The pupae of Ochlerotatus shortti and Oc. elsiae are described and illustrated. These species occur in the Himalaya Mountains at middle range altitudes. Characters to recognize each are explained.

With the objective of providing knowledge about the natural habitat of mosquito larvae, we conducted a study on the culicid fauna and identified larval habitat types at 3 different locations in the Serra do Mar State Park, Brazil, over the 12 months of 1991. We collected 1,425 larvae belonging to 23 species, of which the most frequent were Culex iridescens, Culex spp., Limatus durhami, and Trichoprosopon pallidiventer. The mosquito larval habitats presenting the greatest densities of specimens were bamboo, bromeliads, rubber boots, and streams. We observed that the culicids used a variety of containers as larval habitats and bred under a diversity of ecological conditions. Most of the habitats were natural, formed by bamboo, bromeliads, streams, and depressions in the ground and in rocks, along with artificial habitats consisting of rubber boots and abandoned metal cans. Seven species occurred preferentially in the internodes of closed bamboo stems, 6 in internodes of open stems, and 4 in bromeliads.

A 3-year study was undertaken to examine the parity status, survival, and prevalence of West Nile virus (WNV) in overwintering populations of Culex pipiens pipiens collected from a hibernaculum located in a WNV endemic region in New York City. Nearly 6,000 females were collected from December through April. Parity rates were highest among females collected in December and January, ranging from 12.3% to 21.9%, depending on the year. In each year of the study, the proportion of parous females declined significantly during the course of the winter; the percentage of parous females found in April ranged from 0.9% to 10%. Results provide unequivocal evidence that parous Cx. p. pipiens females from this region of the northeastern US enter hibernacula in the fall in comparatively high proportions not previously recognized for this species, and while these females experience significant mortality during the winter, some survived to April to emerge in the spring. The absence of any detectible blood remnants in overwintering females reaffirms that blood feeding does not occur among diapausing females during the winter. The possibility that a portion of the diapausing population may be autogenous as a result of hybridization with sympatric belowground populations of Cx. p. pipiens “form molestus” is discussed. A single isolation of WNV was obtained in Vero cell culture from a pool of 50 females collected on January 11, 2007, representing an infection prevalence of 0.07% in the overwintering population in 2007 (n  =  1,370 mosquitoes, 33 pools). No isolations of WNV were made from mosquitoes collected in 2008 (n  =  1,870 mosquitoes, 190 pools) or 2009 (n  =  1,767 mosquitoes, 184 pools). Findings provide further evidence for local overwintering of WNV in diapausing Cx. p. pipiens, albeit at very low rates, consistent with the paucity of WNV-positive mosquitoes detected in June and early July despite the emergence of females from hibernacula in early May in this region.

Wolbachia are maternally inherited bacteria that cause various reproductive alterations in their arthropod hosts, including cytoplasmic incompatibility. In this study, we compared mating, oviposition, and host-seeking behavior of Wolbachia-infected (Houston [HOU], Gainesville [GNV]) and Houston uninfected (HT1) Aedes albopictus. In mating assays with virgin mosquitoes, mating success of Wolbachia-infected males was significantly higher than uninfected strains. Mating success was highest with HOU males exposed to infected (95%) and uninfected females (100%), and lowest with HT1 males exposed to infected (20%) and uninfected (25%) females. Results suggested that Wolbachia infection may influence the reproductive behavior of this mosquito. There were no clear differences in oviposition responses between strains, with all strains ovipositing significantly more often on hay infusion and larval rearing water than on water controls and least frequently on 4-methylphenol. Strains of Ae. albopictus females were host-seeking a human when given a choice. Responses to a human arm, acetone, CO₂, and dichloromethane were generally higher from the Houston strains than from the GNV strain. Responses of HOU and HT1 females differed from GNV with greater responses to the arm and CO₂.

We performed a 2-year longitudinal study (2006–2007) of West Nile virus (WNV) infections in wild birds, mosquitoes, and sentinel chickens at 6 WNV-endemic sites in northern Delaware. We determined virus infection rates of Culex pipiens and other mosquito vectors as well as seroprevalence and antibody titers of amplifying hosts. Endemicity status varied widely among the 6 sites based on 3 criteria—mosquito infections, sentinel chicken seropositivity, and wild bird seropositivity. A highly endemic site would display at least 2 of the 3 criteria during each year of the study, while a site with just 1 positive criterion was considered to have low endemicity. Culex pipiens was the principal vector detected at 2 highly endemic sites in 2006 vs. 1 site in 2007. However, in 2006, we also found 2 other WNV-positive vector species as well as an unidentifiable Culex species at 1 highly endemic site, suggesting increased activity at the end of the 1st year of the study. Wild birds were early indicators of WNV at highly endemic sites in mid-July to early August of both 2006–2007. Mosquitoes were positive in mid- to late August, appearing concurrently with seroconverted sentinel chickens, with wild resident birds appearing ∼4 wk prior to those indicators. Of birds tested with n ≥ 9, Northern cardinals had the highest seropositivity rates (47%) followed by Carolina wrens (19%), house sparrows (13%), American robins (13%), tufted titmice (11%), and gray catbirds (9%). The overall seropositive rates in trapped birds increased from 5.0% in 2006 to 20.0% in 2007, while the geometric mean titers of all positive birds increased from 1∶34 to 1∶47 during the comparable periods. Based on these results, we suggest that an epiornitic in birds occurred in 2007, but that greatly reduced abundance of mosquito vectors caused by an extreme drought largely precluded human infection.

This study evaluated the efficacy of a commercially available mosquito trap, the Mosquito Magnet® Liberty Plus (MM), in reducing human biting rates under semi-field conditions when used alone or with different types of repellents. The MM trap significantly reduced the human biting rate with both laboratory-reared Culex quinquefasciatus and Anopheles gambiae sensu stricto. The MM trap catch did not increase when a mosquito coil was burned but did significantly increase when a skin repellent was applied to the human bait. Microencapsulated repellent ankle bands did not increase the MM trap catch with either Cx. quinquefasciatus or An. gambiae s.s., although its combination with the trap was more effective at reducing bites by Cx. quinquefasciatus. The absence of the commercial attractant Lurex3™ in traps significantly lowered the catch efficiency of Cx. quinquefasciatus even when the skin repellent was applied to volunteers. The results from this study showed that the use of a skin repellent and an attractant-baited trap can significantly reduce the human biting rate of both nuisance biting mosquitoes and malaria vectors. Further work is required to investigate how this push-pull system would work in a field environment.

This paper presents results of studies evaluating the efficacy of various granular formulations of VectoBac® (Bacillus thuringiensis israelensis de Barjac [Bti] H-14 strain AM65-52) against immature mosquitoes in 2 distinct habitats in Poland and Germany. Meadows intermittently flooded with sewage water in the city of Wroclaw, Poland, provide ideal habitats for immature stages of Aedes caspius, Ae. vexans, and Culex pipiens pipiens. Helicopter applications of VectoBac G and VectoBac TP sand granules (VectoBac TP-SG) at rates of 5 and 10 kg/ha to the meadows resulted in between 70.9% and 97.4% larval mortality. In Germany, some swampy woodlands in the upper Rhine Valley provide ideal habitats for snowmelt mosquitoes, Aedes cantans, Ae. punctor, Ae. rusticus, and Ae. communis. Ground applications of VectoBac G, VectoBac TP-SG, and VectoBac WG IcyPearls (VectoBac WG-IP) were made to these habitats when the water temperature was ∼7°C. Larval mortality at 7-day post-application ranged from 90.9% (VectoBac TP-SG: 10 kg/ha) to 98.0% (VectoBac WG-IP: 15 kg/ha). In a separate microcosm trial within the same habitat, all 3 granule formulations controlled larvae of Ae. cantans for 3 wk.

Culicoides sonorensis is the primary vector of bluetongue and epizootic hemorrhagic disease viruses in North America. Bluetongue disease is one of the most economically important arthropod-borne diseases of sheep in North America, because it causes significant morbidity and mortality and can lead to local quarantines and international trade restrictions. Long-lasting repellent pesticides could be applied to sheep as they are moved down from mountain pastures to protect them from biting midges until the 1st frost. We tested long-lasting pesticides on sheep as repellents against C. sonorensis. Both PYthon ear tags with 10% zeta-cypermethrin (9.8 g/tag) synergized with 20% piperonyl butoxide (PBO) and a 12-ml low-volume spray application of ready-to-use sheep insecticide (Y-TEX) with 2.5% permethrin and 2.5% PBO in an oil-based formulation were repellent to C. sonorensis for at least 3–5 wk after a single application.

The 20th Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 76th Annual Meeting in Lexington, KY, in March 2010. The principal objective, as for the previous 19 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 40 presentations that were given orally in Spanish or presented as posters by participants from 5 countries in Latin America, the United Kingdom, and the USA. Topics addressed in the symposium included: surveillance, chemical and biological control, and insecticide resistance associated with 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 dengue, West Nile virus, and Triatoma.

Aedes albopictus, Culex corniger, Cx. restuans, and Toxorhynchites theobaldi are reported for the first time for the Mexican State of Morelos. The updated list of species reported is also presented.

A faunal survey of mosquitoes was conducted in 1988 and 1989 at Savanna Portage State Park in north-central Minnesota (Aitkin County). Adults were sampled by sweep net around collectors, aspirator in vegetation, and CO₂ traps in the park. Larvae were taken with dipper from various larval habitats. A total of 32 species were detected, including 16 new records for Aitkin County, MN. Prior to this survey, Aedes decticus and Culiseta melanura were reported in Minnesota once previously.

The Asian exotic mosquito Aedes japonicus was 1st collected in Minnesota in 2007 and was well established in parts of the Metropolitan Mosquito Control District (MMCD) by 2008. Surveillance strategies were devised for 2009 to track the expansion of its range through MMCD and to direct control efforts. Sampling of larvae from container and tire habitats was the primary method used to document Ae. japonicus presence, but larvae were found in other habitats as well. Adult Ae. japonicus were collected by vacuum aspirator, gravid trap, and New Jersey trap but not by CO₂-baited Centers for Disease Control and Prevention light trap. Aedes japonicus were collected from each of the 7 counties surveyed; in 5 of the counties for the 1st time in 2009. Preliminary findings suggest that a control strategy involving intensive source reduction can reduce Ae. japonicus populations.

Investigators have used a variety of techniques to sample resting, engorged mosquitoes for the purposes of studying mosquito blood-feeding behavior. However, evidence exists that mosquito blood-feeding patterns may vary according to collection method. Engorged mosquitoes were collected from rural and urban habitats after the 2007 dry (July) and wet (December) seasons in the Department of Izabal, Guatemala, with the use of Centers for Disease Control and Prevention (CDC) light traps, gravid traps, and aspiration from plastic pots and vegetation. We evaluated the utility of plastic pots as sampling tools for engorged Culex mosquitoes and compared Cx. quinquefasciatus blood host identities among collection methods. The array of vertebrate hosts supplying blood to Cx. quinquefasciatus did not differ significantly by method of collection. The density of engorged Cx. quinquefasciatus per trap-night was not significantly different between CDC light traps, gravid traps, and plastic pots; however, there was a significantly higher proportion of total mosquitoes that were engorged collected from pots than from either CDC light traps or gravid traps.

The seasonal abundance and temporal patterns of the adult sand fly (Lutzomyia shannoni Dyar) were examined at the Patuxent National Wildlife Research Refuge, MD, from August 3, 2005, to July 29, 2006. A total of 138 (53 males, 85 females) L. shannoni was collected from 4 dry ice–baited traps set at the same 4 locations throughout the study. The male∶female ratio was 1∶2.4. All 4 traps, separated by a maximum distance of approximately 1.6 km, operated simultaneously on the collection dates. The collection dates were spaced apart by near weekly intervals during the months of expected sand fly activity. No collections occurred in December–February. August was clearly the period of peak adult abundance as the numbers collected were significantly greater during this month than any other month of collection. Results indicate the existence of a unimodal pattern of abundance with adult emergence beginning in June and ending by September. The temporal pattern and abundance differ from what has been observed for the species on Ossabaw Island, a barrier island located along coastal Georgia, and at San Felasco Hammock Preserve State Park, Gainesville, FL. Continued research is needed to compile multiyear data to confirm the temporal abundance patterns of this species in Maryland.

Organic insect repellents are of interest to many agricultural producers and animal owners. Geraniol, a plant-derived alcohol, is naturally produced by a wide range of plants and is a US Environmental Protection Agency minimum risk pesticide. Previous studies have shown various concentrations of geraniol repel or kill mosquitoes; however, geraniol might cause allergic contact dermatitis in humans or animals. We tested a commercially available 2% aqueous solution of geraniol on ponies as a mosquito repellent. Five trials were conducted on ponies treated with a 60-ml aerosol mist (30 ml per side) of 2% geraniol or as untreated controls. Animals were observed 3 h postapplication to check for skin irritation. Aedes aegypti, in feeding tubes, were held on the ponies for 7 min. The average percent of biting on control animals was 56%, with a range of 16–90%, and the average for the treatments was 13%, with a range of 0–86%. Based on statistical models, there was no significant difference (P  =  0.081) in the percent bites between treated and untreated animals after 3 h. Based on our data, 2% geraniol was not an adequate mosquito repellent for horses. We did not observe any skin irritation on the animals treated with 2% geraniol.

A larval holding chamber was designed to evaluate the movement of a new formulation of a mosquito larvicide. The chamber confines the mosquito larvae to a specific area and allows the larvicide to travel to them. After a 30-h test period, the larvicide being tested had killed all the larvae in the experimental chambers, whereas larvae confined in control chambers were not affected. The larval holding chamber is a good option for testing the movement of a larvicide through water.

Field evaluation of Lurex 3™, 1-octen-3-ol (octenol), and CO₂ sachet as baits in Mosquito Magnet® Pro traps (MMP) for collecting adult mosquitoes was conducted at 2 different locations in northeast Florida. A total of 18 species of mosquitoes were collected by the MMP baited with the 3 attractant baits in St. Augustine, FL. The MMP baited with octenol collected significantly more mosquitoes than the traps baited with Lurex 3 and the CO₂ sachet. A total of 6 floodwater mosquito species were collected by the MMP baited with the 3 attractant baits in Elkton, FL. The MMP baited with Lurex 3 or octenol collected more mosquitoes than the MMP baited with CO₂ sachet or MMP alone.

Aedes albopictus is a primary nuisance pest and disease vector in China. Control of Ae. albopictus using current methods is difficult because of diverse larval breeding sites. In the present study, lambda-cyhalothrin was applied as a barrier spray to vegetation surrounding human dwellings for control of adult mosquito populations. Compared to the landing rate counts in the untreated control site, the barrier spray resulted in an 83–98% reduction of Ae. albopictus within 9 wk posttreatment. The study results indicate that lambda-cyhalothrin applied as a barrier spray to vegetation can reduce Ae. albopictus landing rates collections for more than 2 months.

California pesticide use summary data and use reports from local vector control agencies were reviewed to document public health pesticide use patterns. During the 15-year period 1993–2007, public health pesticide use averaged 1.75 million lb (0.79 million kg) (AI), accounted for <1% of reportable pesticide use statewide, and ranked below major crop uses and many nonagricultural uses. A review of reports from local vector control agencies (2004–07) indicated that their applications were principally for mosquito control and represented >99% of all reported public health pesticide use. Petroleum distillates, principally larviciding oils, accounted for 88% of public health pesticide use. Pyrethrins and naled, used as mosquito adulticides, increased substantially in recent years (post-2004), coinciding with increased West Nile virus control activities and availability of emergency funding.