Effect of Lure Combination on Fruit Fly Surveillance Sensitivity.

Surveillance for invading insect pests is costly and the trapper usually finds the traps empty of the target pest. Since the successful establishment of new pests is an uncommon event, multiple lures placed into one trap might increase the efficiency of the surveillance system. We investigated the effect of the combination of the Tephritidae male lures - trimedlure, cuelure, raspberry ketone and methyl eugenol - on catch of Ceratitis capitata, Zeugodacus cucurbitae, Bactrocera tryoni, B. dorsalis, B. aquilonis and B. tenuifascia in Australia and the USA (not all species are present in each country). The increase in trap density required to offset any reduction in catch due to the presence of lures for other Tephritidae was estimated. The effect of increasing trap density to maintain surveillance sensitivity was modelled for a hypothetical population of B. tryoni males, where the effective sampling area of cuelure traps for this species has been estimated. The 3-way combination significantly reduced the catch of the methyl eugenol-responsive B. dorsalis. Unexpectedly, we found that trimedlure-baited traps that contained methyl eugenol had ×3.1 lower catch of C. capitata than in trimedlure-only-baited traps in Australia, but not in Hawaii where no difference in catch was observed, we cannot satisfactorily explain this result. Based on the data presented here and from previous research, combinations of some male lures for the early detection of tephritid flies appear compatible and where there is any reduction in surveillance sensitivity observed, this can be offset by increasing the density of traps in the area.

Suppression of Mediterranean Fruit Fly (Diptera: Tephritidae) With Trimedlure and Biolure Dispensers in Coffea arabica (Gentianales: Rubiaceae) in Hawaii.

To assess the potential to suppress Mediterranean fruit fly, Ceratitis capitata (Wiedemann; Diptera: Tephritidae), via mass trapping with Trimedlure (TML), we compared fly catch (as catch per trap per time period) provided by either a novel, solid, triple-lure dispenser with TML, methyl eugenol (ME), and raspberry ketone (RK) (TMR) or solid TML plugs, both without insecticides, in addition to Biolure bait stations. Work was done in a coffee plantation that had a dense C. capitata population. Three treatments were compared: 1) TMR or TML (50 traps per ha), 2) Biolure (50 traps per ha), 3) TML (25 per ha) or TMR (25 per ha) + Biolure (25 per ha), and 4) an untreated control. During coffee season, based on C. capitata captures (mean flies per trap per wk) inside plastic McPhail traps, all treatments were significantly different than the control: Biolure (9.57) = TMR (11.28) = Biolure +TMR (13.50) < Control (36.06 flies/trap/wk). During non-coffee season, all treatments were significantly different than the control and TML was significantly lower than Biolure (wax matrix bait stations): TML (0.95) < Biolure (1.43) = Biolure +TML (1.77) < Control (2.81 flies/trap/wk). Surprisingly, captures were not lower in plots treated with combinations of Biolure + TMR or TML, compared to individual plots with Biolure or TML or TMR alone. Mass trapping with either TML or TMR dispensers deserves further study as a component of Integrated Pest Management programs for C. capitata in Hawaii and may have global potential for management of C. capitata.

Chemical Degradation of TMR Multilure Dispensers for Fruit Fly Detection Weathered Under California Climatic Conditions.

Degradation models for multilure fruit fly trap dispensers were analyzed to determine their potential for use in large California detection programs. Solid three-component male lure TMR (trimedlure [TML], methyl eugenol [ME], raspberry ketone [RK]) dispensers impregnated with DDVP (2, 2-dichlorovinyl dimethyl phosphate) insecticide placed inside Jackson traps were weathered during summer (8 wk) and winter (12 wk) in five citrus-growing areas. Additionally, TMR wafers without DDVP, but with an insecticidal strip, were compared to TMR dispensers with DDVP. Weathered dispensers were sampled weekly and chemically analyzed. Percent loss of TML, the male lure for Ceratitis capitata (Wiedemann) Mediterranean fruit fly; ME, the male lure for Bactrocera dorsalis (Hendel), oriental fruit fly; RK, the male lure for Bactrocera cucurbitae (Coquillett), melon fly; and DDVP was measured. Based on regression analyses for the male lures, TML degraded the fastest followed by ME. Degradation of the more chemically stable RK was discontinuous, did not fit a regression model, but followed similar seasonal patterns. There were few location differences for all three male lures and DDVP. Dispensers degraded faster during summer than winter. An asymptotic regression model provided a good fit for % loss (ME, TML, and DDVP) for summer data. Degradation of DDVP in TMR dispensers was similar to degradation of DDVP in insecticidal strips. Based on these chemical analyses and prior bioassay results with wild flies, TMR dispensers could potentially be used in place of three individual male lure traps, reducing costs of fruit fly survey programs. Use of an insecticidal tape would not require TMR dispensers without DDVP to be registered with US-EPA.

Vision-mediated exploitation of a novel host plant by a tephritid fruit fly.

Shortly after its introduction into the Hawaiian Islands around 1895, the polyphagous, invasive fruit fly Bactrocera (Zeugodacus) cucurbitae (Coquillett) (Diptera: Tephritidae) was provided the opportunity to expand its host range to include a novel host, papaya (Carica papaya). It has been documented that female B. cucurbitae rely strongly on vision to locate host fruit. Given that the papaya fruit is visually conspicuous in the papaya agro-ecosystem, we hypothesized that female B. cucurbitae used vision as the main sensory modality to find and exploit the novel host fruit. Using a comparative approach that involved a series of studies under natural and semi-natural conditions in Hawaii, we assessed the ability of female B. cucurbitae to locate and oviposit in papaya fruit using the sensory modalities of olfaction and vision alone and also in combination. The results of these studies demonstrate that, under a variety of conditions, volatiles emitted by the novel host do not positively stimulate the behavior of the herbivore. Rather, vision seems to be the main mechanism driving the exploitation of the novel host. Volatiles emitted by the novel host papaya fruit did not contribute in any way to the visual response of females. Our findings highlight the remarkable role of vision in the host-location process of B. cucurbitae and provide empirical evidence for this sensory modality as a potential mechanism involved in host range expansion.

Captures of Wild Ceratitis capitata, Bactrocera dorsalis, and Bactrocera cucurbitae (Diptera: Tephritidae) in Traps with Improved Multilure TMR Dispensers Weathered in California.

During 2012­2013, solid Mallet TMR (trimedlure [TML], methyl eugenol [ME], raspberry ketone [RK]) wafers impregnated with DDVP (2, 2-dichlorovinyl dimethyl phosphate) insecticide were weathered during summer (8 wk) and winter (12 wk) in five California citrus-growing counties (Kern, Ventura, Orange, Tulare, and Riverside). In addition, TMR wafers without DDVP and with a Hercon Vaportape II insecticidal strip were compared with TMR dispensers with DDVP at Exeter and Riverside. Weathered treatments were shipped every week (overnight delivery) to Hawaii and frozen for a later bioassay in a 1,335-ha coffee plantation near Numila, Kauai Island, HI, where Mediterranean fruit fly, Ceratitis capitata (Wiedemann), oriental fruit fly, Bactrocera dorsalis Hendel, and melon fly, Bactrocera cucurbitae Coquillett, were all present. We compared trap captures of the three species, C. capitata, B. dorsalis, and B. cucurbitae, for the five different weathering locations. Captures of C. capitata, B. dorsalis, and B. cucurbitae with Mallet TMR dispensers (with DDVP) were not significantly different for the five locations. Captures with the Mallet TMR dispenser without DDVP and Vaportape were similar to those for Mallet TMR with DDVP, although there were some slight location differences. In conclusion, based on these results, the Mallet TMR dispenser could potentially be used in California habitats where large numbers of detection traps are currently deployed. Use of Vaportape with dispensers would not require them to be registered with US Environmental Protection Agency (EPA). Dispensers for use as Male Annihilation Technique (MAT) devices will be tested further in Hawaii.

Ammonium Acetate Enhances the Attractiveness of a Variety of Protein-Based Baits to Female Ceratitis capitata (Diptera: Tephritidae).

Ammonia and its derivatives are used by female fruit flies (Diptera: Tephritidae) as volatile cues to locate protein-rich food needed to produce their eggs. This need for external protein sources has led to the development of behaviorally based control strategies such as food-based lures and insecticidal baits targeting pestiferous fruit fly species. In field cage studies conducted in Hawaii, we examined the behavioral response of laboratory-reared male and female Mediterranean fruit fly, Ceratitis capitata (Wiedemann), to seven commercially available protein baits and to beer waste, a relatively inexpensive and readily available substance. Each material was tested alone or in combination with either ammonium acetate or ammonium carbonate. For the majority of baits evaluated, the presence of ammonium acetate, but not ammonium carbonate, elicited a significantly greater level of response of female C. capitata compared with the protein baits alone. The addition of ammonium acetate to selected baits increased bait attractiveness to a level comparable with that elicited by the most widely used spinosad-based protein bait, GF-120. Our findings indicate that the addition of ammonium acetate to commercially available proteinaceous baits and to beer waste can greatly improve their attractiveness to C. capitata, potentially increasing the bait's effectiveness for fruit fly monitoring and suppression.

Weathering and Chemical Degradation of Methyl Eugenol and Raspberry Ketone Solid Dispensers for Detection, Monitoring, and Male Annihilation of Bactrocera dorsalis and Bactrocera cucurbitae (Diptera: Tephritidae) in Hawaii.

Solid male lure dispensers containing methyl eugenol (ME) and raspberry ketone (RK), or mixtures of the lures (ME + RK), and dimethyl dichloro-vinyl phosphate (DDVP) were evaluated in area-wide pest management bucket or Jackson traps in commercial papaya (Carica papaya L.) orchards where both oriental fruit fly, Bactrocera dorsalis (Hendel), and melon fly, Bactrocera cucurbitae (Coquillett), are pests. Captures of B. dorsalis with fresh wafers in Jackson and bucket traps were significantly higher on the basis of ME concentration (Mallet ME [56%] > Mallet MR [31.2%] > Mallet MC [23.1%]). Captures of B. cucurbitae with fresh wafers in Jackson and bucket traps were not different regardless of concentration of RK (Mallet BR [20.1%] = Mallet MR [18.3%] = Mallet MC [15.9%]). Captures of B. dorsalis with fresh wafers, compared with weathered wafers, were significantly different after week 12; captures of B. cucurbitae were not significantly different after 16 wk. Chemical analyses revealed presence of RK in dispensers in constant amounts throughout the 16-wk trial. Degradation of both ME and DDVP over time was predicted with a high level of confidence by nonlinear asymptotic exponential decay curves. Results provide supportive data to deploy solid ME and RK wafers (with DDVP) in fruit fly traps for detection programs, as is the current practice with solid TML dispensers placed in Jackson traps. Wafers with ME and RK might be used in place of two separate traps for detection of both ME and RK responding fruit flies and could potentially reduce cost of materials and labor by 50%.

Attraction and mortality of Bactrocera dorsalis (Diptera: Tephritidae) to STATIC Spinosad ME weathered under operational conditions in California and Florida: a reduced-risk male annihilation treatment.

Studies were conducted in 2013-2014 to quantify attraction, feeding, and mortality of male oriental fruit flies, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), to STATIC Spinosad ME a reduced-risk male annihilation treatment (MAT) formulation consisting of an amorphous polymer matrix in combination with methyl eugenol (ME) and spinosad compared with the standard treatment of Min-U-Gel mixed with ME and naled (Dibrom). Our approach used a behavioral methodology for evaluation of slow-acting reduced-risk insecticides. ME treatments were weathered for 1, 7, 14, 21, and 28 d under operational conditions in California and Florida and shipped to Hawaii for bioassays. In field tests using bucket traps to attract and capture wild males, and in toxicity studies conducted in 1-m(3) cages using released males of controlled ages, STATIC Spinosad ME performed equally as well to the standard formulation of Min-U-Gel ME with naled for material aged up to 28 d in both California and Florida. In laboratory feeding tests in which individual males were exposed for 5 min to the different ME treatments, mortality induced by STATIC Spinosad ME recorded at 24 h did not differ from mortality caused by Min-U-Gel ME with naled at 1, 7, 14, and 21 d in California and was equal to or higher for all weathered time periods in Florida during two trials. Spinosad has low contact toxicity, and when mixed with an attractant and slow release matrix, offers a reduced-risk alternative for eradication of B. dorsalis and related ME attracted species, without many of the potential negative effects to humans and nontargets associated with broad-spectrum contact insecticides such as naled.

Field trials of solid triple lure (trimedlure, methyl eugenol, raspberry ketone, and DDVP) dispensers for detection and male annihilation of Ceratitis capitata, Bactrocera dorsalis, and Bactrocera cucurbitae (Diptera: Tephritidae) in Hawaii.

Solid Mallet TMR (trimedlure [TML], methyl eugenol [ME], raspberry ketone [RK]) wafers and Mallet CMR (ceralure, ME, RK, benzyl acetate) wafers impregnated with DDVP (2,2-dichlorovinyl dimethyl phosphate) insecticide were measured in traps as potential detection and male annihilation technique (MAT) devices. Comparisons were made with 1) liquid lure and insecticide formulations, 2) solid cones and plugs with an insecticidal strip, and 3) solid single and double lure wafers with DDVP for captures of Mediterranean fruit fly, Ceratitis capitata (Wiedemann); oriental fruit fly, Bactrocera dorsalis Hendel; and melon fly, B. cucurbitae Coquillett. Bucket and Jackson traps were tested in a coffee plantation near Eleele, Kauai Island, HI (trials at high populations) and avocado orchards near Kona, HI Island, HI (trials at low populations). Captures of all three species with Mallet TMR were not different from Mallet CMR; therefore, subsequent experiments did not include Mallet CMR because of higher production costs. In MAT trials near Eleele, HI captures in AWPM traps with Mallet TMR wafers were equal to any other solid lure (single or double) except the Mallet ME wafer. In survey trials near Kona, captures of C. capitata, B. cucurbitae, and B. dorsalis with Mallet TMR wafers were equal to those for the standard TML, ME, and C-L traps used in FL and CA. A solid Mallet TMR wafer is safer, more convenient to handle, and may be used in place of several individual lure and trap systems, potentially reducing costs of large survey and detection programs in Florida and California, and MAT programs in Hawaii.

Response of female Ceratitis capitata (Diptera: Tephritidae) to a spinosad bait and polymer matrix mixture with extended residual effect in Hawaii.

The effectiveness of foliar applications of protein baits against pestiferous fruit flies (Tephritidae) can be adversely affected by a rapid loss of attractive volatile compounds and by rainfall due to the high water solubility of the baits. In a large coffee, Coffea arabica L., plantation in Hawaii with high and low populations of Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), the relative attractiveness of GF-120 NF Naturalyte Fruit Fly Bait as either a 40% (vol:vol) spray solution (= GF-120 NF) or as a formulated proprietary amorphous polymer matrix (= GF-120 APM) was compared. The GF-120 APM formulations contained either, 25, 50, or 75% of GF-120 NF (wt:wt). All baits were tested in association with visually attractive yellow bait stations as a way of standardizing the evaluations. With both high and low C. capitata populations, significantly more females were attracted to the fresh sprayed GF-120 NF than to any of the three fresh GF-120 APM formulations. The attractiveness of GF-120 sprayed decreased significantly after 1 wk, whereas 1-wk-old GF-120 APM formulations were as attractive as similar fresh formulations. GF-120 APM 75% aged for 3 wk outperformed similarly-aged sprayed GF-120 NF with comparatively high C. capitata populations. With low populations, both GF-120 APM 75% and GF-120 APM 50% aged for 2 wk outperformed the similarly aged sprayed GF-120 NF. Combined findings indicate that APM mixed with either 50 or 75% GF-120 applied to bait stations can be attractive to female C. capitata for up to 3 wk longer than the standard sprayed GF-120 NF.

Evaluation of methyl eugenol and cue-lure traps with solid lure and insecticide dispensers for fruit fly monitoring and male annihilation in the Hawaii Areawide Pest Management Program.

Methyl eugenol (ME) and cue-lure (C-L) traps with solid lure dispensers were deployed in areas with low and high populations of oriental fruit fly, Bactrocera dorsalis (Hendel), and melon fly, Bactrocera cucurbitae (Coquillett), respectively. In low-density areas, standard Jackson traps or Hawaii Fruit Fly Areawide Pest Management (AWPM) traps with FT Mallet ME wafers impregnated with dimethyl dichloro-vinyl phosphate (DDVP) or AWPM traps with Scentry ME cones and vapor tape performed equally as well as standard Jackson traps with liquid ME/C-L and naled. Standard Jackson traps or AWPM traps with FT Mallet C-L wafers impregnated with DDVP or AWPM traps with Scentry C-L plugs with vapor tape performed equally as well as standard Jackson traps with a lure-naled solution. In high density areas, captures with traps containing FT Mallet wafers (ME and C-L) outperformed AWPM traps with Scentry cones and plugs (ME and C-L) with DDVP insecticidal strips over a 6-mo period. Captures of B. dorsalis and B. cucurbitae with wafers containing both ME and raspberry ketone (FT Mallet MC) were equivalent to those containing separate lures. From a worker safety and convenience standpoint, FT Mallet ME and C-L wafers with DDVP or Scentry plugs, with or without DDVP vapor tape, are more convenient and safer to handle than standard liquid insecticide formulations used for monitoring and male annihilation programs in Hawaii, and for detections traps used on the U.S. mainland. Furthermore, the FT Mallet MC wafer might be used in a single trap in place of two separate traps for detection of both ME and C-L responding fruit flies.