During the 2014 chikungunya (CHIK) outbreak in the Caribbean, we performed entomological surveys on 3 United States Virgin Islands (USVI): St. Croix, St. Thomas, and St. John. We aimed to evaluate the potential for chikungunya virus (CHIKV) transmission in the USVI. The surveys took place between June 19, 2014, and June 29, 2014, during the dry season in USVI. A total of 1,929 adult mosquitoes belonging to 4 species—Culex quinquefasciatus (68.4%), Aedes aegypti (29.7%), Ae. mediovittatus (1.3%), and Ae. sollicitans (<1%)—were detected. Environmental investigations showed that between 73% and 87% of the homes had containers that could serve as mosquito larval habitats. In addition, 47% of the homes did not have air conditioning and between 69% and 79% of homes showed evidence of frequent outdoor activity exhibited by residents. Taken together, these observations suggest a high potential for CHIKV transmission in USVI. The relative abundance of Ae. aegypti on St. John's, St. Thomas, and St. Croix was 21.0, 11.0, and 3.0 mosquitoes/trap per day, respectively, suggesting that the former 2 islands were at the highest risk of CHIKV outbreaks. Insecticide resistance testing detected high levels of resistance to malathion and permethrin in several local populations of Ae. aegypti on St. Croix Island, which suggested that these 2 insecticides should not be used during CHIK outbreaks.

The effect of fluctuating ambient air and water temperatures and relative humidity (RH) on the population parameters of Culex pipiens was studied using life table data during the winter–spring and summer–autumn seasons in Giza Province, Egypt. In winter–spring (20.46 ± 1.8°C and 51.68 ± 3.63% RH), the preadult survival rate for Cx. pipiens was 80.65%, which was higher than the 50.00% observed in the summer–autumn (30.19 ± 0.67°C and 52.68 ± 8.04% RH). During the winter–spring period, the developmental time of egg, larvae, and pupae of Cx. pipiens was 3.52, 12.69, and 5.92 days, respectively. There was a significantly shorter developmental period for summer–autumn (1.0, 8.59, and 2.04 days, respectively). Both female and male adults survived longer during winter–spring (61.83 days for female and 42.62 days for male adults) than during summer–autumn (24.38 days for female and 20.83 days for male adults). The fecundity (F) of female Cx. pipiens (524.7 eggs/female) and the net reproductive rate (R₀) (245.4 offspring) were significantly higher during winter–spring seasons than in the summer–autumn (163.3 eggs/female and 38.10 offspring). Despite the higher F and R₀ values in winter–spring, the intrinsic rate of increase (r_m = 0.1181/day) and the finite rate of increase (λ = 1.1253/day) of the Cx. pipiens population were significantly lower compared to summer–autumn (r_m = 0.1648/day; λ = 1.1792/day). Consequently, the mean generation time during winter–spring was significantly longer (46.6 days) than during summer–autumn (22.09 days). The data suggest that Cx. pipiens is an r-strategist.

We examined the pupicidal, adulticidal, repellent, and oviposition-deterrent activities of essential oils (EOs) from Lippia alba, L. origanoides, Eucalyptus citriodora, Cymbopogon citratus, Cymbopogon flexuosus, Citrus sinensis, Cananga odorata, Swinglea glutinosa, and Tagetes lucida plants against Aedes aegypti under laboratory conditions. Pupicidal and adulticidal activities were assessed at exploratory concentrations of 250, 310, and 390 parts per million (ppm); and 30, 300, and 1,000 ppm, respectively. The greatest pupicidal activity was exhibited at 390 ppm with a 24-h exposure by L. origanoides, and 390 ppm with a 48-h exposure by Citrus sinensis. Lippia origanoides killed all adult mosquitoes at 300 ppm after 120 min of exposure. Only L. origanoides and E. citriodora EOs, applied at 1,000 ppm to human skin, produced the greatest repellency (100%) to host-seeking Ae. aegypti after 2 min of exposure; the repellency decreased between 12% and 10% after 15 min. Complete oviposition deterrence by gravid Ae. aegypti was observed for E. citriodora EOs at 200 ppm with an oviposition activity index of −1.00. These results confirm that the EOs assessed in this study have insecticidal, repellent, and oviposition-deterrent activities against the dengue vector, Ae. aegypti.

The comparative efficacy of ultra-low volume applications of deltamethrin, permethrin, and malathion against specific adult populations of Culex quinquefasciatus, a primary regional vector of Saint Louis encephalitis and West Nile virus, using field cage tests is described. At labeled application rates, the estimated mass median diameters for Fyfanon^®, Evoluer™, and DeltaGard^® were 18.32, 19.24, and 17.44 μm, respectively. No significant differences (P ≥ 0.01) in mean percent control were observed across all 3 wild populations and a susceptible Sebring strain tested with Fyfanon, DeltaGard, and Evoluer, providing 98.25%, 98.20%, and 97.24% mean percent control. Mean percent control for Sebring and 3 wild populations was 99.38%, 97.79%, 97.26%, and 97.15%, respectively, which were not significantly different from one another (P ≥ 0.01). Across all tests, highly significant differences (P ≤ 0.01) in mean percent control were obtained at 30.48, 60.96, and 91.44 m distances downwind, with mean percent control at 91.44 m being significantly less than that observed at 30.48 m, but not at 60.96 m. Individually, tests for DeltaGard, Fyfanon, and Evoluer resulted in no significant differences (P ≥ 0.01) in mean percent control between all mosquito populations tested, ranging from 96.47 to 100. However, Evoluer obtained significantly less (P ≤ 0.01) mean percent control at 91.44 m compared to DeltaGard and Fyfanon. Data suggest that the wild Cx. quinquefasciatus specimens collected were as susceptible as the laboratory Sebring strain. The use of Sebring as positive controls downwind strongly supported determination of the efficacy of all adulticides and susceptibility of wild populations tested.

The droplet spectrum of a mosquito adulticide spray plume determines its ability to drift through the target area, impinge on the mosquito, deliver a toxic dose, and the risk of environmental contamination. This paper provides data on droplet spectra produced from 6 nozzles in a high-pressure nozzle spray system and 5 rotary nozzle systems for common mosquito adulticides. Spray plume spectra were measured by laser diffraction. High-pressure nozzles were evaluated at pressures ranging from 500 psi to 6,000 psi. Rotary nozzles were evaluated at rotational speeds ranging from 500 rpm to 24,000 rpm. Measurements were made at wind speeds of 129 km/h (80 mph) to 225 km/h (140 mph). Adulticides included were Fyfanon^®, Aqua-Reslin^®, Dibrom^®, Duet^®, Permanone^®, and the inert mineral oil, Orchex^® 796. High-pressure nozzles produced spray plumes within the US Environmental Protection Agency (EPA) label requirements for all configurations tested except for one at a wind speed of 225 km/h, BETE^® MW125. Air speed had no significant effect on the spray plume volume median diameter (Dv_(0.5)) at the speeds tested with Fyfanon^®. The spray plume 90% drop volume diameter (Dv_(0.9)) significantly decreased, 13% at the higher wind speed of 225 km/h. Drop size was inversely related to pressure. Dilution of the product formulations increased the Dv_(0.5) of the spray plume but it did not exceed the label requirements. For the PJ15 nozzle, orientation of the nozzle into the wind of up to 135° showed a significant increase in Dv_(0.5) at 500 psi, 750 psi, and 1,500 psi. The Dv_(0.5) varied <5 μm over the 3 angles examined for any specific pressure. Rotary nozzles produced spray plumes within the EPA label requirements for all test configurations examined. Air speed had no significant effect on Dv_(0.5) or Dv_(0.9) of the plume at speeds tested with Fyfanon for the ASC A20 nozzle. The rotary AU5000 nozzle using Orchex 796 produced plumes of larger drops in all configurations than any of the rotary nozzles of similar configurations using active ingredient formulations and within EPA label requirements.

We evaluated 3 over-the-counter pesticides for their ability to suppress host-seeking Ixodes scapularis and Amblyomma americanum nymphs. We applied liquid concentrate and granular formulations of Bayer Advanced Complete Insect Killer, Spectracide Triazicide Insect Killer, and Ortho Bug-B-Gon to forest plots using equipment available for purchase at retail home improvement outlets. All 3 liquid formulations provided rapid knockdown (≥98% control) of both species 1 day after application. Liquid Ortho Bug-B-Gone provided 100% suppression of I. scapularis throughout the 28-day postapplication period, while the other 2 liquid materials provided >95% control after 28 days. All liquid products also provided ≥95% control of A. americanum nymphs after 28 days. Granular formulations provided less consistent results, including lower 1-day knockdown rates for both species, due to very dry conditions, which prevented adequate release of the active ingredient from the carrier materials. After it rained in the study area, 7 and 14 days after application, we observed ≥99% suppression of both species. At 28 days posttreatment, control ranged between 87.5% and 95.6% for I. scapularis and between 89.3% and 94.4% for A. americanum. We show that these over-the-counter acaricides effectively suppressed 2 medically important tick vectors for at least 4 wk, and they provide a cost-effective tick control option for homeowners. In general, liquid formulations provided more rapid and greater and more consistent suppression than granular formulations, which may have implications for homeowner use of these products.

Aedes aegypti is an important subtropical vector species and is predicted to have a limited year-round distribution in the southern United States. Collection of the species has not been officially verified in Oklahoma since 1940. Adult mosquitoes were collected in 42 sites across 7 different cities in Oklahoma using 3 different mosquito traps between May and September 2016. Between July and September 2016, 88 Ae. aegypti adults were collected at 18 different sites in 4 different cities across southern Oklahoma. Centers for Disease Control and Prevention mini light traps baited with CO₂ attracted the highest numbers of Ae. aegypti individuals compared to Biogents (BG)-Sentinel^® traps baited with Biogents (BG)-lure and octenol and Centers for Disease Control and Prevention gravid traps baited with Bermuda grass–infused water. The discovery of Ae. aegypti mosquitoes within urban/exurban areas in Oklahoma is important from an ecological as well as a public health perspective.

Routine West Nile virus (WNV) surveillance in 2016 by the Washington State Department of Health resulted in 1 new state distribution record for Aedes hendersoni, bringing the total number of mosquito species reported from Washington to 52. We also report new county records for Aedes japonicus japonicus, Aedes togoi, and Culex salinarius.

The present study investigates the effect of multiple immersions on Psorophora albigenu eggs and their development cycle under laboratory conditions. Engorged Ps. albigenu specimens were captured in January 2011 around the Transpantaneira Park Road, Mato Grosso, Brazil, using CO₂-baited Centers for Disease Control and Prevention light traps. Psorophora albigenu eggs (n = 1274) were subjected to immersion, with a hatching rate between 49% and 73%. The Williams average showed a peak of 29% hatched eggs in the 3rd immersion; after 4–5 immersions, the effect of additional immersions was generally negligible. The average cycle for both males and females was 5.68 ± 1.00 days. This short development time from the egg stage to adult emergence followed the pattern seen in other species of the genus Psorophora.

Temperature and rainfall are important drivers of mosquito abundance and have been used in previous studies as the basis for predictive models. To elucidate patterns of mosquito population dynamics in urban environments, the variation in mosquito abundance over a year and its association with climatic variables were analyzed. The Akaike information criterion was used to analyze the correlations between abundance and climate variables in mosquito populations collected in 2 urban parks: Alfredo Volpi Park and Burle Marx Park. Our findings suggest that both climatic and density-dependent variations may have an important impact on fluctuations in mosquito abundance, modulating population dynamics in urban parks.

Multiple surveillance traps are currently available for adult mosquito surveillance. In this study, 2 new types, the Maxttrac™ Uno and Maxttrac™ Breeze mosquito traps, were compared against the BioGents™-Sentinel trap (BGS) for overall success in collecting Aedes albopictus in a 1,027-m² vehicle enclosure and in the field. The enclosure test results showed both traps collected significantly fewer Ae. albopictus, compared to the BGS trap. The modification of using all BG lures for each trap did not increase the number of mosquitoes collected in the 2 new traps, when compared to collection with the original lures tested in the vehicle enclosure. Field test results showed that BGS trap collected higher numbers of Ae. albopictus than the 2 new traps, regardless of switching lure or not. Overall, the BGS trap was the most effective trap and the 2 new traps could be used as additional tools for the collection of Ae. albopictus.