Turning Ultraviolet Light Traps On and Off Increases Their Attraction to House Flies (Diptera: Muscidae).

Pairs of electrocutor-grid ultraviolet light traps were assigned to three treatments to evaluate the effects of illumination events, e.g., light traps turned on, on house fly, Musca domestica L., attraction as indicated by numbers of flies captured by the traps. Both traps in treatment 1 were illuminated constantly (no illumination event). Both traps in treatment 2 were turned on, illuminated for 1 h, then turned off for 1 h, then repeated (1 illumination event every 2 h). Traps in treatment 3 were operated singularly. One trap was turned on for 1 h, then turned off. As it turned off, the other trap turned on for 1 h, then turned off, then repeated (1 illumination event every hour). The mean number of flies attracted per trap pair was significantly greater in treatment 1 than in treatments 2 or 3. However, in treatment 3, with one trap illuminated at a time and hourly illumination events, the mean fly catch was just 27% less, numerically, than the mean number of flies attracted to treatment 1 with both traps illuminated constantly. The effects of intermittent lighting and its potential use are discussed.

Evaluation of the DynaTrap Flylight (DT-3009) Against House Flies and Stable Flies (Diptera: Muscidae) Under Indoor Conditions.

Ultraviolet light traps are commonly used to manage house flies in indoor situations. Many indoor traps are longer than their 46-cm fluorescent tubes and have glue boards to capture attracted flies. Smaller traps have been sold to use in homes and small rooms, but few if any trap evaluations can be found in the literature. One trap, the DynaTrap Flylight DT-3009 (DTFL) has become quite common and a performance evaluation between it and an open-front commercial trap seemed warranted. Evaluations were conducted at the USDA-ARS-CMAVE laboratory in Gainesville, FL. The DTFL and the Gardner GT-200 open-front trap were evaluated individually and then in pairs. Traps were placed approximately 90 cm above the floor at the edge of a 2.4- × 0.76-m wide counter. Traps tested individually were centered on the long axis of the counter. For paired tests, traps were placed approximately 2.1 m apart. Fifty mixed-sex, 3- to 5-d-old house or stable flies were released and counts of captured flies were made after 1, 4, and 24 h. In individual tests, the DTFL and the GT-200 captured 38 and 76% of the house flies, respectively, and 3 and 18% of the stable flies, respectively, after 4 h. At 4 h in paired tests, the DTFL and the GT-200 captured 3 and 66% of the house flies, respectively, and 2 and 16% of the stable flies, respectively. Depending on the intended use, either trap was considered efficacious in capturing house flies when used alone. Differences in trap performance are discussed.

Improved capture of stable flies (Diptera: Muscidae) by placement of knight stick sticky fly traps protected by electric fence inside animal exhibit yards at the Smithsonian's National Zoological Park.

Stable flies are noxious blood-feeding pests of exotic animals at zoological parks, inflicting painful bites, and causing discomfort to animals. Stable fly management is difficult because of the flies' tendency to remain on the host animals only when feeding. Non-toxic traps can be efficient but traps placed around exhibit perimeters captured fewer-than-expected numbers of flies. By surrounding traps with square electric fence enclosures, traps could be placed in the exhibits with the host animals and compared with an equal number of traps placed along perimeter fences. During a 21-week study, traps inside exhibits captured 5× more stable flies than traps placed along exhibit perimeters. Traps inside exhibits tended to show more fluctuations in fly populations than traps along perimeters. The increased numbers of flies captured using this technique should provide relief from this pestiferous fly and greatly improve animal health and welfare. We believe this to be the first study where traps were used to capture stable flies in exhibit yards at a zoological park.

Development and Evaluation of an Attractive Self-Marking Ovitrap to Measure Dispersal and Determine Skip Oviposition in Aedes albopictus (Diptera: Culicidae) Field Populations.

Aedes albopictus (Skuse) is a container-breeding species with considerable public health importance. To date, Ae. albopictus oviposition behavior has been assessed in outdoor conditions, but only with laboratory-reared specimens. In outdoor large-cage and field studies, we used an attractive self-marking ovipositional device to assess Ae. albopictus skip oviposition behavior. In field studies, 37 wild Ae. albopictus that visited an attractive self-marking ovisite were subsequently captured at a sticky ovitrap within a 4-d period. Because the average Ae. albopictus gonotrophic period is 4.5-6 d, the wild-caught Ae. albopictus visited at least two oviposition sites within a single gonotrophic period. This provided field-based indirect evidence of skip oviposition. The mean distance traveled (MDT) during the 20-d evaluations ranged from 58 to 78 m. The maximum observed distance traveled was 149 m, which was the outer edge of our trapping ability. As populations of Ae. albopictus increased, the MDT during the 4- and 20-d post-marking period increased significantly. Additional observations of wild-marked and captured Aedes triseriatus (Say) are discussed.

The Effects of Larval Habitat Quality on Aedes albopictus Skip Oviposition.

Aedes albopictus is an invasive mosquito species that transmits human-disease-causing pathogens. It is a container-inhabiting species that oviposits in resource-limited habitats. To mitigate larval competition, Ae. albopictus females may choose to distribute eggs from a single gonotrophic cycle among multiple containers through skip oviposition. With the use of individual females released in indoor and outdoor caged trials, we evaluated the oviposition choices made by gravid Ae. albopictus offered larval habitats with different qualities. Our results demonstrate that Ae. albopictus performs skip oviposition and that the degree of egg distribution is related to the quality of the larval habitat. In a 4-choice arena, individual Ae. albopictus oviposited in fewer containers when presented with ovisites of high-quality larval habitat (uncrowded conditions) compared with oviposition in low-quality (crowded conditions) larval habitats. Additionally, the females selectively oviposited in high-quality habitats when offered both low- and high-quality habitats, but distributed eggs more evenly among multiple high-quality habitats. Our results have important implications for mosquito management plans that include the use of lethal ovitraps, as well as the role of this behavior in distribution of disease-causing pathogens.

Laboratory Colonization of the Blow Flies, Chrysomya megacephala (Diptera: Calliphoridae) and Chrysomya rufifacies (Diptera: Calliphoridae).

Chrysomya megacephala (F.) and Chrysomya rufifacies (Macquart) were colonized so that larval growth rates could be compared. Colonies were also established to provide insight into the protein needs of adult C. rufifacies and developmental rates of the ensuing larvae. The C. megacephala and C. rufifacies laboratory colonies were reared for five and six generations, respectively, at 28°C. C. megacephala developmental mean rate from egg to adult was 20.4 ± 0.38 d. First-instar larvae emerge in 1.4 ± 0.24 d, second-instar larvae develop in 2.6 ± 0.38 d and third instars occur at 6.3 ± 0.72 d. Development from egg to pupation occurred in 12 ± 1.10 d. C. rufifacies developed at a mean rate of 16.2 ± 0.78 d from egg to adult emergence. Each stage occurred in succession from first-instar larvae 1.1 ± 0.25 d, second-instar larvae developed 2.3 ± 0.25 d later, and the third-instar larvae developed 5.7 ± 0.41 d later. The larvae pupated 10.0 ± 0.57 d after oviposition. Both of these flies can be collected in the wild and easily colonized using conditioned chicken as an oviposition and larval medium. C. megacephala apparently prefers a lower development and maintenance temperature than C. rufifacies, as evidenced by the high pupal mortality. Laboratory-reared C. rufifacies benefited from bloodmeal as a protein supplement to enhance egg production. C. rufifacies larvae were not observed preying on each other and additional larval species were not provided to serve as prey.

Spatial distribution, seasonality and trap preference of stable fly, Stomoxys calcitrans L. (Diptera: Muscidae), adults on a 12-hectare zoological park.

Although this study was originally designed to compare the efficacy of two different stable fly traps within 10 sites at a 12-ha zoological park, seasonal and spatial population distribution data were simultaneously collected. The two traps included an Alsynite fiberglass cylindrical trap (AFT) and a blue-black cloth target modified into a cylindrical trap (BCT). Both traps were covered with sticky sleeves to retain the attracted flies. Paired trap types were placed at sites that were 20-100 m apart. Distance between trap pairs within sites ranged from 1 to 2 m, and was limited by exhibit design and geography. Both trap types reflect/refract ultraviolet (UV) light which attracts adult S. calcitrans. During this 15-week study, AFTs captured significantly more stable flies than the BCTs at 8 of the 10 sites. Of the 12,557 stable flies found on the traps, 80% and 20% were captured by AFTs and BCTs, respectively. The most attractive trap site at the zoo was at the goat exhibit where most stable flies were consistently captured throughout the study. This exhibit was 100 m from the other exhibits, next to a small lake, and adjacent to a field containing pastured exotic ungulates, rhea and ostrich. Stable fly populations peaked in early June then slowly decreased as the last trapping date approached. We believe this to be the first seasonality data collected at a zoological park. Results demonstrate the use of urban zoos by stable flies and the need to develop environmentally friendly stable fly management systems for zoos.

Topical Toxicity and Repellency Profiles of 17 Essential Oil Components against Insecticide-Resistant and Susceptible Strains of Adult Musca domestica (Diptera: Muscidae).

The house fly is a significant pest in agriculture and human health that is increasingly difficult to manage due to multiple limitations including resistance development. To explore alternative pesticides, the topical toxicity and repellency profiles of 17 essential oil components (EOCs) were evaluated against a resistant and a susceptible strain of house fly, Musca domestica L., using topical application and Y-tube olfactometers, respectively. Six of the most toxic EOCs based on the LD50 were further investigated against a susceptible strain of house fly. Thymol, (+)-pulegone, eugenol, and carvacrol were always the top four most toxic chemicals tested against the resistant house fly strain. Little to no resistance was observed to the top six EOCs based on the comparison of the results between resistant and susceptible house fly strains. P-Cymene, citronellic acid, R-(+)-limonene, linalool, γ-terpinene, estragole, and eugenol were repellent to adult house flies at certain concentrations while (-)-carvone and thymol were attractive to adult house flies. This screening of a wide variety of individual EOCs provides a stronger foundation of information for further research. This should encourage further investigation into the topical toxicity and repellency in field studies, which will provide more insight into the performance of biopesticides for house fly management and potential commercialization.

High-throughput mosquito and fly bioassay system for natural and artificial substrates treated with residual insecticides.

A high-throughput bioassay system to evaluate the efficacy of residual pesticides against mosquitoes and muscid flies with minimal insect handling was developed. The system consisted of 4 components made of readily available materials: 1) a CO2 anaesthetizing chamber, 2) a specialized aspirator, 3) a cylindrical flat-bottomed glass bioassay chamber assembly, and 4) a customized rack.

Comparison of Trap and Equine Attraction to Mosquitoes.

Mosquitoes are pests of horses, but mosquito trap efficacy data, especially the ability of traps to protect horses, are lacking. Studies were conducted to investigate the comparative attraction between traps and horses, increase trap attraction by adding horse odors to the airstream of a trap, determine the spatial distribution of adult mosquitoes, estimate the numbers of mosquitoes feeding on horses, determine the relative attraction of horses to mosquitoes, and estimate the range of mosquitoes' attraction between two horses. When a horse and a mosquito trap were placed 3.5 m apart, there was a significant reduction in mosquitoes entering the trap. Adding horse odors to the airstream of a trap produced equivocal results because the horse providing the odors influenced the trap catches. Mosquitoes were not evenly distributed across the study site, which emphasized the importance of trap placement. Vacuuming mosquitoes from the horses in different seasons demonstrated that 324 and 359 mosquitoes per hour were feeding during the two studies. Separate analysis of data from the two horses vacuumed simultaneously revealed that one horse attracted twice as many mosquitoes as the other. This caused the results of a study to determine the attraction range of two horses moved from 3.5 to 20.4 m apart to be inconclusive.

Semi-field evaluation of a novel controlled release device using transfluthrin as spatial repellent to prevent entry of mosquitoes into military tents.

Mosquitoes can impact military operational readiness by transmission of disease-causing pathogens or through secondary effects, e.g., annoyance and bites. The focus of this research was to determine if an array of novel controlled release passive devices (CRPD) utilizing the spatial repellent, transfluthrin (TF), as the active ingredient could prevent entry of mosquitoes into military tents for up to 4 weeks. The TF-charged CRPDs were spaced along six strands of monofilament and hung across the tent entrance. Efficacy was evaluated with caged Aedes aegypti to indicate knockdown/mortality effects, and four species of free-flying mosquitoes, Ae. aegypti, Aedes taeniorhynchus, Anopheles quadrimaculatus and Culex quinquefasciatus, to indicate repellent effects. Bioassay cages containing Ae. aegypti were hung vertically at 0.5, 1.0 and 1.5 â€‹m above ground level at designated locations inside of the tents. Knockdown/mortality counts were made every 15 min for the first hour, then at 2, 4 and 24 h post-exposure. Free fliers were recaptured in BG traps operated from 4 to 24 h post-exposure. Knockdown/mortality was gradual until 4 h post-exposure. This increased to near 100% by 24 h in the treated tent but was < 2% in the control tent. There was a significant reduction in the recapture rates of all free-flying species in the treated tent compared with the control tent. Results indicate that TF-charged CRPDs can significantly reduce the numbers of mosquitoes entering military tents and that the four species were affected similarly by the TF. The needs for additional research are discussed.

A push-pull strategy to suppress stable fly (Diptera: Muscidae) attacks on pasture cattle via a coconut oil fatty acid repellent formulation and traps with m-cresol lures.

BACKGROUND: Stable flies [Stomoxys calcitrans (L.)] are economically important pests of cattle and other livestock. As an alternative to conventional insecticides, we tested a push-pull management strategy using a coconut oil fatty acid repellent formulation and an attractant-added stable fly trap. RESULTS: In our field trials we found that weekly applications of a push-pull strategy can reduce stable fly populations on cattle as well as a standard insecticide (permethrin). We also found that the efficacy periods of the push-pull and permethrin treatments following on-animal application were equivalent. Traps with an attractant lure used as the pull component of the push-pull strategy captured sufficient numbers of stable flies to reduce on-animal numbers by an estimated 17-21%. CONCLUSIONS: This is the first proof-of-concept field trial demonstrating the effectiveness of a push-pull strategy using a coconut oil fatty acid-based repellent formulation and traps with an attractant lure to manage stable flies on pasture cattle. Also notable is that the push-pull strategy had an efficacy period equivalent to that of a standard, conventional insecticide under field conditions. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Efficacy of three attractant blends tested in combination with carbon dioxide against natural populations of mosquitoes and biting flies at the Lower Suwannee Wildlife Refuge.

Synthetic blends of chemicals identified previously from human skin emanations were evaluated against mosquito and biting fly populations at the Lower Suwannee Wildlife Refuge near Cedar Key, FL. Mosquito Magnet-Experimental traps were baited with the Red (400 ml acetone: 10 ml 1-hexen-3-ol:10 ml 1-octen-3-ol), Blue (400 ml acetone: 1 g/liter lactic acid:20 ml glycolic acid), or Green blend (400 ml acetone:1.5 g/liter lactic acid:20 ml dimethyl disulfide) plus CO2 or with CO2 alone (control). A relative index of efficacy was determined by dividing each mean blend trap catch by the mean control trap catch. Five mosquitoes (Aedes infirmatus, Ae. taeniorhynchus, Ae. triseriatus, Anopheles crucians, and Culex nigripalpus), 2 ceratopogonid (Culicoides floridensis and C. furens), and 1 tabanid (Diachlorus ferrugatus) and phlebotomine (Lutzomyia shannoni) species were trapped. The Red blend + CO2 treatment significantly increased collections of Ae. taeniorhynchus (3.4x), An. crucians (2.8X), total mosquitoes (2.7x), C. furens (17.6x), and L. shannoni (10.8x) compared with control traps. Traps baited with either the Blue or Green blends generally captured fewer insects than traps baited with the other 2 treatments. However, traps baited with the Green blend caught 7 x as many C. furens as the control traps. Responses clearly varied according to species; therefore, "one size does not fit all" when it comes to attractant blends.

Vector competence of the stable fly (Diptera: Muscidae) for West Nile virus.

In 2006-2007, stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae), were suspected of being enzootic vectors of West Nile virus (family Flaviviridae, genus Flavivirus, WNV) during a die-off of American white pelicans (Pelecanus erythrorhynchos Gmelin) (Pelecanidae) in Montana, USA. WNV-positive stable flies were observed feeding en masse on incapacitated, WNV-positive pelicans, arousing suspicions that the flies could have been involved in WNV transmission among pelicans, and perhaps to livestock and humans. We assessed biological transmission by infecting stable flies intrathoracically with WNV and testing them at 2-d intervals over 20 d. Infectious WNV was detected in fly bodies in decreasing amounts over time for only the first 6 d postinfection, an indication that WNV did not replicate within fly tissues and that stable flies cannot biologically transmit WNV. We assessed mechanical transmission using a novel technique. Specifically, we fed WNV-infected blood to individual flies by using a cotton swab (i.e., artificial donor), and at intervals of 1 min-24 h, we allowed flies to refeed on a different swab saturated with WNV-negative blood (i.e., artificial recipient). Flies mechanically transmitted viable WNV from donor to recipient swabs for up to 6 h postinfection, with the majority of the transmission events occurring within the first hour. Flies mechanically transmitted WNV RNA to recipient swabs for up to 24 h, mostly within the first 6 h. Given its predilection to feed multiple times when disturbed, these findings support the possibility that the stable fly could mechanically transmit WNV.

Seasonal abundance of stable flies and filth fly pupal parasitoids (Hymenoptera: Pteromalidae) at Florida equine facilities.

Beginning in November 2007 and continuing until December 2009, weekly stable fly, Stomoxys calcitrans (L.), surveillance was conducted at four equine facilities near Ocala, FL, by using alsynite sticky traps for adults and by searching immature developmental sites for pupae. Adult stable fly trap captures were highly variable throughout the year, ranging from 0 to 1,400 flies per trap per farm. The greatest adult stable fly activity was observed during the spring months of March and April, with weekly three-trap means of 121 and 136 flies per farm, respectively. The importance of cultural control measures was most apparent on the only farm with no reported insecticide use and the lowest stable fly trap captures, where an intense daily sanitation and composting program was conducted. A survey of on-site filth fly pupae revealed that 99.9% of all parasitoids recovered were Spalangia spp., consisting of Spalangia cameroni Perkins (56.5%), Spalangia nigroaenea Curtis (34.0%), Spalangia endius Walker (5.8%), and Spalangia nigra Latreille (3.7%). The implications of these findings are discussed.

Factors Affecting Numbers of House Flies (Diptera: Muscidae) Captured by Ultraviolet Light Traps in a Large Retail Supermarket.

The house fly, Musca domestica L., is an international nuisance and vector of numerous pathogens that cause disease syndromes in humans and animals. In urban areas, fly exclusion is a major part of the pest management program at many commercial establishments. If flies elude the exclusion techniques, a system for fly management inside the building is the next line of defense. Permission was given to evaluate the fly management system consisting of 12 GT-180 and 6 MX-360 ultraviolet (UV) light traps inside of a large supermarket for 8 wk. GT-180 traps mounted 2 m high on walls captured significantly fewer flies than MX-360s, larger portable traps placed on the floor. Both glue boards in GT-180 traps captured similar fly numbers. In the MX-360 traps, mean fly numbers captured by the two vertically mounted glue boards combined were not significantly different from those captured by the single lower horizontal glue board. Changing from white to black glue boards significantly reduced fly numbers captured by both traps. Three of the six traps capturing the largest mean fly numbers were in the Bakery, followed by the Deli. A total of 3,626 house flies (453/week) was captured during the study. Changes in weekly fly populations inside the store were visibly obvious because fly numbers were so high. Difference in flies trapped because of trap location and height, and glue board color are further discussed.

A Review of Alternative Controls for House Flies.

House flies are the most prevalent synanthropic pest worldwide. Although they seldom reproduce in homes, they invade buildings, cause annoyance, and carry pathogens. Urban pest management personnel are limited in their ability to locate and manage larval habitats, so most house fly management in urban settings focuses on adult fly suppression. Sanitation is probably the most critical component, eliminating odors that attract flies. Source reduction applies where larval habitats can be identified and eliminated. Exclusion involves keeping flies out of structures. Despite all efforts, flies will manage to enter the human environment, so exclusion includes air curtains, fans, screened windows, and doors. Ultraviolet light traps attract and immobilize, while window traps entice flies into devices that entrap them. Sticky tubes and ribbons rely on flies' inclination to land on vertical lines to entangle them in glue. Even low-tech fly swatters can play significant roles in eliminating individual flies. Timed-release aerosol pyrethrin dispensers can be effective against flies confined in enclosed spaces. Toxic baits have limited use in urban settings. Chemical suppression remains a critical component of fly IPM, essential in situations requiring immediate fly elimination.

Potential for stable flies and house flies (Diptera: Muscidae) to transmit Rift Valley fever virus.

Rift Valley fever (RVF), a disease of ruminants and humans, has been responsible for large outbreaks in Africa that have resulted in hundreds of thousands of human infections and major economic disruption due to loss of livestock and to trade restrictions. As indicated by the rapid spread of West Nile viral activity across North America since its discovery in 1999 and the rapid and widespread movement of chikungunya virus from Africa throughout the Indian Ocean Islands to Asia and Europe, an introduced exotic arbovirus can be rapidly and widely established across wide geographical regions. Although RVF virus (RVFV) is normally transmitted by mosquitoes, we wanted to determine the potential for this virus to replicate in 2 of the most globally distributed and common higher flies: house flies, Musca domestica, and stable flies, Stomoxys calcitrans. Neither species supported the replication of RVFV, even after intrathoracic inoculation. However, S. calcitrans was able to mechanically transmit RVFV to susceptible hamsters (Mesocricetus auratus) after probing on infected hamsters with high viral titers. Therefore, S. calcitrans, because of its close association with domestic animals that serve as amplifying hosts of RVFV, should be considered a possible mechanical vector of RVFV, and it may contribute to the rapid spread of a RVF outbreak. Other Stomoxys species present in Africa and elsewhere may also play similar roles.

Response of adult mosquitoes to light-emitting diodes placed in resting boxes and in the field.

The response of adult mosquitoes to 4 light-emitting diode (LED) wavelengths was evaluated using diode-equipped sticky cards (DESCs) and diode-equipped resting boxes at 2 sites in north central Florida. Wavelengths evaluated were blue (470 nm), green (502 nm), red (660 nm), and infrared (IR) (860 nm). When trapping with DESCs, 15 mosquito species from 7 genera (Aedes, Anopheles, Coquillettidia, Culex, Mansonia, Psorophora, and Uranotaenia) were captured. Overall, approximately 43.8% of all mosquitoes were trapped on DESCs fitted with green LEDs. Significantly more females of Aedes infirmatus, Aedes vexans, and Culex nigripalpus were captured on DESCs fitted with blue LEDs compared with red or IR LEDs. DESCs with blue LEDs captured significantly more Culex erraticus females than those with IR LEDs. Using resting boxes, 12 species from 5 genera (Anopheles, Coquillettidia, Culex, Mansonia, and Uranotaenia) were collected. Resting boxes without LEDs captured 1,585 mosquitoes (22.2% of total). The fewest number of mosquitoes (16.7%) were collected from boxes affixed with the blue LEDs. Significantly more Anopheles quadrimaculatus females were aspirated from resting boxes fitted with red and IR LEDs than from those with blue or green LEDs, or from the unlit control. Blood-fed mosquitoes were recovered in highest numbers from unlit resting boxes, followed by resting boxes fitted with green, IR, and blue LEDs. Culex erraticus accounted for the majority of blood-fed mosquitoes followed by Coquillettidia perturbans. No blood-fed mosquitoes were recovered from resting boxes fitted with red LEDs.

Evaluation of different insecticides and fabric types for development of treated targets for stable fly (Diptera: Muscidae) control.

Stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), once only a pest of pastured cattle, has become a serious pest of range cattle in the United States. Because of the difficulties associated with stable fly management under range conditions, a pesticide-impregnated cloth target is being developed as a management tool. We conducted studies to determine the influence of weather, time, fabric type, insecticide type, and insecticide concentration on the mortality of stable flies from a susceptible laboratory colony exposed for 30 s to treated cloth targets. We found that 100% of the flies exposed to trigger (Trigger-Royal Box, 65% polyester and 35% cotton) fabric targets that were treated with 0.1% h-cyhalothrin or 0.1% zeta-cypermethrin and weathered outdoors in Gainesville, FL., for up to 3 mo, were dead within 20 min after a 30-s exposure. The results of this study support the concept that treated targets can be developed for integration into stable fly control programs.