Phenotypic disruption of cuticular hydrocarbon production in hybrids between sympatric species of Hawaiian picture-wing Drosophila.

Interspecies hybrids can express phenotypic traits far outside the range of parental species. The atypical traits of hybrids provide insight into differences in the factors that regulate the expression of these traits in the parental species. In some cases, the unusual phenotypic traits of hybrids can lead to phenotypic dysfunction with hybrids experiencing reduced survival or reproduction. Cuticular hydrocarbons (CHCs) in insects are important phenotypic traits that serve several functions, including desiccation resistance and pheromones for mating. We used gas chromatography mass spectrometry to investigate the differences in CHC production between two closely related sympatric Hawaiian picture-wing Drosophila species, Drosophila heteroneura and D. silvestris, and their F1 and backcross hybrid offspring. CHC profiles differed between males of the two species, with substantial sexual dimorphism in D. silvestris but limited sexual dimorphism in D. heteroneura. Surprisingly, F1 hybrids did not produce three CHCs, and the abundances of several other CHCs occurred outside the ranges present in the two parental species. Backcross hybrids produced all CHCs with greater variation than observed in F1 or parental species. Overall, these results suggest that the production of CHCs was disrupted in F1 and backcross hybrids, which may have important consequences for their survival or reproduction.

Cucumber Lure Trapping of Zeugodacus cucurbitae (Diptera: Tephritidae) in Hawaii and Taiwan: Longevity and Nontargets Captures.

The melon fly, Zeugodacus cucurbitae (Coquillett), is a serious pest of tropical horticulture, causing damage to cucurbits, tree fruits, and fruiting vegetables. Melon flies are especially attractive to freshly sliced cucumber, and this has led to the identification of a nine-compound kairomone lure that can be used to trap both female and male flies. In this study, a seven-compound lure, containing (Z)-6-nonenal, (Z)-6-nonen-1-ol, 1-octen-3-ol, (E,Z)-2,6-nonadienal, (E)-2-nonenal, hexanal, and 1-hexanol, was formulated into PVC plugs (100 or 300 mg/plug) for field testing in wet traps. In Hawaii, 100 mg of the seven-compound cucumber lure, loaded in either plugs or glass capillaries, attracted more flies than traps containing Solulys protein over a 9-wk period. However, both cucumber lure formulations showed marked declines in the number of flies trapped after 3 wk. Similar results were obtained during a 6-wk field trial using 100 mg cucumber lure plugs in Taiwan. Increasing the cucumber lure loading rate to 300 mg/lure increased the effective trapping life of the attractant during a second 9-wk field trial conducted in Hawaii. The synthetic cucumber lure showed female-biased sex ratios in trap captures in the Taiwanese and second Hawaiian field trials. Protein lures captures were female-biased in all three field trials. Wet traps in Hawaii containing the cucumber lure were found to capture 25-30 nontarget insects/trap/week, less than half that captured with Solulys. Captured nontarget insects represented 37 families in 10 orders. The most common families caught were Ceratopogonidae (∼9 flies/trap) and Gryllidae (∼7 crickets/trap).

Raspberry Ketone Trifluoroacetate, a New Attractant for the Queensland Fruit Fly, Bactrocera Tryoni (Froggatt).

Queensland fruit fly, Bactrocera tryoni (Q-fly), is a major pest of horticultural crops in eastern Australia. Lures that attract male Q-fly are important for detection of incursions and outbreaks, monitoring of populations, and control by mass trapping and male annihilation. Cuelure, an analog of naturally occurring raspberry ketone, is the standard Q-fly lure, but it has limited efficacy compared with lures that are available for some other fruit flies such as methyl eugenol for B. dorsalis. Melolure is a more recently developed raspberry ketone analog that has shown better attraction than cuelure in some field studies but not in others. A novel fluorinated analog of raspberry ketone, raspberry ketone trifluoroacetate (RKTA), has been developed as a potential improvement on cuelure and melolure. RKTA placed on laboratory cages containing 2-week-old Q-flies elicited strong behavioral responses from males. Quantification of Q-fly responses in these cages, using digital images to estimate numbers of flies aggregated near different lures, showed RKTA attracted and arrested significantly more flies than did cuelure or melolure. RKTA shows good potential as a new lure for improved surveillance and control of Q-fly.

Field Evaluation of Melolure, a Formate Analogue of Cuelure, and Reassessment of Fruit Fly Species Trapped in Sydney, New South Wales, Australia.

In Australia, tephritids are usually attracted to either cuelure or methyl eugenol. Methyl eugenol is a very effective lure, but cuelure is less effective likely due to low volatility. A new formate analogue of cuelure, melolure, has increased volatility, resulting in improved efficacy with the melon fruit fly, Bactrocera cucurbitae Coquillett. We tested the efficacy of melolure with fruit fly species in Sydney as part of the National Exotic Fruit Fly Monitoring programme. This monitoring programme has 71 trap sites across Sydney, with each trap site comprising separate Lynfield traps containing either cuelure, methyl eugenol, or capilure lure. In 2008, an additional Lynfield trap with melolure plugs was added to seven sites. In 2009 and 2010, an additional Lynfield trap with melolure wicks was added to 11 trap sites and traps were monitored fortnightly for 2 yr. Capture rates for melolure traps were similar to cuelure traps for Dacus absonifacies (May) and Dacus aequalis (Coquillet), but melolure traps consistently caught fewer Bactrocera tryoni (Froggatt) than cuelure traps. However, trap sites with both a cuelure and melolure traps had increased capture rates for D. absonifacies and D. aequalis, and a marginally significant increase for B. tryoni. Melolure plugs were less effective than melolure wicks, but this effect may be related to lure concentration. The broader Bactrocera group species were attracted more to cuelure than melolure while the Dacus group species were attracted more to melolure than cuelure. There is no benefit in switching from cuelure to melolure to monitor B. tryoni, the most important fruit fly pest in Australia.

Field Estimates of Attraction of Ceratitis capitata to Trimedlure and Bactrocera dorsalis (Diptera: Tephritidae) to Methyl Eugenol in Varying Environments.

Measuring and modeling the attractiveness of semiochemical-baited traps is of significant importance to detection, delimitation, and control of invasive pests. Here, we describe the results of field mark-release-recapture experiments with Ceratitis capitata (Wiedemann) and Bactrocera dorsalis (Hendel) to estimate the relationship between distance from a trap baited with trimedlure and methyl eugenol, respectively, and probability of capture for a receptive male insect. Experiments were conducted using a grid of traps with a central release point at two sites on Hawaii Island, a Macadamia orchard on the East side of the island and a lava field on the West side. We found that for B. dorsalis and methyl eugenol there is a 65% probability of capture at ∼36 m from a single trap, regardless of habitat. For C. capitata, we found a 65% probability of capture at a distance of ∼14 m from a single trap in the orchard and 7 m in the lava field. We also present results on the spatial and temporal pattern of recaptures. The attraction data are analyzed via a hyperbolic secant-based capture probability model.

Disruption of Darna pallivitta (Lepidoptera: Limacodidae) by Conventional and Mobile Pheromone Deployment.

Identification of the Darna pallivitta (Moore) pheromone component n-butyl (E)-7,9-decadienoate (E7,9-10:COOn-Bu) has made it possible to investigate communication disruption to control this lepidopteran pest. Conventional communication disruption trials showed marked decreases in the mean number of male moths captured in E7,9-10:COOnBu-treated fields compared with control fields. For traps baited with E7,9-10:COOnBu, percent disruptions were 94.4% and 92.1% for septa (1 g pheromone/ha, 1-wk trial duration) and spirals (6 g pheromone/ha, 8-wk trial duration) respectively. For traps baited with virgin female moths, percent disruption was 73.3% using septa disruptors (1 g pheromone/ha, 1-wk trial duration). Mobile communication disruption using Bactrocera cucurbitae (Coquillett) as carriers for E7,9-10:COOn-Bu was evaluated in the following three areas: fly survivorship, attraction of male moths to treated flies, and moth disruption in a small-scale field trial. Topical application of E7,9-10:COOnBu showed no significant decrease in survivorship at 50 and 80 µg/fly. However, decreased survivorship was observed at 100 µg/fly and linear regression showed E7,9-10:COOnBu dose was significantly correlated with B. cucurbitae survivorship. Traps containing honey-pheromone-fed flies attracted and caught D. pallivitta over a 1-wk period, demonstrating the attractiveness of the carrier. Releasing E7,9-10:COOnBu-fed B. cucurbitae (∼2 g pheromone/ha, 1-wk trial duration) resulted in significantly reduced trap catches in treatment fields compared with control fields on the first 2 d of the field trial. Percent disruptions were 84.7% (day 1) and 56.0% (day 2). These results suggest that both conventional communication disruption and mobile communication disruption have potential to control D. pallivitta.

A qPCR-based method for detecting parasitism of Fopius arisanus (Sonan) in oriental fruit flies, Bactrocera dorsalis (Hendel).

BACKGROUND: Parasitism detection and species identification are necessary in fruit fly biological control. Currently, release of mass-reared Fopius arisanus is practiced worldwide, as it is effective in controlling Bactrocera dorsalis and Ceratitis capitata. To detect and assess parasitism in parasitoid mass-rearing colonies and parasitism levels in field populations across all life stages of hosts, the development of a rapid, specific and sensitive method is important. RESULTS: A species-specific probe was designed for F. arisanus, as well as a universal tephritid probe. Utilizing rapid DNA extraction techniques coupled with quantitative-PCR, a simple and fast assay has been developed to detect parasitism of F. arisanus that is sensitive enough to detect the parasitoid across all developmental stages, including a single egg per host egg or 0.25 ng of parasitoid DNA in 40 ng of host DNA. The qPCR methods also detect a higher parasitism rate when compared with rearing-based methods where parasitism rate is based on wasp emergence and where unemerged wasps are not included. CONCLUSION: This method is a rapid, sensitive and specific technique to determine the parasitism rate of F. arisanus across all life stages of B. dorsalis, which will be useful to predict parasitoid output from mass rearing and evaluate the outcome of pest suppression after mass release in the field.

Lethal and sublethal effects of cyantraniliprole on Bactrocera dorsalis (Hendel) (Diptera: Tephritidae).

BACKGROUND: The oriental fruit fly, Bactrocera dorsalis (Hendel), is one of the most globally important insect pests. Studies were conducted with the novel anthranilic diamide insecticide cyantraniliprole to determine its lethal and sublethal effects on B. dorsalis. RESULTS: An ingestion toxicity bioassay showed that cyantraniliprole was active against B. dorsalis, and the 72 h feeding LC50 was 3.22 µg g(-1) in adult diet for a susceptible strain. Sublethal doses of cyantraniliprole (1.30 µg g(-1) adult diet) induced a hormesis effect on B. dorsalis. The mating competitiveness of B. dorsalis treated with cyantraniliprole at 3.27 µg g(-1) adult diet was significantly lower when compared with the controls. The lower dose (1.30 µg g(-1) adult diet) of cyantraniliprole improved the total mating times of both mating pairs in treated groups and also the mating competitiveness of the treated males when compared with the higher dose and controls. Cyantraniliprole-treated females of the mated pairs with the lower dose laid more eggs. On the fifth day, female receptivity in the treated group was significantly reduced when compared with the controls. CONCLUSION: These results indicate that cyantraniliprole is effective against B. dorsalis. The inhibition and stimulation effect of cyantraniliprole on the adult's mating performance at different concentrations was proved.

Differential field responses of the little fire ant, Wasmannia auropunctata (Roger), to alarm pheromone enantiomers.

The little fire ant, Wasmannia auropunctata (Roger) (Hymenoptera: Formicidae), is an invasive ant with negative impacts on both biodiversity and agriculture throughout the tropics and subtropics. Field experiments were conducted in order to elucidate the relative attractiveness of the enantiomers of the alarm pheromones, 2,5-dimethyl-3-(2-methylbutyl)pyrazine and 3-methyl-2-(2-methylbutyl)pyrazine. The enantiomers tested were synthesized from commercially available (S)-2-methylbutan-1-ol or kinetically resolved (R)-2-methylbutan-1-ol, prepared using Pseudomonas cepacia lipase (PCL). Bioassays conducted in a macadamia orchard on the island of Hawaii demonstrated that W. auropunctata were preferentially attracted to the (S)-enantiomers of both alkyl pyrazines over the racemic mixtures in all experiments. To our knowledge, this is the first instance of differential attraction of ants to the enantiomers of chiral pyrazine pheromones despite many examples of these compounds in the literature. In addition, using a chiral column it was determined that (S)-2,5-dimethyl-3-(2-methylbutyl)pyrazine and (S)-3-methyl-2-(2-methylbutyl)pyrazine are the only enantiomers produced by W. auropunctata.

Freezing as a treatment to prevent the spread of Hypothenemus hampei (Coleoptera: Curculionidae), in coffee.

Coffee berry borer, Hypothenemus hampei (Ferrari) is the most serious insect pest of coffee around the world. Although it is already present in most of the world's major coffee growing regions, it is important to delay further spread and to prevent reintroductions that might include hyperparasites or improve the genetic base of existing populations. Green coffee is shipped around the world for custom blending and roasting and such shipments carry the risk of spreading H. hampei. We used heavily infested coffee berries as a surrogate for green coffee to test the freezing tolerance of H. hampei. After freezing, all life stages of H. hampei were dissected from coffee berries and mortality was assessed. Counting all life stages, > 15,000 insects were measured in this study. A temperature of approximately -15 degrees C (range, -13.9 to -15.5) for 48 h provided 100% control of all life stages. A logit regression model predicted < or = 1 survivor in a million for treatments of -20 degrees C for 5 d or -15 degrees C for 6 d. A freezing treatment for green coffee might be more economical and acceptable compared with fumigation with methyl bromide, especially for small-scale and organic growers and millers in Hawaii who ship green coffee beans to other islands for custom roasting. Freezing treatments could also be used to kill H. hampei in coffee seeds before export with minimal effects on seed germination if coffee seeds are first dried to critical water content levels in accordance with published methods.

Performance of methyl eugenol + matrix + toxicant combinations under field conditions in Hawaii and California for trapping Bactrocera dorsalis (Diptera: Tephritidae).

The oriental fruit fly, Bactrocera dorsalis (Hendel) is a major pest of many fruit crops worldwide. Current detection programs by federal and state agencies in the United States use a grid of traps consisting of liquid methyl eugenol (lure) and naled (toxicant) applied to cotton wicks and hung inside the trap. In recent years efforts have been made to incorporate these chemicals into various solid-type matrices that could be individually packaged to reduce human exposure to the chemicals and improve handling. New solid formulations containing methyl eugenol and either naled or dichlorovinyl dimethyl phosphate toxicants were compared with the standard formulations on cotton wicks in large scale field evaluation in Hawaii. Two reduced risk toxicants (spinosad and Rynaxypyr) were also evaluated. In one test the solid lure-toxicant-matrix combinations were sent to California to be weathered under California climate conditions and then sent back to Hawaii for evaluation. The polymer matrices with lure and toxicant were found to be as attractive as baited wicks and have the same longevity of attraction regardless of being weathered in Hawaii or in California. The new ingestible toxicants were also effective, although further testing of these ingestible lure + toxicant + matrix products is necessary.

Irradiation of adult Epiphyas postvittana (Lepidoptera: Tortricidae): egg sterility in parental and F1 generations.

Adult Epiphyas postvittana Walker were irradiated using a Cobalt 60 source to determine the dose needed to achieve complete egg sterility of mated female moths, and egg sterility of female moths mated to F1 generation males. Adult male and female E. postvittana were irradiated at 100, 200, 250, and 300 Gy and their fertility (when crossed with normal moths) was compared with nonirradiated moths. Viable progeny (determined by egg hatch) were found at doses of 100 and 200 Gy, but very little at 250 and 300 Gy. In particular, there was no survival of female progeny into the F1 generation. Males irradiated at 250 and 300 Gy had very low egg eclosion rates (2.25 and 1.86% at 250 and 300 Gy, respectively) when mated with normal females. The F2 generation from those male progeny had a mean percent hatched of < 1.02%. Based on our results, a dose of 250-300 Gy is recommended for irradiation of E. postvittana adults used for sterile insect technique (SIT) if sterility of parental moths is the desired outcome. Our data also suggests that inclusion of F1 hybrid sterility rather than parental generation sterility into programs using the SIT may allow for doses lower than what we have reported, especially during initial phases of an eradication program where increase fitness of moths might be desirable. Further research is needed to verify the use of F1 hybrid sterility in light brown apple moth SIT programs.

Field trapping the little fire ant, Wasmannia auropunctata.

Two detection methods for the little fire ant, Wasmannia auropunctata (Roger) (Hymenoptera: Formicidae), both employing the pheromone attractant 2,5-dimethyl-3-(2-methylbutyl)pyrazine (2-MeBu-diMePy), were compared with peanut butter based detection, in order to evaluate differences in species specificity and detection reliability. Trapping was conducted using a transect through a macadamia orchard on the island of Hawaii. The transect consisted of a series of three-tree plots, each plot contained a peanut butter coated stick (the most common detection method used for W. auropunctata in Hawaii), a one-way trap treated with 2-MeBu-diMePy, and a piece of double-sided tape treated with 2-MeBu-diMePy. While there were no differences in the number of W. auropunctata counted with each detection method, and no differences in detection reliability (detecting the known presence of W. auropunctata in a plot), the pheromone-incorporating methods showed greater species specificity, retaining W. auropunctata almost exclusively. These results demonstrate the potential of pheromone-detection methods to selectively capture target ant species even when other ants are present and abundant. Combined data from all three detection methods and a previous visual survey along the transect showed a marked difference in the frequency of cohabitation among ant species. Of the 10 ant species collected, W. auropunctata was found as the sole ant species on a given tree at a significantly higher frequency than all other ant species except Pheidole fervens. 94% percent of the trees with W. auropunctata had only W. auropunctata, supporting previous observations that this species tends to displace other ant species. In addition, W. auropunctata microhabitat preferences were investigated using one-way traps containing 2-MeBu-diMePy, which were placed in three arboreal and three non-arboreal locations. While the number of ants captured did not differ by trap placement, when grouped, captures were significantly higher in arboreal than non-arboreal microhabitats.

Morphological features of the ovaries during oogenesis of the Oriental fruit fly, Bactrocera dorsalis, in relation to the physiological state.

Determination of physiological state in insects is useful in furthering the understanding of how insect behavior changes with age. Central to this determination is the identification of characters that allow assessment of physiological age. While non-destructive measures produce the most desired outcomes, internal markers may be more diagnostic and reliable. In this study, key morphological characters during previtellogenesis through vitellogenesis and ovulation were assessed as markers to determine physiological states of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). Ovary length and width, ovarian index (length × width), and egg load of laboratory-reared B. dorsalis females recorded daily from eclosion up to 80 days old suggested significant differences in the ovarian index and egg load between females from each oogenesis stage. Parity status determined by the presence of follicular relics was found to provide high-accuracy classifications for B. dorsalis females. The presence of follicular relics with distinct morphological features provides a reliable identification tool to determine the physiological state of wild female oriental fruit fly. The potential applications of this technique to identify the physiological age of female fruit flies to study behavioral attributes in their natural habitat, and also the potential applications in relation to field control, are discussed.

Di- and tri-fluorinated analogs of methyl eugenol: attraction to and metabolism in the Oriental fruit fly, Bactrocera dorsalis (Hendel).

Oriental fruit fly, Bactrocera dorsalis (Hendel), males are attracted to the natural phenylpropanoid methyl eugenol (ME). They feed compulsively on ME and metabolize it to ring and side-chain hydroxylated compounds that have both pheromonal and allomonal properties. Previously, we demonstrated that mono-fluorination at the terminal carbon of the ME side-chain significantly reduced metabolic side-chain hydroxylation, while mono-fluorination of ME at position 4 of the aromatic ring blocked ring-hydroxylation but surprisingly enhanced side-chain hydroxylation. Here, we demonstrated that the introduction of fluorine atoms on both the ring and side-chain of ME blocks both positions that undergo enzymatic hydroxylation and, in particular, completely inhibits oxidative biotransformation of the allyl group. In laboratory experiments, B. dorsalis males initially were more attracted to both 1-fluoro-4,5-dimethoxy-2-(3,3-difluoro-2-propenyl)benzene (I) and 1-fluoro-4,5-dimethoxy-2-(3-fluoro-2-propenyl)benzene (II) than to ME. However, both I and II were taken up by flies at rates significantly less than that of ME. Flies fed with difluoroanalog II partially metabolized it to 5-fluoro-4-(3-fluoroprop-2-en-1-yl)-2-methoxyphenol (III), and flies fed with trifluoroanalog I produced 4-(3,3-difluoroprop-2-en-1-yl)-5-fluoro-2-methoxyphenol (V), but the rates of metabolism relative to rates of intakes were much lower compared to those of ME. Flies that consumed either the tri- or difluorinated analog showed higher post-feeding mortality than those that fed on methyl eugenol. In field trials, trifluoroanalog I was ∼90% less attractive to male B. dorsalis than ME, while difluoroanalog II was ∼50% less attractive. These results suggest that increasing fluorination can contribute to fly mortality, but the trade off with attractancy makes it unlikely that either a di or trifluorinated ME would be an improvement over ME for detection and/or eradication of this species.

Mobile mating disruption of light-brown apple moths using pheromone-treated sterile Mediterranean fruit flies.

BACKGROUND: Public opposition to aerial application of sex pheromone for mating disruption of light-brown apple moth (LBAM), Epiphyas postvittana (Walk.), in California stopped its further use in the ca $74 million eradication programme in 2008, underscoring the need for other eradication tactics. It is demonstrated that pheromone-treated sterile Mediterranean fruit flies (medflies), Ceratitis capitata Wied., can disrupt communication in male moths. RESULTS: Medflies topically dosed with moth pheromone (E)-11-tetradecenyl acetate showed a no observed effect level (NOEL) of ~10 µg fly(-1) , with increasing toxicity from 30 to 100 µg fly(-1) . Greater potency and longevity of attraction and lower mortality were achieved using microencapsulated pheromone. Releases of 1000 pheromone-treated medflies ha(-1) prevented male moth catch to synthetic lures in treated 4 ha plots for 1 day in suburban Perth, Australia. Releases of ca 3000 pheromone-treated medflies ha(-1) disrupted catch to single female moths in delta traps, and to synthetic pheromone lures. Percentage disruption on the first four nights was 95, 91, 82 and 85%. CONCLUSIONS: Disruption of moth catch using pheromone-treated medflies is a novel development that, with future improvement, might provide a socially acceptable approach for application of the insect mating disruption technique to control invasive insects in urban environments. Adequacy of payload and other issues require resolution.

Response of melon fly (Diptera: Tephritidae) to weathered SPLAT-Spinosad-Cue-Lure.

Studies were conducted in Hawaii to measure attraction of male melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), to SPLAT-Cue-Lure (C-L) and SPLAT-Melo-Lure (M-L) (raspberry ketone formate). Direct field comparisons of SPLAT-C-L and SPLAT-M-L at low (5%) and high (20%) concentrations indicated few differences in attraction over a 15-wk period. Subsequently, only SPLAT-Spinosad-C-L (5%) was compared with Min-U-Gel C-L with naled (standard used in California) in weathering studies. Treatments were weathered for 1, 2, 4, and 8 wk in Riverside, CA, and shipped to Hawaii for attraction/toxicity tests under field and semifield conditions by using released males of controlled ages, and for feeding tests in the laboratory. In terms of attraction, SPLAT-Spinosad-C-L compared favorably to, or outperformed the current standard of Min-U-Gel-C-L with naled. In terms of toxicity, the cumulative 24-h mortality did not differ between the two insecticide-containing C-L treatments in field cage studies after 8 wk. However, in feeding studies in which individual males were exposed for 5 min to the different C-L treatments after 4 wk of weathering, SPLAT-Spinosad-C-L demonstrated reduced mortality compared with the Min-U-Gel-C-L with naled, suggesting reduced persistence of the spinosad material. Spinosad has low contact toxicity and when mixed with SPLAT and C-L offers a reduced risk alternative for control of B. cucurbitae and related C-L-responding species, without many of the negative effects to humans and nontargets of broad-spectrum contact poisons such as naled.

Area-wide suppression of the Mediterranean fruit fly, Ceratitis capitata, and the Oriental fruit fly, Bactrocera dorsalis, in Kamuela, Hawaii.

The United States Department of Agriculture's Agricultural Research Service initiated an area-wide fruit fly management program in Hawaii in 2000. The first demonstration site was established in Kamuela, Hawaii, USA. This paper documents suppression of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), in a 40 km2 area containing urban, rural and agricultural zones during a 6 year period. The suppression techniques included sanitation, GF-120 NF Naturalyte Fruit Fly Bait sprays, male annihilation, Biolure traps, and parasitoids against C. capitata and B. dorsalis. In addition, small numbers of sterile males were released against B. dorsalis. Substantial reductions in fruit infestation levels were achieved for both species (90.7 and 60.7% for C. capitata and B. dorsalis, respectively) throughout the treatment period. Fruit fly captures in the 40 km2 treatment area were significantly lower during the 6 year period than those recorded in three non-treated areas. The strategy of combining suppression techniques in an area-wide approach is discussed.

Cucumber volatile blend attractive to female melon fly, Bactrocera cucurbitae (Coquillett).

The melon fly, Bactrocera cucurbitae (Coquillett), is a serious crop pest throughout the Asia Pacific sub-continent and Southeast Asia, causing damage to tree fruits, cucurbits, and related crops. Attractants for female melon flies are of particular interest as they could be used in control tactics to reduce pest levels. Previous work has shown that freshly sliced cucumbers are attractive to female melon flies, but the compounds responsible for this attraction were not identified. The objective of the present study was to create a synthetic lure for female B. cucurbitae based on its close association with Cucurbitaceae. Coupled gas chromatography-electroantennogram detection (GC-EAD) analysis of fresh and aged puréed cucumbers identified 31 compounds that were detected by females. Compounds that elicited EAD responses initially were screened as single components in glass McPhail traps in outdoor rotating olfactometer experiments. Four criteria were used to select compounds for testing in blends: a) strength of EAD response elicited; b) amount of compound present; c) relative attractiveness of a single compound; and d) compound novelty to Cucurbitaceae. Several synthetic blends attracted significant numbers of females in outdoor rotating olfactometer experiments; a nine-component blend (lure #7) was the most attractive. Field captures of female B. cucurbitae in traps baited with lure #7 were twice those in traps baited with Solulys protein bait. Besides having a female-biased attraction, this lure may have several advantages over protein baits: it can be used with a dry trap, is long lasting, and it captured low numbers of non-target species. Possible applications of this lure include trapping (for detection and/or monitoring/delimitation) and control/eradication (e.g., mass trapping, attract-and-kill, or as an attractant for existing protein insecticide bait sprays such as GF-120).