ae (4) A ee Pe Se 9 DA eee TS
CO 3 oe i ee aps ye cd een | eater oe a Uae US eh ee | [eres te Hepes Pn eet Gee setig 3 4 even
Oe eae. ee A Ie as a as ae] Aas eae Reet ice 7d Sse a 3 4. Rea ae
INO et mre ae rie al mes cial Soi ees ops astra ais fin sree lars i eee 8 Oe een =
De Fae aoa ae essence bapace ness eatese om emee ess walbceseeee 4 Ofte
pS a eee ae i Spa wee here Pere en eee e See 7A eee sae 0 10 sae
UA eee Setanta eet eee Ra | a ees Bete leet ee Dpeseoss © 3 Dine ae
1 eR SE ae eet 8 Sind Nae ee a (ape ee | ae ey Se agence Seer Dil ese ra ae 0 ay fae
Li CRs Ts eS SSE |S ease | eee | eee ep Sd Renae td CGS Aires 0 Oi
“OTN AS hs eee i Be a 2 es l(t ete en || eee O32 S52. 2=3 0 A \ eee eee
DAY Bs SN CRESS Be ace ee | gd rae a ero UO hele eae Oise 2 2 O:| tae
DPN a Be es eR aes Oe RO [et Ste AI | NS Seen (Ee A Vo he Se 0 Ole see
Net pe POS EE eee cre cei Se | See te | ee aS te Qi) ee ees 3 Of | Saas
TIA pe Se aR SAE be ie Seta | eae ps Ye | Saye ee (eae eee a eee 4 Os emr =:
Doser eee IGN ed ts ee | Beet eek Secyos et SE ae, 257. (ieee dae 7 Oj) feet
DAG Day Ee Ee a ene eee EE ee Se Sete | Se ee Ie) a ae Dee | | eee ee TR Se Se 0 Sa eee
A Se cn Cee ey eet REE Se Be Are Rie Ce SE Reels SR Cy ee Shi ee sek ee 0 OSiRSs eee
ey sc neg er RO ees emir, See Meal DPN eI 2 | Siete 2, tel eee (Ee eed PANE ES Coie 3 Os ees s
OE een RATA rene Sh LPN RE VS Rape eR | a eS oe See 37 Ss ee 0 OR Aza
SY Foes AES wd aoe: Bae Se eS eee ae el oe ee | ee eee ee 7 Jin SS 3 sea 0 | eee ae
See Soe Be See eA it en 8 Ta Eee Ne Sa | ee ee || ee Gal beet ee 0 Gules
PAS eden Saree Sea ee ea) oat Se eels t ce | Sn ow Selec wee ee Sl eae tare 0 AR eos
DESEO EER Ase Soe ee aso tS es ebc|anicweebel hen ed Us| eae a (2) cee ai
a ae aa eB | Se ys la sc ee Pe cao bead ore a Sree CS as es Py Seen OA |) eee ieee
Les eS aS Bo ee as ee ee tel eee | eee Dy lasek SSe|aum eee AES 2 Se
Tee Ee Fg a || REE > a | Sips Si ee re fe Leona apr es 25s ee [Pee eee Salbeeseees
T fess So ek oe Re a S| A cep eae co pe free ee ee as Aya | Beare hee) (Same QRZ ae
Pe ANS Mie REE RS Fear aN [Ras nae | Se eer 1 Pa) eee Sees bam eaep Ree S (eS Se een oe ee pS) 8 tae ee
VEAL SE cee ee See eee ee te | a oe i a ee aaa SP fee Seer |e eee ae Qulsiaceee
Niet esi CR ee aS ae Te peat | eee ee eee ae ees LE ep aces |e SRR « OSes
pee aa eee ee ee ey es ee |e ce eR Roos eel Rticcac ce Li Nel IS Bees Seal ee sre oe PA Reece ce
Ta Sa hc eb ae | a [sees ees Oe | SS eee | ee Be Ae ee
ES Bete Son SSG SEH Ge Gees | SB OSS neers Meester Ua ve seeese asset inet eis 15 | ae eens
IL ieee epee oe ee Re ee OS A er Je ted AR ain eti oy eek ee Otioes es
Ly fee aS phe a el feet a eine | ete a [en era ee Seite ase. le PeeeE: G5 |e
TR Soe Soe eee ee eis iit POE lan) Panera ens eat ae oR SEE es Fes One
Oper te see eee eee A. Le eel tae te Pla ea Seat al peowass oe Dal Ree
TL ES ae rn ani etn ates eel (ei nee, Seen [ey ee ain) Wale ae ta AS heb: Sete pas Facer ke ORiesecmree
DOF Osa ee See ope eet pe heue | Ie Ns mete oy ae eceseaten| Lepeacekee | Patty oe ed Sotees EEE A eae: Oa eeheees
PA. wa Rei Se SB oe es | Ne i Gs od ie Pg ee ee ene Oe fees ee eee Oxlbeaseees
Fi So oe ee ere | (eee Ieee IR | [OR RR cay Wena Gti see eee OF aes
02 eS ee ee oe Eee eo ee eS ae ee (ere Bae SHIR rere sets Of Se Bee:
SO re een ee Sm en | eee ene a [ere et esl Mee ee aa | fae eS (el eases Rs (OQ) tes Rea se
SOpbr2. 53 tase esc ced ese alee ne ge |. eee oe |ESSS see OP seat Sass. cee chee es CIEE EEE
Ponsoe tse cede sobs S-ses/SeSseee|eossoads|Psadacec TES ite el (OV AR aR Ess el (da nea | ee eee ea os Sete
el RE Fee a eae 191 34 86 | 314 622 312 426 405 z

1 Died on this date; 16 eggs present in abdomen.

i 3 Died on this date; 2 eggs in abdomen.
2 Died on this date; no eggs in abdomen. 4 Died on this date; 3 eggs in abdomen.

ABILITY OF FEMALES TO BEGIN OVIPOSITING REGULARLY AFTER A PERIOD OF
SEVERAL MONTHS DURING WHICH HOST FRUITS WERE NOT AVAILABLE.

Females which have been kept in confinement without an oppor-
tunity to oviposit in host fruits will begin actively ovipositing when
such fruits are made available. Thus, females emerging on Febru-
ary 28, 1914, were kept in glass jars until about 4 months old, when,
on June 28, they were placed with fruits and a record kept of the
eggs deposited. These data secured from 6 females show that for
the days on which they oviposited they laid an average of 8.1, 4.6, 0,
6.3, 4, and 7.2 eggs. These averages compare favorably with the
averages for females given an opportunity to oviposit from the
time they were sexually mature until death. Fly No. 1, with its
average of 8.1 eggs, deposited 22 eggs on July 26, or when it was

72 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

148 days old, and this is the largest number of eggs ever obtained
by the writers during one day from any female. The flies of Table ~
XX oviposited on the sides of their containing jars during the period
up to the time they were given fruits in which to deposit eggs, but
not in a normal manner.

.

TABLE XX.—Daily rate of oviposition of the Mediterranean fruit fly.

[Females emerged on February 28, 1914; hence were 4 months old on June 28, 1914. Given an opportunity
to oviposit on fruit for first time on July 1.

Number of eggs deposited. Number of eggs deposited.
E
Date. } Date.1 5
Fly | Fly | Fly | Fly | Fly | Fly Fly | Fly | Fly | Fly | Fly | Fly
No. 1. |No. 2. |No. 3. |No. 4. |No. 5. | No. 6. No. 1. |No. 2. |No.3. |No. 4. |No. 5. |No. 6.
1914. 1914.

Tialivaneles 0 0 0 0 6 0 || July 19.. 6 Deileeees es 0 OU Ee. uar
Qs 9 0 0 0 2 0 200e 0 Dy een ae 4 OSes sae
3.4 0 0 0 0 4 0 Zi 5 77a Pane ae 6 QS|Reaee
4.. 10 4 0 0 0 6 22)... 0 8 e228 52 7 Os 2228
ee 4 0 0 0 0 0 Zone 0 Dilees sins Onl OMS eee
Ges 5 6 0 4 0 | 0 24.. 2 Gi eases WEE (Oe ee esac
Use 0 0 0 0 0 12 oes 6 Disease Oss sesse see
8.. 10 6 0 0 0 | 6 26... 22 Poe aew eer Oneal eee
9.3 0 4 0 9 0 13 PA = 9 Dil sie is Onfesee alee

10.. 15 6 0 3 0 2 PASS 9 OE eee OS eerie =
rae 5 2 0 0 0 4 29... 6 idl Bee Oa] ses eee
Bae 12 7| @) 5 0 0 BE ane 0 HAS Bee (3) eS ere | eee
142! 2 Ouleeesee 5 0; ©) PASO Willer OO) Weessee On| Sse eee
ee 7 Ones mete 0 Op\assese Din ok Onlaieee leases Oia = eee ee eee
16.. 0 Saleen 0 OFseee se Beer fa) el eared rll Se (2) Boe eee
Woe 13 Balese eee 11 OF seas — ———_ ——— |.
1Soe 5 OU Fees 4 Onleeasee Total..| 162 97 0 76 12 43

1 Dates on which none of the flies oviposited are omitted from the table.
2 Died on this date; no eggs in abdomen.

3 Died on this date; 11 eggs in abdomen.

4 Died on this date; 5 eggs in abdomen.

5 Died on this date.

6 Died on this date; 4 eggs in abdomen. °

One female emerging March 3, 1914, was isolated from fruits until
August 29, or for 5 months and 26 days. When placed with. fruit
on August 29 she deposited 4, 5, 11, 14, 9, and 9 eggs on August 31,
September 3, 4, 5, 6, and 7, or an average of 8.7 eggs for each day
on which she oviposited. She deposited 11, 14, 9, and 9 eggs, respec-
tively, on the first 4 days of ae coment monte of her life, but
died on the fifth day.

NUMBER OF EGGS DEPOSITED BY SINGLE FEMALES.

No attempts have been made by previous writers to determine
the egg-laying capacity of the female. In 1906 Fuller assumed as
a basis for data on multiplication that each female deposited 50
eggs at one time. Silvestri, after becoming familiar with the work
of the writers while in Honolulu, stated that the total number of
eggs deposited is not less than 300. In general, entomologists
invariably have used the number of eggs found in the body as a
basis for computing the egg-laying capacity.

In Table XIX the only data obtained by the writers on this sub-
ject show that the total number of eggs deposited by a single female

MEDITERRANEAN FRUIT FLY IN HAWAII. 73

may be as high as 625. Fly No. 5 deposited 622 eggs and held 3 ~
well-formed eggs in her oviducts at death: Fly No. 9, on the other
hand, deposited only 3 eggs during her life. The writers believe that
hardy females may deposit as many as 800 eggs, or even more,
under favorable conditions. Fly No. 5, which deposited 622 eggs,
lived only 153 days, while other females have oviposited for periods
covering more than 10 months and might be expected to deposit
more eggs. As noted above, one female deposited 11, 14, 9, and 9
eggs during the first 4 days of the seventh month of her life.

NUMBER OF EGGS DEPOSITED AT ONE TIME.

During the period from January 23 to 27, 1914, when the tempera-
tures during the heat of the day ranged between 74° and 76° F
15 females were observed to oviposit in apples. The time required
from the instant the females started ovipositing until the ovipositor
was withdrawn varied from 2 to 5 minutes, with an average of 3.8
minutes. Each puncture was found to contain from 1 to 4 eggs,
and averaged 2.4 eggs.

During the warmer period of the year, on April 13, 1914, when the
temperature averaged about 82° F., 8 females consumed from 2.5 to
4.5 minutes in completing the process of oviposition in apples, and
deposited from 3 to 9 eggs, or an average of 5.4 eggs in each puncture.

NUMBER OF EGGS DEPOSITED IN A SINGLE EGG CAVITY.

Females oviposit repeatedly in egg cavities or punctures in table
fruits, especially in those fruits in which they have difficulty in
making egg chambers. Thus while females, as already noted,
deposit normally only from 3 to 9 eggs in a puncture in apples at one
time, cavities in apples left with females from 3 p. m. until the fol-
borne morning contained from 42 to 106 eggs. As many as 300 eggs
have been taken from one egg cavity in the rind of grapefruit, 129
from a cavity in a lemon, and 926fromacavityinamango. (PI. XIII,
fig. 3.) Observations indicate that after depositing a few eggs the
females feed and move about only to return in many instances to the
same spot to continue ovipositing. Frequently newly laid eggs can
be found in punctures in citrus fruits in which several batches of eggs
already have been hatched. Bearimg in mind that only from 1 to 9
eges are usually deposited in an egg cavity at one time, the dotag m.
Table XI will prove interesting.

OVIPOSITION BY VIRGIN FEMALES.

Females confined in jars immediately after emergence and given no
opportunity to mate will deposit eggs, but none of the eggs will hatch.
On September 10, 1913, 500 newly emerged virgin females were
placed in a jar and began ovipositing in a normal manner on Sep-
tember 16, or after 6 days. One hundred and twenty-eight eggs

°

74 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

deposited September 16 did not hatch. The temperature during this
period varied between 71 and 84° F., with a mean for the period of
78.5° F., and the relative mean humidity averaged about 66 per cent.
Two hundred females emerging November 13, 1914, were confined
without males and began ovipositing November 23, or after 10 days.
During this period the temperature ranged between 65 and 80° F.,
with a mean of 74.6° F.; the relative humidity, averaging 69.2 per cent,
ranged between 52 and 85 per cent. Although no daily oviposition
records of these females were kept, 450 eggs deposited by them in
apples on 17 different occasions when they were given an opportunity
to oviposit between November 13 and March 4-5 failed to hatch. In
three other experiments not one of 2,264 eggs deposited by virgin
females hatched.

Virgin females which have been depositing eggs that failed to hatch
may mate later and deposit fertile eggs. Thus 200 virgins emerging
on March 13,1915, oviposited quite regularly until May 14, when males
were placed in the jar with them. Previous to May 14 all-eggs -
deposited had failed to hatch. On May 16, 11 eggs were deposited;
of these all hatched but 2.

INFLUENCE OF WEATHER CONDITIONS ON ADULT ACTIVITIES.

No satisfactory data on this subject can be secured out of doors in
the Hawaiian Islands, as the colder temperatures which seriously
affect adult activities are not to be had except at higher altitudes,
where the fly is not to be found. At the Volcano House, Hawai, at
about 4,000 feet elevation, where the November mean is about 60° F.
and the daily range is between 45° and 72° F., adults in jars were
inactive during the early mornings and late afternoons. During the
warmer period of the day adults became active and oviposited in
apples hung in their jars after the temperature reached 61° F. At
Honolulu, at a temperature of 65° to 67° F., 27 eggs were deposited
in peaches by about 40 females, and 40 eggs by a lot of 60 females.
At higher temperatures many more eggs would have been deposited
under otherwise similar conditions. Adults in jars were noted to
mate as usual on March 17, when the temperature was 69° F. On
March 18, 9 a. m., at 67° F., adults endeavored to oviposit in apples,
but did not seem to succeed in puncturmg the skin. A female
emerging on August 12, 1914, was placed in a large glass refrigerator,
the temperature of which averaged 61° F., but varied for the period
between 58° and 62° F. She was accompanied by males and depos-
ited 3 and 6 eggs on September 12 and 20, respectively, but died on
September 25. This fly was replaced by another of like age, which
deposited 9, 5, 8, 4, and 6 eggs, respectively, on September 26, 27, 28,
29, and October 2.

At a mean temperature of about 78° F., adults may deposit eggs
during the night, but deposition during this portion of the day has

MEDITERRANEAN FRUIT FLY IN HAWAII, 05

been found most unusual. In the laboratory and out of doors adults
feed and oviposit at all times of the day during the warmer months.
Lounsbury has stated that m South Africa adults seek shelter
beneath dried leaves, etc., in rearing cages during the colder weather,
and Compere has observed adults active on orange trees in Spain
during the warm hours of a day following freezing night temperatures.

LENGTH OF LIFE CYCLE.

During the warmest Hawaiian weather, when the mean tempera-
tures average about 79.5° F., the egg, larva, and pupa stages may be
completed in as few as 13 or as many as 33 days, according to the
individual and its host. At this season large numbers pass through
the immature stages in from 18 to 20 days. As the length of the
adult life has been found to vary from a few days to 230 and 315 days,
it is evident that the life cycle may be as long as 11 months when the
fly passes its immature stages during the warmest portions of the year.
At an average mean temperature of about 68° F., which is the coolest
mean found by the writers where host fruits were readily available
for study, the immature stages required from 40 to 69 days. Data
already discussed indicate the difficulty in stating just what varia-
tions there may be in the length of the life cycle in still cooler climates.
Thus the egg stage has been increased from 2 to 24 or 25 days by the
application for 22 days of a temperature of from 48° to 53° F. A
third-stage larva survived a temperature of 48° to 54° F. for 79 days,
while another larva remained in the first instar 57 days at an out-of-
door temperature ranging from 27° to 73° F., with a mean of about
48°F. The fruit fly has been held in the pupa stage at an out-of-door
temperature ranging between 38° and 72° F., with a mean of about
53° to 54° F. for about 2 months. At Kealakekua, where the tem-
perature ranged between 58° and 80° F., with a mean of about
68° F., 3 larvee in very firm apples required 28, 58, and 74 days to
become fully mature and leave the fruit to pupate. Add to the 74
days required for larval maturity 4 days for the egg stage and 20
days for the pupa stage, and one has a cycle for these stages of 98
days, or over 3 months. A very conservative estimate for the pos-
sible length of the immature stages, or a period sufficiently long to
outlast the coldest seasons of semitropical regions, is 3 to 4 months.

SEASONAL HISTORY.

In littoral Hawaii there may be as many as 15 or 16 generations of
the Mediterranean fruit fly each year, provided one considers the
length of a generation as extending from the time the eggs are de-
posited until the female of the next generation begins to oviposit.
With such an understanding a generation at Honolulu may require
under the most favorable conditions as few as 17 days during the
warmest weather, or as few as 31 days during the coolest winter

76 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

weather. As the females are capable of living long periods and of
depositing small batches of eggs almost daily, the generations become
hopelessly confused. Im those portions of the islands where the
winter monthly means drop to about 68° F., as in the Kona district
of Hawaii at about 1,300 feet elevation, there may be not more than
10 to 12 generations. The number of generations is naturally less in
colder habitats. At Strawberry, a ranch station on Hawaii at about
4,500 feet elevation, there appears to be only asingle generation a year,
which is evident in the last fruit to ripen on a few peach trees.

As may be expected, adults are abundant at all seasons in the
littoral regions of Hawaii where host plants are grown. With the
hopeless confusion of generations that exists, there can be no seasonal
broods. Instead, adults may be found actively ovipositing every
day of the year. That the cooler weather of the winter months does
lengthen the life cycle has already been proved. This slowing down
of development naturally results in the emergence of fewer adults.
This is indicated by the data of Table X XI.

TABLE XXI.—Seasonal abundance of adult Ceratitis capitata at Honolulu.

[Average daily catch of 147 kerosene traps for the weeks indicated below, from Apr. 21, 1913, to Aug. 4, 1914.
Traps exposed in Punahou district of Honolulu, east of Punahou Street and south of Wilder Avenue.}

Num- Num- Num- || Num- Num-
Date. | “her. Date. ner Date. ber. || Date- per. || Date. we
Apr. 26..-| 279 || Aug. 2....| 905 || Nov. 8...-.| 353 || Feb. 13.... 58 || May 23.... 291
ay, 3-.- S47 ||| Amiens 937al| Novel 52 |. 23 i7al Helo. 20 ssl catia yer (eeu 259
May 10..- 677 || Aug. 16---| 763 || Nov. 22...) 137 || Beb. 28... 64 |} June 6...-- 389
May 17..- 901 || Aug. 23.-=| 562 |) Nov. 29.--| 132 || Mar. 7..... CUM Uowa@ 133.5 729
May 24.-| 1,738 || Aug. 30...| 4389 || Dec. 6..-.-- 219 || Mar. 14.... 49 || June 20....) 1,074
May Sl. =|) 35-498" )| Sept. 62-21). s316, ||) Decyilases) 93240) Man 2ieee. 74 |) June 27. ..- 935
June 7..-} 1,413 || Sept. 13-2.) © 219) 1), Dees 19... -|'* 355° ||; Mar.28- = - 64 || July 4..... 1,676
June 14.-| 1,047 || Sept. 20... 152 eDeca 2a. 2 240) Ast Aeneas 92, | Jrliyalil s S) e25503
June 21--| 855 || Sept. 27...) 141 |} Jan. 2...-..| 176%) Aspre V2. 3) 223-1) Sualy WShe2 2) 25002
June 28..| 1,084 || Oct. 4.._-- 167 || Jan. 9.-.... 48 || Apr.18....| 150 || July 25....| 1,677
Juilyzoas- 16971) OCt-1le 4 | 2008 vane Gaeee 84° || Aipre-2o--- =|) 1245!) Ang ieee 964
July 12.. (23 RO. Ctl Sears 200 || Jan. 24..-.. AGal Mia ya oa ae 188 || Aug. 4...- 523
July 19.. 769) || Octs 252225 205 || Jan. 31..-- 51 || May 9. .... 343
July 26..- (20.|\ Noved=-aeh $270) | heb iee--s 72) || May 16522.) 455

These data on the number of males captured in 147 traps in an area
equal to about four city blocks are taken as indicating the relative.
abundance of adults in a single year, in a section of Honolulu where
many host trees occur. The adults are most numerous during late
May, June, and July, and less numerous during January, February,
and March. The numerical abundance of adults in Honolulu, where
the climate never seriously retards development, is affected more by
the numerical abundance of ripening host fruits, which is greatest
during the early summer and least during the winter. The fact that
there are relatively fewer adults during the winter months is of no
practical value to growers of fruit in Hawaii, since the smaller amount
of fruit ripening at that season is nearly as badly affected as are the
fruits ripening during the summer.

MEDITERRANEAN FRUIT FLY IN HAWAII. T7

NATURAL CONTROL.

No striking examples of control by natural agencies were evident
in Hawaii previous to the introduction of parasites. As indicated
below, there are several minor factors of natural control, aside
from parasites, but they are of no practical value under Hawaiian
conditions. A certain amount of natural mortality occurs among
larve and pup, but it is small under ordinary conditions. It has
been suggested that there occurs an unusually high mortality among
pupez formed by larve developing in such juicy fruits as the mango,
but this has been disproved by experimental work. The high nate
of mortality among pupz derived from mangoes in laboratories is
produced by the severe sifting process necessary to separate the
pup from the wet sand in which they form, or from insanitary

conditions.
EXCESSIVE HEAT.

The larve within fruits which lie in the direct sunlight after they
have fallen are killed in large numbers. Often all the larve in the
portion of a fruit exposed to the sun will be found dead. During
August, 1914, mangoes were exposed to the sun for two days over sand
in shallow trays. Examinations later proved the 17 fruits to contain
17 living and 84 dead third-instar larve, with 14 larvee dead on the
surface of the fruits. One larva died when partly out of a fruit and
103 succeeded in pupating normally. In 23 other fruits held in the
shade as a check there were found 168 living and 9 dead third-instar
larve, and beneath them 167 pupz. While every larva in certain
of the fruits exposed to the sun was killed, it is evident the many
larve in the protected portion of the fruit may escape and pupate
normally.

PREDACIOUS ENEMIES.

Although Compere reported certain staphylinid beetles in Brazil and
-forficulids in India attacking larve of fruit flies, they seem to be of little
value as practical checks. The writers have observed earwigs within
decayed areas of fruits infested by C. capitata and drosophilid larvee
in Hawaii under conditions which indicated that they were feeding
upon fruit-fly larve. Earwigs confined in jars within the laboratory
were observed to attack and devour well-grown C. capitata larve.
Their numbers, however, are far too small to have any effect upon
fruit-fly increase..

The small brown ant (Pheidole megacephala Fab.), known lee as
the Madeira house ant and the harvester ant, unquestionably is an
important factor in natural control. This ant, which inhabits most
abundantly the littoral regions, is frequently found swarming over
and throughout fallen fruits, killing many larve as they leave the
fruit to pupate. Ants were observed to remove from a fallen ball
kamani nut 86 medium sized C. capitata larve between 11.18 and
11.58 a. m., April 5, 1913. - An examination at the end of this period

78

showed that 34 larve in a firm portion of the flesh had escaped attack.
Within the laboratory this ant has demonstrated its ability to
destroy pupe.

BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

CLIMATIC CONTROL.

There is little opportunity in Hawaii to study the effect of adverse
climatic conditions upon the Mediterranean fruit fly. Development
appears to progress most rapidly after the Hawaiian temperature
means reach 75° or 76° F. At a mean of 68° F. the developmental
period is about doubled. A temperature ranging between 58° and
62° F. has no detrimental effect upon the development as shown by
the emergence of adults from pupe held in a well-lighted refrigerator.
These emergence data, recorded in Table XXII, and supplemented by
four other experiments, indicate that the pupa stage may be increased
from 38 to 41 days, or that, at this temperature, the length of develop-

ment may be increased to three or four times the normal during the

warmest weather. Only 9 out of 39,500 pupe held at a tempera-
ture of from 49° to 51° F. yielded adults within refrigeration, while
the remainder died. All cold-storage data obtained by the writers
indicate that approximately 50° F. is the temperature at which little
-or no development can take place and below which complete mortality
occurs if exposures are continued sufficiently long.

TaBLeE XXII.—The effect upon pupal development of the Mediterranean fruit fly of
58° to 62° F.

Days in storage.

4 day. | 1 day. 2 days. |3 days. 4 days. | 5 days. | 7 days. |8 days. | 9 days. |10 days.

| i. | vr Lota See ae

Dee a. Sao SE 3 anes | mscin ae =f eS opi pea arene | a Pe 27

) ene ian epee satan Henn Oe eerie Mere ynee| 2 bho Sl ed ee, od ea Se 11 334 | 1,290

Ss eRe rei ae ate) eset eer We eae Pets fae ana eee See a ER ote aleee el 3 949 657

Botis sist edt. fase blog. acne). Led Eee ee As Sey eer ee ae Bere 20 | 1,469 28

Diao Ree eas Somes one aete ES NESS Ps Sie ras Mette ea el Ae i Sra Sed 10 135 96 14

Gis E Ses fet sh epee [eee Fs EERE CEE Rhee ele ee eee ap 8 | 2,066 38: [Seve

| Ea prea ete (ee SME ay | SE dl ae (i AG ere 4 36 918 EYE aes Se

Bi Resa ee Et HG eee PAO AS eee aera 2 687 55 2 1

Qo SOSA eee RRR Cab Ae Pe hare al ee gece ne 10 | 2,118 13 2 1

Ts rs eee Pek E eee ree ty ELST ee Se AS oe eared: 23 479 4 1| 1
Pie Shier 2. Es ee ae SEE ee ay oe eee 2 ee 1 18 43 Anes ee 1
UDi tite topes. [Repel to Pee eg HOSS 2 | 2 604 95 [boa tei 6.4 fa S5G
ESS aera nt POR kT RA eee oe 6 1 5 930 5. (Se eee
Way oe tes HT cece or Ss Alte £ eh 6 640 |. -.22 a) TSE eas
AU eta te SP 19 RENE lie eee 1 3 eee ee 1 (Ee See ee pee ee ace) cee
16g rt se SEO ON i 2 2 | 3 4) 14 769). i. .Oll serena Lee
1g ae Se AE Se AD | Di act nel Ves RS) ial eer gapee 33 SB Sete tee [See Shee pees:
BSc iets: —) AE eh es ey. CF | 15 2 566 73 Pee ROLe Gera Gre Ree rogie ee)
ES oe Ret a Ss Fee ee 2 | in| ore 1,324 71 i eet hy Pack ein Rit pe ne
“| eee arenas | Fy ESE 4 | 29 25 381 | 19... .... .iRERO TRE See
D1. 5 eh oir ae ete Ae te, 13 319 38 | Fe se Beit le eet) ee
Pe els. ae Oay i 4} 203] 1,316 | 4 | Pyar eeim ec leenb yess ori oP RSS
DON 5 SEN ROS 4 6 399 335 | DS aS ale SRO een. Se ne
PEG bis TF be hee fhe ed: 12 4| 1,477 21 | leat LA ee [Js fh, Sea eee
745 elite oe Bodh, Ley AAS 9 36 | 1,013 6 Bolo wih ee tees lesan cole eae
DUN EET LET 8 Oo! 16 392 158 |... S291 Eas ee LOL OLG 3 LOE aS:
7 ph Aa capt Th Na, 44} 1,515 15 i fag So (gee Ree dS ie peeraren (Ser gale eee
Bilis UNIT igg 367 708 AN SLL ALIS RELA TROBE GEL 1. ee aaa
DO ee ea 12h Cie age) ieee rs pa AES RE SO a3 oe ogee lwo a ean eke one ae eee
SOT eh VE 159 Bh) OR . ce oe ig eee ee ee Pepeeeeae peesa gos) 78S
SE rote alate tor 1 a Sey Se Nieteadaliah| OE Mehta Piney PAE phe Sg! whe PR Mee Se cater fe
5 Ue end 1 ae ae TO. R Oey E.Gt |) eeed ON are Rétss...' ISAS Oe eee
Boe ae Oe eee Bee ee sage Beton a [peter tee eka ee ap ae |e cee ohciep lb cic costar a I eee nee
34 es 1 eoeeeneeae ¢ Se ee ee | -—seee eee | ee
BBG cy tne Meek ema i Ma ee lg {he ice rest ew, Oe | an cemcpallosee as ep eces gees hte ee eee

MEDITERRANEAN FRUIT FLY IN HAWAII. 79

This conclusion drawn from cold-storage experiments! will be
found, the writers believe, to hold true for out-of-door conditions.
During January to March, 1914, the writers exposed infested apples
on the slopes and summit of the extinct volcano Hualalai, at eleva-
tions of about 5,000 and 8,250 feet. At about 5,000 feet elevation,
where the temperature ranged from 31° to 64° F., during January,
with a mean of about 51° F., the larval development was apparently
held at a standstill, although as the minimum temperatures increased
with the approach of spring, larvee were able to more than hold their
own. During March, when the daily temperatures ranged from 40°
to 70° F., with a mean of about 55° F., development of all stages
occurred attended by no unusual mortality. At 8,250 feet elevation,
where the minimum temperatures ranged from 27° to 43° F., with the
maximums between 42° and 70° F., and a mean for the maximums and
minimums of about 48° F., no development took place. Instead, the
mortality was very great. As spring approached, the temperatures
increased until, during March 20 to 25, they ranged between 38° and
67° KF. The result of examinations made of infested apples after
indicated periods of exposure are given in Table XXIII.

TaBLe XXIII.— Mortality among eggs and.larvxe of the Mediterranean fruit fly in apples
exposed on the summit of Hualalai from Jan. 31 until date of removal.

Larve.

est | Date of
Fruit removed from . Eggs un- wi ate E a 3

mountain. ne hatched: First instar. Second instar. Third instar.

Alive. Dead. Alive. Dead. Alive. Dead.

aaa Sie satis 1D OB tal a eu 1 TI [se Sines Goes aati, 7 Fe alae neato ult 2 Oe | eater aera epee
12) Reape eR Ae ee Hebra15:|2 25s. ee 334 522 82 Jas soseen ecee
[De] on Wi setae Mpa eee ta Feb. 19 5 115 97 16 DA Em 8
IND OBA ane os ee Feb. 26 28 27 350 37 434 3 154
Marae re eh Mar. 6 10 55 481 33 DAI | See ces rg a Neca eae
Marestde2 an ae ae Mar. 19 2 3 ot Weeca= Jee 278 6 500
MAES 208 sco oe Mar. 27 24 1 872 2 56 2 965

_ These data prove that at the Hualalai temperatures a very few
larve may survive, although by far the largest percentage are killed.

The data given elsewhere (p. 108-111) on the effect of cold storage
and freezing temperatures upon the various stages of the fruit fly prove
how easily this pest can withstand for short intervals colder tem-
peratures than are likely to occur for long periods in fruit-fly coun-
tries. Thus the egg itself has been known to withstand a freezing
temperature of from 24° to 30° F. for 7 days and still hatch. These
low temperatures, however, produce a very great mortality that has
been emphasized by data already published.

That adverse climatic conditions have been a valuable aid in curb-
ing fruit-fly attack is appreciated by entomologists dealing with this

1 See Journal of Agricultural Research, y. 5, 1916, p. 657-666; v. 6, 1916, p. 251-260.

80 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

pest. Newman, in Western Australia, has found that a very large
percentage of the pupe are killed by a cold, wet winter when the
ground is frequently flooded. Such conditions so lessen the abun-
dance of the fruit-fly that there are relatively few flies, numerically
speaking, to infest the early fruits of the succeeding season. On the
other hand, unusually severe outbreaks of the pest in both South Africa
and Australia have been attributed to exceptionally dry, mild winters |
which made it possible for many adults to be present the following
spring to start large early summer generations. The successes attrib-
uted to clean cultural methods for the eradication of the fruit fly in the
apple orchards at Harvey, Western Australia, and possibly in New Zea-
land and Tasmania, may be due quite as much to the work of adverse
climatic conditions. The effect of climate upon fruit-fly development
can not be intelligently interpreted, inasmuch as previous writers
have not included climatological data with their statements.

PARASITES.

CERATITIS AND Dacus PARASITES.

Literature contains numerous references to parasites reared from
various species of fruit fles. The only parasites discussed at length
here are those which have been successfully introduced and give
promise of being useful as factors in controlling Ceratitis capitata.
Of the parasites at present being reared from Ceratitis capitata under
natural conditions, Opius humilis is the only one reared originally
from this fruit fly.1_ All other parasites now known to attack Ceratitis
capitata in the field in Hawaii have adapted themselves to this host.
There appears to be no reason why certain others of the parasites
already reared from other fruit flies may not be used ultimately in con-
trolling the Mediterranean fruit fly. Silvestri records and discusses
the following parasites studied by him:

BRACONIDA.

Subfamily Opiinae: Optus concolor Szepligeti (ex Dacus oleae, Susa, Tunisia), O.dacicida
Silvestri (ex Dacus oleae, Eritrea), O. lounsburyi Silvestri (ex Dacus oleae, Transvaal),
O. dexter Silvestri (ex Dacus longistylus, Dakar, Senegal), O. perproximus Silvestri (ex
Dacus brevistylus and Ceratitis giffardi, Kotonou and Segboroue, Dahomey), O. per-
proximus modestior Silvestri (ex Ceratitis nigerrima Aburi, Gold Coast, and Olokemeji,
Nigeria), O. humilis Silvestri (ex Ceratitis capitata, Constantia, Cape Colony), O. in-
consuetus Silvestri (ex Ceratitis tritea, Olokemeji, Nigeria), O. inquirendus Silvestri
(identity of host unknown, Victoria, Kamerun), O. africanus Szepligeti (ex Dacus oleae,
South Africa and Transvaal), O. africanus orientalis Silvestri (ex Dacus oleae, Eritrea),
Hedylus giffardi Silvestri (ex Ceratitis punctata, Conakry, French Guinea), Diachasma
fullawayi Silvestri (ex Ceratitis giffardv and tritea, Dakar, Senegal, Olokemeji, Nigeria,
and Kakoulima, French Guinea), D. fullawayi robustum Silvestri (ex Dacus bipartitus,

1 The writers reared a single specimen of a parasite from a C. capitata pupa which was identified by D. T.
Fullaway as Spalangiasp. It seems probable that this was primarily a parasite of some other dipteron, as
no other specimens were reared.

MEDITERRANEAN FRUIT FLY IN HAWAII. 81

Conakry, French Guinea), D. tryont Cameron (ex Bactrocera tryoni, New South Wales -
and Queensland, Australia), Biosteres caudatus Szepligeti (ex Ceratitis giffardi, tritea,
nigerrima, anonae, antistictica, and Dacus bipartitus and brevistylus, West Africa).
Subfamily Sigalphinae: Sigalphus daci Szepligeti (ex Dacus oleae, Transvaal).
Subfamily Braconinae: Bracon celer Szepligeti (ex Dacus oleae, Stellenbosch and
Wellington, South Africa).
PROCTOTRUPIDAE.

Subfamily Diapriinae: Galesus silvestrit Kieffer (ex Ceratitis anonae, Olokemeji,
Nigeria; ex C’. nigerrima, Aburi, Gold Coast; ex C. giffardi, Kotonou, Dahomey),
G. silvestrirobustior Silvestri (ex Ceratitis punctata, Oonakry, French Guinea), Tricho-
pria capensis Kieffer (ex C. capitata, Constantia, Cape Colony).

CHALCIDIDAE.

Subfamily Chalcidinae: Dirhinus giffardit Silvestri (ex Ceratitis anonae, Olo-
kemeji, Nigeria), D. ehrhorni Silvestri (ex Ceratitis giffardi, Olokemeji, Nigeria).

Subfamily Pteromalinae: Spalangia afra Silvestri (ex Ceratitis anonae, Olokemeji,
Nigeria).

Subfamily Eulophinae: Tetrastichus giffardit Silvestri (ex Ceratitis antistictica,
giffardi, colae, and Dacus bipartitus, West Africa), T. oxyurus Silvestri (ex Ceratitis
tritea, Olokemeji, Nigeria), T. giffardianus Silvestri (ex Ceratitis giffardi, Nigeria and
Dahomey), 7. dacicida Silvestri (ex Dacus bipartitus, West Africa), Syntomosphyrum
indicum Silvestri (ex Dacus, India).

In addition to these, Ihering records the following parasites from Brazilian fruit
flies: Hucola (Hexamerocera) brasiliensis Ashmead, Bvtosteres brasiliensis Szepligeti,
B. areolatus Szepligeti, B. sp., and Opiellus trimaculatus. Gowdey states that he
reared a single chalcidid parasite from C. capitata pupe in one out of many attempts
to secure parasites.

To the foregoing list of fruit-fly parasites should be added Pacny-
crepoideus dubwus, introduced by D. T. Fullaway at Honolulu from the
Philippines during the early part of 1914. Although a parasite of a
dung fly (species not recorded) and introduced to aid in the control
of the horn fly, it has since been reared from C. capitata pupe by the

writers.
GENERAL HISTORY OF PARASITE INTRODUCTIONS.

Attempts have been made to introduce fruit-fly parasites to control
Ceratitis capitata from India into Western Australia by Compere,
from India into South Africa via Western Australia by Lounsbury,
from India into Italy by Silvestri, from Brazil into South Africa by
Lounsbury and Fuller, and from Africa and Australia into the
Hawaiian Islands by the Hawaiian Board of Agriculture and Forestry.
So far as is at present known, these attempts have failed in all coun-
tries except in the Hawaiian Islands. Compere arrived at Perth,
Australia, on December 7, 1907, with fruit-fly pup secured at
Bangalore, India. Although he reared from these pupe an esti-
mated 2,000,000 specimens of Synitomosphyrum wndicum and 300
specimens representing two braconid species and was able to make
numerous liberations in badly affected areas, the West. Australian

81340°—18—Bull. 536——6

82 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

fruit growers have received no appreciable benefit. Newman, in
1908, stated that he had collected in the field during that year pupe
of C. capitata parasitized by the introduced parasites. In 1909 he
stated, however, that the chalcid and braconid parasites, although
liberated for over 15 months, had not yet produced evident results,
and in 1911 he wrote that although Syntomosphyrum indicum had
been reared and liberated in large numbers during the previous four
years, it did not appear to be estabiished and there seemed little
prospect of favorable results.

In 1905 Lounsbury and Fuller investigated fruit-fly conditions in
Brazil and secured parasitized pupe of Anastrepha fratercula, but
they were unable to reach South Africa with hving parasites. Para-
sitized pups of C. capitata were sent from Western Australia to Dur- -
ban and Cape Town during 1908, but Lounsbury reported in 1909
that the introduction was unsuccessful. Silvestri, on his return in
1913 to Hawaii from West Africa, left in South Africa specimens of
Dirhinus and Galesus, but they were unable to survive the following
winter according to Lounsbury. Silvestri states that although he
introduced Syntomosphyrum indicum into Calabria, Italy, he had not
been able to prove that it had become established.

INTRODUCTION OF PARASITES INTO HAWAII.

The search for and discovery, the introduction, and subsequent
establishment of parasites of Ceratitis capitata in the Hawaiian Islands
form an interesting and important chapter in the history of this world-
wide pest. The writers are able to state definitely, as a result of
their biological work between September, 1912, and May, 1913, that
no parasites of Ceratitis capitata were present in Hawaii up to the time
when the first introductions were made in May, 1913, if we except the
Spalangia sp. referred to on page 80 (footnote). At the present time,
January 1, 1916, all larval parasites (Opius humilis, Diachasma tryoni,
D. fullawayi, and Tetrastichus giffardianus) that have been liberated
are being recovered in the field, and practically every lot of larve
reared from samples of fruit collected in the littoral regions are found
to be parasitized by one or more parasites. From exceptional lots all
four parasites have been reared. The two pupal parasites, the proc-
totrupid Galesus silvestria and the chalcid Dirhinus giffardi, have
never been recovered by the writers and will not be the subject of
further discussion.

The parasites at present attacking Ceratitis capitata in Hawaii have
been introduced by the Hawaiian Board of Agriculture and Forestry.
Much credit. is due Mr. W. M. Giffard, who, as president of this board,
was able to make arrangements for the Silvestri and the Fullaway-
Bridwell expeditions to Africa. Dr. Silvestri set out from Italy during

MEDITERRANEAN FRUIT FLY IN HAWAII. 83

July, 1912, and arrived at Honolulu May 16, 1913. During this time
he searched for parasites in the West African States of Senegal, French
Guinea, Nigeria, Kamerun, Gold Coast, Dahomey, the Kongo, and
Angola; also in South Africa and in Australia. It is needless to say
that Dr. Silvestri was unable to make a complete survey of fruit-fly
conditions during so short a time, yet his investigations were success-
ful, not only because they cleared the way for the Fullaway-Bridwell
expedition, but also because they resulted in the introduction and
establishment of Opius humilis and Diachasma tryom. Messrs. D.T.
Fullaway and J.C. Bridwell sailed from Honolulu on the second expe-
dition during June, 1914, and arrived at Lagos, Nigeria, on July 24.
On August 19 Mr. Fullaway took the parasitized material collected by
the expedition at Olokemeji, near Lagos, and sailed for Teneriffe,
Canary Islands, where he was able to use C. capitata in rearing addi-
tional specimens of the parasites emerging from the Nigeria material.
With fresh material, Fullaway sailed from Teneriffe September 27 for
Hawaii via Havana, Key West, Jacksonville, New Orleans, and San
Francisco, arriving at Honolulu on October 27. On arrival he had
living material of Tetrastichus giffardianus, Diachasma fullawayi, Opius
sp., and Spalangia sp.

Mr. Bridwell proceeded from Lagos atin an excellent supply of
parasitized material, particularly of what appeared to be a new opiine
collected at @lskemoy: during the period August to October, 1914, to
Honolulu via Cape Town and Australia. Unfortunately, he was
overtaken before reaching Cape Town with a severe illness which
necessitated stops for recuperation in South Africa and Australia of
sufficient duration to make it impossible for him to bring living
parasites with him to Hawaii.!

It has already been stated that early in 1914 Mr. D. T. Fullaway
introduced at Honolulu a species of dung-fly parasite, Pachycrepordvus
dubwus Ashm. (Pl. XX, fig. 2) which was reared in small numbers
by the writers from C. capitata pupe during 1915.

TETRASTICHUS GIFFARDIANUS SILV.

HISTORY.

Tetrastichus giffardianus Silv. was confused with 7. giffardw Silv.,
both in the mind of its author and in those of entomologists in
Hawaii: The latter species was first reared from Ceratitis colae by
the entomologist (1912-13) of the agricultural station at Aburi, Gold
Coast, Africa. These specimens were identified by Dr. Silvestri as

1 For full accounts of these parasite expeditions one should consult: Report on an Expedition to Africa
in Search of the Natural Enemies of Fruit Flies. F. Silvestri. Bull. 3, Haw. Bd. Agr. and Forestry,

Feb., 1914; Report of the Work of the Insectory. D. T. Fullaway. In Rept. Div. Ent. Haw. Bd.
Agr. and For., for the biennial period ending Dec. 31, 1914.

84 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

new to science. Silvestri reported having reared giffardzi during the
period November, 1912, to February, 1913, from Ceratitis antistictica
and C. giffardia at Oieet Southern Nigeria; from C. giffardii at
Kotonou, Dahomey, and from Dacus bipartitus at Victoria, Kamerun.
Silvestri was unable to keep adults alive during the passage from
West Africa to Honolulu.

In March, 1915, Silvestri published the description of T. giffardi-
anus, stating that previous to then he had confused the species with
giffardu. T. giffardianus was reared by Silvestri from Ceratitis
gifiardu. Bezzi, collected at Olokemeji, southern Nigeria, and at
Kotonou, Dahomey.

It was 7. giffardianus Silv. and not T. giffardii that was collected
by the Fullaway-Bridwell expedition and introduced into Hawaii at

Honolulu on October 27, 1914. This
fact should be borne in mind, because
much of the literature dealing with
parasites of C. capitata in Hawaii refers
to T. giffardianus as T. giffardi.
References to Tetrastichus as a para-
site of Ceratitis capitata in Hawaii
should be interpreted to refer only to
TT. guffardianus.

Fullaway introduced into the Ha-
waiian Islands 300 living specimens of
both sexes of T. giffardianus. By De-
cember 31, or after about two months
of breeding in the laboratory, these

Fic. 17.— Tetrastichus giffardianus: a, Ven- pt nad umpEnased #0 alyaee specumans:
tral aide of mature aah, dorsal Taw Of these, 18,050 were liberated on
of same, showing spiracles; c, mouth Oahu, Hawaii, and Kauai by Janu-
ae a ae, % ess. Greatly ary 1, 1915. Although many thousand

specimens have been liberated since De-

cember, 1914, none had been recovered as late as February, 1916,

from any island except Oahu.t' In Honolulu specimens have been
reared from widely separated pomts, which would seem to indicate
that this parasite has been established successfully. The first recoyv-
eries were made by the writers during September, 1915, in Honolulu.

DESCRIPTION.

Adult.—Both sexes of the adult are black with a slightly dark-
green iridescence. The antenne are rather dark, as are also the

1 Exception: One lot of 46 pup2 of C. capitata from coffee cherries collected June 18, 1915, at Kainaliu,
Hawaii, showed a parasitism of 63 per cent by Opius humilis, 30.4 per cent by Diachasma tryoni, and 2.1
per cent by Tetrastichus giffardii.

Bul. 536, U. S. Dept. of Agriculture. PLATE XX.

N

AY

Fic. 1.—OPIUS HUMILIS: ADULT FEMALE. GREATLY ENLARGED. (ORIGINAL.)

ner =
Sele tree
Se eg

Al

SEES se

Fic. 2.—PACHYCREPOIDEUS DUBIUS: ADULT FEMALE. GREATLY ENLARGED. (ORIGINAL.)

PARASITES OF THE MEDITERRANEAN FRUIT FLY.

Bul. 536, U. S. ‘Dept. of Agriculture. PLATE XXl.

SS Se

-—

Fic. 1.—DIACHASMA FULLAWAYI: ADULT FEMALE. GREATLY ENLARGED. (ORIGINAL.)

ees ———
Si

BF IS Za Ss.

oe a os pe

ie

Hs

Fic. 2.—DIACHASMA TRYONI: ADULT FEMALE. GREATLY ENLARGED. (ORIGINAL.)

PARASITES OF THE MEDITERRANEAN FRUIT FLY.

MEDITERRANEAN FRUIT FLY IN HAWAII. 85

femora, but the tibiz and tarsi are more yellowish. Length of body,
about 2mm. For the original description see Bolletino del Labora-
torio di Zoologia, Portici, volume 9, page 374 (1914-15).

Egg.—The egg is pure white, about 0.11 mm. long, and shaped as
shown in figure 17, d.

Larva.—The well-grown larva is white and grub-like, about 1.8
— mm. long (fig. 17, @). When viewed from above, spiracles are evident
' on segments 3-9 (fig. 17, b). The mandibles are microscopic (fig.
| 17,c). When first hatched, larve are about 0.28 to 0.3 mm. long.

Pupa.—tThe pupa is about 1.9 mm. long. (See fig. 18.)

BIOLOGY.

Silvestri was unable to keep adults of giffardu (or giffardianus 2)
alive for more than 15 days. His original statement that the female
deposits her eggs within the eggs or young larva of
the host has been proved by Fullaway and the
writers to be incorrect. Oviposition by T. giffardi-
anus occurs largely in the well-grown larve as in
the case of the Opinae. The adult parasite will
enter larval chambers and breaks in the host fruit
in search of fruit-fly larve as has been proved by
the writers under laboratory conditions, and accu-
mulating data seem to indicate that adults oviposit
for the most part im larve within fruit already
fallen to the ground. Adults are capable of begin-
ning oviposition as soon as they emerge from the
puparium of the host. The female does not neces-
sarily make a new puncture in the epidermis of its
host for each egg deposited; in one instance 41 eggs
were deposited through 17 punctures. When the tis
female comes upon a larva within a larval channel, Fic. 18. —Zetrastichus
she deposits her eggs at points about its posterior “/7dinnus: ee
portion, but when access to the larva can be had Normal length, 1.9
through a thin membrane of the host fruit, she may = ™™ (O™s7!)
deposit her eggs in any portion of the body. The punctures in the
epidermis are evident as small dark brown depressions. Of a total
of 322 adults reared from 20 pupe, 194 were females and 128 were
males; the number of adults reared from single pup varied from 1
to 35.

When the temperature ranges between 66° and 82° F., with a mean
of about 74° F., eggs hatch in about 3 days, the larve become full
grown in about 8 days, and the pupe yield adults in from 11 to 15
days.

86 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

OPIUS HUMILIS Srnyv.

HISTORY.

Opius humilis Silv. (Pl. XX, fig. 1) was first reared and described by
Silvestri from pup of Ceratitis capitata collected at Constantia, Cape
“Colony, Africa, during March, 1913. This parasite does not appear
to be an effective factor in the control of Ceratitis capitata under
South African conditions. Silvestri reared only a few specimens of
which he had only 5 representing both sexes in a living condition
when he arrived at Honolulu, May 16, 1913. Although after Silvestri
arrived at Honolulu he was able to rear
fresh material, the danger that the prog-
eny would be males only was so great that —
3 females, with males, were liberated in
the coffee fields of Kona, Hawaii, on June
12,1913. This precaution alone saved the
species from extinction in the islands, as
the progeny of the specimens kept in the
laboratory proved to be males. During
October, 1913, large numbers of Opius
humilis were recovered from Ceratitis ca-
pitata larvee in coffee cherries in Kona,
Hawaii, and it was found that the species
was wellestablished. From the specimens

Wee Opa hamden eee recovered from Kona, colonies were reared
day old, length 0.45 mm.;b,egg3 and liberated in other parts of the islands.
days old, length 0.8 mm. (Orig: No specimens were liberated in Honolulu

nal.) 5

until December, 1913. By July, 1914,
humilis was found well established in the city, and by December of
that year data already published! prove it to have become very
abundant and widespread.

DESCRIPTION.

Adult.—The original description of the adult by Silvestri is as
follows:

2 Body ochraceous in color, antennz brownish-fulvous, wings hyaline with the
veins brownish and the central part of the stigma ochraceous-ferruginous, legs with
pretarsi brown and the posterior tarsi also in great part brown. Head scarcely more
than one-third wider than long, hairy; face with a slight median carina; epistoma
slightly elevated; antennz a little longer than the body, with 35 segments; eyes a
little more than twice as long as wide, their lower margin attaining the level of the
superior margin of the epistoma. Mesothoracic scutum entire, smooth, with very
short parapsidal furrows anteriorly; transverse prescutellar sulcus with eight small

1 Back, E. A., and Pemberton, C. E. Parasitism among the larvee of the Mediterranean fruit fly (C.
capitata) in Hawaii during 1914. Rept. Hawaii Bd. Agr. and For., Dec. 31, 1914.

MEDITERRANEAN FRUIT FLY IN HAWAII. 87

pits; scutellum smooth with 3 or 4 small pits and a large deep one; metanotum with a
short median carina, on the submedian part shortly crenulate before the sublateral
pit; propodeum with a median carina, in some specimens divided from the base into
two almost contiguous parallel arms posteriorly diverging, the remainder rugose;
mesopleuralsulcusfalveolate. Wings with venation as shown in figure [PI]. XX, fig. 1.]
Abdomen with the first segment rugose on the dorsum, the remainder smooth, with
a few hairs; ovipositor almost straight, a little shorter than the abdomen.

Length of body, 2.6 mm.; width of thorax, 0.79 mm.; length of antennz, 3.3 mm.;
length of front wing, 2.6 mm.; width of same, 1.15 mm.; length of third pair legs, 2
mm.; length of ovipositor, 1.15 mm.

Egg.—The egg when first deposited is about 0.45 mm. long, white
and of the shape indicated in fig. 19,@. As the embryo develops, the
entire egg increases in size
until when between 2 and 3
days old (Feb., 1916) it be-
comes about 0.8 mm. long,
and over twice as wide as
when first deposited, with a
protuberance at the anterior
end. The developmg em-
bryo may be readily seen
through the egg membranes
(fig. 19, 6). a

Larva.—The white, newly
hatched larvais about 1mm.
long. It has a rather large
head and 12 distinct body
segments. (Seefig.20.) On
the anterior ventral portion
of the first body segment is
a pair of appendages (fig. 20,

6, d), which the larva does me. 29—opius humilis. Larva: a, Ventral, and 6, lateral
not appear to beabletomove View of newly hatched larva; c, ventral aspect of head of
paar toscenc-an aid to. same; d, enlarged thoracic appendage. (Original.)
locomotion. The jaws are very large and strong, being much larger
in proportion than in the succeeding instars (fig. 20, c). The ven-
tral portion of the head, behind the mandibles, is rather strongly
chitinized, forms a support for the latter, and bears on its anterior
margin two toothlike projections. On the ventral anterior portion
of the head are two fleshy antennal protuberances. The thoracic
appendages and large mandibles are lost after the larva molts into
the second instar.

Pupa.—The pupa is about 2.38 mm. long (fig. 21). It is very
readily distinguished from the other opiine pupz by the short
ovipositor sheath.

88 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

DIACHASMA TRYONI CAMERON.

HISTORY.

Diachasma tryoni Cameron (Plate XXI, fig. 2) is primarily a para-
site of the Queensland fruit fly (Bactrocera tryont) and was first reared
by Brooks and Gurney in New South Wales during 1908, and described
as a new species by Cameron in 1911. Of 1,575 pupx of Bactrocera
tryont secured by Gurney from 18 different lots of fruits during the
period from January, 1910, to February, 1911, 30.2 per cent were
parasitized; the highest percentage of parasitized being 52.2 per cent
of 136 pupz secured at Narara during February, 1910. During
April, 1913, at Gosford the parasitism equaled 70 per cent. While
Diachasma tryonit in Australia attacks principally the Queensland
fruit fly, it has been definitely reared there from.
Ceratitis capitata under field conditions, and the
indications are strong that it may attack also the
island fruit fly, Trypeta musae Frogg. It was
the opinion of Gurney that this parasite might,
upon occasion, become a valuable check upon
C. capitata.

While en route to Honolulu from West Africa,
Silvestri, aided by Gurney, secured pup of Dacus
tryont in New South Wales. From these pupx
Silvestri reared adults of Diachasma tryont, of
which he succeeded in introducing at Honolulu 4
female and 3 male specimens on May 16, 1913.
Silvestri soon found in his rearing experiments im
Honolulu that the progeny were largely of the

_ male sex, hence 4 females, with males, were liber-
Fig. 21.—Opius humilis: z : : ae
Lateral view of pupa. ated June 12 in the Kona coffee district of Hawau,
(anes Ee 3 females, with males, on July 4 at Waianae, and
: 9 females, with males, on July 11 in Kona, Hawaii.
As all the progeny of the remainder of the material held at the
insectary were males, the specimens of this parasite now in Hawaii
are the progeny of 24 females liberated during June and July, 1913.
The first recovery of Diachasma tryont was made by Ehrhorn during
August, 1914, from C. capitata pupe from the Kona district of
Hawaii. During October, 1914, a systematic collection of infested
coffee cherries throughout this district proved tryonz to be thoroughly
established. Although 3 females were liberated at Waianae, Oahu,
on July 4, 1913, no specimens were liberated in and about Honolulu
until early in 1915. Yet by October, 1915, this parasite was being
reared ‘in small numbers from C. capitata pupe obtained in various
parts of the city.

1 Back, E. A., and Pemberton. C. E., Parasitism among the larve of the Mediterranean fruit fly
(C. capitata) in Hawaii during 1915. Jour. Econ. Ent., v. 9, 1916, p. 306-311.

MEDITERRANEAN FRUIT FLY IN HAWATI. 89

DESCRIPTION.
Adult.—Silvestri’s description of the adult is as follows:

©. Head, thorax, first segment of the antenne, front and middle legs testaceous-
ferruginous in color; abdomen in great part brown or shining blackish brown; wings
slightly infuscate, with the stigma and veins brown; third pair of legs entirely brown
from apex to trochantérs. Head a little broader than the thorax, about one-fourth
wider than long with a slight median longitudinal ridge on the face, epistoma slightly
semicircularly produced in the middle; antennz longer than the body, with 45 seg-
ments; eyes small, twice as long as wide. Mesothoracic
scutum with the parapsidal furrows smooth and deep, con-
vergent, uniting in a deep median pit situated a little before
the posterior margin; transverse prescutellar sulcus with
a large pit divided into four small ones and each provided
also with an incomplete posterior division; scutellum smooth;
parascutellar pit with an internal scarcely visible crenulation;
metanotum with a short very slight median carina flanked by
two small depressions, lateral pit with an abbreviated carina;
propodeum with asmall anterior conical protuberance directed
forward, median and submedian surface almost smooth, a lit-
tle rugose at the sides and posteriorly, mesoplural sulcus
crenulate. Wings with the venation shown in figure [PI.
XXI, fig. 2.] Abdomen with all the segments smooth and
shining, with few hairs; ovipositor about as long as the body.
Length of body, 3.5-4.5 nine, width of thorax, 0.95 sE
length of antenne, 5 mm.; length of front wing, 4 mm.
width of same, 1.7 mm. ; length of third pair of es 4.4mm.
length of ovipositor, 4. panes "Fic. 22.—Diachasma try-

¢. Similar to the female. oni: Lateral view of

Larva.—Oval in form, whitish, with the skin smooth and ap- TOL ee ey
parently naked, but under strong magnification may be
seen to be provided with dense, small, and slender points. Mandibles short, slightly
arcuate and gradually attenuate, terminating in a point. Antennz very short.
Length of body, 3 mm.; width, 1.6 mm.

Egg.—The egg of Diachasma tryonz is glistening white, about 0.57
mm. long and distinctly attenuated at each end.

Larva.—The newly hatched larva, which is about 1 mm. long, is
similar to that of Opius humilis (fig. 20, a, b) and Diachasma fullawayr
in general shape and in the possession of two ventral appendages
upon the first body segment. The proportionately large jaws are
similar to those of newly hatched larve of humilis and fullawayr
but slight distinguishing characters can be found in the large chitinous
ventral plate of the head.

Pupa.—tThe young pupa is white in color, about 4 mm. long,
1.7 mm. wide, and may be distinguished from that of either humilis
or fullawayi by the length of the ovipositor. (Fig. 22.)

DIACHASMA FULLAWAYI SILV.

HISTORY.

Diachasma fullawayi (Plate X XI, fig. 1) was first reared and de-
scribed by Silvestri from pup formed by larve of Ceratitis giffards

90 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

po tag Ie

collected in the fruits of Chrysobalanus on August 2-3, 1912, at ~

Dakar, Senegal. Silvestri later reared specimens from C. giffardi and
C’. tritea at Olokomeji, Southern Nigeria, and from C. giffardi at
Kokoulima, French Guinea. He was also able to rear this parasite
at Dakar from pupex formed by larve of C. giffardi parasitized ex-
perimentally during the period September 6 to 8, 1912. He was
unable, however, to arrive at Honolulu with living specimens and it
remained for the Fullaway-Bridwell expedition of 1914 successfully to
introduce D. fullawayz into Hawaii from Olokomeji via Teneriffe,
Habana, and the southern United States. Fullaway arrived at Hono-
lulu on October 27, 1914, with 12 female and 19 male specimens.
These had multiplied in the laboratory to 419 females and 1,000 males
by December 31, and of this number 35 ‘and 160 specimens were
hberated during December at Maunawili, Oahu, and Kona, Hawaii,
respectively. Although many
specimens have been and are still
being reared and liberated, this par-
asite appears to be well established
on the Island of Oahu. In the
Kona District of Hawaii, however,
where it should have become estab-
lished with greater ease, only two
specimens have been reared from
larvee emerging from coffee cherries.
These two specimens of D. fullawayi
FIG. 23.—Diachasma fullawayi: Ventralaspectof O01 Hawaii were reared by the

head of newly hatched larva; greatest width, wyiters from larve colleeted at

a Kainaliu on January 15, 1915, and
February 13, 1916, or about 1 and 13 months, respectively, after the
original liberations at this point.

On Oahu, particularly in and about Honolulu, this parasite has
multiplied with rapidity and was found well established in all parts
of the city during September and October, 1915.

DESCRIPTION.
Adult.—The original description of the adult is as follows:

2. Body ferruginous or ochraceous-ferruginous with the antenne fulvous brown,
the wings hyaline, with the veins fulvous brown and the stigma, in part fulvous-
ferruginous, tarsi of the posterior legs sightly brownish. Head somewhat broader than
long, densly covered with piliferous points, with the face slightly inflated in the
middle to form a carina, antenne longer than the body, with 44 segments. Eyes
small, about twice as long as wide. Mesothoracic scutum with deep converging
parapsidal furrows which meet a little before the posterior margin in a deep common
pit; from this pit a median furrow proceeds directly forward, at first deep but gradu-
ally disappearing on the surface near the middle of the scutum; the entire surface

1 Examinations made by C. E. Pemberton in Kona during May and June, 1916, found it to be established
beyond question,

MEDITERRANEAN FRUIT FLY IN HAWAII. 91

rather densly and closely hairy; transverse prescutellar sulcus provided with four
deep pits, of which the lateral ones are deeper than the median; the scutellum is
smooth and rather hairy; slightly crenulate laterally before the prealar pit; metano-
tum with a small median pit divided by a short carina, crenulate on the sides; pro-
podeum strongly and irregularly foveolate. Front and hind wings with the venation
shown in figure [P1. X XI, fig. 1]. Abdomen with the first segment smooth; ovipositar
straight, longer than the abdomen. Length of body, 3.6 mm.; width of thorax, 0.1
mm.; length of antenne, 5.2mm.; length of front wing, 3.7 mm.; width of same, 1.37
mm.; length of third pair of legs, 4 mm.; length of ovipositor, 3.5 mm.
g. Differs from the female in having the wings more or less infuscate.

Larva.—The newly hatched larva is similar to that of Opius humilis,
as illustrated by figure 20, a, 6, as well as that of Diachasmatryon,
but it may be readily distinguished from that of D-tryonz by the pos-
session of three instead of two toothlike projections
on the anterior margin of the ventral chitinized
plate of the head (fig. 23).

Pupa.—The pupa, which is about 3.2 mm. long,
is most easily recognized from that of humilis and
tryont by the length of the ovipositor. (Fig. 24.)

BIOLOGY OF THE OPIINE PARASITES.

Very little is known regarding the details of the
life history of the three opiine parasites introduced
into Hawau. The biology of parasites now attack-
ing Ceratitis capitata in Hawaii is at present being
made the subject of special investigation by the
junior writer. No data on the length of the vari-
ous stages have been published except by Silvestri
and Gurney. Suilvestri’s statements may be sum- F Se apogee
marized as follows: That adults of Opius humilis ena yocmailienerh:
emerging on April 3, 1913, were still alive on his = about 4 mm. (Origi-
arrival at Honolulu on May 16, when they depos- ae
ited eggs from which adults developed within 14 days; that eggs of
-Diachasma fullawayi, at Dakar, Senegal, deposited on September 6 to
8, 1912, developed adults September 21 to 24, and that D. tryoni can
‘complete its egg, larval, and pupal development in from 14 to 16
days. The data supphed by Gurney deal with D. tryont only and
will be considered later. The information of the writers is not com-
plete and therefore is given as follows in the form of biological notes
in anticipation of a more complete publication. It might be added
that such data as are presented here were obtained incidental to other
work... .

Length of adult life-—Adults die in about 48 hours if not fed.
When confined in test tubes 14 inches in diameter and about 8 inches
long and fed daily, they live much longer, as indicated by the datain

Table XXIV.

92 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

TABLE XXIV.—Longevity records of Opius humilis and Diachasma tryoni} at Hono-
lulu from November, 1914, to March, 1915.

| i
Number ofspecimens | | Number of specimens
dead. | dead.
Age on ||. Age on
date of date of |
observa- | O.humilis. | D.iryoni. || observa- | O. humilis. | D.tryoni.
’ tion. | tion.
Sf 2 3 2 Cf 2 of 2
} i

24 1 a Bs Shes tee © G7TkpeL PMG AS OS) eee
DARN |e Re Maes Ee es a LY fie wees 68 4\¢-s ee hey lees ae Se OR
26 yes ee Ps (a BR a 60s Dun aires S| pee ee
28 Ce eeeae fl deme TO | thee: dreolek set . Fase
29 ee oe ea eee | Tales Ny IRE, Be oes 9

30 3 75 hal eS | eee | (Bh elanies 27 es rere 1
Spal ee Sat bet saat 1 ae. 2 Serie cee’ tery:
34 || elie ioee eee eae: Toye Beclecee s beppre ct
sie || co rae. salieri (Oo | sees. gl a 858 ig
37 2 5 1 Ue fea te | Oe eben A eee SES eee

38 [oA eee | Bae ee ee SOM Rte 1 LR) ees = 2 1
43 3 7 2 Sime Sh a a Bs alee
45 7 Sees 1 82 1 Beas a eee
46 J iailgs teers 1 4 SSeS ee Li scieptiee ees see
47 2 6 Tel ee aeaes 84 |; 1 CTA Oe ae | eee
49 | 3 TAN epee|. te: Shree ees depos be 2

50 1 Ra Linills, Seen Ieee Shale ss CSE aS Baas 1
51 1 (et | eae 1 887) |.Gee SAiineal 2A
52 1 6 1 1 Obs a5 32 Pea RES a eT Nei
Peele i ales de Wigal ial O47 Oa Sh oles hee uae
54 1 2) | 2. See oe ee Be | a Nie ee aes A A SS
GW lea TOT Dearth eect O82) Wease Py Benen eo
56 2 St aes 1 | LOO lk ae ee fel tes Shes (OR ee
LY a ges SB ee A Bee 2 TORS Nok Se. DS Shee (2 eh
58 5 al ee oe 103 7} -27 5: Pri as. Seer
59 1 ROIS AEG | LOS FIA is. YE Tey.
GO) | 2... al ac Pg [gabe a | ee Dee ae ee
62 1 GS-08 Cth Fad 107. 249-7 Ht) SPS) 2
G3 a eons aya {|e eee ae 1 01D 1) La Fae ee Dili? alee em
65 3 S aie 1 124s Flas F8 DSAAGA ALE ee ey

(ioe ae 2 Som Ss ee |e, ean | TPA ete eee | Pd a) ee 1

‘|

1 No record was kept of adults dying during first 23 days after emergence.

Fourteen females of Opwus humilis lived to be over 100 days old;
the last two being 125 days old. One female Diachasma tryoni
lived to be 125 days old, although this species appears to be more
frail and less able to survive captivity. Unfortunately no record
was kept of the number of adults of either species dying during
the first 23 days after emergence.

Proportion of setes.—A count of the sexes of 25 lots of Opius
humilis reared from C. capitata developing in various fruits during
September and October, 1914, showed 145 specimens to be females,
and 141 males.

Mating. Mating may occur immediately after emergence in all
three species, Opius humilis, Diachasma tryoni, and D. fullawayr.
Virgin females may deposit parthenogenetic eggs which, however,
develop males only.

Length of life cycle—There are no satisfactory data on the length
of the life cycle under varying climatic conditions. The statement
of Silvestri that the egg, larva, and pupa stages may be completed
in from 14 to 16 days is a safe estimate for the minimum length
required for the development of these stages. Specimens of O.
humilis, developmg from eggs deposited August 21 to 22, 1914,

MEDITERRANEAN FRUIT FLY IN HAWAII. 93

were already in the pupa stage when examined on August 31, and
emerged as adults 13 to 16 days after the eggs were deposited. The
temperature during this period ranged between 74° and 85° F., with
a mean of about 79° F. In Table X XV are the summaries of emer-
gence from 35 lots of C. capitata pupe secured from various fruits,
and these are presented since they demonstrate clearly that which
more detailed data will prove further—that O. humilis passes through
its immature stages more rapidly than either D. tryoni or D. fullawayi.
As the eggs of the parasites are deposited within the well grown
larva before it leaves the host fruits, from 1 to 4 days should be added
to the duration of the immature stages indicated in Table XXYV.

Three O. humilis emerged April 3 from C. capitata pupx formed
at Honolulu February 2, 1915, placed on Hualalai (temperature
range, 31°-70° F.) February 11, taken to Kealakekua March 26, and
to Honolulu March 29; i. e., the duration of the immature stages
was increased by this combination of cool weather to about 60 days.
Many records on file, not included in Table XXV, indicate that
detailed data will show more convincingly that O. humilis is less
affected by cold weather than either D. tryon or D. fullawayi.

Dormancy.—There appears to be no tendency for the larve of
O. humilis to pass through a period of dormancy. The larve of
D. tryom and D. fullawayi often apparently suspend activity when
they become full grown and remain dormant for several months.
Gurney first observed this phenomenon in the development of
tryon. C. capritata pupe collected on February 2, 1915, produced
adults of tryont normally as indicated by the data in Table XXV,
but two individuals emerged on May 5 and 27, respectively, or 92
and 114 days after the pupation of the host. Larve of tryona and
fullawayi in C. capitata larve in fruits gathered November 27, 1915,
were still in the mature larva stage at the end of eight months (July,
1916). Similar data on the duration of other individuals are on
file. Mr. J.C. Bridwell has stated to the writers that he has observed
this same resting period among the larve of an undetermined African
opiine, certain adults of which emerged three and four months after
the pupation of the host fruit fly.

Instar of larve parasitized.—It is generally admitted by those
rearing parasites in Hawaii that the adult parasites deposit their
eges, for the most part, in well grown third-instar larve while the
fruits are still attached. to the tree or have fallen to the ground.'
The data in Table XXVI show a rapid decrease in the percentages
of parasitism among larve emerging from fruits during each suc-
ceeding two or three day interval after the gathering of the host
fruit.

1 A former statement by the writers that the opiines oviposit for the most part in larve in fruits still

attached to the tree is subject to modification. While oviposition occurs chiefly in coffee cherries ate
tached to the tree, oviposition in kamani nuts occurs largely after the fruits have fallen.

BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

94

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MEDITERRANEAN FRUIT FLY IN HAWAII. 95

TABLE XXVI.—Percentage of parasitism among larvee of the Mediterranean fruit fly
emerging during various periods after the gathering of the host fruit (coffee).

Percentage of parasitism.

Number :
ae Date of Dae a of DUDS —_
ity. collection arva. yielding : ‘
= of fruit. | emergence. |aiults or| Opius on ore aes Total
parasites.| humilis. tryoni. |fullawayi.

Oct. 21-23 37 78.4 0 16.2 94.6
pee Street, Hono- oct. Fy a Lpieinioe ne 23-25 34 64.7 0 15 79.7
: Oct. 25-27 52 20.0 0 5.4 25.4
Dee. 8-10... 256 0. 0.4 92.1| 92.5

c. 10-13... 338 k .6 78.1 79
Booth Estate, LeauoaiVal; \Dec. 8, 1915 Dee 13-16... 609 | 6 <1 43.8| 44.5
y- c. 16-18... 258 0 0 12.8 12.8
Dee 18-20... 76 0 0 6.6 6.6

Dee: levine 5 4 60 0 100

(| a 15 86.7 123 0 100
Fe oataeKUas Kona dis- \Dec. 1,1915 Dee ent 21 71.4 23. 8 0 95.2
ec. 4-5 33 66.6 21k2 0 87.8
ree 5-6 46 - 54.3 13 0 67.3
; June 18-19... 46 63 30.4 0 93.4
Kainaliu, Kona district...| June 18,1915 |< June 19-20.. 65 50.7 41.5 0 92.2
June 20-21.. 107 56 32.7 0 88.7
41 80.4 2.2 0 82.6
Kahaloa, Kona district...| Oct. 30,1914 Nov. 38. e 240 23.3 0.4 0 23.7
Nov. 6-9. 125 BE 7/ 0 0 SLi

Nov. 9-11. 64 0 0 0 0
Oct. 31- 52 16.7 40.7 0 57.4

Nov. 3.

Hookena, Kona district...| Oct. 31,1914 |{ Nov. 3-6... 36 17 19 0 36
Nov. 6-9... 86 1.2 0 0 31,2

0 0 0

Nov. 9-11. - 79 0

Resistance to cold-storage temperatures.—Indications are that Opwus
humilis can withstand greater cold for longer periods than can its
host. Thus 5 O. humilis emerged from 2,500 C. capitata pupe after
they had been refrigerated for 9 days at about 26° F. Four lots of
1,200 pupe refrigerated at the same temperature for 5, 6, 7, and 8
days yielded on removal to normal temperatures 30, 32, 8, and 4
Opius. No adult C. capitata emerged from those pupe refrigerated
from 5 to 9 days, but from 1,300 pupe, refrigerated at about 26° F.
for a period of 4 days, 3 adults emerged along with 40.0. humilis.

No adult C. capitata emerged from two lots of 1,900 and 4,500
pupe refrigerated for 9 and 10 days, respectively, at 32° F., but 7
and 13, respectively, of O. humilis emerged. From 1,228 pupe
pee ad for 18 days at 34° to 36° F. there emerged no wee
C. capitata but 2 O. humilis.

REARING PARASITES.

In rearing parasites the writers have followed, in the main, the
methods employed by the Hawaiian Board of Agriculture and
Forestry as developed by Messrs. Silvestri, Fullaway, and Bridwell.
The board failed to rear the opiine parasites successfully until Mr.
J. C. Bridwell, then assistant superintendent of entomology, altered

96 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

the procedure so that the parasites were given an opportunity to
oviposit in the larve within host fruits under more normal conditions.
The methods previously used permitted much moisture to gather on —
the sides of the glass jars in which the host fruits and parasites were
placed. The method now recommended by Mr. Bridwell consists in
the use of two ordinary nursery flats, the boxes being 16 by 12 by 3
inches. Into one of these is placed a layer of dry sand and a wire
container so arranged that it will hold the infested host fruits exposed
within it clear of the sand. The second tray, the bottom of which ~
has been replaced by fine-mesh copper wire, is used as a cover and
is made sufficiently small so that it can be inverted and thrust down
into the tray containing the sand and fruits as soon as vials containing ~
the adult parasites have been unstoppered and placed upon the fruits.
By pressing the edges of the covering tray well into the sand the adult
parasites are prevented from escaping and ants are, temporarily at
least, prevented from interfering with the experiment. When the
covering tray is in place, the wire-screen top is not far from the ex-
posed fruits; hence the parasites are forced to confine their activities
where they net the best results. The Bridwell method has not only
made it possible to rear large numbers of opiines quickly and without
skilled labor but is largely responsible for the success of the Fullaway-
Bridwell parasite expedition to Africa.

The writers have been able to rear both sexes of the opiine parasites
in large numbers very easily since the summer of 1914 by merely
placing in test tubes about 2 inches in diameter a number of infested
host fruits and parasites. This method requires greater care and
produces much sweating of the sides of the containers, but parasitic
material of both sexes can be very quickly secured for experimental
work, and the investigator has the advantage of being able to observe
the activities of the adult parasites. The objectionable feature of
excessive moisture was overcome by the use, in the summer of 1914, —
of a wooden box, the top and bottom of which was of fine-mesh
copper wire which contained a sliding shelf made of coarse-mesh
wire supported midway between the top and bottom of the box and
_ which could be easily removed through one end of the box which
was hinged. This device possessed the advantage, demonstrated by
Bridwell, in that it prevented accumulations of excessive moisture
and confined the parasites closely to their hosts, but was not so well
adapted to the purposes of parasite work since\the host larvee which
pupated on the bottom of the box could not be so readily. secured.
After the host larve have emerged from the exposed fruits the pupz
may be easily sifted from the sand beneath the fruits and held in
glass jars until the adult parasites have emerged.

It was not necessary to expose adult opine parasites to strong
sunlight for a few minutes each day to hasten mating, as reeommended

MEDITERRANEAN FRUIT FLY IN HAWAII, | 97

by Bridwell, and both sexes were obtained within the laboratory
without this precaution, possibly owing to the fact that the labora-
tories were remarkably well lighted.

Canmibalism.—Although thousands of adults representing all three
of these opiine parasites have been reared during the past two years,
not more than a single individual has been reared from one fruit-fly
puparium. lLarve of the Mediterranean fruit fly within coffee cher-
ries which had been exposed to the attack of Diachasma fullawayi
during January, 1916, were found to have been attacked in several
places, and examination made of the body contents of the parasitized
fruit-fly larvee proved that as many as 8 eggs had been deposited in
certain instances. It seems very probable, therefore, that in the
field, under normal conditions, adult parasites do not discriminate
against larve already parasitized when seeking a host and that due
to an excessive number of parasitic larve within a single host a cer-
tain amount of cannibalism occurs. Cannibalism among opiline
parasites was first observed by the senior writer while examining the
body contents of larve parasitized by Diachasma fullawayi as pre-
viously mentioned. A newly hatched larva was observed vigorously
and effectively to attack a second larva of the first instar with its
large mandibles. Later examination of large numbers of fruit-fly
larvee by the junior writer have proved conclusively (1) that the last
opline parasite to hatch within a host first kills all other parasitic
larvee within the same host; (2) that the newly hatched larva is
more capable of vigorous attack than one which has become engorged;
and (3) that it may attack not only larve of another species but
those of its own as well. As many as eight dead and one living first-
instar larve have been found in a single host.

STRUGGLE FOR SUPREMACY AMONG PARASITES. ©

The parasites of Ceratitis capitata have been introduced too recently
into Hawaii to warrant conclusive statements regarding the outcome
of the struggle for supremacy which is clearly taking place. Optus
humilis has an advantage among the opiines of being more hardy and of
being able to pass through the immature stages more rapidly, and it
is somewhat less affected by cool weather, whereas Diachasma tryont
and D. fullawayi have the advantage of possessing much longer
ovipositors and are consequently better equipped to reach their host
larvee through the tissues of infested fruits. The more rapid develop-
ment of the egg and larva stages of Opius humilis is, however, not in
its favor when it is forced to compete within the same host with either
Diachasma tryoni or D. fullawayt, owing to the cannibalistic habits
of the newly hatched opiine larva, which impel it to seek out and
destroy larve that have hatched earlier and already commenced
feeding within the same host.

81340°—18—Bull. 536——_7

98 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

While it will probably take a number of years to determine just
what advantage the longer ovipositor will afford Diachasma tryoni
and D. fullawayi over Opius humilis, the data in Table XXVII
clearly demonstrate the value of the cannibalistic habits of the newly
hatched larva to the more slowly developing species.

TaBLe XXVII.—Percentage of parasitism by Opius humilis and Diachasma tryoni in
larve of Ceratitis capitata in Kona, Hawaii.

|

Pesce of para- | Percentage of para-
sitism.
Dales a ; | Dates of |_ SIUSH
Be res arva === SE hn larval
Locality. emergence, —o Locality. emergence, ie
1915. oe chasma} Total. | 1915. ores chagna Total.
‘| tryoni. | . tryoni.
Jan. 15-16| 97.6 0.8] 98.4 | Mar. 24-26] 981.2 0 81.2
Jan. 16-18 92.7 -8 93.5 June 17-18 46.7 40.3 87.0
June 19-20 40 49.6 89.6
Feb. 68| 985.3] 9.3] 94.6 || Homaunau..-
Ser Mar. 15-18 92 0 92. 0 Sept. 19-20 13.9 65. 1 79.0
Kainaliu....- Mar. 18-19] 85.1 0| 85.1 Sept. 20-21} 10.6] 69.6| 80.2
June 18-19 63 30. 4 93.4 Feb. 6-8 79 0 79
June 19-20 50. 7 41.5 92. 2
June 20-21 56 32.7 88. 7 June 16-18 31.4 23.9 d= &
Kealakekua .
Jan. 19-20 82.8 3.4 86. 2 Sept. 18-19 17.6 67.6 85. 2
Honaunau...|{Feb. 9-10 64. 2 4.7 68. 9 Sept. 19-20 23 56. 4 79.4
Mar. 19-24 73.9 -6 74.5 Sept. 20-21 37.3 48.3 85. 6

Data previously published by the writers have shown that O.
humilis itself is capable of killing as high as 80 to 100 per cent of
the larve of Ceratitis capitata developing in coffee cherries in the
Kona district of Hawaii. The data secured during 1915 showed
that there was a decided increase in the percentage of parasitism
caused by D. tryont. This increase, however, as shown by the data
of Table X XVII, was largely at the expense of O. humilis, since the
total percentage of parasitism was not in excess of that which QO.
humilis could have brought about by its own efforts. In the absence
of large amounts of data necessary to the definite estabushment of
this point, the writers are of the opinion that similar fluctuations in
the relative importance of humilis and tryona are likely to occur each
year unless fullawayi becomes thoroughly established, in which case
it is likely to supplant tryont. The gradual increase in the abund-
ance of ¢ryont during the year is accounted for by the gradual removal,
as the summer months approach, of the restrictions upon parasite devel-
opment which cause a greater relative acceleration in the development
of tryont than in the case of humilis. This, aided by cannibalism,
explains the ascendancy of tryont durmg the summer and of humilis
during the colder winter months. It would appear that C. capitata
in the coffee sections of Hawaii would have been quite as effectively
controlled had no opine other than humilis been introduced.

It is doubtful if the same fluctuation in the relative abundance of
tryont and fullawayi on the one hand and of humilis on the other

MEDITERRANEAN FRUIT FLY IN HAWAII. 99 .

will take place in the warmer littoral regions about Honolulu where
checks due to cool weather are not so effective asin Kona. <A study
of the data in Table XXVIII shows that Diachasma fullawayi gives
promise of being a most efficient parasite, particularly of fruit-fly
larve in coffee cherries, since almost unaided it produced a mortality,
in one instance, of 92.5 per cent of 256 larve emerging from coffee
cherries in Honolulu on December 8 to 10, 1915, which date was about
one year after it had been liberated.
- Datamore recently secured by the junior writer indicate that instead
of supplementing the work of the opiines, Tetrastichus giffardianus will
prove a competitor, as its larve appear to be able to hold their own
against opiine larvee within the same host, usually causing their death.
While both Tetrastichus giffardianus and Pachycrepodeus dubius (PI.
XX, fig. 2) have been reared during 1915 and 1916, neither is suffi-
ciently abundant to become an effective factor in control at present.

GENERAL EFFECTIVENESS OF PARASITE CONTROL.

Only a beginning has been made in determining the effectiveness
of parasites as a control factor in the Hawaiian Islands, yet the
rapidity of establishment and increase of the parasites has been very
gratifying. The data already published recording the percentage
of parasitism secured during 1914 and 1915, together with the addi-
tional data of Table XXVIII, indicate, however, that while para-
sitism + such fruits as the coffee cherry is remarkably high, in fruits
with a thicker pulp, such as the orange, it is very low. The data of
Table XXVIII have been chosen particularly as they demonstrate
that immense numbers of adult Ceratitis capitata are developed in
spite of the excellent work of -the parasites in certain host fruits.
Since adult fruit flies can live many months and oviposit quite regu-
larly as shown by the biological data, they have been able, with the aid
of the unprecedented variety and abundance of host fruits growing in
Hawaii, thus far to keep such an ascendency over their parasites
that they cause the infestation of practically all fruits which are per-
mitted to ripen. It would appear that unless effective pupal or egg
parasites are introduced, or unless care is given to the elimination of
host fruits which more thoroughly protect the larve from parasite
attack and to the planting of fruits in which the fly is heavily para-
sitized, little of practical value can be expected from the parasites dis-
cussed in this paper either in rendering host fruits entirely free from
attack or in raising the present quarantine against Hawaiian fruits.
In Kona, Hawaii, where the percentage of parasites in coffee cherries
has been phenomenally high for two years, 1t has been high enough
merely to render an occasional fruit free from attack. The control

__ 1The statement of W. M. Giffard that the infestation of coffee cherries during 1914 was at least 50 per
cent less than during the previous year, and that in some fields it was difficult to find any great infesta-
tion, should be interpreted as referring to the cherries which, although nearly all infested, were infested
so late in development that their pulp was little affected when the fruits were picked.

100

BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

executed by parasites has, however, effected a benefit to coffee grow-
ers which has probably already repaid the Territory of Hawaii for
all money expended in parasite introduction, since the parasites, by
greatly reducing the abundance of adult flies, have postponed the
infestation of the pulp until the cherries have become quite well
ripened, at which stage little loss to the coffee results.

TaBLE XXVIII. —Percentage of parasitism among larvx of the Mediterranean Jruit fly
developing in host fruits during November, 1915-February, 1916.”

Locality. Host fruit.
Hilo, Hawaii:
Biman Streetic.) ego ee Cofiee? 54
ee eee oa ere aioe Wing kamani
Hilo Hotel Bee ree a cae Se OffeOc. seer
BT VOe MAL GS Fee ie Hae see oan dow eae
Boarding Schoolsees-cesee4|e=o-5 GOES S35 ee
Kona, Hawaii:
Keqlakektaesss 2 sea eee GOs eee
VEGETA YEN ODES mee ae ee Sa ea e GOs ee
FON AUN AU Se oe see eee eee G0 ..223222055%
Honolulu:
1560 Beretania Street.....-.- oquate <2: 3222
1 OXOR SE Sane nee Fanae coe lesen do Bee netu ne
DOSS sR eee ENR Bae es se
Neila le ae eee Ae eee oe Ball eaAAL.
Ohnatbanesss2 ae ae ee OSs ea
Aaa a awe Sie ee ea er COs ees
Ohwaanes ses. Asse se alee dose
Queens Hospital....-....-- C. oliviforme .
DE) Oe Tae Re OE SNE don ee!
TD Oi 3 See Rese eee Pas Oe
J Bo ep Ente Fe eae YS ep Ae | a doar:
DO sere ce ee ua ee M. elengi...-...-
STD ORG ES eee ia ad | pees GOMeSeee ae
1D oS Senay eae Sh ra a ae GOs he es
1814 Ahuula Street......... Bunchosia......
Punahoulstreet ose Chinese orange. .
Wilder and ‘Thurston |..... GO 2s acne
Streets.
DOS ee ea eee eee Os eee
Wilder and _ Pensacola |....- Ole Saoaee ene
Streets.
Upper Pauoa Valley ......-|..... Chose eaatscee
Wilder and Keeamaku |..... donee ees
Streets.
Sty MatysMissione ses se eee aeae COLON aaa Ae yee
IZ BYG) NAOH SUK nce coconecllossas dose. ea
HNOSHVANO ee asses Cl EESs Vetoes

Makikiand Lunalilo Streets}..... do

Hunalilosbomeseenen sacs eae (Laan ee
1571 Makiki Street......... Coffee: 3 ess
1752 USO) SULCCl= sete gases | seer Ck atsee esos
Beaty, Paulos Valleyeese espe. do ERS Se

Lyn ha ene ar i Wy HCO Oi Bo case
eer Manoa Valley....-..|--.-- dopises. it here
2030 Nuuanu Street.......-}..-.-- GOs eee
PauoavValloyetiessesceecee tence GO es ae

Date of larval
emergence.

Nov. 18-22, 1915.

-| Nov. 20-25, 1915 -

Nov. 19-22,1915 -
Nov. 18-22, 1915 .
Nov. 20-29, 1915 .

Dec. 1-5,1915.,--

(Dec, 3-4,1915..-.

Dec. 4-6,1915....
Dec. 2-3,1915...-

Dec. 15-20, 1915..
Dec. 21-24,1915..
Jan. 3-7,1916. ...

-| Dec. 20-27, 1915...

Dec. 22-31,1915-.
Dec.29,Jan.1,1916
Jan. 4-14, 1916...

-| Jan.25, Feb. 2 1916

Jan. 27, Feb.4, 1916

Jan.29, Feb. 9,1916 1,954

Feb. 4-18, 1916. - .

Jan.29-Feb.9,1916]1, 543

Feb. 4-18, 1916. .
Feb. 7-18, 1916...
Nov. 24-29, 1915 .
Jan. 1-10, 1916.
Dec. 17-22, 1915..

Dec. 22-31,1915..
Dec. 22-27, 1915...

{en 17-20, 1916. -

Jan. 20-24, 1916. -
Dec. 17-20,1915-..

Dec. 16-24,1915..
Dec. 13-16, 1915...
Dec. 9-20, 1915 ..
Dec. 8-13, 1915...
Nov. 26-29, 1915 .
Nov. 29, Dec. iis
1915.
Dec. 1-6,1915....
Nov. 29, Dec. 1,
1915.
Dec. 8-13,1915...
Dec. 8-10,1915-...
Dee. 13-16,1915..
Dec. 9-13, 1915...
Dee..11-13,1915..
Jan, 1-3,1916.-..

Percentage of parasitism.

Total number pups
yielding adults or
parasites.

Opius humilis.

Diachasma

tryoni.

Diachasma
fullawayi.

Tetrastichus:

giffardianus.

oo)

60

NIDON CDOSCCS
No

Cibo bo bo

,. NSSCCOUNSCS NKKE

MSS) SSS)

Ore et

, eoooo coco cooo

Nm, COOMOS SOOO WO
CO Or

818

Nao

eee

870

eR OLrOorsI > bo

-|1,194
alt 998
45
321
14

286
45

162
817
143

316
5)
182
59
4
43

oo

(J)
=
Sore te

no
Taas
ow
bo 0
iw)

—

—
—
Latin fe)

—_

Se ee MS)
NT OH BORE AWRROOM

“ID

Soo .co) J ooo

ve} on
ocoooooco oOo
we OT oo
~I
—~
Moron oS
ho le9)

oa ahwso,
nowy

© 00 GO STF CO i)
io)

w
SO al GS

Tea ea

eco, Se Seo SeorSeSsSo Foo Sof SeSSCSCSCSCSCSCCS,
woo ost

—
S
COR WNTOTOr bo =)

1 The losses to coffee growers due to excessive fruit-fly attack have been discussed on p. 34.
2 Braces are used only when denoting the same lot of fruit.

Ow Ae ONE aARoORPONON

Te ee nt ee ee ey

ae) Loe

Pea a ae

re en Me

.

5 OTS oo ee -* -

Se ee eee ee Oy ee

MEDITERRANEAN FRUIT FLY IN HAWAII. 101

While it seems evident that the favored host fruits of C. capitata
will always be well infested if present cultural conditions persist, it is
hoped that the value of the parasites may be sufficiently enhanced to
free from attack such fruits as the avocado pear, which at present is
infested just at the stage at which it becomes fit for harvesting.

The general effectiveness of parasite control will be increased

with the discovery and introduction of a suitable egg parasite.

ARTIFICIAL CONTROL.

The only method employed at the present time in Hawaii satis-
factorily to protect fruits from attack of the Mediterranean fruit fly
is the covering of the fruits while they are still too green to be affected.
The value of the use of cold storage as a method of rendering fruits
already harvested free from danger as carriers of the pest has been
demonstrated, but cold storage, of course, can have no bearing on the
activities of the fruit fly in the orchard. No satisfactory substance
has yet been discovered for trapping adult females, and the killing
of adults of both sexes by poison sprays is not a feasible method of
control in Hawaii under present cultural conditions any more than is
the destruction of the immature stages by the burial, submergence,
burning, or boiling of the infested host fruits. The exceptional con-
ditions found in Hawaii make impracticable at the present time the
application of any of these field methods of control, except that of
covering the young fruit, notwithstanding the fact that the value of
these control measures when they can be consistently, intelligently,
and universally applied, has been demonstrated. |

PROTECTIVE COVERINGS.

The only certain method now known of protecting fruits from attack
by the Mediterranean fruit fly is to cover them when still quite young
with some type of covering through which the female will not deposit
eggs. During 1898 Fuller reports that about 22,000 running yards
of mosquito netting were imported into South Africa for use in
covering trees to protect the fruit from fruit-fly attack. The cloth
was sewed into bags sufficiently large to be slipped over the trees and
tied about the trunk. This method has been employed by the writers
in protecting ripening peaches. Care must be taken, in Hawaii at
least, to place the bags over the trees when the fruits are very small
or early infestations will have already occurred which, after the cover-
ings have been placed, will produce generations of adults that will
result in the infestation of the entire crop beneath the covering.

Covering the entire tree is too expensive to be followed out on a

_ large scale, and entirely impractical with large trees or in windy areas.

Protecting fruits with individual coverings made of cloth or paper is

more popular in Hawaii. Fruits inclosed in paper bags are well

102 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

and cheaply protected. Coverings of cheese-cloth are often matted
against the fruit by rains, thus making it possible for the female fly
to oviposit in the fruit. The practice of covering mangoes with paper
bags will afford pr otection to certain scale insects and permit them to
develop and ruin the fruit.

Frequently all the fruits on a tree may pee seen inclosed in paper
bags. While this method of covering each fruit gives protection from
the fruit fly, it involves much labor and patience and its practicability

owner. So severe is fruit-fly attack in Hawaii that this method, in
some one of its many modified forms, is the only peuaae Re if fruits are
to be brought to maturity aminfested?

CLEAN CULTURE.

Clean culture in its broadest sense includes not only the detection,
collection, and destruction of all infested fruits but also the elimination

can only be determined by the value placed upon the fruit by the —

a

of useless or unnecessary host trees or shrubs. In some one or all of

its phases it has been recommended and practiced in every country

where the fruit fly is a pest, and in each one of these countries the |

lethargy displayed by a majority of the people, no matter how much
they have regretted their losses, has rendered the clean cultural
methods inefficient. The effectiveness of clean culture depends upon
many factors, of which cooperation among property owners, honesty
on the part of inspectors, climatic and host relationships, the to-
pography of the country, and a thorough knowledge of host fruits
on the part of the director are the most important. Clean culture
in the Bermudas, where conditions are exceptionally favorable for
stamping out the pest, was rendered less effective, up to 1914, be-
cause there was lacking a thorough knowledge of the complete list
of host fruits subject to infestation. The fruit fly has been stamped
out at Blenheim, Napiers, and Davenport, New Zealand, and at
Launceston, Tasmania, by the application of such clean. cultural
methods as the destruction of the fruits and the treatment of the soil
beneath the trees with kerosene immediately after the discovery of
the pest. The only other recorded instance of success attained as a
direct result of clean cultural methods is that of the orange growers
of the Blackall Range, in Queensland, Australia. These growers held
a council and voted to grub out every kind of fruit tree except the
orange, which was their staple crop. As a result of this drastic
remedy the fly had nothing in which to breed during nine months of
the year in this section, and therefore ceased to be a pest.

The clean-culture campaign instituted by the Hawaiian Board of
Agriculture during the fall of 1911 and continued by the Federal
Bureau of Entomology from October, 1912, until April, 1914, was
unsuccessful from its inception, since it did not protect the fruit

MEDITERRANEAN FRUIT FLY IN HAWAII. 103

from attack. The main factors contributing to failure were lack
of adequate police powers, adverse host and climatic conditions,
and the absence, at that time, of any commercially grown orchard crop
worth protecting. The impracticability of control by the clean-culture
method was recognized by Mr. C. L. Marlatt, who, as a Federal rep-
resentative immediately in charge of the Hawaiian investigations,
was in personal touch with the problem during September, 1912. It
was felt, however, that inadequate as this method had proved itself
after a nine months’ trial from the standpoimt of alleviating the
Hawaiian situation, it seemed still to offer the best-known way of
safeeuarding the interests of mainland fruit growers. Therefore, for
the purpose of lessening the opportunities-of spread to the coast, the
destruction of fruits which could be carried on board ships was con-
tinued. It was not until after representatives of California,! Hawaii,
and the Federal bureau had reached the conclusion that no benefit
was accruing either to the local or to the mainland interests that the
campaign was discontinued.

It is doubtful if ever a clean-culture campaign against the Mediter-
ranean fruit fly was organized so efficiently or on so large a scale as
that organized by Mr. W. M. Giffard of the Hawaiian Board, to include
the city of Honolulu. That this method should prove a failure under
Hawaiian conditions is no reflection upon the ability of those in charge
of the work. Inspectors were prohibited from gathering and destroy-
ing fruits unless they could first ptove to the satisfaction of the prop-
erty holder that each fruit was infested, and this restriction upon the
activities of the inspectors naturally led to numerous difficulties,
particularly with the poorer and uneducated classes who often ex-
erted every effort to save their fruit. This restriction also prevented
a systematic gathering of all host fruits within a given area, but
necessitated many examinations for the removal, on ripening, of the
fruits of each individual tree. As fruits ripen rapidly in the semi-
tropics, it proved a physical impossibility to arrange visits by the
inspectors frequently enough to prevent infested fruits from falling
to the ground.

The data of Tables IIT to V illustrate the immense number of host
trees and shrubs available for infestation in Honolulu, and the ease
with which the fruit fly, uncurbed by climatic conditions, may find
fruit for oviposition during any day of the year. A glance at Plates
IV, VI, XII, and XIX will convince one of the absurdity of endeay-
oring to remove all the fruits from many of the huge host trees of
the islands. The writers know of many winged kamani trees, beneath
which infested nuts may be gathered each week of the year, so tall

1 Report of Investigation of the Fruit-fiy situation in the Territory of Hawaii, F. Maskew. Monthly Bul.

Cal. St. Com. Hort., v. 3, 1914, p. 227-238.
2 W. M. Giffard, Letter of Transmittal to Bulletin No. 3, Haw. Bd. Agr. and For., 1914, p. 7.

104 BULLETIN 536, U. 8. DEPARTMENT OF AGRICULTURE.

and brittle that to remove the fruits before they ripen would be im-
possible. To this example might be added many others in which the
removal of ripening fruit would be equally impracticable.

That the campaign was successful in eliminating the bulk of the
fruit ripening in Honolulu during the greater part of the year is evi-
denced by the inability of the Hawaiian Board to obtain any large
amount for their experimental work with parasites during the period
the campaign was in progress. Excepting May, June, and early
July, it was not an impossibility to gather the bulk of fruits ripening
in Honolulu, but during these three months tons of ripening mangoes,
falling continuously, presented a situation that could not be success-
fully combated. (See Pls. XII and XIII.) While tons of mangoes
were carried daily to the incinerator or the city dumps, except from
the standpoint of city sanitation nothing of value was accomplished.

Notwithstanding the fact that the bulk of the ripening and infested
fruits were collected and fruit-fly conditions were unquestionably im-
proved from thestandpoint of the numerical abundance of adult flies,
the important fact remains that the number of fruit flies that suc-
ceeded in reaching maturity was sufficiently large to infest practi-
cally every fruit ripening within the city. Kerosene traps placed
throughout one of the cleanest sections of the city captured large
numbers of flies as proved by recorded data on file both with the
Hawaiian Board and this bureau. (See Table XXI, p. 76.)

So far as the writers know, there is no way in which clean culture
can be made effective in Hawaii under present conditions. There
are no impelling incentives. The islands are thoroughly overrun
with the fruit fly, and this applies quite as much to the guava scrubs
in pastures (PI. IT), on lava flows, and in mountain valleys and ra-
vines as within the city limits. By far the larger proportion of host
trees and shrubs are grown more for protection from the semitropic
heat and for their ornamental value than for their fruits (Pl. V1).
Large numbers of the host fruits are not edible. The destruction of
host vegetation is out of the question until it can be proved that some
advantage worth while can be gained. To cut down all host trees
of Honolulu at the present time would be to remove a large percentage
of her prized vegetation without giving her citizens adequate com-
pensation.

ELIMINATION OF HOST TREES.

It has been stated under a discussion of clean-culture methods
that the elimination of host trees and shrubs in Hawaii is impracti-
cable at the present time. Should the Mediterranean fruit fly ever
become established in California or the Southern States, wherein there
is no such wealth of host fruits and where climatic conditions would
assist in control, the elimination of host trees other than the orchard
cultures to be protected would play a most valuable part in control

MEDITERRANEAN FRUIT FLY IN HAWAII. 105

measures. Dr. Trabut found that in Algeria the infestation of oranges
greatly increased after the introduction of such crops as peaches and

_ persimmons, since these fruits furnished food for the fly during the

summer and early fall months, which for the fruit fly had been starva-
tion months previous to the cultivation of these fruits. Aided by
these introduced summer crops, the fruit fly was able greatly to
increase, so that when the orange crop began to ripen during the

_ fall and winter months, the pest could attack it with increased force.

The elimination of a comparatively few host trees, numerically speak-
ing, in Bermuda would mean the elimination of breeding places over
considerable areas. The destruction of unnecessary and valueless
host trees serves to restrict the breeding ground, as well as to destroy
the sequence of ripening hosts so that many adult flies will die while
attempting to bridge the ensuing starvation periods, during which
no host fruits can be found for oviposition.

SPRAYING.

It has been demonstrated that the Mediterranean fruit fly must
feed for about four days after emergence in the warmer months
before the females are capable of ovipositing in fruits. This feed-
ing period may be extended to 10 days during winter in littoral
Hawaii. Although the interval between emergence and oviposition
is short, it offers the best opportunity to kill this pest by means of
poisoned baits or sprays. Mally, in South Africa, first appreciated
the vulnerability of this point in the life cycle and developed and
demonstrated the value of poison sprays as a factor in the control of
the Mediterranean fruit fly. Berlese, in Italy, however, working
quite as independently, carried out similar experiments to check the
olive fly (Dacus oleae). Equal credit is due Mally and Berlese for
the use of poison sprays in combating fruit flies.

The results of the experimental work of Mally during 1904-5 and
of Dewar during 1915 were not successful, although encouraging.

The later work of Mally during 1908-9 proved conclusively the value

of poison sprays under South African conditions. Mally states that
“a severe outbreak of the pest in a commercial peach orchard was

- brought to a sudden and practically complete halt, and the fruit

maturing later was marked under the guarantee of freedom from
maggots,” while the infestation among fruits on check trees increased
until practically all fruits had become infested. These experiments
lead Mally to state that Ceratitis capitata can be controlled most
perfectly under orchard conditions by means of alight sprinkling of a
poisoned sweet over the trees just before or during the ripening
period of the fruit. In 1912 Lounsbury demonstrated the applica-
bility of the poison spray under town conditions in South Africa during
‘most unfavorable weather conditions, and concluded that if spray-

106 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

ing is properly done this remedy is applicable under town conditions,
even where the summer rainfall may be heavy.

In Western Australia Newman carried on spraying experiments —

during a 53-months period (December 5, 1913, to May 25, 1914)
when the fruit fly was most destructive. From the orchard at
Crawly Park, in which he experimented, little or no sound fruit,

+,

other than grapes, had been picked for several years. The extreme —
dryness of the Western Australia summer, during which little or no —

rain or dew falls, affords an especially opportune time for making
the best use of poison sprays. Newman estimated the cost of spray-

i

ing an acre, where an application of one pint of spray was made —
every 12 to 14 days, to be from $1.50 to $2 per fortnight, and stated —
| that this sum was a mere bagatelle to the loss of fruit during a similar —
period over a like area. His work convinced Newman that good —

results will follow the consistent application of poison sprays, par-

ticularly when supplemented by the proper destruction of infested —

fruits.

In the Hawaiian Islarfds there are no real orchards in which |

spraying experiments can be conducted under commercial conditions.

Severin states that while he captured in 10 kerosene traps, hung —
among 400 trees, 10,239 flies during a 5-weeks period before starting —

spraying work, in the following 5 weeks, during which these trees

were sprayed about once a week, the same traps caught only 182 —
flies, and of these 93 were caught during the first 6 days after the ©
first application of spray. Inasmuch as the orchard in question is —
composed of small citrus trees interplanted with peach and con- —

tains a few strawberry-guava, fig, Chinese-orange and rose-apple
trees, and is surrounded on one side by wild guava scrub, it is unfor-
tunate that no data were given on the time of the year the spraying
was done or on the eonriion of the host es in and about so
small an orchard.

The conclusions of Weinland following his spraying experiments —

conducted during 1912 in dooryards of Honolulu are misleading.

He used the data from 7 traps as a basis for his favorable report; —
had he used the data from 10 other traps in the same series of his —
experiments which are on file with the Hawaiian Board of Agri- —
culture and Forestry he could have shown that on the whole his |

experiments were not successful, and that in several instances he
caught more flies after spraying than before. The writers have

demonstrated from an immense amount of data on the number of —

flies caught in single traps throughout a given year that even when
no spraying is done there may be a sufficient falling off in the num-
bers of fruit flies captured to mislead one into thinking that the
trees had been sprayed.

a

MEDITERRANEAN FRUIT FLY IN HAWATI, 107

The only test of poison sprays made by the writers was in an
attempt to control the Mediterranean fruit fly under adverse town con-
ditions such as have been described on page 11. The city block in
Honolulu bounded by Punahou, Beretania, Wilder, and Makiki
Streets was sprayed every 2 or 3 days from July 17 to August 28,
1913. The adjoining blocks to the southeast were held as a check
and the number of flies captured in 145 traps in the sprayed area
and in 147 traps in the check area constituted the basis for deter-
mining the benefits of the poison spray. Knapsack sprayers only
were used, and while all trees and shrubs received spray, none were
sprayed more than 9 feet above ground. The average number of
flies caught daily each week is recorded in Table XXIX.

TABLE XXIX.—Number of Mediterranean fruat flies caught in 145 and 147 traps hung
an sprayed and unsprayed areas, respectively; spraying begun July 17, ended Aug. 28,
1913. =

Average number of Average number of
flies caught each day flies caught each day
during week ending. during week ending.

Date. Date.
Sprayed | Unsprayed Sprayed | Unsprayed
area. area. | area. area.
Be BS 2 oe ES ig geet tn 1,191 UEDSPF NW AOS ORF OSs Fe ae es A ae 215.8 561.8
Diliyal Dee aes eo oe seme 881.4 (PPE WW INURE A oes eaaeeuseeesaee 111.1 439
Sumliy; HO Co. Soa ie 936 169.4 | SeptiGassass 2 he 222 ou 102.7 315.5
uliyZ26 sane eee eee 541.2 (OUI oA SE) Dipl Boseaeeeesoe ss oaekee (a2, 219.1
INDO Ss Seer Re Be be 472.5 904F SEIES@ Dt 20s2: 2 tas eects 76.5 151.8
PAW Obey Biss oie ops ise etn 383. 8 937 Sept27cpe eae. oa. Gaeee 90 141.2
YNWDVES QMO} HOSA Bs tak ie ie A 269. 4 762.8

The data show that. the number of flies caught in the sprayed area
was greatly reduced by the spraying. ‘The reduction in flies was not
ereat enough, however, to save fruit of any host ripening from becom-
ing badly infested. Similar experiments conducted during May and
June, 1914, in an attempt to protect peaches ripening in town door-
yards were failures. Of several thousand fruits only three reached
maturity uninfested.

The composition of the poisoned-bait spray used against the Mediter-
ranean fruit fly consists of some poison, a sweet substance attractive
to the adults, and water. Mally in 1909 used the following formula:
Sugar, 3 pounds; arsenate of lead, 4 ounces; water, 5 gallons. He
found that from 1 to 14 pints were sufficient for the average 10-year-
old peach or nectarine tree. Lounsbury in his town demonstration
work used a spray consisting of 6 pounds brown sugar, 6 ounces
arsenate of lead paste, and 8 gallons water. Weinland used a spray
of 34 pounds lead arsenate paste, 10 pounds brown sugar, 5 gallons
plantation molasses, and 50 gallons water. Severin used the Mally
formula, but increased the lead arsenate from 3 to 5 ounces. The
writers used the formula of Weinland.

108 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

The writers believe that poisoned-bait sprays if carefully applied
under such commercial conditions as exist in California and Florida
would prove successful. Their observations indicate that honeybees
are in no way affected by these sprays. It is doubtful, however, if
poisoned-bait sprays will ever be practical under present-day cultural
conditions in Hawaii, where no fruit crop is grown commercially,
where the majority of host fruits are either inedible or not worth the
cost of spraying, and where sources of reinfestation from without are
sogreat. The entire subject of control byspraying with poisoned baits
is still open for investigation under varying conditions.

COLD STORAGE.

A discussion of the use to which cold-storage temperatures may be
put as an aid in offsetting the disastrous results of attack by the Med-
iterranean fruit fly was published by the writers? in 1916. The
experimental work was undertaken primarily with the hope that it
would be an aid in solving the discouraging problems of local horti-
culturists. But whatever its value in this direction, it now appears
that the results may be of much greater commercial importance in
defining the conditions under which cold-storage temperatures will
kill the fruit fly in stored fruits, thus rendering them free from danger
as transporters of this pest from one country to another, or even from
one infested district to another. It seems reasonable to conclude
that sooner or later the certification of properly refrigerated fruit will
be practicable. When an association of fruit growers or a community
awakens to a realization of the financial value of the cold-storage
treatment there is reason to believe it will result in the operation of
central refrigeration plants under the supervision of officials whose
guarantee will insure that all fruits sent out from the plant are abso-
lutely free from danger as carriers of the Mediterranean fruit fly.

Experimental work in Australia, as an example, has shown that
such perishable fruits as peaches and Japanese plums can be placed on
the European markets in good condition if sent in cold storage, and
such exports have been encouraged under Government guarantees.
While cold storage can never lessen the damage already done by
larve within fruits offered for sale or shipment, and in no way deals
with the root of the trouble, as a palliative, guarding fruits against
further attack while in storage or transit, it may become of imesti-
mable value. Fruits, such as apples, that contain freshly-laid eggs
or very young larve may be placed upon the market, provided
further fruit-fly development is checked by cold storage.

For the details of the effect of cold-storage temperatures upon the
eggs, larve, and pupe of the Mediterranean fruit fly, as well as for

1 Back, E. A., ang Pemberton, C. E., Effect of cold-storage temperatures upon the Mediterranean
fruit fly. Jour. Agr. Research, v. 5, no. 15, 1916, p. 657-666; Back, E. A., and Pemberton, C. E., Effect

_ of cold-storage temperatures upon the pupe of the Mediterranean fruit fly. Jour. Agr. Research, v. 6,
no. 7, 1916, p. 251-260. \

a a we a

OO a

MEDITERRANEAN FRUIT FLY IN HAWAII. 109

historical facts dealing with the use of such temperatures, one should
consult the two articles to which reference has been made. Fruits of
almost any variety commonly placed in cold storage are held at
temperatures varying from 32° to 45° F., with preference shown to a
range of 32° to 36° F. By way of general summary of many experi-
ments, including observations upon over 26,000 eggs, 60,000 larve,
and 173,000 pupe to determine the effect of such temperatures as 32°,
32° to 33°, 33° to 34°, 34° to 36°, 36°, 36° to 40°, 38° to 40°, and 40°
to 45°, it may be said that no stage of the Mediterranean fruit fly can
survive refrigeration for seven weeks at 40° to 45° F.; for three weeks
at 33° to 40° F., or for two weeks at 32° to 33° F.

EFFECT OF FREEZING TEMPERATURES UPON THE EGG, LARVA, AND PUPA.

The only freezing temperatures available in Hawat for experi-
mental work with eggs, larve, and pupe were those found in cold-
storage plants maintaining rooms for the refrigeration of fish and
meat. The temperature of these rooms ranged between 21° and 30° F.
though averaging close to 26° F. Out-of-door freezing tempera-
tures have been experienced by the writers on the Island of Hawaii
at an elevation of over 8,000 feet, but lasted only for a few hours
at a time and occurred on mountain slopes not easily accessible.

THE EGG.

Apples in which fruit-fly eggs had been deposited on November 3, 1914, were
placed in cold storage at a temperature varying from 24° to 30° F. Fruit was re-
moved daily for 10 consecutive days and observations made on a total of 5,434 eggs
contained within them. No eggs survived more than 7 days of refrigeration at this
temperature. Of 507 eggs subjected to 25° F. for one day 414 hatched on removal to
normal temperature; 275 of 308 eggs subjected to 24° to 25° F. for 2 days hatched
after removal; 588 of 741 eggs hatched on removal aiter refrigeration for 3 days at
24° to 26° F.; 430 of 748, 65 of 384, 7 of 534, and 1 of 255 eggs hatched on removal after
refrigeration at 24° to 30° F. for 4, 5, 6, and 7 days, respectively. Allof 606, 624, and
727 eggs removed to normal temperature aiter 8, 9, and 9 days of similar refrigeration
were dead.

In a second experiment carried out during July, 1913, peaches containing eggs
were picked promiscuously in the field, and placed in storage at 26° to 30° F. The
results were similar to those mentioned above, as 42 of 178, 7 of 10, and 20 of 145 eggs
hatched on removal, after refrigeration for 1, 2, and 6 days, respectively; 57, 148, 82,
134, and 14 eggs refrigerated for 7, 9, 10, 11, and 12 days were dead on removal from
storage.

THE LARVA.

First-instar larve.—A total of 2,116 first-instar larvee were placed in cold storage at
21° to 28° F. None survived more than 5 days of refrigeration, and the following
observations were recorded: 62 of 248 larvee in refrigeration for 5 days were found
living on examination after removal to normal temperature; 297 of 340 survived one
day of refrigeration at 22° to 23° F.; 239 of 275 survived two days of refrigeration at
21° to 23° F.: 110 of 243, and 44 of 240 survived refrigeration at 21° to 28° F. for 3 and
4 days, respectively; 264, 132,213, and 141 larve refrigerated for 6, 7,8, and 9 days,
respectively, were dead on removal from storage.

110 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

In a second room, the temperature of which ranged from 26° to 30° F., infested
peaches were placed. An examination of the contained larve after refrigeration gave
results similar to those above; 21, 9, 9, and 19 larvee were found dead after 5, 6, 9, and
12 days of refrigeration, and 336 removed after refrigeration from 13 to 15 days were
dead.

Second-instar larve.—A total of 3,216 second-instar larvee were subjected to freezing
temperatures with the following results: 367 of 377, 77 of 123, and 9 of 195 larvee were
found living on removal to normal temperatures after refrigeration for 1, 2,and 3 days,
respectively, at 21° to 29° F. An average of 361 larvee removed after refrigeration
4,5,6,7,8,9,and 10 days weredead. No living larve were found after the third day
of refrigeration.

Third-instar larve.—Of a total of 6,774 third-instar larve in kamani nuts (Termi-
nalia catappa) subjected to freezing temperatures ranging between 22° and 27° F. for
1 to 9 days, 82 of 157 and 4 of 510 larvee were found alive upon removal aiter refrigera-
tion at 24° to 27° F. for 1 and 3 days, respectively. Only 3 of 524 were alive on
removal after 4 days of refrigeration at 22° to 27° F. An average of 1,221 larve
removed daily between the fifth and ninth days of refrigeration were dead.

After refrigeration at 26° to 30° F. 114, 7, 1, 12, and 124 larvee in peaches were
found dead on removal after 5, 6, 9, 12, and 15 days, respectively, of refrigeration.
Ten badly infested peaches were removed to the laboratory after 3 days of refrigera-
tion and from two of these there later emerged 1 and 9 full-grown larve which pupated
normally and produced adults. No adults were reared from 15 peaches removed
aiter 14 days of refrigeration.

Fourteen peaches held in refrigeration 5 days at 26° to 30° F., then successively for
24 hours each at 33° to 38° F. and 40° to 45° F., were removed to the laboratory. A
total of 36 third-instar larve, found within the fruit, were dead.

THE PUPA.

A total of 21,450 pupz have been subjected to freezing temperatures varying irom
24° to 32° F. and averaging about 26° F. All pupz were fatally injured before the
end of the fourth day of such refrigeration. Three hundred 3-day-old pupz, 100
2-day-old pup, and 200 i-day-old pupz on removal to normal temperature aiter
32 days of refrigeration at about 26° F. produced 1, 1, and 1 adults, respectively.
Under similar conditions only 2 of 100 4-day-old pupz and 3 of 200 3-day-old pupz
produced adults after 3 days of refrigeration. Each lot of pup ranging from 1 to 9
days old and totaling 1,900 individuals yielded from 2 to 22, or a total of 78 adults,
after 2 days of refrigeration. Even 1 day of refrigeration at 26° F. proved fatal toa
large percentage of pupx, especially the younger, as evidenced by data in Table
XXX covering observations on 1,500 pupe.

TABLE XXX.—L ffect of 26° F. upon pupal life. Pupex placed in cold storage Oct. 27,
1914; removed to normal temperature Oct. 28.

Number of adults emerging on—

"| Oct.30. Oct. a1, Nov. 1.| Nov. 2. | Nov.3.| Nov. s| Nov. Nov. 6.| Nov. 7.| Nov. 8.

mb WH Oro 5700 ©
i)
So
Oo

MEDITERRANEAN FRUIT FLY IN HAWAII. a8

During May, 1913, 500, 119, and 331 pupe of all ages were placed in cold storage,
the temperature varying from 22° to 24° F. for 5, 7, and 12 days, respectively. After
removal to normal temperature all pupze were found to be dead. During July, 1913,
2,000 pup of various ages were subjected to a temperature varying from 24° to 30°
F. and averaging about 26° F. for 3 to 16 days; none yielded adults after removal

from storage even after only 3 days of refrigeration. On June 24, 1913, 2,500 pupz
~ removed from storage after one month of refrigeration at about 26° F. were found dead.

Pupe held in refrigeration 4 days at 24° to 30° F. were removed to normal tempera-
ture after being held 2 successive days at 33° to 38° F. and 40° to 45° F., respectively,

but none yielded adults.
TRAPS.

_ The idea of exposing in infested areas a substance that will attract
- both sexes of the Mediterranean fruit fly is an excellent one, and may
lead to the discovery of some medium which will prove an effective
method of control. It was the writers’ idea to simulate, in such a
substance, the odor emanating from the male C. capitata, but the
experiments proved unsuccessful. Severin exposed various oils de-
rived from crude petroleum, but found them ineffective. He also
used, without satisfactory results, turpentine, coconut oil, citronella,
whale and fish oils, vinegar, and vanilla. Hooper in Western Austra-
ha experimented with naphtha and turpentine in 1907 without suc-
cess, and similar results followed the exposure by Gurney in New
South Wales of citronella, linseed, salad, whale, neatsfoot, and fish-
oils. Howlett, in India, was able to attract males of Dacus zonatus
and D. dwversus by exposing citronella oil. Later he believed that
_he had found the actual substances which are responsible for the
attraction of these two species in isoeugenol and methyleugenol.
Three traps containing, in the order mentioned, eugenol, methyl-
eugenol, and isoeugenol hung in orange trees in a badly infested area
of Honolulu captured in 6 days only 2,10, and 1 male C. capitata, as
compared with 77, 153, and 48 males captured in check traps con-
taining kerosene hung within 50 feet of them. These three substances
were furnished the writers by Severin, who had received them in turn
from Howlett.
Much of the experimental work to which reference has just been
_ made represents but a small amount of that undertaken to determine
the effectiveness of traps. It has grown out of the accidental dis-
covery in Australia by a housewife that a coating of kerosene oil, put
_ about a post for the protection of a glass of preserves from ants,
_was attractive to adult C. capitata. This observation led to the
heralding, in 1907, of the use of kerosene as a method of control as
the ‘‘best discovery against the fruit fly in years,’ and to regulations
‘in Western Australia requiring fruit growers to place from one to
__two traps in each fruit tree. It is natural that, entomologists com-
-bating this pest should carry on experiments, but the worthlessness
of kerosene as a factor of control was not demonstrated until a
considerable literature upon the subject had been published.
- Kerosene is ineffective, inasmuch as it attracts for the most part only

112 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

males. Of 2,639 adults, representing four lots examined by the
writers, only eight were females. Only 36 of 10,239 adults captured
by Severin were females. Many thousands of adults captured in
kerosene oil in connection with the present investigations have
demonstrated the worthlessness of kerosene as a factor in reducing
the infestation of fruit.

While the use of kerosene to trap the adults of the Mediterranean
fruit fly is of no value in checking the ravages of this pest, the writers
have made use of the number of males captured in traps to arrive
at conclusions regarding the relative abundance of adults in any
given area. The use of the kerosene trap for this purpose when sup-
plemented by other observations has a value, provided conclusions
are not attempted from too small a number of catches. The writers
have data on file covering the number of flies caught in 292 traps for
16 consecutive months. As a rule traps hung in dense foliage of any
sort captured more flies, while traps hung on porches and set upon
stumps or in other exposed situations from 30 to 80 feet away from
foliage captured only an occasional male. It would seem that in
countries where host trees and shrubs are less abundant than in
Hawaii the number of flies caught could be used as a basis for valuable
deductions on such subjects as seasonal abundance and migrations of

adults.

Description of trap.—The trap used by the writers is a simple affair consisting of an
ordinary pie tin suspended by three tin strips from a tin cone through the top of which
extends a wire by which the entire trap may be suspended from a branch. A trap
can be made cheaply by any tinsmith. If properly painted, traps will last several
seasons. The pan may be removed as often as desired. In Honolulu the oil was
replenished every 2 or 3 days. In dry areas no protective covering for the pan
containing the oil is needed. Oil to cover the bottom of the container to a depth
of one-fourth of an inch is sufficient. The trap should be so long that no oil will spread
to the bark of the tree.

SUBMERGENCE IN WATER.

Submergence of host fruits as a method of control has been recom-
mended many times by writers and investigators of fruit flies.
Harris recommended weighting sacks of infested fruit and sinking
them at sea. Gurney found that larve in sea water in test tubes
pupated at the surface against the glass and that a large percentage of
larvee in oranges submerged in cold water for 6, 8, 24, and 45 hours
survived, pupated, and matured into normally healthy adults, and
concluded that no casual treatment such as throwing infested fruit
into a stream can be considered an effective method of destroying
fruit-fly larve. Severin showed that many well-grown larve found
floating on the top of a barrel of water, into which infested oranges
had been thrown 24 hours previous, resumed activity within several
hours after being placed on moist filter paper, in spite of the fact

MEDITERRANEAN FRUIT FLY IN HAWAII. gates

that they were distended and apparently dead when removed from
the water. A small percentage of other larve taken from the water
after 3 days showed traces of life, but no adults developed from the
fruit submerged for 4 days.

With the temperature ranging between 67° and 80° F. the writers
were able to demonstrate that well-grown larve placed in tightly
stoppered vials of fresh water died by the end of the third day. Thus
486 of 490 larve survived submergence 21 hours, 96 of 100 for 24
hours, and 78 of 100 for 48 hours; two lots of 100 larve each sub- .
merged 70 and 74 hours, respectively, were dead. It was found,
however, that larve live longer when placed in water in open vials.
Under such conditions certain individuals may remain suspended
from the surface film of water much as do mosquito larve and
pupe. This is made possible by the circlet of small hairs about the
posterior stigmal plates. While larve ordinarily become rigid and
apparently dead within 2 or 3 hours after submergence in ,water,
larve thus suspended were found to remain active for as long as 7
days in one instance. One larva removed to fresh fruit after sus-
pension for 5 days pupated 7 days later and emerged as an adult after
9 days in the pupa stage.

TaBLE XXXI.—E fect of submergence of host fruits in water upon the larve of the
Mediterranean fruit fly.

Dead larve. ! |

A Living larve.
Number Nurabep
hours im- Host fruit. Coe
mersed. fred 5 First Second Third First Second Third
me Beh instar. instar. instar. instar. instar. instar.
23 e 4 ‘ MY 64 . it 18
41 2 10: 0 0
7 |fApple.-------------- 6 0 91 32 0 0 0
94 | 8 0 262 107 0 0 0
4 21 0 0 0 0 63 279
22 22 0 0 5 0 113 448
49 23 0 0 88 0 0 ol
72 |}Winged kamani.-... 33 0 0 179 0 0 12
96 253 0 0 1,376 0 0 1
98 | | 21 0 0 142 0 0 0
120 |; 3 0 0 147 0 0 0
i 4 4 36 80 0 0 0 0
24 5 0 9 0 0 8 17
70 |-Rose apple.......... 50 0 0 AT al cate Fee Mr yr ee ten | se OR AS
7. 1 0) 12 0 0 0 0
98 3 0 37 0 0 0 0
i 18 94 0) 123 USO a| soe ee aL 72 97
ge 39 0 “1 163 J 022s.) ee sees 3
79 |{Chinese orange... fee Pe) Oph...) 2 BON Hl oes
94 SOR Seek we serie 57 OS ie eee MA ee en ee ee ae
116 SS Pal Ton eee pee | ey TM So ea pay Ay Veh ate Cahier: tel Ral seamen ) dae EE nk
18 Gas eee ATi 63 OF ee eee 51 168
46 = Ca ue te ea) Pa ee eta Cet haa en ee es BE | Pe pane NS 3
ere a alee 19 65 R 2 TO ME Ree ee
94 | Teall ese ee arena | et Mn ed cl a) | Viper es Gee Al ea Pte | serge SC
49°] =r ANG a | BF a ra 11
72 |eStrawberry guava... BAN es et Co 17 i fel |S eae ata ea SPER es YE oe
96 LOPE ese Paes, Soe ee Soules nora i Un | Seas aA
4 | NE SElENG? = rie aye CN 5 AST NAY TPA AE tots clea an Fen] Capen Be 40 36
7 Delors st 9 fe | EERE SA Re Sie SECIS OOK.
96 | PEO PATIO OBE is MUN li) | li a 14 Bion haicttesey aot oh| Mere tales Cen Den Meera
121 | Sete ee br 9 Pes SSS Sa ee eae Bens aoe W SS :
66 |\ Bek Shs Te Si Ee a A die ed Ne as yl a a st
91 \Peach wes eseceeee eee i AMM Ceam ale aa sw Naga oy me ame RE airy el AO

81340°—18—Bull. 536——8

1li4 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

The examination of various host fruits submerged in ordinary tap
water, when the temperature ranged between 67° and 80° F., gave
the data recorded in Table XXXI. The data indicate that while
larve are little affected after 1 or 2 days of submergence, a large
percentage are dead after submergence for 3 days. Seventeen second-
instar larve and 1 third-instar, however, were found living after
submergence for 4 days. It is safe to conclude that submergence
for 5 days will either kill all larve or incapacitate them for further
development. It might be added that fruits held in water for as long
as 3 to 5 days are, in Hawaii, rendered unfit as food for fruit-fly larve
after removal from water. |

TaBLeE XXXII.—E fect of submergence in tap water upon pupx of the Mediterranean

Sruit fly.
Number | Number Date of Number of | Number of
Lot ofpupe | ofdays Date of anniCe Date of adult jadult Opius| Date of

number. | under ob- im- pupation. removal. |C.capitata| humilis | emergence.

servation. | mersed. ae emerging. | emerging.
650 3 | June 27-28
191 15 | June 29.
PSre 390 1,016 2 | June 14-17 | June 24 | June 26 4 18 | June 30.
SESCAE ANU. A RE Ee SSUES me oA ID ote oP ae fi ee Pe 16 | July 4.
BP? el 1 | July 5.
62 0 | July 1.
7 a Phage eo | 440 Be ae do da.s 2 June 27 16 3 | July 2.
1 17] duly 3:
| 4 0 | July i.
So Re aoe 312 1 | Ae do.. ER GOxtHa: June 28 3 0 | July 2.
0 1] Jaly:4:
Ae aad TEL Ee 410 i es ae: do.. adonsic: June 29 0 0
Habs ee 258 Oh eee do. EGOweee June 30 1 0 | July 7.
Gr 214 ‘ial eases Gees dor July 1 0 0
32 0 | June 29,
207 5 | June 30.
190 7 | Julyl
(foe, Ber 950 2| June 17-22 |...do..... June 26 156 18 | July3
39 8 | July 4
6 0 | July5
18 2 | July 6
64 0 | July i
Ais eee eae he July 3
Sees. 460 3 |...--d0..22-.|...do.2..-| Tune 27 inl ee eee ete
9 1 | July6
Bl eee el See July 9
1 eters ee July 1
253a|L eee eee July 3
23 3 | July 4
OR aes 210 a Goss |-eaOOseeee June 28 9 2 | July 5
es ick 5 eee July 6
19 1! July7
1 1 | July8
IX) Mes OE EE Bo July 3
LOS eee aero July 4
1! a ee ee July 5
(eee eoeaee 557 5H bashes doll ess. donee June 29 42 josie uses July 6
1S) Joes. Soke July 7
Dd: | eee ae ae July 8
Gp) betes 2 Sener oe. 2 July 9
US | Deer eeeeeie se July 7
[iy alc 372 oye dol ge dor." June 30 Naina “ae ae ee
| SI. See July 12.
i: Sees | 476 Cs ee do down. July 1 0
|
Total....| 5, 675 |

Pupe from 1 to 4 days old were submerged in vials of tap water
when the temperature ranged from 72° to 85° F. A record of the

MEDITERRANEAN FRUIT FLY IN HAWAII, TES

emergence from these pupe is given in Table XXXII. The data
covering lots 1 to 6 show that the more mature pupx succumbed to —
immersion more quickly than the younger pup of lots 7 to 12. Thus
many of the young pup emerged as adults after being submerged
4, 5, and 6 days, while submergence for these periods killed nearly
all the older pup. Submergence for at least 7 days is necessary to
assure the death of all pupe.

BURIAL IN SOIL.

Many entomologists have made statements regarding the efficacy
of burying infested fruits in the soil as a method of destroying fruit
flies. These references have been summarized by Severin, hence
need not be considered at length here, particularly as they deal with
a method that is decidedly unsatisfactory and seldom effective.
Gurney found that pupe buried 6, 8, and 12 inches below the surface
of the soil produced adults that were able to escape. Severin found
that adults could make their way to the surface from pupz buried
2,3, and 4 feet beneath dry sand, and from pupz buried 2 feet beneath
wet sand, but that no adults escaped through 2, 3, or 4 feet of dry
soul. Mally found that 10 inches of soil shoveled loosely over fruits
did not prevent adults from escaping later, but that no adults could
reach the surface through 10 inches of well-tamped soil. No adults
escaped from 20 pupz placed in the center of a cake of mud one-half
inch square taken from the heavy, tenacious soil of the vegetable
gardens at Waikiki. The mud became thoroughly dry without
cracks before the end of the normal pupa stage. A cake of the same
soil 14 inches square, however, on drying developed a crack through
which 50 adults made their escape from 75 pupe buried within the
center of the square. While adults can not make their way through
a foot of well-tamped soil, it is difficult to bury host fruits in such a
manner that the soil covering will remain firm. The rapid decay and
settling of fruit, if any amount be buried in the same excavation,
cause cracks to develop through which adults can escape readily.
While many fruit flies can be killed by proper burial, indifference and
carelessness among workmen will always make possible the escape

of many adults.
BURNING AND BOILING HOST FRUITS.

Burning or boiling host fruits is a sure method of destroying the
immature stages of the Mediterranean fruit fly provided the work
is feasible and can be done thoroughly. The usual practice of throw-
ing fallen infested fruits into a compost pit and burning over them
every few days such trash as may have accumulated is not a trust-
worthy method of destruction, inasmuch as the heat produced is
very often insufficient to cook or burn the fruit thoroughly or to reach
the pup in the soil beneath the fruit.

116 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.
SUMMARY.

The Mediterranean fruit fly (Ceratitis capitata) was discovered at
Honolulu in the Hawaiian Islands in 1910. Since that time it has
spread to all the islands of the Hawaiian group, and because of the
equable climate and abundance of host fruits, has effected a serious
and permanent check to horticultural pursuits, and put an end to all
export trade in fruits except that in bananas and pineapples.

Research seems to have fixed the native home of C. capitata in
tropical Africa. Its spread has been slow but persistent throughout
tropical and semitropical countries, until at the present time it is
known to have become a pest in every continental area except that
of North America. With the Mediterranean frmt fly now well
established in Bermuda and the Hawaiian Islands, it would seem that
it is only a matter of time before it will be inadvertently introduced
and become established in California and the Southern States. The
frequent interception and destruction of infested fruits from Hawaii
at California ports, by officers of the Federal Horticultural Board,
indicates the ease with which the mtroduction of the Mediterranean
fruit fly might occur were Hawaian fruit permitted unrestricted
entry to the mainland of the United States.

No edible fruit in Hawaii, except the pmeapple, escapes attack.
The banana, when in good condition, is never infested, infestation
having been noted only when the fruits were overripe or injured.
The Mediterranean fruit fly has been reared in Honolulu from 72
species of host fruits, including the peach, plum, pear, guava, mango,
orange, lemon, grapefruit, banana, etc. A large proportion of the
host fruits are inedible. Throughout the littoral regions a continu-
ous cycle of host fruits is available for infestation throughout the
year; hence there are no starvation periods for the fly to survive.

With such a quantity and variety of host fruits, nuts, and vege-
tables in which to propagate, and enjoyimg an ideal climate, the
mean temperatures of which vary between 68° and 79° F. for the
regions in which the fly is a most serious pest, the Mediterranean
fruit fly finds no check to its rapid increase. While a single genera-
tion may require as few as 17 days during the warmest weather,
there are usually 15 to 16 generations a year at Honolulu, and 10 to
12 generations in areas where the winter mean drops to 68° F. There
is considerable variation in the length of the immature stages, par-
ticularly during the coolest weather. Inasmuch as adults have been
kept alive for 10 months and may deposit eggs in lots of a few to 32
daily quite regularly throughout life, the generations become hope-
lessly confused. While adults are not forced in Hawaii to pass
through periods of several months when food is not available for
oviposition, females deprived of host fruits for such periods will
resume active and normal oviposition when the fruits become avail-

MEDITERRANEAN FRUIT FLY IN HAWAIL 117

able. One female deposited 622 eggs between June 4 and September
2. The long adult life, and the ability of the female to deposit eggs
regularly succeeding the period of from 4 to 8 days after emergence
which is required to complete sexual maturity, make it possible for
the annual progeny of a single pair of adults to reach enormous
numbers.

Attempts at control by clean culture have been failures, owing
largely to msurmountable obstacles placed in the way of man by a
favorable climate and an unprecedented quantity of varied host
fruits. Many fruits and nuts subject to attack grow on huge trees
which blossom irregularly, and produce, in many instances, fruit
susceptible to attack throughout the year. There is no procedure
by which clean culture may be made effective under the present
Hawaiian cultural methods. The islands are thoroughly overrun
with the fruit fly, and this applies quite as much to the wild guava
scrub in pastures, on lava flows, and in mountain valleys and ravines,
as it does within the city limits. By far the larger number of host
trees and shrubs aie grown more for the protection they offer from the
semitropical sun and for their ornamental value than for their
inedible fruits. The destruction of host vegetation will not be
practicable until it can be demonstrated that a distinct advantage
would be gained thereby. To destroy all host trees of Honolulu at
the present time would be to remove a large percentage of her prized
vegetation without any compensating returns.

The ideal chmatic and host conditions of Hawau have rendered
less effective and impracticable the usual artificial methods of con-
trol the value of which has been demonstrated in other countries pos-
sessing natural features less favorable to fruit-fly increase. At the
present time the only hope of relief lies in the establishment of para-
sites. Six parasites have been introduced during the past three
years and are now well established. While they have more than
repaid the Territory of Hawaii for the cost of their introduction by
bringing about an improved condition in the coffee-growing industry,
it is doubtful whether they will effect a sufficient decrease in the
proportion of infested host fruits to be considered efficient factors
in control. This conclusion appears inevitable in spite of the remark-
able success attendant on their introduction, unless a campaign is
inaugurated for a reapportionment of host fruits; otherwise the hordes
of adult flies maturing in thick-meated fruits, or in fruits protecting
larve by other means from attack by parasites, will neutralize the
effective work of parasites attacking larve in thin-skinned and thin-
pulped fruits. There is great need of an effective egg parasite that
will kill the fruit fly before the larva can do injury.

From a practical or commercial standpoint the results of the inves-
tigations reported herewith are of value (1) in furnishing data to

118 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE.

determine the probable range of this pest should it be introduced and
gain a foothold in continental United States; (2) in verifying the
practicability of poison sprays; (3) in indicating the utilization of
cold-storage temperatures in making safe the movement of fruits
from areas which might otherwise be cut off by quarantines from
outside markets; and (4) in placing upon a sound basis the banana
and pineapple export trade of the Hawanan Islands.

At 50° F. little if any development takes place, and freezing tem-
peratures can be withstood successfully only for short periods. Ac-
cumulated data indicate that the Mediterranean fruit fly will not
become a serious pest in climates where the mean temperature is
below 50° F. during periods covering three months of the year.

While Hawaiian conditions are unfavorable to the use of poison
sprays, the work of the writers has convinced them that these sprays
can be employed as successfully in combating this pest in commercial
orchards of California and of Southern States, should they ever
become infested, as in Africa and Australia.

While at present cold storage is not utilized to modify existing
quarantine, it is a recognized fact that, commercially used, it has
been of value in safeguarding fruits from additional infestation while
en route over long distances. The data set forth herewith indicate
for the first time the duration of time required for various tempera-
ture ranges to kill the stages of the fruit fly within stored fruits, and
from these records it is reasonable to conclude that the certification
of properly refrigerated fruit is practicable. When an association of
fruit growers or the people discover that refrigeration is financially
worth while, there is reason to believe that it will result in the opera-
tion of central refrigeration plants under the supervision of officers
whose guarantee will insure that all fruits sent out from the plant are
absolutely free from danger as carriers of the Mediterranean fruit fly.

PUBLICATIONS OF THE UNITED STATES DEPARTMENT OF AGRICUL-
TURE RELATING TO INSECTS INJURIOUS TO CITRUS AND OTHER
SUBTROPICAL FRUITS.

AVAILABLE FOR FREE DISTRIBUTION BY THE DEPARTMENT.

Scale Insects and Mites on Citrus Trees. (Farmers’ Bulletin 172.)

Control of the Citrus Thrips in California and Arizona. (Farmers’ Bulletin 674.)

Carbon Disulphid as an Insecticide. (Farmers’ Bulletin 799.)

Citrus Mealybug and its Control in California. (Farmers’ Bulletin 862.)

Citrus Fruit Insects in Mediterranean Countries. (Department Bulletin 134.)

The Mediterranean Fruit Fly in Bermuda. (Department Bulletin 161.)

Katydids Injurious to Oranges in California. (Department Bulletin 256.)

Argentine Ant: Distribution and Control in the United States. (Department Bulletin
377.)

Fumigation of Ornamental Greenhouse Plants with Hydrocyanic-acid Gas. (Depart-
ment Bulletin 513.)

Spraying for White Flies in Florida. (Entomology Circular 168.)

FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS, GOVERNMENT PRINTING
OFFICE, WASHINGTON, D. C.

The Melon Fly in Hawaii. (Department Bulletin 491.) Price, 25 cents.

Preparations for Winter Fumigation for Citrus White Fly. (Entomology Circular 111.)
Price, 5 cents.

Mango Weevil. (Entomology Circular 141.) Price, 5 cents.

Mediterranean Fruit Fly. (Entomology Circular 160.) Price, 5 cents.

Fumigation for Citrus White Fly, as Adapted to Florida Conditions. (Entomology
Bulletin 76.) Price, 15 cents.

Fumigation Investigations in California. (Entomology Bulletin 79.) Price, 15 cents.

Hydrocyanic-acid Gas Fumigation in California. (Entomology Bulletin 90, 3 pts.)
Price, 20 cents.

Fumigation of Citrus Trees. (Entomology Bulletin 90, pt. I.) Price, 20 cents.

Value of Sodium Cyanid for Fumigation Purposes. (Entomology Bulletin 90, pt IT.)
Price, 5 cents.

Chemistry of Fumigation with Hydrocyanic-acid Gas. (Entomology Bulletin 90,
pt. III.) Price, 5 cents.

White Flies Injurious to Citrus in Florida. (Entomology Bulletin 92.) Price, 25
cents. ;

Orange Thrips, Report of Progress. (Entomology Bulletin 99, pt. I.) Price, 5 cents.

Red-banded Thrips. (Entomology Bulletin 99, pt. II.) Price, 5 cents.

Natural Control of White Flies in Florida. (Entomology Bulletin 102.) Price, 20
cents.

Argentine Ant. (Entomology Bulletin 122.) Price, 25 cents. ia

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