Attractiveness for Ceratitis capitata (Wiedemann) (Dipt.,Tephritidae) of mango (Mangifera indica, cv. Tommy Atkins)airborne terpenesG. Herna ndez-Sa nchez, I. Sanz-Berzosa, V. CasanÄ a-Giner and E. Primo-Yu feraInstituto de Tecnologõ a QuõÂmica, Universidad Polite cnica de Valencia ± CSIC, Valencia, Spain

1 Abstract: The airborne volatiles of the Tommy Atkins cultivar of mango (Mangifera indica L.), a fruit frequentlydamaged by Ceratitis capitata, were analysed by aeration of fresh fruits, adsorption and thermal desorption coupled to

gas chromatography±mass spectrometry. Ethanol and acetic acid were identi®ed as the major components, togetherwith longifolene, which has not been described before in the mango aroma and other terpenes (a-pinene, 3-carene,p-cymene, limonene and a-terpinolene). The attractiveness of the identi®ed terpenes for C. capitata was tested in

laboratory cages and the results showed that p-cymene and limonene were the best terpene attractants for both malesand females.

1 Introduction

Mango fruit (Mangifera indica L.) is frequentlydamaged by Ceratitis capitata females that lay eggsinside the fruit. The lack of an e�ective female med¯y(C. capitata) attractant has prompted several studiesto examine host odours (mango, co�ee, and litchi ornectarine) as lures (KEISER et al., 1975; LIGHT et al.,1988, 1992; COSSEÂ et al., 19952 ; WARTHEN andMCINNIS, 1989;3 PROKOPY and VARGAS, 1996). Themango ¯avour has been studied by several authors(MACLEOD et al., 19884 ; MACLEOD and SNYDER, 1985,1988;5 BARTLEY and SCHWEDE, 19876,7 ; BARTLEY, 19886,7 ;KOULIBALY et al., 1992; COSSEÂ et al., 1995), but, toour knowledge, the airborne volatiles from wholefresh mangoes of cv. Tommy Atkins have not beenpreviously studied. This kind of analysis wasmost interesting because it could identify theactual volatiles which med¯ies might detect inopen ®elds. This study concentrated on the identi-®cation of the mango airborne volatiles and laborat-ory tests of identi®ed terpenes as lures for femalemed¯ies.

2 Materials and methods

2.1 Chemicals

The purity of all compounds was tested by gas chromatog-raphy, being in all cases > 98%. Limonene, a-pinene,a-cariophylene and longifolene were obtained from Sigma(Geel, Belgium) and 3-carene, and p-cymene were obtainedfrom ExtrasyntheÁ se (Barcelona, Spain).

2.2 Trapping of volatiles

To trap the volatiles, a 5 l ¯ask containing approxi-mately 3 kg of fresh mangoes was used. The ¯ask had aninlet and an outlet tube that allowed the air be renewed by aircirculation. A puri®ed synthetic air stream (30 ml/min) wasinduced over 96 h. It was connected on-line to the outlettube, which was a quartz tube (9 cm long and 0.4 mm insidediameter) containing 300 mg Carbotrap C, 200 mg Carbo-trap B and 30 mg Carbosieve S-III8,9 (Supelco, Bellefonte, PA8,9 ),in which mango volatiles were trapped. An identical tube wasplaced in front of the inlet tube for trapping and identi®ca-tion of air impurities.

2.3 Gas chromatography±mass spectrometry

After the adsorption of volatiles, the tubes were desorbed(280°C for 4 min) in a thermal desorber (model 890;Dynatherm Analytical Instruments Inc., Oxford, PA10 ) con-nected to a gas chromatograph (GC; model Star 3400;Varian, Walnut Creek, CA11 ) and tandem mass spectrometer(MS; model Saturn II; Varian). The GC column used was a25 m ´ 0.2 mm ´ 0.25 lm HP-5 (Hewlett-Packard, Madrid,Spain). The column temperature was held at 40°C for 10 minand then programmed to increase at 3°C/min to 240°C. Themass spectrometer used an ion-trap detector at 70 eV and theion source was at 170°C.

2.4 Identi®cation of volatiles

For identi®cation purposes, the described retention indexesof compounds, the retention times of authentic samples,previously described spectra and the spectra obtained fromauthentic samples in our GC-MS was examined. Compoundswere identi®ed when both the retention index and spectra ofthe mango volatile matched those of authentic samples (whenavailable) or with previously described retention index valesor spectra.

JEN 125 (2001)

J. Appl. Ent. 125, 189±192 (2001)Ó 2001 Blackwell Wissenschafts-Verlag, BerlinISSN 0931-2048

U. S. Copyright Clearance Center Code Statement: 0931±2048/2001/2504±0189 $ 15.00/0 www.blackwell.de/synergy

20Table

1.Identi®cationofcompoundsfrom

theairbornevolatilesofwhole

freshTommyAtkinsmangoes

bymeansofadsorption-thermaldesorption-G

C±MS

Retentionindexes

Identi®cationcriteria

Peaks

Retention

time

Area

(%oftotal)

Sample

Authentic

Compound

Inliterature

RIauthentic

insample

RIdescribed

inliterature

MSauthentic

insample

MSdescribed

inliterature

Compound

Identi®cation

12.84

0.33

630

625

++

+ethanol

I2

3.81

71.32

721

720

++

+ethylacetate

I3

16.56

0.02

936

+1-m

ethylethylcyclohexane

T4

16.71

0.01

939

935

938

++

++

alfa-pinene

I5

19.31

0.21

976

+4-ethyl-1,2-dim

ethylbenzene

T6

22.15

25.60

1017

1005

1011

++

++

3-carene

I7

22.79

0.11

1028

1023

1023

++

++

p-cymene

I8

22.98

0.51

1032

1029

1031

++

++

limonene

I9

23.34

1.24

1038

+4-m

ethyl-2-propyl-1-pentanol

T10

26.47

0.26

1089

1087

1089

++

++

terpinolene

I11

30.00

0.01

1155

+2,6,6-trimethyl-2,4-cycloheptadien-1-one

T12

40.07

0.02

1359

+sesquiterpene

13

41.39

0.04

1388

+sesquiterpene

14

41.99

0.02

1401

1392

++

beta-elemene

T15

42.18

0.04

1405

1403

1403

++

++

longifolene

I16

42.52

0.11

1414

1418

1419

++

++

beta-caryophyllene

I17

44.41

0.01

1458

1461

++

alloaromadendrene

T18

45.44

0.01

1483

+sesquiterpene

I,positivelyidenti®ed;T,tentativelyidenti®ed;RI,retentionindex;MS,mass

spectrometer.

190 Herna ndez-Sa nchez et al.

2.5 Attractiveness tests

The ¯ies were reared in our laboratory in a 16 h light : 8 hdark photoperiod with 40% relative humidity and tempera-ture of 27°C.

Experiments to determine attractiveness were carried outusing Plexiglas cages, 30 cm ´ 30 cm ´ 20 cm, with 250 adult(> 5 days old) med¯y males or females per cage. Theattractants (1 ll) were dissolved in 100 ll acetone and then50 ll were placed in a rubber-septum, from which theacetone was rapidly evaporated at room temperature.Attractiveness was measured by means of two-choice testsbetween a control (rubber-septa impregnated with 50 llacetone and then evaporated) and test compound. Wecounted the number of ¯ies which landed on a Petri plate(5 cm inside diameter) with a rubber septum impregnatedwith the test compound in its centre, or without compoundfor the control (two rubber septa and Petri plates per test).

3 Results and discussion

3.1 Identi®cation of mango air-borne volatiles

A total of nine compounds were identi®ed, and afurther six were tentatively identi®ed12 (table 1). Fromthe identi®ed compounds, ®ve (3-carene, a-terpinolene,p-cymene, limonene and ethanol) have been previ-ously described in Tommy Atkins mango puree byKOULIBALY et al. (1992). In accordance with otherstudies of mango volatiles, there are a wide variety ofterpenes which contribute to mango odour. Althoughdi�erences in sensitivity between compounds can bemeasured by the detector, the high percentage of ethylacetate that is detected using this method (71.32% oftotal) is particularly noteworthy. A similar analysis ofair-borne volatiles from persimmons (CASANÄ A-GINER,1998) also showed a considerable amount of ethylacetate and ethanol (52.78 and 27.20%, respectively),which was directly dependent on the ripening state.The most abundant terpene found in mangoes was3-carene (25.69%), followed by limonene (0.51%).

3.2 Med¯y attractiveness tests

The results of the attractiveness tests (table 2) showthat only terpinolene, p-cymene and limonene di�ered

signi®cantly from the control (16, 15 and 8 times13 ,respectively, with respect to the control). However,the power of attraction of these terpenes was lessthan that of trimedlure14 , the usual male attractantemployed for monitoring purposes. It should benoted that, in all cases in the laboratory assays,males were more receptive to attractants thanfemales, although in the ®eld p-cymene and limoneneattract more females than males and terpinoleneattracts both sexes equally (CASANÄ A-GINER, 1998). Inthe case of trimedlure it was shown that the expectedphenomenon of attraction almost exclusively a�ectedmales.

References

BARTLEY, J. P., 1988: Volatile ¯avours of Australiantropical fruits. Biomed. Environ. Mass Spectrom. 16,201±205.

BARTLEY, J. P.; SCHWEDE, A., 1987: Volatile ¯avor compo-nents in the headspace of the Australian or `Bowen'mango. J. Food Sci. 52, 353±355.

CASANÄ A-GINER, V., 1998: Me todo de Lucha no contam-inante contra La plaga mosca del Mediterra neo, Ceratitiscapitata (Wiedemann).15 Doctoral Thesis. Valencia, Spain:Universidad Polite cnica de Valencia (Spain).

COSSEÂ , A. A.; TODD, J. L.; MILLAR, J. G.; MARTIÂ NEZ, L. A.;BAKER, T. C., 1995: Electroantennographic and coupledgas chromatographic-electroantennographic responses ofthe Mediterranean fruit ¯y, Ceratitis capitata, to male-produced volatiles and mango odor. J. Chem. Ecol. 21,1823±1836.

KEISER, I.; HARRIS, E. J.; MIYASHITA, D. H.; JACOBSEN, M.;PERDUE, R., 1975: Attraction of ethyl ether extracts of232 botanicals to oriental fruit ¯ies, melon ¯ies andMediterranean fruit ¯ies. Lloydia 38, 141±152.

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LIGHT, D. M.; JANG, E. B.; DICKENS, J. C., 1988: Electro-antennogram responses of the Mediterranean fruit ¯y,Ceratitis capitata, to a spectrum of plant volatiles.J. Chem. Ecol. 14, 159±180.

LIGHT, D. M.; JANG, E. B.; FLATH, R. A., 1992: Electroan-tennogram responses of the Mediterranean fruit ¯y,Ceratitis capitata, to volatile constituents of nectarines.Entomol. Exp. Appl. 63, 13±26.

Table 2. Attractiveness tests of mango volatiles for C. capitata adults

Compound(0.5 ll)

Test 1

mean � SEControl

mean � SEStudent'st-test P

Relationshipmale/female

3-carene 21.23 � 7.08 2.53 � 0.59 2.202 0.158 6.6b-caryophyllene 6.43 � 0.25 6.37 � 1.52 0.036 0.974 2.0p-cymene 19.44 � 5.51 1.32 � 0.44 4.211 0.049 3.0limonene 33.33 � 3.78 4.13 � 0.49 5.777 0.028 4.2longifolene 1.78 � 0.50 2.62 � 0.31 )0.552 0.635 2.6a-pinene 5.93 � 0.97 5.10 � 0.70 5.644 0.787 3.6terpinolene 25.90 � 2.90 1.57 � 0.20 2.107 0.022 14.0mixture 1 2 4.63 � 0.65 1.67 � 0.51 2.761 0.109 3.5mixture 2 3 3.73 � 0.56 2.10 � 0.44 1.278 0.329 1.2trimedlure 48.07 � 17.38 4.97 � 3.61 5.381 0.032 34.1

1Mean number of ¯ies attracted to a Petri plate containing a rubber septum with 0.5 ll of the tested compound.2Mixture at equal ratio: limonene, 3-carene, a-pinene, terpinolene, b-cariophyllene, longifolene, p-cymene.3Mixture at equal ratio: limonene, 3-carene, terpinolene, p-cymene.

Attractiveness for Ceratitis capitata of mango airborne terpenes 191

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WARTHEN, J. D.; MCINNIS, D. O., 1989: Isolation andidenti®cation of male med¯y attractive components inLitchi chinensis stems and Ficus spp. stem exudates.J. Chem. Ecol. 15, 1931±1946.

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Authors' addresses: G. HERNAÂ NDEZ-SAÂ NCHEZ, I. SANZ-BERZ-

OSA, E. PRIMO-YU FERA (corresponding author) E-mail:eprimo@itq.upv.es, Instituto de Tecnologia QuõÂmica, Uni-versidad Polite cnica de Valencia, Avd. Los Naranjos s/n,46022, Valencia, Spain; VICTOR CASANÄ A-GINER, USDA-ARS-PSI, Insect Chemical Ecology Laboratory, BeltsvilleAgricultural Research Center, BARC-W, Bldg. 007 ± Rm303, 10300 Baltimore Av., Beltsville, MD-20707, USA

192 Herna ndez-Sa nchez et al.