Visual targets for capture and management of house flies, Musca domestica L.

House flies and stable flies were collected on a Florida dairy farm using a commercial Alsynite sticky cylinder trap that was either used alone or covered with white, blue, or black outdoor awning fabric. Collections of both species of flies were highest on exposed Alsynite (house flies, 506.2 flies/day; stable flies, 19.1) followed by blue fabric (house flies, 308.1 flies/day; stable flies 12.5). Responses of both species to white and black fabric were 70% lower than to either of the former materials. When blue fabric was used to cover 50% of the surface area of Alsynite cylinders, house fly responses were significantly higher (290.2 flies/day) than to blue fabric alone (165.2); stable fly responses to the bi-colored target were significantly higher (152.6) than to Alsynite alone (93.8). Comparison of fly counts in the blue-covered versus uncovered Alsynite with traps of a single material indicated that house fly attraction to blue fabric was enhanced by the presence of clear Alsynite, whereas stable fly attraction to Alsynite was enhanced by the presence of blue fabric. The presence of blue+Alsynite visual targets increased collections of house flies in pans of dry fly bait but not in baited jug traps. Visual targets treated with 1.2% bifenthrin controlled >50% and 90% of house flies in large cages by days two and four after placement, respectively.     

Releases of Psyttalia fletcheri (Hymenoptera: Braconidae) and sterile flies to suppress melon fly (Diptera: Tephritidae) in Hawaii

Ivy gourd, Coccinia grandis (L.) Voigt, patches throughout Kailua-Kona, Hawaii Island, HI, were identified as persistent sources of melon fly, Bactrocera cucurbitae (Coquillett). These patches had a low incidence of Psyttalia fletcheri (Silvestri), its major braconid parasitoid natural enemy in Hawaii, and were used to evaluate augmentative releases of P. fletcheri against melon fly. In field cage studies of releases, numbers of melon flies emerging from ivy gourd fruit placed inside treatment cages were reduced up to 21-fold, and numbers of parasitoids were increased 11-fold. In open field releases of P. fletcheri into ivy gourd patches, parasitization rates were increased 4.7 times in release plots compared with those in control plots. However, there was no significant reduction in emergence of melon flies from fruit. In subsequent cage tests with sterile melon flies and P. fletcheri, combinations of sterile flies and P. fletcheri produced the greatest reduction (9-fold) in melon fly emergence from zucchini, Cucurbita pepo L. Reductions obtained with sterile flies alone or in combination with parasitoids were significantly greater than those in the control, whereas those for parasitoids alone were not. Although these results suggest that the effects of sterile flies were greater than those for parasitoids, from a multitactic melon fly management strategy, sterile flies would complement the effects of P. fletcheri. Cost and sustainability of these nonchemical approaches will be examined further in an ongoing areawide pest management program for melon fly in Hawaii.     

Parasites that attack stable fly and house fly (Diptera: Muscidae) puparia during the winter on dairies in northwestern Florida

Throughout the winter and early spring months, stable fly, Stomoxys calcitrans (L.), and house fly, Musca domestica L., puparia were collected from silage, hay, and manure from six dairies in northwestern Florida and evaluated for parasitism. Of the puparia producing flies or parasites, 23% of the stable flies and 46% of the house flies were parasitized. The predominant parasite observed attacking muscoid flies (76% for stable flies and 58% for house flies) was Spalangia cameroni Perkins. Muscidifurax sp. was recovered from 11 and 36% of the stable fly and house fly pupae, respectively. Other parasite species encountered were Spalangia endius Walker and S. nigroaenea Curtis. Significantly more parasitized fly pupae were collected from silage than from hay residues or manure. Winter and early spring parasite populations in northwestern Florida appear to be present as long as viable fly pupae are available to support the developing parasites.     

Studying the “fly factor” phenomenon and its underlying mechanisms in house flies Musca domestica

The “fly factor” was first discovered >60 years ago and describes the phenomenon that food currently or previously fed on by flies attracts more foraging flies than the same type and amount of food kept inaccessible to flies. Since then, there has been little progress made to understanding this phenomenon. Our objectives were (i) to demonstrate the existence of the fly factor in house flies, Musca domestica and (ii) to study underlying mechanisms that may cause or contribute to the fly factor. In 2‐choice laboratory bioassays, we obtained unambiguous evidence for a fly factor phenomenon in house flies, in that we demonstrated that feeding flies are more attractive to foraging flies than are nonfeeding flies, and that fed‐on food is more attractive to foraging flies than is “clean” food. Of the potential mechanisms (fly excreta, metabolic output parameters [elevated temperature, relative humidity, carbon dioxide]), causing the fly factor, fly feces, and regurgitate do attract foraging flies but none of the metabolic output parameters of feeding flies does. Even though feeding flies produce significantly more CO₂ than nonfeeding flies, elevated levels of CO₂ have no behavior‐modifying effect on flies. Preferential attraction of house flies to fly feces and regurgitate indicates that the flies sense airborne semiochemicals emanating from these sources. Hypothesizing that these semiochemicals are microbe‐produced, future studies will aim at isolating and mass producing these microbes to accumulate semiochemicals for identification.     

Salivary gland hypertrophy virus of house flies in Denmark: prevalence, host range, and comparison with a Florida isolate

House flies (Musca domestica) infected with Musca domestica salivary gland hypertrophy virus (MdSGHV) were found in fly populations collected from 12 out of 18 Danish livestock farms that were surveyed in 2007 and 2008. Infection rates ranged from 0.5% to 5% and averaged 1.2%. None of the stable flies (Stomoxys calcitrans), rat-tail maggot flies (Eristalis tenax) or yellow dung flies (Scathophaga stercoraria) collected from MdSGHV-positive farms displayed characteristic salivary gland hypertrophy (SGH). In laboratory transmission tests, SGH symptoms were not observed in stable flies, flesh flies (Sarcophaga bullata), black dump flies (Hydrotaea aenescens), or face flies (Musca autumnalis) that were injected with MdSGHV from Danish house flies. However, in two species (stable fly and black dump fly), virus injection resulted in suppression of ovarian development similar to that observed in infected house flies, and injection of house flies with homogenates prepared from the salivary glands or ovaries of these species resulted in MdSGHV infection of the challenged house flies. Mortality of virus-injected stable flies was the highest among the five species tested. Virulence of Danish and Florida isolates of MdSGHV was similar with three virus delivery protocols, as a liquid food bait (in sucrose, milk, or blood), sprayed onto the flies in a Potter spray tower, or by immersiion in a crude homogenate of infected house flies. The most effective delivery system was immersion in a homogenate of ten infected flies/ml of water, resulting in 56.2% and 49.6% infection of the house flies challenged with the Danish and Florida strains, respectively.     

Dividing the pie: differential dung pat size utilization by sympatric Haematobia irritans and Musca autumnalis

Horn flies [Haematobia irritans (Diptera: Muscidae) (L.)] and face flies [Musca autumnalis (Diptera: Muscidae) De Geer] use the same larval resource, but their interactions are poorly studied. Dung pats (n = 350) were core sampled in the summers of 2012 and 2013 from irrigated pastures in Pomona, California, U.S.A. (34°03′N, 117°48′W) and held for face fly and horn fly emergence. Surface areas and estimated weights were recorded for each whole pat. Almost half (42.0%) of the pat cores yielded neither fly, 29.7% yielded horn flies only, 12.9% yielded face flies only and 15.4% yielded both flies. Of the fly‐positive pats, surface area and mass were larger for face fly‐occupied pats, whereas horn fly‐occupied pats were smaller. Pats shared by the two species were intermediate. Horn flies per positive core were unaffected by the absence/presence of face flies, but half as many face flies emerged when pats were co‐inhabited by horn flies. Face flies inhabited larger pats, which might better resist heating and drying, to which they are susceptible; horn flies inhabited a broad pat size range. Horn fly tolerance of lower dung moisture probably allows horn flies to colonize and survive in a wide range of pats in dry areas like southern California.     

Effects of horn fly and house fly (Diptera: Muscidae) larvae on the development of parasitic nematodes in bovine dung

Laboratory studies were conducted to determine the effects of horn fly, Haematobia irritans (L.), and house fly, Musca domestica L., larvae on the development of a mixed population of parasitic nematodes in compressed and crumbled bovine dung. Fresh dung (100 g per sample) from a single calf passing trichostrongyle type eggs was infested with 150 horn fly or 150 house fly eggs. After 14-15 d, more horn flies and house flies had emerged from the compressed dung than from the crumbled dung, but more third stage parasitic nematode larvae were recovered from the crumbled dung containing either fly species than from dung containing no flies.     

Repellent effectiveness of seven plant essential oils,sunflower oil and natural insecticides against horn flies on pastured dairy cows and heifers

Plant essential oils (basil, geranium, balsam fir, lavender, lemongrass, peppermint, pine and tea tree), mixed with either sunflower oil or ethyl alcohol, were applied at 5% concentrations to the sides of Holstein cattle. Pastured cattle treated with essential oils diluted in sunflower oil had less flies than the untreated control for a 24‐h period. However, the essential oil treatments were not significantly different than the carrier oil alone. Barn‐held heifers treated with essential oils and sunflower oil alone had significantly less flies than the untreated control for up to 8 h after treatment. Basil, geranium, lavender, lemongrass and peppermint repelled more flies than sunflower oil alone for a period ranging from 1.5 to 4 h after treatments applied to heifers. All essential oils repelled > 75% of the flies on the treated area for 6 and 8 h on pastured cows and indoor heifers, respectively. Geranium, lemongrass and peppermint stayed effective for a longer duration. Essential oils mixed with ethyl alcohol demonstrated less repellence than when mixed with the carrier oil. Safer's soap, natural pyrethrins without piperonyl butoxide and ethyl alcohol alone were not efficient at repelling flies. Essential oils could be formulated for use as fly repellents in livestock production.     

Mortality of Rhagoletis indifferens exposed to hydrolyzed protein baits and spinosad in the absence and presence of yeast extract

Western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), is the major quarantine pest of sweet cherry, Prunus avium (L.) L. (Rosaceae), in the Pacific northwest of the USA and in British Columbia in Canada. Although spinosad bait (GF‐120 NF Naturalyte® Fruit Fly Bait) is used for the control of R. indifferens in this region, the effects of alternate food sources on fly responses to this bait have not been studied. In this study, experiments were conducted to determine mortalities of flies exposed to hydrolyzed protein baits in the presence of sugar only and sugar + yeast extract food. All baits contained Entrust® (termed ‘spinosad alone’). When flies were exposed to GF‐120 with or without added ammonia compounds (uric acid, ammonium acetate, and ammonium carbonate) for 48 h, mortalities were higher in the presence of sugar only than in the presence of sugar + yeast extract, but when flies were exposed to spinosad alone, mortalities were similar in presence of either of the two foods. In another experiment comparing GF‐120, Nu‐Lure, Mazoferm, Baker's yeast extract, and spinosad alone, mortalities in the GF‐120, Mazoferm, and Baker's yeast extract treatments were higher in the presence of sugar only than in the presence of sugar + yeast extract, but in the Nu‐Lure and spinosad alone treatments, mortalities were similar in the presence of either of the two foods. Overall results suggest that the indirect effects of yeast extract food on mortality are dependent on bait type and that mortalities caused by spinosad alone and baits are similar. Nu‐Lure and spinosad alone may have an advantage over other treatments for fly control, because their effects do not appear to be affected by the presence of nitrogenous food.     

House fly (Diptera: Muscidae) activity near baits containing (Z)-9-tricosene and efficacy of commercial toxic fly baits on a southern California dairy

Sticky card captures of house flies, Musca domestica L. (Diptera: Muscidae), were used to compare efficacy of screen-covered baits containing sugar, sugar and 0.1% (Z)-9-tricosene, sugar and 1.0% (Z)-9-tricosene, Golden Malrin [1.1% methomyl and 0.049% (Z)-9-tricosene], and Quick-Bayt [0.5% imidacloprid and 0.1% (Z)-9-tricosene]. The QuickBayt treatment caught more flies per hour (mean = 116.5) than sugar alone (mean = 81.0), but the addition of (Z)-9-tricosene to sugar did not increase fly capture compared with sugar alone. More males (65% of total) than females were collected on the sticky cards for all treatments. Fly kill by plain sugar (control) and the commercial baits Golden Malrin, QuikStrike Fly Abatement strips (1.0% nithiazine), and QuickBayt was tested over a 90-min period. An average of 1.4, 5.6, 363.0, and 1,266.0 flies were killed using sugar, Golden Malrin, QuikStrike, and QuickBayt, respectively. The similarity between Golden Malrin and plain sugar reflects severe resistance to this once effective methomyl bait. A no-choice feeding assay using lab-reared methomyl-susceptible and methomyl-resistant house flies was conducted with and without (Z)-9-tricosene. Adult mortality was significantly higher in the methomyl-susceptible strain exposed to treatments containing methomyl. Lower consumption of the methomyl treatments by resistant flies suggested resistance was behavioral and mortality was not influenced by (Z)-9-tricosene for either fly strain.     

秋家蝇对两种卫矛植物的趋性

卫矛是常见的绿化植物,而秋家蝇Musca autumnalis De Geer是畜牧业的重要昆虫。在室内利用Y型嗅觉仪对欧洲卫矛Euonymus europaeus和胶东卫矛E. kiautschovicus气味对秋家蝇Musca autumnalis De Geer的引诱效果进行了研究。结果表明：两种植物都对秋家蝇的雌性成虫有引诱作用,而欧洲卫矛引诱效果更好。进一步对叶和花的气味进行的观察表明,卫矛吸引秋家蝇主要依靠花的气味,但叶的气味也有一定的吸引作用; 叶的气味对花的引诱效果有增效作用。利用几种试剂（水、乙醇和正己烷）对欧洲卫矛花的气味物质进行了抽提,测试结果表明水或乙醇抽提物比正己烷抽提物引诱效果更好; 冷冻花与新鲜花的引诱效果没有显著的差异。     

Response of Ceratitis capitata, Bactrocera dorsalis, and Bactrocera cucurbitae (Diptera: Tephritidae) to metabolic stress disinfection and disinfestation treatment

Metabolic stress disinfection and disinfestation (MSDD) is a postharvest treatment designed to control pathogens and arthropod pests on commodities that combines short cycles of low pressure/vacuum and high CO2 with ethanol vapor. Experiments were conducted to evaluate the effect of MSDD treatment on various life stages of Ceratitis capitata (Wiedemann), Mediterranean fruit fly; Bactrocera dorsalis Hendel, oriental fruit fly; and Bactrocera cucurbitae Coquillett, melon fly, in petri dishes and in papaya, Carica papaya L., fruit. In some experiments, the ethanol vapor phase was withheld to separate the effects of the physical (low pressure/ambient pressure cycles) and chemical (ethanol vapor plus low pressure) phases of treatment. In the experiments with tephritid fruit fly larvae and adults in petri dishes, mortality was generally high when insects were exposed to ethanol and low when ethanol was withheld during MSDD treatment, suggesting that ethanol vapor is highly lethal but that fruit flies are quite tolerant of short periods of low pressure treatment alone. When papaya fruit infested with fruit fly eggs or larvae were treated by MSDD, they produced fewer pupae than untreated control fruit, but a substantial number of individuals developed nonetheless. This suggests that internally feeding insects in fruit may be partially protected from the toxic effects of the ethanol because the vapor does not easily penetrate the fruit pericarp and pulp. MSDD treatment using the atmospheric conditions tested has limited potential as a disinfestation treatment for internal-feeding quarantine pests such as fruit flies infesting perishable commodities.     

Aggressive behaviours of female Drosophila melanogaster are influenced by their social experience and food resources

Abstract Aggressive behaviours of female Drosophila melanogaster (Meigen) (Diptera: Drosophilidae) were studied in the laboratory. These behaviours included 'approach', a seemingly intentional movement of a fly to another fly, 'lunge', a dash at another fly, and 'wings erect', a brief erection of wings toward another fly. These behaviours were influenced by social experience and food resources. First, event frequencies of aggressive behaviours were higher in flies that had been held in isolation than in those that had been held in crowded conditions. This difference was the result of the social experience of attacking flies and not that of attacked flies. Second, flies showed aggressive behaviours more frequently when they were on food containing yeast colonies than when they were on food without yeast colonies. Third, flies conditioned to a food solution containing live yeast prior to observation showed lower frequency of aggressive behaviours than flies conditioned to a boiled food solution. Development of aggressive behaviours became apparent one day after eclosion.     

Susceptibility of low-chill blueberry cultivars to Mediterranean fruit fly, oriental fruit fly, and melon fly (Diptera: Tephritidae)

No-choice tests were conducted to determine whether fruit of southern highbush blueberry, Vaccinium corymbosum L., hybrids are hosts for three invasive tephritid fruit flies in Hawaii. Fruit of various blueberry cultivars was exposed to gravid female flies of Bactrocera dorsalis Hendel (oriental fruit fly), Ceratitis capitata (Wiedemann) (Mediterranean fruit fly), or Bactrocera cucurbitae Coquillet (melon fly) in screen cages outdoors for 6 h and then held on sand in the laboratory for 2 wk for pupal development and adult emergence. Each of the 15 blueberry cultivars tested were infested by oriental fruit fly and Mediterranean fruit fly, confirming that these fruit flies will oviposit on blueberry fruit and that blueberry is a suitable host for fly development. However, there was significant cultivar variation in susceptibility to fruit fly infestation. For oriental fruit fly, 'Sapphire' fruit produced an average of 1.42 puparia per g, twice as high as that of the next most susceptible cultivar 'Emerald' (0.70 puparia per g). 'Legacy', 'Biloxi', and 'Spring High' were least susceptible to infestation, producing only 0.20-0.25 oriental fruit fly puparia per g of fruit. For Mediterranean fruit fly, 'Blue Crisp' produced 0.50 puparia per g of fruit, whereas 'Sharpblue' produced only 0.03 puparia per g of fruit. Blueberry was a marginal host for melon fly. This information will aid in development of pest management recommendations for blueberry cultivars as planting of low-chill cultivars expands to areas with subtropical and tropical fruit flies. Planting of fruit fly resistant cultivars may result in lower infestation levels and less crop loss.     

Disease dynamics and persistence of Musca domestica salivary gland hypertrophy virus infections in laboratory house fly (Musca domestica) populations

Past surveys of feral house fly populations have shown that Musca domestica salivary gland hypertrophy virus (MdSGHV) has a worldwide distribution, with an average prevalence varying between 0.5% and 10%. How this adult-specific virus persists in nature is unknown. In the present study, experiments were conducted to examine short-term transmission efficiency and long-term persistence of symptomatic MdSGHV infections in confined house fly populations. Average rates of disease transmission from virus-infected to healthy flies in small populations of 50 or 100 flies ranged from 3% to 24% and did not vary between three tested geographical strains that originated from different continents. Introduction of an initial proportion of 40% infected flies into fly populations did not result in epizootics. Instead, long-term observations demonstrated that MdSGHV infection levels declined over time, resulting in a 10% infection rate after passing through 10 filial generations. In all experiments, induced disease rates were significantly higher in male flies than in female flies and might be explained by male-specific behaviors that increased contact with viremic flies and/or virus-contaminated surfaces.     

Normal prion protein in Drosophila enhances the toxicity of pathogenic polyglutamine proteins and alters susceptibility to oxidative and autophagy signaling modulators

To investigate the in vivo functions of normal prion protein (PrP) in Drosophila, we utilized characterized transgenic flies expressing 3F4-tagged mouse PrP (Mo-PrP^3F4). The neurotoxicity of pathogenic Machado-Joseph Disease (MJD) glutamine (Q) 78 and 127Q proteins were enhanced by the co-expression of Mo-PrP^3F4 in the fly eyes, while the eyes of controls flies and flies expressing Mo-PrP^3F4 alone or together with MJD-Q27 or 20Q proteins did not show any defect. Susceptibilities to H₂O₂, paraquat, and Dithiothreitol (DTT) were altered in Mo-PrP^3F4 flies. In addition, Mo-PrP^3F4 flies were significantly more susceptible to the perturbation of autophagy signaling by an autophagy inhibitor, 3-methyladenine (3-MA), and inducer, LiCl. Taken together, our data suggest that Mo-PrP^3F4 may enhance the neurotoxicity of pathogenic Poly-Q proteins by perturbing oxidative and autophagy signaling.     

Impact of control measures and dynamics of sand flies in southern Brazil

We report the results of control measures introduced to reduce the density of sand flies in domiciles and subsequent monitoring of the effects of these measures on the sand fly populations. The most common species of sand flies were Nyssomyia neivai and Nyssomyia whitmani, which are naturally infected by Leishmania. A total of 268,382 (93.4%) sand flies were collected in ecotypes constructed with the aim of attracting sand flies, and 19,091 (6.6%) sand flies were collected in the ecotypes consisting of residences and other buildings. Human actions determine the growth or reduction of the sand fly population in human‐occupied space. Understanding the dynamics of sand flies in this environment can substantially contribute to the prevention of cutaneous leishmaniasis.     

Susceptibility of black soldier fly (Diptera: Stratiomyidae) larvae and adults to four insecticides

Dosage-mortality regressions were determined for black soldier fly, Hermetia illucens (L.), larvae fed cyromazine or pyriproxifen treated media. Cyromazine LC50 for larvae dying before becoming prepupae ranged from 0.25 to 0.28 ppm with dosage-mortality regression slopes between 5.79 and 12.04. Cyromazine LC50s for larvae dying before emergence ranged from 0.13 to 0.19 ppm with dosage-mortality regression slopes between 3.94 and 7.69. Pyriproxifen dosage-mortality regressions were not generated for larvae failing to become prepupae since <32% mortality was recorded at the highest concentration of 1,857 ppm. LC50s for larvae failing to become adults ranged from 0.10 to 0.12 ppm with dosage mortality-regression slopes between 1.67 and 2.32. Lambda-cyhalothrin and permethrin dosage-mortality regressions were determined for wild adult black soldier flies and house flies, Musca domestica L., and for susceptible house flies. Our results indicate that the wild house fly, unlike the black soldier fly, population was highly resistant to each of these pyrethroids. Regression slopes for black soldier flies exposed to lambda-cyhalothrin were twice as steep as those determined for the wild house fly strain. Accordingly, LC50s for the black soldier fly and susceptible house fly were 10- to 30-fold lower than those determined for wild house flies. The differential sensitivity between wild black soldier flies and house flies might be due to behavioral differences. Adult house flies usually remain in animal facilities with the possibility of every adult receiving pesticide exposure, while black soldier fly adults are typically present only during emergence and oviposition thereby limiting their exposure.     

Exchange of Inoculum of Beauveria bassiana (Bals.) Vuill. (Hyphomycetes) Between Adult Flies of the Cabbage Maggot Delia radicum L. (Diptera: Anthomyiidae)

Adult cabbage maggots ( Delia radicum L.) were exposed to dry conidia of isolates of several hyphomycetous fungi by placing them in a centrifuge tube containing conidia, then releasing them into small screened plastic cages. Mortality was assessed after 48, 120 and 160 h. A Beauveria bassiana isolate (P89 from Musca domestica ) caused the highest mortality after 48 h, resulting in 100% mortality and 100% infection. Isolate L90 ( B. bassiana ) and one Metarhizium anisopliae isolate (ARSEF 2521) also caused fatal infection in more than 50% of the flies. To investigate exchange of inoculum, flies were placed in a small container with a dry powder formulation containing B. bassiana (Mycotrol ® ) on the bottom. The flies were removed to small screened cages containing untreated flies. This experiment confirmed the ability of flies to pass inoculum to other flies. In a similar experiment, one treated fly was placed in each cage with one untreated fly. When each fly died, one untreated fly was added to each cage after the dead fly was removed. This study showed that fly to fly transfer of fatal doses of inoculum was possible for a series of at least six flies. When female flies were exposed to the inoculum, then transferred to small cages containing males and an oviposition substrate, no eggs were laid. Further studies are being conducted to develop a system where flies attracted to a trap will be inoculated with the fungus and spread it to a field population.     

Effectiveness of plastic matrix lures and traps against Bactrocera dorsalis and Bactrocera cucurbitae in Hawaii

Trapping trials were conducted in two locations on the island of Hawaii with plastic‐matrix formulations of methyl eugenol (ME) (1‐2‐dimethoxy‐4‐allylbenzene) and cuelure (CL) [4‐(p‐acetoxyphenyl)‐2‐butanone] in traps with or without a toxicant (2, 2‐dichlorovinyl dimethyl phosphate, DDVP) against wild fly populations of oriental fruit fly, Bactrocera dorsalis (Hendel) and melon fly, Bactrocera cucurbitae (Coquillett) respectively. Both 5 g disks and 10 g cones of ME and 2 g plugs of CL caught flies for >9 months which varied relative to the population fluctuations. In all of these trials a one‐way entrance design trap caught more flies than the toxicant‐baited trap. The similar‐sized entrance holes (0.70 cm) of the latter may have slowed the dispersal of the toxicant vapour, thus causing flies to be repelled or killed outside the entrance to the trap when DDVP vapour was evolving at a maximum rate. The effect decreased as the toxicant aged. One‐way entrance traps are appropriate where toxicant traps are not allowed (e.g. organic farms), present a health hazard (e.g. yards with children), or would need to be replaced more frequently than lures. The results of these studies are discussed in relation to areawide fruit fly suppression programs where large populations of these flies are persistent, as well as to detection programs in areas where fruit flies have not established.