JAE 012 "0888#

J[ Appl[ Ent[ 012\ 596Ð501 "0888#Þ 0888\ Blackwell Wissenschafts!Verlag\ BerlinISSN 9820!1937

Evaluation of synthetic food-based attractants for femaleMediterranean fruit flies (Dipt., Tephritidae) in McPhail type trapsB[ I[ Katsoyannos\ N[ T[ Papadopoulos\ R[ R[ Heath\ J[ Hendrichs and N[ A[ Kouloussis

University of Thessaloniki\ Department of Agriculture\ Laboratory of Applied Zoology and Parasitology\Thessaloniki\ Greece

Abstract] During summer 0886 _eld experiments were conducted on the island of Chios\ Greece\ to compare capturesof female Mediterranean fruit ~ies "med~ies#\ Ceratitis capitata "Wiedemann#\ in traps baited with either synthetic female!targeted lures or a standard protein bait "NuLure and borax#[ The synthetic lures contained ammonium acetate\0\3diaminobutane "putrescine#\ and trimethylamine[ Two trap types "International Pheromone|s McPhail Trap "IPMT#and the Tephri trap# were tested as either wet or dry[ Wet IPMT traps baited with the synthetic attractants were themost attractive of all trap combinations tested and captured 1[0 times more female med~ies and 0[7 times more totalmed~ies than traps baited with NuLure and borax[ Traps containing the synthetic attractant captured approximately3[5 times fewer nontarget insects than NuLure baited traps[ Vapona used in IPMT traps was repellent to med~ies anddry traps with lower concentrations of Vapona were approximately 0[4 times less attractive to female med~ies than trapscontaining water[ Even with a decrease in attractiveness\ the dry traps were signi_cantly more e}ective for females andmore practical for mass trapping and monitoring than the currently used traps baited with protein solutions[

0 Introduction

General aspects concerning trapping systems for theMediterranean fruit ~y "med~y# Ceratitis capitata"Wiedemann# "Diptera\ Tephritidae#\ have been dis!cussed in several publications "see KATSOYANNOS\0883^ HEATH et al[\ 0886^ EPSKY et al[\ 0887^ KAT!

SOYANNOS et al[\ 0888^ VILLEDA et al[\ 0877#[ Untilrecently\ potent\ speci_c and selective attractant andtrapping systems for C[ capitata females for use in popu!lation monitoring\ mass trapping\ and in sterile insecttechnique "SIT# programmes have been lacking and theneed to develop such systems emphasized[ To meet thisneed\ we conducted extensive _eld experiments from0883 to 0886 on the island of Chios Greece\ in theframework of an international program coordinated bythe Interational Atomic Energy Agency "IAEA#[ Fromthe 0885 data\ the most important _ndings of thesestudies "obtained under low population levels# were thatthe International Pheromone|s McPhail trap "IPMT#provided with water¦ surfactant and baited with threesynergistically acting\ female!targeted\ food!based syn!thetic attractants "FA!2#\ was much more med~yattractive\ especially for females\ and selective than thetraditionally used\ protein!baited McPhail trap types"KATSOYANNOS et al[\ 0888#[ The three components ofFA!2 attractants were] ammonium acetate "AA#\ 0\3diaminobutane "putrescine\ P# and trimethylamine"TMA#[

The experiments reported here were carried out tocon_rm the _ndings described above in populationshigher than the 0885 levels and\ in addition\ to test thee}ectiveness of the FA!2 attractants when used in dryMcPhail type traps\ which are much easier to service

U[ S[ Copyright Clearance Center Code Statement] 9820Ð1937:88:1209Ð9596 , 03[99:9

than wet ones\ and to detail how to avoid some possiblenegative e}ects from the use of insecticides to kill the~ies in dry traps[

1 Materials and methods

1[0 Experimental area and orchards

The experiments were conducted from 6 July to 03 September0886 on the island of Chios[ During the experimental period\the weather was characterized by no rainfall\ moderate tem!peratures "max[ 16[9Ð21[9>C\ min[ 01[1Ð15[0>C# and humidity"30Ð62)#\ and a slight to moderate wind\ usually from thenorth[

The experiments were conducted approximately 0 km westof the eastern coast of the island at an altitude of 0Ð1 m abovesea level\ in the middle of a 19!km1 area cultivated mostlywith various Citrus spp[ trees\ including mandarin "Citrusnobilis Lour[#\ orange "Citrus sinensis Osbeck# and bitterorange "Citrus aurantium L[#[ In the same area\ other C[ cap!itata!host trees were also present and included apricot "Prunusarmeniaca L[#\ pear "Pyrus communis L[#\ and _g "Ficus caricaL[#[ Bitter oranges are the most preferred and severelyattacked host from June to early July\ whereas _gs are thepreferred host in which the ~y breeds from mid August untillate October[ The fruit phenology and population dynamicsof the med~y in the area has been described by KATSOYANNOS

et al[ "0887#[ Med~y adult populations in the area are usuallypresent in high numbers from the end of June until earlyDecember[

The main experiment "experiment 0#\ was conducted in twoadjacent citrus orchards\ containing mandarin trees as themain culture\ and a few to several orange\ bitter orange andlemon "Citrus limon "L[# Burm[ f[# trees planted mostlybetween the mandarin trees[ On the margins of the farms\there were also a few other host trees\ such as _g and certain

597 B[ I[ Katsoyannos et al[

nonhost trees[ Additional experiments "experiments 1Ð3# wereconducted in two other citrus orchards with similar host com!position and located 199 m or 0 km apart[

In all orchards during the period of experimentation\ thedi}erent citrus trees bore only unripe fruits\ unsuitable foroviposition\ and these remained uninfested[ However\ someisolated bitter orange trees bore ripe fruits during the _rstweeks of July and these were infested by med~y[ These fruitslater fell to the ground[ The relatively low adult populationtrapped during July\ and early to middle August\ apparentlyoriginated from these citrus fruits[ Ripe _gs in the areaappeared during the _rst week of August and soon becamehighly infested[ Adult ~ies\ trapped in increasing numbersduring late August to September\ apparently originated fromthe infested _gs[

1[1 Traps and treatments

Two McPhail trap types were used] "a# The InternationalPheromone|s McPhail trap "IPMT# consisted of a 6!cm!tallyellow base with a 3[4!cm diameter opening "for dispersal ofthe chemicals and as an entrance for the attracted ~ies#\ _ttedwith a 01!cm tall clear top[ The trap was 06 cm in diameter atits widest point "International Pheromone Systems Limited\South Wirral\ England#[ "b# The Tephri trap "Agro Alcoy\Alcoy\ Spain# consisted of a 00!cm!tall yellow base _tted witha 2 cm opaque top[ It was 02 cm in diameter at its widestpoint[ In addition to the bottom opening "2 cm diameter# theTephri trap had four lateral openings of 1 cm diameter "3 cmfrom trap top#[

Two types of female!targeted attractants were tested] "a#the _rst was a 299 ml aqueous solution of liquid protein bait"8) NuLure "Miller Chemical and Fertilizer Co[\ Hanover\PA\ USA# "v:v# ¦ 2) borax "w:v# "NU ¦ B# and was used inIPMT traps[ "b# The second attractant was a three!componentfood!based synthetic lure "FA!2# which consisted of threedispensers containing AA\ P\ and TMA\ respectively[ A com!mercial formulation of AA was used "BioLure\ Consep Inc[\Bend\ OR\ USA#[ Putrescine lures were prepared using apolyethylene membrane system "EPSKY et al[\ 0884#[ TheTMA lures were formulated using 4 g of the hydrochloridesalt "Aldrich Chemical\ Milwaukee\ WI\ USA# loaded ontothe same membrane system as that used for the AA lures"BioLure#[

A male!targeted trapping system was also included as areference for male captures and consisted of Jackson trapsbaited with 1 ml of the standard mixture of the para!pheromone trimedlure "TML# "69) by weight# set in athermoset polymeric matrix "AgriSense\ Fresno\ CA\ USA#[White cardboard inserts coated with sticky insect adhesive"Tangle Trap\ Tanglefoot Co[\ Grand Rapids\ MI\ USA# wereused to retain attracted ~ies[

The FA!2 attractants were evaluated in wet "provided withwater# and dry IPMT and Tephri traps[ In the IPMT traps\9[90) of the surfactant Triton X!099 "Union Carbide\Danbury\ CT\ USA# was added to the water[ To kill the ~iesin the dry traps\ as well as in the wet Tephri traps\ in mostexperiments\ a 4 mm × 04 mm × 14 mm plug containing dich!lorvos "Vapona^ Biological Control Systems#\ was used[

1[2 Experiment 0

Here we evaluated the following trap systems] "0# The IPMTtrap baited with a 299 ml solution NU ¦ B ¦ 77) water"IPMT\ NU ¦ B#^ "1# The IPMT trap\ baited with FA!2 andcontaining 299 ml of water and 9[90) of surfactant "IPMT!FA!2\ wet#^ "2# The IPMT trap baited with FA!2\ withoutwater\ but with a Vapona plug "IPMT!FA!2\ dry#^ "3# TheTephri trap\ baited with FA!2 without water\ but provided

with a Vapona plug placed in a special basket positioned inthe upper part of the trap "Tephri!FA!2\ dry#^ "4# The Tephritrap\ baited with FA!2\ containing 149 ml water\ and providedwith a Vapona plug "Tephri!FA!2\ wet#[ Because of the lateralholes in the upper part of this trap\ captured insects couldeasily escape from wet traps if there was no insecticide[ TheVapona plugs "dimethyl\ dichlorovinyl phosphate\ DDVP#were used in the experiments[

The traps were hung on the citrus trees "mostly fruitlessmandarins#\ on 6 July about 09Ð04 m between the lines"blocks# and 09Ð04 m within blocks\ and randomly distributedwithin blocks[ Treatments were replicated 09 times "in 09blocks#\ with all treatments placed in each block[ Traps werechecked twice a week until 0 September "7 weeks#[ After eachcheck\ the position of the traps within each block was re!randomized[ In seven blocks\ a TML!baited Jackson trap wasalso included[ Although the TML dispensers were renewedevery 04 days\ dispensers of the FA!2 and the Vapona plugswere renewed only once\ 0 month after the initiation of theexperiment[ After every second check\ the liquid in the IPMTand Tephri traps was replaced with fresh solution[

At each check\ the number and sex of med~ies capturedand the total number of specimens of other nontarget insectspecies captured were recorded [ The numbers of some impor!tant species such as the olive fruit ~y\ Bactrocera oleae "Gme!lin#\ the celery ~y\ Euleia "Philophylla# heraclei L[\ a leaf minerof celery "Dipt[\ Tephritidae#\ Chrysopa spp[ "Neuropt[\ Chry!sopidae#\ and the yellowjacket wasp\ Vespula germanica "F[#"Hym[\ Vespidae#\ were also recorded[ Evidence of med~ypredation by yellowjackets "residues of ~ies\ etc[# was noted[After every second trap check\ med~y females\ captured bythe FA!2 attractants "wet traps# and by NU ¦ B baited traps\were checked for the presence of mature oocytes[ The fewfemales showing degenerated or otherwise decomposed oocy!tes were not considered[ Further experiments were designedto investigate the e}ect of water and the killing agent "insec!ticide# in IPMT traps baited with the FA!2 attractants[

1[3 Experiment 1

In this experiment\ conducted from 5 August to 1 September\we compared FA!2 baited IPMT traps provided with waterand surfactant\ with the same treatment in which a Vaponaplug "hereafter called Vapona!0# was used[ Vapona!0 was thesame as that used in the main experiment and the plug wasattached to the ceiling of the trap[ There were _ve traps foreach treatment and they were placed at a distance of 04Ð19 mapart[ The traps were checked twice a week for 3 weeks "eighttrap checks#[

1[4 Experiment 2

Since\ in the previous test\ it was found that Vapona!0 hadrepellent e}ects for the ~ies\ a further test was conducted to_nd other less repellent insecticide formulations[ The experi!ment was conducted from 1 September to 01 September usingIPMT traps baited with the FA!2 attractants[ One treatmentconsisted of a wet trap as in previous tests "control#\ whereas\the other four were dry traps\ each provided with a plug ofone of the following insecticides] "a# Vapona!0\ used in pre!vious tests[ "b# Vapona!1\ a smaller "1 mm × 09 mm × 09 mm#plug of the formulation {Vaportape| "Hercon LaboratoriesCorp[\ South Plain_eld\ NJ\ USA#\ containing 09) dimethyl\dichlorovinyl phosphate "DDVP#\ used in traps by theUSDA:USA[ "c# Tetrachlorvinphos\ a 1 mm × 09 mm ×09 mm plug containing 1!chloro!0 "1\3\4!trichlorophenyl#vinyl dimethyl phosphate "03[44)#[ "d# Naled\ a 1 mm ×09 mm × 09 mm {dog collar| piece containing 0\1!dibromo!1\1!dichloroethyl dimethyl phosphate "The Hartz Mountain

598Synthetic food!based attractants for female Mediterranean fruit ~ies

Table 0[ Mean numberof insectscaptured per trap per03 days\ in themain experiment[Except for treatment 0\ allothers were baited withammoniumacetate\ putrescine\ andtrimethylamine "FA!2#

Mean no[ per trap per 03 days "2SE#0

******************************Traps Med~iesand * Other********************treatments Females Males Total insects

********************************************IPMT"NU ¦ B# 14[3 2 5[6d 16[0 2 6[1bc 41[3 2 02[1c 494[6 2 55[3aIPMT\ wet 46[2 2 6[7a 24[0 2 4[5a 81[2 2 02[1a 009[4 2 02[4bIPMT\ dry 18[6 2 3[8bc 19[5 2 2[5bc 49[2 2 7[2bc 15[0 2 1[3dTephri\ dry 13[9 2 3[9cd 03[7 2 1[4c 27[7 2 5[3c 02[9 2 0[4dTephri\ wet 27[0 2 5[9b 13[7 2 3[0b 51[8 2 09[9b 55[0 2 8[1c

F] 7[62 13[08 06[02 036[78"d[f[ � 3\072\ P ³ 9[90#

0 Means followed by the same letters in the same column\ are not signi_cantly di}erent at the 9[94level[ Data were submitted to ANOVA\ and means were separated using Tukey|s HSD test[ Beforeanalysis\ data were transformed using the z"x ¦ 9[4# transformation\ but\ in the table\ the untrans!formed means are given[

Corp[ Secaucus\ NJ\ USA#[ There were _ve blocks of _ve traptreatments each\ placed at a distance of 09Ð04 m apart[ Trapswere checked every second day\ _ve times in total[

1[5 Experiment 3

This experiment\ in which the live captured ~ies were counted\was conducted to obtain a direct comparison between cap!tures in dry and wet traps\ excluding possible repellent e}ectsof the insecticides used to kill the insects[ We tested the fol!lowing two treatments of IPMT traps baited with FA!2attractants[0[ Wet trap[ Over the water in the trap\ a perforated plasticcover was placed\ to allow evaporation of the water and pre!vent the drowning of captured insects[1[ Dry trap "without insecticide#[

No food or water for the ~ies was provided in these twotrap types[ The experiment was conducted from August 03Ð12[ There were _ve blocks of two treatments "paired#\ placedat a distance of 09Ð04 m apart[ Traps were check every after!noon\ for nine consecutive days[ At every check\ the numberof live\ and\ if any\ dead insects were counted and removedusing an aspirator[ Trap positions were interchanged afterevery check[

1[6 Statistical analysis

Capture data from experiments 0 and 2 were submitted to two!way analysis of variance "ANOVA# "ANALYTICAL SOFTWARE\0881# and means were separated using Tukey|s HSD test[ Tonormalize data before analysis for experiment 0\ data weretransformed using z"x ¦ 9[4# transformation[ Data fromexperiment 2 were transformed by a ln"x ¦ 0# transformation[For data from experiments 1 and 3\ the Student|s t!test wasapplied[

2 Results and discussion

2[0 Experiment 0

The mean numbers of med~ies and other nontargetinsects captured per trap per 1 weeks during the entireexperimental period are given in table 0[ As can be seenin these results\ wet IPMT traps baited with the FA!2attractants were the most attractive for males and

females as well as for total captures\ followed by wet\FA!2 baited\ Tephri traps[

Wet\ FA!2!baited\ IPMT traps captured about twiceas many females and about 0[7 times more total med~iesthan did dry traps\ which captured less\ but still sig!ni_cantly higher numbers of med~y females thanNU¦B!baited IPMT traps[ The FA!2!baited wet trapscaptured signi_cantly more mature females thanNU¦B ones "68[3 versus 60[6)\ n�263 and 133\respectively\ x1 �3[7^ P�9\91#\ but the di}erencesbetween the two treatments were not high "6[6)#[

The seven TML!baited Jackson traps\ used as a ref!erence for male capture comparison\ captured 2Ð3 timesmore males than the other e}ective treatments "average093[12 10[3 males per trap per 03 days#[ High di}er!ences in male captures were observed during the _rstweeks of experimentation\ whereas\ later in the season\the trends in male captures by IPMT wet traps andJackson traps converged[ In experiments conducted inthe same orchards during 0885\ FA!2!baited wet IPMTtraps captured almost as many males as did TML!baitedJackson traps "KATSOYANNOS et al[\ 0888#[ During0885\ the trap installation date coincided with the begin!ning of the ~y activity\ whereas\ in the present study\when the experiments were initiated\ the population wasalready high[ Hence\ yearly di}erences in the populationsize and composition might be the reason for theobserved di}erences in male captures between the twoyears of the study[

It is interesting to note that\ in several cases\ pre!dation of the captured insects was observed and wasmost probably by yellowjacket wasps\ V[ germanica[This was evidenced by _nding parts of med~ies andother insects inside the traps[ In some cases\ predationwas apparently severe\ while it was mild in others[ Whenpossible\ the parts of med~ies from which the sex couldbe determined e[g[ heads or abdomens\ were consideredin the counts[ Otherwise\ they were omitted[ From atotal of 059 individual trap checks\ 42 cases of predationwere noticed in wet\ FA!2!baited IPMT\ 03 in wetTephri\ _ve in dry Tephri\ one in dry IPMT and none

509 B[ I[ Katsoyannos et al[

Table 1[ Mean number of specimens of nontarget insect species captured per trap per 03 days\ in the expt 0[ Exceptfor the _rst treatment\ all others were baited with FA!2

Mean number of insects captured per 03 days************************************************

Treatments Bactrocera oleae Euleia heraclei Chrysopa spp[ Vespula germanica Other species*************************************************************

IPMT"NU ¦ B# 002[8 13[3 15[2 07[3 213[2IPMT\ wet 04[1 11[8 0[8 9[1 69[2IPMT\ dry 9[7 8[7 9[1 9[9 04[3Tephri\ dry 9[5 0[5 9[0 9[9 09[5Tephri\ wet 2[0 1[4 0[2 9[0 48[0

Table 2[ Number ofmed~ies andother insects capturedin FA!2 baited\ IPMT trapswith and withoutVapona "n�39# "_vetraps:treatment×eightchecks#

Mean number:trap:check "2SE#0

*******************************Traps Med~iesand * Other**********************treatments Females Males Total insects

********************************************IPMT wet "Triton# 8[6 2 0[8a 7[3 2 1[1a 07[1 2 2[6a 15[3 2 2[6aIPMT wet "Vapona# 3[7 2 9[8b 1[8 2 9[6b 6[7 2 0[4b 01[0 2 1[6b

0 Means followed by the same letters in the same column\ are not signi_cantly di}erent at the 9[94level "t!test#[

in NU¦B!baited traps[ Despite the predation "andexclusion from the data of the med~ies removed by thewasps#\ wet IPMT traps baited with FA!2\ were\ in allcases\ the most e}ective[

The results concerning nontarget insects captures"table 0# clearly show that the wet FA!2!baited IPMTtraps were much more med~y selective than NU¦B!baited traps\ capturing 3[5 times fewer nontarget insectsthan dry traps\ and dry traps were much more selectivethan wet ones capturing 3[1 times fewer target insectsthan wet ones[ NU¦B!baited IPMT traps were by farthe most attractive to the olive ~y "B[ oleae#\ a severepest of olives in Mediterranean countries\ whereas FA!2!baited IPMT traps captured similar numbers of celery~ies E[ heraclei "L[# a leaf miner of celery\ as didNU¦B!baited ones "table 1#[ During spring and earlysummer of this year\ the citrus trees were highly infestedby aphids and\ as a result\ high populations ofbene_cials\ such as Chrysopa spp[\ were present in theorchards[ NU¦B!baited IPMT traps captured largenumbers of these bene_cials\ and hence were destructiveof the biological equilibrium of the agro!ecosystem\whereas FA!2!baited traps did not[ Large to moderatenumbers of yellowjacket wasps were captured only byNU¦B!baited traps[

2[1 Experiment 1

In this experiment\ it was expected that traps providedwith Vapona would perform better because more rapidkilling of trapped insects by the insecticide would reducethe possibility of escape from the trap[ Contrary to ourexpectations\ the addition of Vapona!0 to the wet IPMTtraps signi_cantly reduced med~y captures "table 2#[

Apparently Vapona!0\ at least in IPMT traps\ had arepellent e}ect for med~ies[ This was possibly due to thelarge quantity of insecticide emitted from these plugs[

2[2 Experiment 2

Although the wet IPMT traps again captured the high!est numbers of both male and female med~ies\ therewere no statistical di}erences between them and the drytraps with either Vapona!1 or Naled "table 3#[ Wet trapscaptured 1[5 times more females and total med~ies thandid dry traps provided with Vapona!0\ and 0[4Ð0[6 timesmore females and total med~ies than did dry traps pro!vided with Vapona!1 or Naled[ Low captures in trapswith tetrachlorvinphos is due to the fact that\ from thesecond trap check on\ 3 days after trap deployment\large numbers of live insects were found at every trapcheck in these traps and these numbers were notincluded in the results[ Hence\ this insecticide was note}ective after 3 days[ Live insects in the other treatmentswere found in limited numbers[ Apparently\ Vapona!1and Naled are less repellent than Vapona!0\ or notrepellent at all[ The higher repellency of Vapona!0observed in this experiment\ as compared to the resultsobtained in the main experiment "1[5 versus about 1[9times more females and total med~ies\ respectively#\ isprobably due to the fact that the traps in experiment 2were deployed with the same Vapona plugs for only 8days while Vapona!0 remained unchanged for 29 daysin the main experiments[ Since the results suggest thatthe higher quantity of insecticide vapour emitted by themuch bigger Vapona!0 plugs "compared with those ofVapona!1# is responsible for the observed repellente}ect\ it can be assumed that during the long period

500Synthetic food!based attractants for female Mediterranean fruit ~ies

Table 3[ Numbers ofmed~ies and other insectscaptured in FA!2baited\ IPMT traps\ wet ordry\ provided withdifferent insecticides"n�14# "_ve trapsper treatment×_ve checks#

Mean number:trap:check "2SE#1

*****************************Traps Med~iesand * Other*********************treatments0 Females Males Total insects

********************************************Wet "surfactant# 39[3 2 6[3a 03[4 2 2[5a 43[8 2 09[8a 17[4 2 1[8aDry "Vapona Ð 0# 04[2 2 1[0b 4[5 2 0[1bc 19[8 2 1[8b 6[2 2 9[7bDry "Vapona Ð 1# 15[1 2 1[8a 7[2 2 0[1ab 23[4 2 2[7a 09[0 2 0[3bDry "tetrachl[#2 06[0 2 2[3b 5[3 2 0[4c 12[4 2 3[7b 2[5 2 9[5bDry "Naled# 13[6 2 1[6a 6[5 2 0[1abc 21[1 2 2[5a 5[7 2 9[8b

F] 02[2 5[6 02[2 21[6"d[f[ � 3\ 001^ P ³ 9[90#

0 For more details see text[1 Means followed by the same letters in the same column\ are not signi_cantly di}erent at the 9[94level[ Data were submitted to ANOVA\ and means were separated using Tukey|s HSD test"P ³ 9[94#[ Before analysis\ data were transformed using the ln"x ¦ 0# transformation\ but in thetable the untransformed means are given[2 Tetrachlorvinphos[ After the second check of this treatment\ many insects were alive in the trapand were not counted[

Table 4[ Number of livemed~ies and other insectscaptured in FA!2baited\ IPMT traps\ wet ordry\ without insecticide"n�34# "_ve traps pertreatment×ninechecks#

Mean number per trap per check "2SE#1

********************************Traps Med~iesand * Other**********************treatments Females Males Total insects

********************************************Wet0 7[0 2 9[7a 6[2 2 9[7a 04[3 2 0[2a 5[1 2 9[8aDry 5[9 2 9[4b 3[0 2 9[4b 09[1 2 9[6b 0[9 2 9[1b

0 Wet traps were provided with a special ring to prevent ~ies from drowning "see text#[1 Means in the same column followed by the same letter are not signi_cantly di}erent "paired t!test\P ³ 9[94#[

of _eld deployment of Vapona!0\ its repellency wasreduced\ resulting in less pronounced repellent e}ects[However\ a certain slight repellency of the Vapona!1and Naled cannot be excluded "compare these data withthose of the experiment 3#[ The number of nontargetinsects captured by dry traps was 2Ð3 times lower thanthe number captured by wet traps[ The number of thedi}erent insecticides tested in this experiment was small[Further tests are needed to select insecticides whichmight be better suited for use in dry traps[

2[3 Experiment 3

The results are given in table 4[ Based on trap checks"every 13 h#\ almost all ~ies captured in both trap treat!ments were still alive\ despite the lack of food and water[Wet traps captured 0[2\ 0[7 and 0[4 times more females\more males and more total med~ies\ respectively\ thandid dry traps[ These di}erences in captures between wetand dry traps baited with FA!2 were lower than thoseobtained by comparing wet traps with dry ones pro!vided with insecticides "see above#[ It is noteworthy thata proportion of ~ies can escape from the dry traps\ and

this is a density!dependent phenomenon "unpublished#[Hence\ the relatively small di}erences between the twotreatments found in this experiment\ may be due\ inpart\ to more escapes occurring from the more e}ectivewet traps than from the less e}ective dry traps and inpart to the absence of insecticide!repellent e}ects[ Thenumber of males captured in this experiment was ratherhigh in comparison with our other experiments[ Thismay be because during the period of experimentation\large numbers of sterile males were handled in di}erentcages for the purposes of other experiments we run inthe locality[ Possible escape from these cages of a num!ber of sterile males may have increased the male popu!lation in the area at that time[ Therefore\ only the resultsconcerning females are comparable with the previousexperiments[ The female captures by wet traps in thisexperiment were only 0[2 times more than those cap!tured by the dry ones\ compared with 1Ð1[5 times morecaptured by dry traps provided with Vapona!0 "experi!ment 0Ð1# or 0[4Ð0[5 times when Vapona!1 or Naledwas used "experiment 2#[ It can be concluded that therelationship found in the last experiment re~ects moreaccurately the actual e}ectiveness of the dry traps "if we

501 B[ I[ Katsoyannos et al[

consider possible escape as unimportant#\ and that thebest insecticide formulations we used "Vapona!1 andNaled#\ still had some low repellent e}ects to med~ies[

The overall results of this study con_rmed the _nd!ings and conclusions of a previous study "KAT!

SOYANNOS et al[\ 0888#\ that IPMT traps baited withthe FA!2 and provided with water and a surfactantconstitute the most e}ective trapping system existingtoday\ capturing more med~ies in total and morefemales than males from other systems tested[ We alsocon_rmed that this trap is much more med~y!selectivethan NuLure!baited traps[ The wet Tephri trap followsin e}ectiveness[ Dry IPMT traps baited with the FA!2\although somewhat less e}ective than wet ones\ weremuch more med~y!selective than water!provided ones[Since dry traps\ are in addition\ much more easy toservice "no need to replace the water#\ they are con!sidered more practical than wet ones\ especially for masstrapping purposes[ Special attention should be given toselection of a proper insecticide for dry traps\ sinceour results showed that some formulations may haverepellent e}ects on the ~ies[

Acknowledgements

We thank G[ MAVROGIANNIS\ G[ TSOKOS and S[ P[ KOK!

KINAKIS for allowing us to use their farms[ The work wassupported by the IAEA grant 6540:R2:RBF[

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HEATH\ R[ R[^ EPSKY\ N[ D[^ DUEBEN\ B[ D[^ GUZMAN\ A[^RIZZO\ J[^ JERONIMO[ F[\ 0886] Adding methyl!sub!stituted ammonia derivates to a food!based syntheticattractant on capture of Mediterranean and Mexican fruit~ies "Diptera] Tephritidae#[ J[ Econ[ Entomol[ 89\ 0473Ð0478[

KATSOYANNOS\ B[ I[\ 0883] Evaluation of Mediterraneanfruit!~y traps for use in the sterile insect!technique pro!grammes[ J[ Appl[ Entomol[ 007\ 331Ð341[

KATSOYANNOS\ B[ I[^ KOULOUSSIS\ N[ A[^ CAREY\ J[ R[\ 0887]Seasonal and annual occurrence of Mediterranean fruit~ies "Diptera] Tephritidae# in Chios island\ Greece]Di}erences between two neighboring citrus orchards[Ann[ Entomol Soc[ Am[ 80\ 32Ð40[

KATSOYANNOS\ B[ I[^ HEATH\ R[ R[^ PAPADOPOULOS\ N[ T[^EPSKY\ N[ D[^ HENDRICHS\ J[\ 0888] Field evaluationof Mediterranean fruit ~y "Diptera] Tephritidae# femaleselective attractants for use in monitoring programs[ J[Econ[ Entomol[ 88\ 472Ð478[

VILLEDA\ M[ P[^ HENDRICHS\ J[^ ALUJA\ M[^ REYES\ J[\ 0877]Mediterranean fruit ~y Ceratitis capitata] behavior in nat!ure in relation to di}erent Jackson traps[ Florida Ento!mol[ 60\ 043Ð051[

Authors| addresses] Dr B[ I[ KATSOYANNOS "correspondingauthor#\ Dr N[ T[ PAPADOPOULOS\ and Dr N[ A[ KOULOUSSIS\University of Thessaloniki\ Department of Agriculture\ Lab!oratory of Applied Zoology and Parasitology\ 439 95 Thes!saloniki\ Greece\ e!mail] katsoyÝagro[auth[gr^ Dr R[ R[HEATH\ Center for Medical\ Agricultural and VeterinaryEntomology\ USDA:ARS\ Gainesville\ FL 21597\ USA^ Dr[J[ HENDRICHS IAEA\ Insect and Pest Control Section\Vienna\ Austria