Structure of host-odour plumes influences catch of Anopheles gambiae s.s. and Aedes aegypti in a dual-choice olfactometer

The effects of structure, concentration and composition of host‐odour plumes on catch of female Anopheles gambiae Giles sensu stricto and Aedes aegypti (L.) (Diptera: Culicidae) were investigated in a dual‐choice olfactometer. We demonstrate that the fine‐scale structure of host‐odour plumes modulates capture of An. gambiae and Ae. aegypti. In both species homogeneous skin‐odour plumes result in trap entry, whereas homogeneous CO₂ plumes reduce trap catch. Reduced trap catch also result from combining skin odour with a homogeneous CO₂ plume. Trap capture rates in homogeneous CO₂ plumes were concentration‐dependent and differed between the two species. Electric nets placed in front of the trap entrances intercepted mosquitoes before they could enter the traps. This showed that An. gambiae flew along CO₂ plumes, but did not enter the traps. Survivorship analysis of the trap‐entry times of Ae. aegypti indicated interactions between the time until capture and treatment. The assay's duration therefore can alter the distribution in a dual‐choice olfactometer.     

Comparative efficacy of three suction traps for collecting phlebotomine sand flies (Diptera: Psychodidae) in open habitats

The efficacy of three suction traps for trapping phlebotomine sand flies (Diptera: Psychodidae) was compared. Traps were baited with Co₂ and used without any light source. CO₂‐baited CDC traps were evaluated either in their standard downdraft orientation or inverted (iCDC traps). Mosquito Magnet‐X (MMX) counterflow geometry traps were tested in the updraft orientation only. Both updraft traps (iCDC and MMX) were deployed with their opening ～10 cm from the ground while the opening of the downdraft (CDC) trap was ～40 cm above ground. Comparisons were conducted in two arid locations where different sand fly species prevail. In the Jordan Valley, 3,367 sand flies were caught, 2,370 of which were females. The predominant species was Phlebotomus (Phlebotomus) papatasi, Scopoli 1786 (>99%). The updraft‐type traps iCDC and MMX caught an average of 118 and 67.1 sand flies per trap night, respectively. The CDC trap caught 32.9 sand flies on average per night, significantly less than the iCDC traps. In the Judean desert, traps were arranged in a 3×3 Latin square design. A total of 565 sand flies were caught, 345 of which were females. The predominant species was P. (Paraphlebotomus) sergenti Parrot 1917 (87%). The updraft traps iCDC and MMX caught an average of 25.6 and 17.9 sand flies per trap per night, respectively. The CDC trap caught 7.8 sand flies on average per night, significantly less than the iCDC traps. The female to male ratio was 1.7 on average for all trap types. In conclusion, updraft traps deployed with their opening close to the ground are clearly more effective for trapping sand flies than downdraft CDC traps in open habitats.     

A carbon dioxide, heat and chemical lure trap for the bedbug, Cimex lectularius

Abstract A trap for the collection of bedbugs, Cimex lectularius Linnaeus (Hemiptera: Cimicidae), is described. The trap was baited with CO₂ (50–400 mL/min), heat (37.2–42.2 °C) and a chemical lure comprised of 33.0 μg proprionic acid, 0.33 μg butyric acid, 0.33 μg valeric acid, 100 μg octenol and 100 μg L‐lactic acid, impregnated into a gel. Laboratory studies, conducted in a square arena measuring 183 cm on each side, showed that traps with and without baits captured adult bedbugs, but traps with CO₂ emissions of 50–400 mL/min caught significantly (P < 0.05) more bedbugs than traps without CO_2. In an infested unoccupied apartment, traps with heat and with or without the chemical lure were tested without CO₂ on 29 trap‐days and with CO₂ on 9 trap‐days. The numbers of bedbugs captured were 656 and 5898 in traps without and with CO₂, respectively. The numbers of bedbugs of all development stages captured were significantly greater in traps with CO₂ (χ² = 15 942, d.f. = 1, P < 10^?9). A non‐parametric two‐way analysis of variance evaluation of six different traps with or without CO₂, heat or a chemical lure monitored over 19 trap‐days in an infested apartment showed that trap type was highly significant (n = 2833 bedbugs collected) (P < 10^?7). The trap with CO₂, heat and a chemical lure captured more bedbugs than the other traps, but only caught significantly more fourth and fifth instar nymphs than all other traps. Otherwise, the catches in this trap did not differ significantly from those caught by traps that contained CO₂ and heat only. The total numbers of bedbugs collected for each trapping date (pooling all six traps) followed an exponential decline over the trapping period. This type of trap, which caught bedbugs in unoccupied apartments with and without furniture, and in an occupied apartment, may have utility in studying the ecology of bedbugs, in detecting bedbug infestations and in reducing numbers of bites by trapping host‐seeking bedbugs.     

Monitoring oriental fruit moth (Lepidoptera: Tortricidae) with the Ajar bait trap in orchards under mating disruption

Studies in Oregon, California, Pennsylvania and Italy evaluated the relative performance of the Ajar trap compared with several other traps for the capture of Grapholita molesta (Busck), in pome and stone fruit orchards treated with sex pheromone dispensers for mating disruption. The Ajar is a delta‐shaped trap with a screened jar filled with an aqueous terpinyl acetate plus brown sugar bait solution (TAS) that opens inside the trap and is surrounded by a sticky liner. The TAS‐baited Ajar trap was evaluated with and without the addition of a sex pheromone lure and compared with a delta trap baited with a sex pheromone lure and a bucket trap filled with the TAS bait. Although the Ajar trap had a 90% lower evaporation of the TAS bait than the bucket trap, both of them caught similar numbers in the majority of the field tests of both sexes of G. molesta. The addition of the sex pheromone lure did not increase moth catches by the TAS‐baited Ajar trap. The TAS‐baited Ajar trap caught significantly greater numbers of moths than the sex pheromone‐baited delta trap in 18 of the 20 orchards. Few hymenopterans were caught in orange TAS‐baited Ajar traps, but the catch of flies and other moths relative to the target pest remained high. Flight tunnel and field tests evaluated the effect of several screen designs on the catches of G. molesta and non‐target species. All exclusion devices significantly reduced the catch of larger moths. However, designs that did not reduce the catch of male G. molesta did not reduce the catch of muscid flies. Exclusion devices with openings <7.0 mm significantly reduced the catch of female G. molesta. The addition of (E)‐β‐farnesene, (E)‐β‐ocimene or butyl hexanoate septa lures to TAS‐baited Ajar traps significantly increased total moth catch. The addition of (E)‐β‐ocimene also significantly increased female moth catch.     

Tabanid Flies (Diptera: Tabanidae) of the Northern Part of Gyeonggi Province, Republic of Korea

Tabanid flies were surveyed using New Jersey light traps and Mosquito Magnet® traps at US Army installations and training sites in the northern part of Gyeonggi Province, Republic of Korea. A total of 344 tabanid flies, comprising 14 species and 5 genera, were collected from June to August during 2003‐2004. Dominant species were Chrysops vanderwulpi (57.3%), Haematopota sinensis (29.1%), Haematopota koryoensis (4.4%) and Tabanus mandarinus (2.3%). Mosquito Magnet traps that generated CO₂through the combustion of propane gas were nearly 6 times more effective in collecting tabanid flies than New Jersey light traps. Based on Mosquito Magnet trap collections, peak populations occurred from mid‐June to early July.;     

Comparative field study to evaluate the performance of three different traps for collecting sand flies in northeastern Italy

Three standard methods for collecting sand flies (sticky trap, CDC light trap, and CO₂ trap) were compared in a field study conducted from June to October, 2012, at a site located in the center of a newly established autochthonous focus of canine leishmaniasis in northeastern Italy. Six traps (two sticky traps, two CDC light traps, and two CO₂ traps) were activated at the same time for a single night every two weeks during the season of sand fly activity. A total of 5,667 sand flies were collected and 2,213 identified, of which 82.1% were Phlebotomus perniciosus, 17.4% P. neglectus, 0.3% Sergentomya minuta, and 0.2% P. mascitti. The performances of all traps were influenced by their position inside the site, increasing with proximity to the animal shelters. CO₂ traps were more attractive for females of P. perniciosus and P. neglectus. CDC light traps showed an intermediate efficiency and were more attractive for P. neglectus, compared to other two traps. Results suggest that in northern Italy the CO₂ trap is a suitable sampling method for sand fly monitoring programs that include transmitted pathogen surveillance.     

Effect of trap background on cabbage root fly landing and capture

Pieces (600 mm × 800 mm) of coloured board, plastic sheeting and woven materials, place beneath water traps prevented the traps from becoming soiled during rainy weather. Such backgrounds are not recommended for use with traps for monitoring populations of the cabbage root fly (Delia radicum L. — Diptera: Anthomyiidae), however, as, instead of increasing trap catch they reduced the numbers of female flies caught by 70%–90%. The main effect was that the visually attractive stimuli from the introduced backgrounds competed with those from the trap. A white background competed with a white trap on a direct fly/unit area basis. Green backgrounds stimulated males to land and the vertical stems of both real and artificial grass induced trivial flights that resulted in greater numbers of males entering traps resting on short grass. Most females were caught over bare soil. To minimize the variation in catch between traps used for monitoring cabbage root fly populations, the background beneath each trap should be similar. For maximum capture, the background should be of grass for male flies and of bare soil for female flies. Care is required if data from traps within mulched crops are used to make pest control decisions, as they will underestimate considerably the numbers of flies in such crops.     

Specific detection of the Old World screwworm fly,Chrysomya bezziana,in bulk fly trap catches using real‐time PCR

The Old World screwworm fly (OWS), Chrysomya bezziana Villeneuve (Diptera: Calliphoridae), is a myiasis‐causing blowfly of major concern for both animals and humans. Surveillance traps are used in several countries for early detection of incursions and to monitor control strategies. Examination of surveillance trap catches is time‐consuming and is complicated by the presence of morphologically similar flies that are difficult to differentiate from Ch. bezziana, especially when the condition of specimens is poor. A molecular‐based method to confirm or refute the presence of Ch. bezziana in trap catches would greatly simplify monitoring programmes. A species‐specific real‐time polymerase chain reaction (PCR) assay was designed to target the ribosomal DNA internal transcribed spacer 1 (rDNA ITS1) of Ch. bezziana. The assay uses both species‐specific primers and an OWS‐specific Taqman^® MGB probe. Specificity was confirmed against morphologically similar and related Chrysomya and Cochliomyia species. An optimal extraction protocol was developed to process trap catches of up to 1000 flies and the assay is sensitive enough to detect one Ch. bezziana in a sample of 1000 non‐target species. Blind testing of 29 trap catches from Australia and Malaysia detected Ch. bezziana with 100% accuracy. The probability of detecting OWS in a trap catch of 50 000 flies when the OWS population prevalence is low (one in 1000 flies) is 63.6% for one extraction. For three extractions (3000 flies), the probability of detection increases to 95.5%. The real‐time PCR assay, used in conjunction with morphology, will greatly increase screening capabilities in surveillance areas where OWS prevalence is low.     

Maximum radius of carbon dioxide baited trap impact in woodland: implications for host-finding by mosquitoes

CDC traps were used to determine the maximum radius of carbon dioxide attraction within forest habitat (a forest plant community with Carpino betuli-Quercetum roburis). A central CDC trap with dry ice (CO₂) was set as the source of attractant (Ck). Around Ck trap two circles (A and B) of CDC traps without attractants were placed. Circle A was constituted of 6 CDC traps and Circles B with 12 CDC traps. Radius from Circle A and B to the Ck trap were used to determine CO₂ maximum range. During the experiment, the average emissions of CO₂ were 0.08 to 0.1 g s^?1. Regarding the data, optimal radius attraction where CO₂ was affected on mosquitoes was between 55 and 70 m from the source. Results propose that the distance between traps should be greater than 140 m, to ensure the absence of bias by each of the traps. Changes in CO₂ maximum concentration and wind velocity directly affected the catch of different species. The number of Ochlerotatus sticticus collected was positively correlated with wind speed.     

Vertical distribution of haematophagous Diptera in temperate forests of the southeastern U.S.A.

The vertical distribution of blood‐feeding flies in two temperate forests in the southeastern U.S.A. was determined by placing 15 Centers for Disease Control and Prevention miniature light traps (12 CO₂‐baited, three unbaited controls), without lights, at three heights (1.5 m, 5.0 m, 10.0 m). More than 6550 haematophagous flies, representing 49 species in four families, were collected. Eighteen species were taken almost exclusively (90–100%) at 1.5 m or 10.0 m, and the mean number of flies per trap differed significantly with height for another six species. Five species exhibited shifts in vertical distribution between the two forests, indicating that forest structure could influence the height of host searching. Most (52.5%) mammalophilic flies were collected at 1.5 m, whereas most (56.4%) ornithophilic flies were taken at 10.0 m, suggesting that host associations influence vertical distributions. The significant differences in the composition of haematophagous fly populations among forest strata emphasize the importance of trap placement in vector surveillance and of understanding the ecological relationships of blood‐feeding flies.     

The impact of CO2 on collection of Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say by BG-Sentinel(r) traps in Manaus,Brazil

Carbon dioxide (CO₂) is an important component for activating and attracting host-seeking mosquitoes. The BG-Sentinel^(r) trap is a well-established monitoring tool for capturing Culicidae, but CO₂ role for the trap effectiveness has not been evaluated in highly urbanised areas. The objective was to evaluate the effectiveness of BG-Sentinel traps baited with and without CO₂ for capturing urban mosquitoes. Fifteen areas were selected within the city of Manaus, Brazil, where four BG-Sentinels were operated for 24 h, two of them with CO₂ and two without CO₂. Captured Aedes aegypti females were dissected for the determination of their parity status. A significantly higher proportion of traps (from 32-79%) were positive for female Ae. aegypti when using the BG-Sentinel with CO₂ (χ² = 11.0271, p ≤ 0.001). Catches of female Culex spp were six times higher in CO₂ traps (Mann-Whitney U test = 190.5; p = 0.001). Parity rates were similar for both traps. This study showed that CO₂ has primarily an enhancing effect on the efficacy of BG-Sentinel for capturing Culex spp in Manaus. For Ae. aegypti, the positivity rate of the trap was increased, when CO₂ was added.     

Evaluation of commercial and field‐expedient baited traps for house flies,Musca domestica L. (Diptera: Muscidae)

A comparison of nine commercial baited fly traps on Florida dairy farms demonstrated that Terminator traps collected significantly more (13,323/trap) house flies (Musca domestica L.) than the others tested. Final Flight, Fly Magnet, and FliesBeGone traps collected intermediate numbers of flies (834‐2,166), and relatively few were caught with ISCA, Advantage, Fermone Big Boy, Squeeze & Snap, or OakStump traps (<300). Terminator traps collected about twice as many flies (799.8/trap) as FliesBeGone traps (343.8) when each trap was baited with its respective attractant, but when the attractants were switched between the two trap types, collections were significantly lower (77‐108) than was observed with traps baited with their respective attractant. Solutions of molasses were significantly more attractive to house flies than honey, maple syrup, or jaggery (date palm sugar). Field‐expedient traps constructed from discarded PET water bottles were much less effective than commercial traps, but painting the tops of such traps with black spray paint resulted in a six‐fold increase in trap capture.     

Migration to and dispersal from oilseed rape by the pollen beetle,Meligethes aeneus,in relation to wind direction

1 Host‐plant‐odour‐induced upwind anemotaxis is accepted as the main mechanism by which herbivorous insects find their host plant within an heterogenous environment, but field data supporting this hypothesis are scarce. 2 The flight directions of the pollen beetle Meligethes aeneus to and from a plot of winter oilseed rape and the direction of the wind were recorded concurrently. The beetles were sampled by eight double‐sided window traps encircling the plot. Distal sides of the traps, relative to the plot, sampled the beetles as they flew towards the plot, whereas the proximal sides of the traps sampled them as they flew away from the plot. Paired data on daily catch of beetles in distal or proximal traps and the volume of air impacting each trap were compared. 3 Correlations between daily catch of M. aeneus into distal traps and trap wind volume were negative, indicating that flights by both overwintered‐ and new‐generation insects towards the plot were upwind. 4 Correlations between daily catch of M. aeneus into proximal traps and trap wind volume varied with generation. Catch of overwintered‐generation M. aeneus was negatively correlated with trap wind volume, indicating that flight was upwind. Proximal trap catch of the new‐generation M. aeneus was weakly/modestly positively correlated with trap wind volume, indicating that flights were downwind or crosswind. 5 Understanding the effect of wind direction on flight of M. aeneus holds potential for improving the forecasting of their arrival and spatial distribution on the crop for integrated pest management.     

Influence of light and kairomone baiting systems on trap collections of biting midges in southern Sweden

Effective surveillance is essential for protecting livestock from Culicoides biting midges and the viruses they transmit. The objective of this study was to determine how the baiting system used in traps (UV, incandescent light, incandescent light with CO₂, and incandescent light with CO₂ and 1‐octen‐3‐ol) influences estimates of midge population abundance, parity, and diel activity. This was achieved through a standardized trapping protocol conducted in three habitats in Sweden. UV light traps caught the most Culicoides species and more C. obsoletus complex females than incandescent light traps. Traps baited with CO₂ plus 1‐octen‐3‐ol caught more female C. impunctatus than incandescent light traps. No consistent effect of bait type was found on C. obsoletus parity rate, as estimated from the proportion of midges with presence or absence of pigmentation. Midge activity, as reflected by trap catches, peaked between ‐3 h and +3 h relative to sunset, with UV traps catching significantly more female C. obsoletus complex and C. impunctatus at and after sunset than before sunset. We conclude that baiting system can influence biting midge collections, even using identical traps. Effective surveillance may require more than one bait type and kairomones to attract species that do not feed exclusively on cattle.     

Improving monitoring tools for spotted wing drosophila,Drosophila suzukii

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) were trapped in the field using colored plastic sphere traps coated with insect Tangle‐trap. Red and black spheres captured significantly more D. suzukii than white spheres. Translucent deli‐cup traps deployed in cherry orchards and baited with yeast, the Alpha Scents lure, or the Scentry lure captured significantly more flies than the Trécé lure and Suzukii bait; all attractants had poor selectivity for D. suzukii. No‐choice evaluations of attractants conducted in field cages corroborated the cherry orchard field study, though translucent deli‐cup traps provisioned with the yeast bait captured significantly more flies than those baited with the Alpha Scents lure. Red sphere traps baited with the Scentry lure captured 3–6× more flies than the deli‐cup trap baited with the same lure, and 3–4× more flies than the deli‐cup trap baited with yeast bait, demonstrating that a trap integrating both visual and olfactory cues is a superior tool for monitoring D. suzukii. Moreover, this simple sticky, dry trap design requires far less labor and maintenance than does a liquid‐based deli‐cup trap.     

Factors affecting the efficacy of a vinegar trap for Drosophila suzikii (Diptera; Drosophilidae)

Drosophila suzukii, Matsumura, is a relatively new pest in the United States attacking a variety of fruit crops. Studies were conducted to develop a standardized, economical trap for monitoring. Laboratory bioassays found that flies were attracted to dark colours ranging from red to black. Similarly, fly catches in 237‐ml plastic ‘spice’ jars with ten 0.48‐cm holes and baited with apple cider vinegar were significantly higher in jars with red or black than white caps. The use of an alternating set of three, horizontal red, black and red bands (‘Zorro’ trap) significantly increased fly catches compared with the use of all‐red or all‐black strips. This increase was associated with a significantly higher proportion of flies first landing on the side near the openings of the trap instead of on the cap with the ‘Zorro’ trap compared with the other traps. Laboratory data were used to develop a predictive model to define total fly capture as a function of trap colour/colour pattern, cumulative area of entry holes and the length of the trapping portion of the trap. Total fly catches by the ‘Zorro’ trap were compared with other red and clear plastic traps in five field trials conducted in several cultivated and uncultivated sites. Comparisons included a commercial red‐capped 200‐ml trap with two 0.63‐cm holes, an all‐red spice jar with ten 0.48‐cm holes and clear and red 473‐ml and clear 946‐ml plastic cups with six or ten 0.48‐ or 0.63‐cm holes. The model was successfully validated, suggesting that performance of cup traps can be predicted based on a few characteristics. The current ‘Zorro’ trap did not catch most of the flies among trap designs, but showed some advantages, including the durability and potential to recycle the plastic, small size, commercial availability and its greater selectivity for D. suzukii than the other traps tested.     

Investigations of Phlebotomus perniciosus sand flies in rural Spain reveal strongly aggregated and gender‐specific spatial distributions and advocate use of light‐attraction traps

The spatial and temporal distribution of Phlebotomus perniciosus (Diptera: Psychodidae) (Newstead, 1911), the sand fly vector of pathogens of public and animal health importance, was investigated in a high sand fly density rural area in Spain using light‐attraction and sticky‐interception traps. Traps were placed inside animal buildings and outside at increasing distance from animals. A total of 8506 sand flies were collected, 87% with light traps. Species frequency differed between trap types. The abundance of P. perniciosus decreased exponentially with increasing distance to animals and, while females were most common in the animal enclosure, males predominated in adjoining storage places. Increasing CO₂ concentration had an additional positive effect on female abundance only. Both male and female density increased with rising temperature, and there was some indication that females were more active than males at higher relative humidity. The study confirms that P. perniciosus aggregates around animal premises, although male and female distributions differ and should be analysed separately to account for biological and behavioural differences. This provides further evidence that light traps offer an accurate estimation of the relative spatial and temporal abundance of P. perniciosus, conferring an added value for the study of this species and the risk of pathogen transmission.     

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.     

Sensory interaction during trap-finding by female onion flies: implications for ovipositional host-plant finding

Using various three-dimensional traps alone and in combination with the onion volatile, dipropyl-disulphide (Pr₂S₂), we found that visual behaviour of female onion flies, Delia antiqua (Meigen), varied with the visual context (background composition and trap spacing) in which traps were presented and the females' reproductive state (mated vs. unmated). Against a background of real onions, females alighted more frequently on spherical than cylindrical traps, and white than green spheres, but females responded equally to white and green cylinders. In an onion field, baiting traps with Pr₂S₂ significantly increased female response to white over green traps, but had no influence on their response to trap shape. When traps were spaced 10 m apart and against a background of bare soil, females orienting to Pr₂S₂ baits alighted more frequently on vertical than horizontal traps, but shape and spectral reflectance were insignificant. However, when traps were spaced 0.25 m apart, females orienting to Pr₂S₂ baits alighted more frequently on cylinders than spheres. Mated females alighted more frequently on green than white cylinders, but unmated females responded to cylinders independent of spectral reflectance. When located 20 m downwind from Pr₂S₂ baits, mated females alighted on green cylinders significantly more often than unmated females. Response to traps mimicking onion plants suggests that ovipositional host-finding in female onion flies is dominated by olfactory responses at long range (several metres) and by visual cues at short-range (ca. 1 m). The view that host location by female onion flies is a hierarchical response pattern mediated by multiple sensory modalities and modified by resource level (habitat) and reproductive status, is discussed.     

Influence of carbon dioxide on numbers of Culicoides midges collected with suction light traps in South Africa

To implement risk management against diseases transmitted by species of Culicoides Latreille, 1809 (Diptera: Ceratopogonidae), it is essential to identify all potential vectors. Light traps are the most commonly used tool for the collection of Culicoides midges. Given the indiscriminate artificial attraction of light, traps will collect all night‐flying insects rather than only livestock‐associated Culicoides midges. Factors that may increase the efficacy of traps, especially for livestock‐associated Culicoides midges, require investigation. In the present study, results obtained with Centers for Disease Control (CDC) and Onderstepoort light traps baited with carbon dioxide (CO₂) were compared with those of unbaited controls. Comparisons were made using two replicates of a 4 × 4 randomized Latin square design. With both trap types, the mean numbers of Culicoides midges collected in 16 baited traps were higher than those caught in 16 unbaited traps. Although exceptionally low numbers were collected with the CDC traps, the increases in the numbers and frequency of collection of Culicoides imicola Kieffer, 1913 were more pronounced in the CDC traps compared with the Onderstepoort traps. These results indicate that the addition of CO₂ may increase the efficiency of these traps for the collection of C. imicola and other livestock‐associated Culicoides species.