Female and male adults, male genitalia, pupae, and larvae of Culex (Lophoceraomyia) singhbhumensis, a new mosquito species, are described from Orissa, India.

Aedes aegypti and Culex quinquefasciatus were found in large numbers emerging from septic tanks in southern Puerto Rico during the dry season. Previous studies suggested that Ae. aegypti uses subterranean aquatic habitats only during dry periods when surface containers do not have water. This research investigated whether septic tanks are alternative aquatic habitats that this mosquito uses during unfavorable times of the year, or whether Ae. aegypti uses this aquatic habitat throughout the year. To assess temporal change, exit traps were used to collect mosquitoes emerging from septic tanks in Playa/Playita, southern Puerto Rico, from November 2006 to October 2007. We also investigated the hypotheses that 1) the production of Ae. aegypti in septic tanks was larger than in surface containers and 2) adult mosquitoes emerging from septic tanks were larger than those emerging from surface containers. This study demonstrated that unsealed septic tanks produced large numbers of Ae. aegypti and Cx. quinquefasciatus throughout the year, without any significant relationship with rainfall. The number of adult Ae. aegypti emerging per day from septic tanks in each community was 3 to 9 times larger than those produced in surface containers. It was also demonstrated that Ae. aegypti emerging from septic tanks were significantly larger than those emerging from surface container habitats. It is recommended that dengue prevention programs include regular inspection and maintenance of septic tanks in communities lacking sewerage.

Dengue is a serious public health problem worldwide. Biological control of its vector, Aedes aegypti, remains a feasible option in light of increasing urbanization and insecticide resistance. We studied the dispersal and oviposition activity of Toxorhynchites moctezuma in a dengue-endemic urban area in Sonora, Mexico, to provide information about the potential of Toxorhynchites as a control agent for Ae. aegypti in arid areas. We released 210 and 100 laboratory-reared gravid females of Tx. moctezuma in 2 city blocks during the summer and fall of 1993. We set 3 1-liter containers and 1 car tire as sentinel traps at each of 10 backyards within each city block. Spatial and temporal patterns of dispersal and oviposition activity differed between city blocks and between releases. However, a Cox regression analysis showed no significant difference in the per-day probability of Tx. moctezuma oviposition events in sentinel traps between summer and fall releases. Per-day oviposition probability was nearly 5 times greater for sentinel traps that contained larvae of Ae. aegypti, suggesting a high specificity of the predator for its prey. The proportion of sentinel traps positive for Tx. moctezuma eggs did not increase substantially after the 8th day post-release, reaching 66% and 23% for sentinel traps with and without Ae. aegypti larvae, respectively.

Bloodfeeding activity, host preference, and seasonal abundance of the Anopheles dirus complex in relation to environmental factors were measured during a 2-yr period at Pu Teuy Village, Sai Yok District, Kanchanaburi Province, western Thailand. Anopheles dirus s.l. was found more abundant during the wet season compared with the dry and hot seasons. Bloodfeeding by An. dirus s.l. commenced immediately after sunset with a distinct peak of activity at 2000 h. Anopheles dirus s.l. fed more readily on cattle than on humans, demonstrating a significant but slightly stronger zoophilic behavior (P  =  0.02). The biting activity of An. dirus s.l. in Pu Teuy appears to differ from other localities in Thailand, suggesting the existence of significant biological variability within the species complex depending on the local circumstances.

Host avidity and deet repellency were measured in partially bloodfed Aedes albopictus provided 10% sucrose, water, or nothing when access to a human host was postponed for 1 to 72 h after a partial blood meal. Carbohydrate availability and postfeeding time influenced host avidity, but partial blood meal effects were not significant. Mean host avidity declined significantly between hours 1 and 6 (range 50–18%) but increased significantly between hours 24 (54%) and 72 (68%) after a partial blood meal. Females provided sucrose solution and females denied sucrose or water showed the least (29%) and most (39%) host avidity, regardless of other treatment effects. The longest and shortest deet protection times were 8.5 h against females provided sucrose and 7.3 h against females denied sucrose or water, respectively. Denial of carbohydrate sustenance significantly increased host avidity and deet repellency in partially bloodfed female Ae. albopictus, whereas sucrose availability led to reduced host responding activity and decreased repellency of deet.

The objective of this study was to quantify the contact irritant (CI) and spatial repellent (SR) behaviors of male Aedes aegypti upon exposure to standard chemicals currently used for vector control under laboratory conditions. Results indicate that male Ae. aegypti test populations exhibited significant (P < 0.01) escape responses upon contact to varying doses of alphacypermethrin, deltamethrin, permethrin, and DDT. Analysis of data generated from the SR assays indicated that only DDT elicited a significant (P < 0.01) SR response, while alphacypermethrin, deltamethrin, and permethrin elicited no directional movement in the assay system. These findings are consistent with data generated previously using female Ae. aegypti of the same strain. It is hoped that information from this study will be used to stimulate additional research of male vector behavior in response to chemical stimuli. Determining the CI and SR responses of male vectors against chemicals used in current intervention strategies is important in understanding the impact these chemical actions will have on overall vector population dynamics and therefore disease transmission.

The repellent activity of Piper aduncum essential oil against Aedes albopictus was investigated under laboratory conditions with human volunteers. The lowest median effective dose (ED₅₀) value was 1.5 µg/cm² at 60 sec of exposure when compared to 90 sec (2.1 µg/cm²) and 120 sec (1.8 µg/cm²) of exposure. At 0.4 g, the essential oil gave a high protection (95.2%) against Ae. albopictus bites or landing at 2 h postapplication. The percentage of protection was reduced to 83.3% after 4 h, 64.5% after 6 h, and 51.6% after 8 h postapplication. As a comparison, treatment with 10% deet gave 100% protection against mosquito biting/landing for 4 h postapplication. There was no significant difference in percentage protection reduction between the plant extract and the commercial product deet, respectively (P  =  0.739). The essential oil, which was not as good as deet, still gave moderate protection against Ae. albopictus biting even until 4 h postapplication. In conclusion, the P. aduncum essential oil has the potential to be used as a repellent against the dengue/dengue hemorrhagic fever vector, Ae. albopictus.

Four chemicals (1-octen-3-ol [octenol], lactic acid, acetone, and carbon dioxide) were evaluated for their attractiveness to the biting midge, Forcipomyia taiwana. The attractiveness was based on the number of adult biting midges attracted to each chemical. Results showed that the attractiveness of each chemical changed with different release rates. The optimal attractive release rates for octenol, lactic acid, and acetone fell in the range 0.5–0.9 mg/h, 0.2–1.4 mg/h, and 3.4–10.9 mg/h, respectively. The most attractive release rates were 0.7 mg/h, 0.2 mg/h, and 4.8 mg/h, respectively. Octenol, lactic acid, and acetone were evaluated simultaneously but in separate traps, at the best attractive release rate mentioned above to compare their attractiveness efficacies. Octenol was the most attractive to F. taiwana, followed by lactic acid and acetone; however, there was no significant difference between the mean numbers of adults attracted by the 3 attractants. Carbon dioxide (CO₂) with release rates of 100, 250, and 500 ml/min showed no differences in attractiveness. When combinations of CO₂, octenol, and blue light (BL, λ_max  =  405 nm) were evaluated, the number of adults attracted by the treatment of CO₂ BL was the lowest, and that of the CO₂ octenol BL was the highest.

Spinosad, a fermentation product from the naturally occurring soil actinomycete bacterium Saccharopolyspora spinosa, has been reported to have a high level of activity against phytophagous insects and insects impacting human and animal health. It has low mammalian toxicity and a favorable environmental profile, including low persistence and no toxicity to fish and wildlife at mosquito larvicidal rates. In order to determine the activity and efficacy of spinosad against larvae of Culex mosquitoes, technical powder and liquid formulations of spinosad were tested against mosquito larvae under laboratory and field conditions. In the laboratory, spinosad powder was highly active against 2nd and 4th instars of Culex quinquefasciatus after 24 h of exposure. The extent of mortality increased slightly after 48 h of exposure. Second instars were slightly more susceptible than 4th instars. The liquid formulation showed somewhat higher activity (about 2×) than the technical powder material at both the LC₅₀ and LC₉₀ levels. In field microcosm tests against natural populations of mosquitoes, the liquid formulation yielded excellent control of immature Culex spp. for 21 days at concentrations of 0.05 mg (AI)/liter and 35 days at 0.1 to 0.5 mg (AI)/liter in outdoor tubs. This formulation also yielded excellent control of natural Culex mosquitoes for 14 days or longer at 0.025 to 0.1 mg (AI)/liter in outdoor ponds. From our data, it appears that spinosad as a new mode of action has a good potential for controlling mosquito larvae.

The effectiveness of a novel fuselage boom configuration was tested with flat-fan nozzles on US Air Force C-130H aircraft to create ultra-low volume sprays to control mosquitoes (Culicidae) and biting midges (Ceratopogonidae). The mortality of mosquitoes and biting midges in bioassay cages and natural populations, using the organophosphate adulticide, naled, was measured. Mosquitoes in bioassay cages had 100% mortality at 639 m downwind in all single-pass spray trials, and most trials had >90% mortality up to 1,491 m downwind. Mosquito mortality was negatively correlated with distance from the spray release point (r²  =  0.38, P < 0.001). The volume median diam of droplets collected was 44 µm at 213 m and decreased to 11 µm at 2,130 m downwind of the release point. Droplet density decreased from an average of 18.4 drops/cm² at 213 m to 2 drops/cm² at 2,130 m. Droplet densities of 10-18 droplets/cm² were recorded at sampling stations with high mosquito mortality rates (>90%). In wide-area operational applications, numbers of mosquitoes from natural populations 1 wk postspray were 83% (range 55%–95%), lower than prespray numbers (P < 0.05). Biting midge numbers were reduced by 86% (range 53%–97%) on average (P  =  0.051) after 7 days. The results of these field trials indicate that the fuselage boom configuration on C-130H aircraft are an effective method to conduct large-scale aerial sprays during military operations and public health emergencies.

This article compares the collection characteristics of a new rotating impactor Florida Latham Bonds (FLB) sampler for ultrafine aerosols with a mimic of the industry standard (Hock-type). The volume and droplet-size distribution collected by the rotating impactors were measured via spectroscopy and microscopy. The rotary impactors were colocated with an isokinetic air sampler for a total volume flux measurement and a laser diffraction instrument for droplet-size distribution measurement. The measured volumetric flux and droplet-size distribution collection efficiencies were compared across 3 wind speeds (1, 1.8, and 3.5 m/sec). The FLB sampler had higher flux collection efficiencies than the Hock-type sampler. The FLB sampler collected 89%, 87%, and 98% of the total volume available per unit area at 1, 1.8, and 3.5 m/sec, respectively, whereas the Hock-type sampler collected 68%, 19%, and 21% of across the same wind speeds. Changes in wind speed had less impact and resulted in less data variability for the FLB sampler.

Different procedures for drying polyamide (nylon) hammock nets (∼10 m²) posttreatment were evaluated. Forty-three nets were soaked for 10 min in a plastic bowl containing a solution of water and lambdacyhalothrin 0.05% (target dose of 10 mg/m²). Twenty-two freshly treated nets were put to dry in the sun: 13 of them hung vertically with the roof of the hammock net at the top and the hem at the bottom, and the other 9 were folded and laid flat on a plastic sheet. The rest of the nets (21) were dried in the shade: 11 of them hung vertically and 10 were folded flat on a plastic sheet. After 6–7 h, 2 15-cm² samples of each net were cut, one on top of the lateral side and one 40 cm from the edge. Concentrations of lambdacyhalothrin were determined by gas chromatography–mass spectrometry on subsamples of netting (1 cm²). The mean insecticide concentrations of samples were compared between nets that were dried in the sun or in the shade, and placed to dry either hanging vertically or folded flat. In general, no differences were found between the mean insecticide concentrations of nets that were dried vertically in the sun or in the shade, or those dried flat in the shade. However, the mean dose was considerably lower in the remaining nets, which were dried flat in the sun. The reason for this is unclear but is hypothesized to be an effect of temperature. Results indicated that nets hung vertically either in the sun or shade dried faster than those laid flat. Based on the time to dry and mean insecticide extracted, it is recommended to hang treated nets vertically in the sun for drying.

The 19th Annual Latin American symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 75th Annual Meeting in New Orleans, LA, in April 2009. The principal objective, as for the previous 18 symposia, was to promote participation in the AMCA by vector control specialists, public health workers, and academicians from Latin America. This publication includes summaries of 37 presentations that were given orally in Spanish or presented as posters by participants from 5 countries in Latin America, Puerto Rico, the United Kingdom, and USA. Topics addressed in the symposium included: surveillance, chemical and biological control, insecticide resistance and repellency of Aedes aegypti; distribution, behavior, and control of Culex; bionomics, ecology, and chemical and biological control of Anopheles vectors of malaria; insecticide resistance; and studies of Triatoma and Leishmania.

A population of Culex pipiens pipiens form molestus was detected in a drainage sump in Calumet Water Reclamation Plant on the South Side of Chicago, IL. This is the first documented collection of a molestus population within the city of Chicago and the second collection of a molestus population in the Chicago metropolitan area in >60 years. Field-collected specimens were used to initiate a colony without bloodfeeding, and the colony is autogenous and stenogamous.

Gonotrophic dissociation and fecundity in adult female Aedes albopictus affect the transmission of arbovirus and mosquito population dynamics. Female Ae. albopictus bloodfed on guinea pig and human hosts produced significantly (P < 0.05) higher number of eggs (80 and 82/female, respectively) than females fed on chicken (67 eggs/female). Fecundity in mosquitoes that took a double blood meal (chicken and guinea pig), a triple blood meal (3 separate guinea pigs), or mixed blood meals (chicken, guinea pig, and human) was significantly (P < 0.001) higher than in females fed on a single chicken or on 2 separate chickens (refeeding). Gonotrophic dissociation in laboratory colony of Ae. albopictus was first observed and its frequency decreased with multiple blood meals with triple feeding or mixed feeding (3 meals on 3 host types). Blood meal source did not significantly influence gonotrophic dissociation in Ae. albopictus.

Field experiments were conducted on the Fort Sam Houston Military Reservation, San Antonio, TX, in fall 2008 to observe the attractiveness of selected botanical infusions to ovipositing female mosquitoes. The following infusions were tested in Centers for Disease Control and Prevention gravid traps: Bermuda grass (Cynodon dactylon), oak leaf (Quercus virginiana), acacia leaf (Acacia schaffneri), rabbit chow (alfalfa pellets), and algae (Spirogyra sp.). Four (Bermuda, acacia, oak, and algae) of the 5 infusions were effective in collecting Culex quinquefasciatus, Cx. nigripalpus, and Cx. erraticus. Of the 4 infusions, Bermuda collected the greatest number of the mosquitoes sampled. Female Aedes albopictus mosquitoes were collected in moderate numbers during this study.

Field trials comparing repellent formulations containing IR3535 (ethyl butylacetylaminopropionate) and deet (N,N-diethyl-3-methylbenzamide) against mosquitoes in Queensland, Australia, were conducted. Two repellents were compared: Avon Bug Guard, containing 7.5% IR3535; and Australian Defense Force (ADF) deet, containing 35% deet in a gel. Two tests were conducted, one in February–March 2006, and the second in February 2007. In the 1st test, the predominant mosquito species collected were Mansonia uniformis (58.9% of collection) and Culex annulirostris (33.4%), and in the 2nd test, the predominant species was Aedes vigilax (85.7% of collection). In the 1st test, Avon Bug Guard provided >95% protection against all mosquitoes for only 1 h, and ADF deet provided the same level of protection for 5 h. In the 2nd field test, Avon Bug Guard provided only 85% protection against all mosquitoes 1 h after repellent application, while ADF deet provided 5 h of protection. The study showed that ADF deet provided significantly better protection against mosquitoes than Avon Bug Guard (IR3535).

To study the indoor behavior of Anopheles gambiae populations in a temperate climate, we have devised a walk-in mesocosm, built within a greenhouse. The structure provides conditions more natural than laboratory cages, including sufficient room for swarming and for flight between resting sites, sugar-bearing plants, a human host, and an oviposition site. These activities impose energy demands closer to those encountered in the field. The structure also has predators, fluctuating temperatures, natural daylight, and an evening crepuscular period. Most important, its resting sites comprise a bank of tubes that can be inspected or removed individually to obtain, at regular time intervals, random representative samples of an experimental population while all individuals are inactive. Samples from aging cohorts of mosquitoes, released at emergence, can yield information on behavioral sequences, mate competition, reproductive success, and survival under different nutritional regimes.

We describe the methodology used to take images of the eggs of 3 container-breeding mosquito species recovered from ovitraps in north-central Florida using the Auto-Montage™ software package. This software allows for high-resolution imagery, thereby providing a new tool for mosquito egg identification. Images, as well as a brief comparison of the mosquito eggs using previously described literature, are provided.

A field study was conducted to explore the suitability of 5 pesticide deposition samplers for airborne spray and ground deposits from ultra-low-volume (ULV) space sprays. Samplers included horizontally stretched stationary cotton ribbons at 2 heights, rotating ribbon, rotating Teflon slides, and filter paper. Slides were also used for droplet-size analysis. A set of 7 samplers of each type was placed at 1, 7, 15, 25, 40, 65, and 90 m from the spray line along the spray swath. Water and BVA13 oil with fluorescent dyes as tracers were sprayed with the use of a truck-mounted ULV sprayer at dusk and dawn. Results suggest that the horizontal and rotating cotton ribbons are best for quantification of airborne spray and filter paper is best for ground deposition collection. The rotating slide samplers only detected the BVA13 oil-based sprays.