Precise mosquito species identification is an essential step for proper management and control of malaria vectors. Misidentification of members in the Anopheles dirus complex, some which are primary malaria vectors in Thailand and mainland Southeast Asia, remains problematic because of indistinguishable or overlapping morphological characters between sibling species. Moreover, there is a need for alternative methods, since the existing molecular techniques in the literature are not entirely satisfactory in differentiating all members in the An. dirus complex. The nucleotide polymorphisms in the mitochondrial cytochrome c oxidase subunit I (COI) sequences were developed to identify the 4 species within the An. dirus complex using an allele-specific (AS) multiplex polymerase chain reaction (PCR). The identified primers amplified and clearly differentiated the 4 members of the complex found in Thailand, Anopheles dirus, An. cracens, An. scanloni, and An. baimaii with PCR products 428/104, 236, 625, and 428 bp, respectively. These results demonstrate that an AS-PCR based on the COI region can accurately identify 4 members of An. dirus complex and would be useful as an alternative PCR-based method for accurate species identification.

A temporal observational study was conducted with the aim of characterizing Culicidae richness, diversity, abundance, and species similarity in fragments of Atlantic Forest within the Itatiaia National Park, state of Rio de Janeiro, Brazil. A total of 31 mosquito species were collected in 2 sampling stations, during the day and night, and the abundance index and dominance coefficient for each species were calculated. The results showed that the culicid density was higher during the day, and the time preference was directly influenced by the climate variables analyzed, which acted as limiting factors for mosquito occurrence. The mosquito fauna at the Itatiaia National Park presented high richness, including some epidemiologically important species: Anopheles cruzii, Haemagogus leucocelaenus, Aedes scapularis, and Sabethes identicus. Studies of this region supply information on biodiversity, and consequently help to understand epidemiological aspects of potential pathogen vector species.

The recent introduction of Zika virus (ZIKV) into the Americas and the occurrence of birth defects associated with infection during pregnancy have created a concern about the spread of this virus into more northern countries in the Americas. Therefore, we examined several species of mosquitoes found in southern Manitoba, Canada, for their susceptibility to infection and their ability to transmit ZIKV. Aedes cinereus, Ae. euedes, Ae. fitchii, Ae. sticticus, Ae. vexans, Coquillettidia perturbans, Culex restuans, and Cx. tarsalis were captured in the vicinity of Winnipeg, Manitoba; brought to the laboratory; and allowed to feed on a ZIKV–sheep blood suspension to determine oral susceptibility. In addition, some of the nonfed individuals were inoculated intrathoracically to examine for the presence of a salivary gland barrier. Despite ingesting blood containing 10^5.4 plaque-forming units/ml, infection rates were very low, and infected individuals were only detected for Ae. vexans. Transmission was observed for Ae. vexans, Cq. perturbans, and Cx. restuans that had been inoculated with ZIKV, although rates were low. Based on the extremely low vector competence found in this study and the lack of a preferential feeding on humans, it is unlikely than any of the mosquito species tested in this study would be involved in any large-scale transmission of ZIKV in Canada.

The pyrethroid prallethrin, an AI in DUET™ (Clarke Mosquito Control, St. Charles, IL), is widely marketed ultra-low volume (ULV) mosquito adulticide. Volatilized prallethrin is intended to stimulate mosquito flight, increasing its adulticide effectiveness. However, field tests using volatilized prallethrin have not produced significant differences in mosquito trap catches, leading to questions regarding prallethrin's behavioral impact efficacy. Thus, we conducted laboratory tests of prallethrin's effect on flight behavior of adult female Asian tiger mosquitoes, Aedes albopictus. Mosquitoes were divided into 3 groups: untreated control, exposed to volatilized prallethrin, and exposed to a liquid spray calibrated to simulate a ULV application at label rates. After exposure, mosquito behavior in an airstream of 0.5 m/sec was recorded and analyzed using motion-tracking software. No significant differences in flight behavior were found between the control and treated mosquitoes exposed to volatilized prallethrin. The ULV-sprayed mosquitoes exhibited a significant increase in the number of flight events, the turning frequency, overall movement speed, and flight speed compared to the control—a significant difference in locomotor stimulation response that would increase exposure to a ULV spray cloud. However, our results showed that volatilization alone was insufficient to increase ULV efficacy in the field and suggested that incorporating a more volatile flight stimulant into ULV adulticides would provide a measurable improvement in mosquito control.

The efficacy of the BG-Sentinel™ (BGS) trap as a “pull” component of a “push–pull” system (PPS) for management of the dengue vector, Aedes aegypti, was evaluated using local households in Pu Tuey, Kanchanaburi, Thailand. The pull component was the concluding phase of a 3-part investigation using a PPS combination spatial repellent (SR) and BGS trap to capture adult vector mosquitoes. Two sentinel households were selected for evaluation of BGS trap efficacy based on the highest pretrial indoor resting densities of Ae. aegypti using Centers for Disease Control and Prevention (CDC) mechanical backpack collections. Potential Ae. aegypti resting sites around the selected houses were identified as possible competing sites that might influence the BGS trap capture efficiency. Results showed that BGS traps were productive in capturing Ae. aegypti females (93.4% of all Aedes collected) in the presence of competing man-made, artificial resting sites. The CDC backpack aspirator collections provided an indirect measure of local Aedes population, although technically not comparable for supporting productivity of BGS traps due to different collection days and households sampled. The predominant competing resting sites were water containers found within 3 m around the outside of sentinel households. The most productive BGS collections between houses differed by location. The most productive period of operation for Ae. aegypti BGS trapping was between 1330 and 1730 h. The BGS trap appears an effective “pull” device in the PPS strategy in natural settings.

Attraction of Aedes aegypti to various binary, trinary, and quaternary blends of lactic acid and ketones with or without ammonia was studied using a dual choice olfactometer. A dose dependent attraction was observed in cases of single compounds where cyclopentanone attracted the highest percentage (36.9 ± 1.8%) of Ae. aegypti when tested alone. No significant difference was observed between the attraction levels of trinary and binary blends of lactic acid and acetone or butanone when tested against clear air. However, in competitive bioassays, the trinary blend of lactic acid, acetone, and butanone was significantly preferred over binary blends of individual compounds (P < 0.05). Acetylacetone was weakly attractive when tested alone but showed additive attraction when blended with lactic acid. However, acetylacetone acted as an attraction inhibitor when blended with other compounds. Cyclopentanone was attractive, but enhancement of attraction was not observed when blended with other components. Addition of ammonia to binary or trinary blends of lactic acid, acetone, and/or butanone did not increase the attraction significantly. In competitive bioassays, the blends containing ammonia were significantly preferred over the blends lacking ammonia (P < 0.05). This highlights ammonia as an essential component of synthetic blends. A quaternary blend of lactic acid, ammonia, acetone, and butanone was most attractive (65 ± 1.5%) and preferred blend of all other combinations.

Effectiveness in controlling mosquito larvae in stormwater catch basins in the North Shore Mosquito Abatement District (northeastern Cook County, IL) was determined for 2 extended-duration larvicides indicating up to 180 days of control on their labels (Natular™ XRT, FourStar® Briquet) and 3 larvicides indicating up to 30 days of control (Natular™ T30, Natular™ G30, and VectoLex® FG). Over the course of the 26-wk study, catch basins receiving the extended-release products were treated twice (an initial treatment in early April followed by a re-treatment after 16 wk), and catch basins receiving the shorter-duration products were treated every 28 days, with the 1st treatment occurring during the 1st week in April. Control in an individual catch basin was considered to have failed if late-stage larvae or pupae were found in 2-dip samples taken from the catch basin. Control for a treatment was considered to have failed if >25% of catch basins treated with the product failed at a given time period posttreatment. All of the products evaluated in the study demonstrated some degree of control; however, the Natular XRT–, FourStar Briquet–, and Natular T30–treated basins rarely achieved the effectiveness threshold of ≤25% of catch basins failing. By comparison, basins treated with Natular G30 were below that threshold for 3 of 4 wk every treatment round and VectoLex® FG was consistently below that threshold for all 4 wk posttreatment for every treatment round. Compared with untreated catch basins, the total season pupal production was reduced by approximately 48% in the Natular XRT–, FourStar Briquet–, and Natular T30–treated basins, and by 87% and 99% in the Natular G30– and VectoLex FG–treated basins, respectively. Operational quality control observations indicated that effective control (i.e., ≤25% of catch basins failing) ranged from 3 to 12 wk posttreatment for catch basins treated with Natular XRT and from 5 to 9 wk with VectoLex FG, and that there was considerable geographic variation in the duration of effectiveness. The results indicate that 30-day re-treatments with granular formulations in difficult-to-control areas may provide a more cost-effective outcome than using 1 or 2 applications of extended-duration larvicides.

Aedes albopictus and Culex pipiens are commonly distributed in Italy and represent the main species found in catch basins. The application of a silicone-based film (e.g., Aquatain®) is a new tool recently introduced for treating catch basins. While the efficacy of Aquatain has been experimentally demonstrated, its use is still lacking an appropriate monitoring procedure. The present study compared the differences in the efficacy of treatment assessment between a newly developed floating system (FS), which was designed to collect emerging adults, with the standard dipper procedure, used for estimating the abundance of mosquito larvae. Forty catch basins, half treated with Aquatain and half untreated (control basins), were monitored weekly using dipper (10 treated 10 control basins) or FS (10 10) 5 times after 2 subsequent treatments. Both monitoring procedures recorded high percentages of larvae and adult reduction for the 1st 1−3 wk after treatments, confirming the simultaneous activity of Aquatain against all stages of mosquitoes. Differences in adult emergence were recorded also when monitoring of larvae was ineffective, suggesting that the newly developed FS is a promising method for assessing the efficacy of monomolecular films in catch basins.

Culex quinquefasciatus is one of China's major house-dwelling mosquito species and an important vector of filariasis and encephalitis. Chemical treatments represent one of the most successful approaches for comprehensive mosquito prevention and control. However, the widespread use of chemical pesticides has led to the occurrence and development of insecticide resistance. Therefore, in-depth studies of resistance to insecticides are of vital importance. In this study, we performed a gene expression analysis to investigate genes from Cx. quinquefasciatus that may confer pyrethroid resistance. We aimed to understand the mechanisms of Cx. quinquefasciatus resistance to pyrethroid insecticides and provide insights into insect resistance management. Using a resistance bioassay, we determined the deltamethrin LC₅₀ values (lethal concentration required to kill 50% of the population) for Cx. quinquefasciatus larvae in the F₂₁, F₂₃, F₂₄, F₂₆, F₂₇, and F₃₀ generations. The 7 tested strains exhibited pesticide resistance that was 25.25 to 87.83 times higher than that of the SanYa strain. Moreover, the expression of the OBPjj7a (odorant-binding protein OBPjj7a), OBP28 (odorant-binding protein OBP28), and E2 (ubiquitin-conjugating enzyme) genes was positively correlated with deltamethrin resistance (R² = 0.836, P = 0.011; R² = 0.788, P = 0.018; and R² = 0.850, P = 0.009, respectively) in Cx. quinquefasciatus. The expression of 4 additional genes, H/ACA, S19, SAR2, and PGRP, was not correlated with deltamethrin resistance. In summary, this study identified 3 Cx. quinquefasciatus genes with potential involvement in deltamethrin resistance, and these results may provide a theoretical basis for the control of mosquito resistance and insights into resistance detection.

Mosquitoes are a nuisance and can transmit pathogens to humans and other animals, resulting in notable morbidity and mortality. Organized mosquito control programs conduct surveillance, source reduction, treatment of mosquito oviposition sites, and adulticiding to protect public health. However, in some regions, there has been a decline in county and municipal mosquito control programs, and homeowners increasingly contract with private mosquito control companies or address mosquito-related issues themselves at the household level. The extent to which these services are being used, the potential for mosquito and/or insecticide exposure around the home, and the access to these services by individuals of different socioeconomic categories are not known. We conducted regional (western, central, eastern) assessments of public perception and knowledge of mosquito control services in a variety of communities of different socioeconomic categories (low, moderate, high) and types (urban, suburban, rural) in 3 North Carolina counties. We also assessed the respondents' basic knowledge of mosquito-borne diseases. Most respondents thought mosquito control was important to protect against both nuisance mosquitoes and mosquito-borne disease. The majority of people would pay ≤$50/year for mosquito control and most thought this should be covered by municipal/county taxes. Many respondents (31%, 95% confidence interval [CI] 26–35%) personally undertake mosquito control on their properties, but only 5.3% (95% CI 3.1–7.5%) contract with professional mosquito control services, with no significant differences between region, community type, or socioeconomic category in the proportion using private mosquito control services. While there were significant differences between factor levels (3 regions, 3 community types, 3 socioeconomic categories) in some responses, there were no significant differences observed between respondents, regardless of factor level, in the willingness to contribute funds to a community-based mosquito control program.

The presence of Aedes j. japonicus in Florida is reported for the first time. Four adult females were collected by a Mosquito Magnet® X trap baited with pressurized CO₂ in Okaloosa County, FL, in August 2012 and later identified as Ae. japonicus in 2014. Additional adult and larval specimens were collected during 2014–17 from Bay, Leon, Okaloosa, Santa Rosa, or Walton counties, Florida. Notes are provided on the location, general habitats, and mosquito associates that may be found with Ae. japonicus in northwestern Florida. The role of Ae. japonicus in arbovirus transmission within Florida is currently unknown and should be further explored.

Culex coronator has been identified in Shelby County, TN, for the first time as an established species. This is an important discovery since the range of Cx. coronator is unknown in Tennessee and it has been found positive for West Nile virus. Larvae and an adult were discovered during routine surveillance. Larvae were collected at 9 different locations, while the 1 adult captured was at the 10th isolated location.

Three repellent products, OFF! Mosquito Lamp, Insecticandel, and Rescue DecoShield, were comparatively evaluated against Aedes aegypti in 130-m² enclosed areas with a 317-m³ air volume. The results showed that the OFF! Mosquito Lamp with metofluthrin had a greater effect than the Insecticandel with transfluthrin, which had greater effect than the DecoShield with lemongrass oil and several other plant oils against Ae. aegypti. The OFF! Mosquito Lamp was the only product to exceed 50% mortality. An outdoor semi–field evaluation was conducted to determine the effect by distance of the product. Mosquitoes were stationed in cages at 3, 6, 9, 12, and 15 m away from the treatment in a downwind linear array and exposed for 10 min. They were recorded for knockdown after treatment and at 24 h for mortality. The OFF! Mosquito Lamp produced 100% mortality indoors and >80% knockdown and 90% mortality within 6 m while outdoors against Ae. aegypti.

Activity of ethanolic extracts of the algae Ulva rigida, Asparagopsis taxiformis, Dictyota dichotoma, and Cystoseira barbata, collected along Italian coasts, was tested against larvae of the Asian tiger mosquito (Aedes albopictus), a vector of pathogens for animals and humans. Tests were carried out using 10 specimens of 3rd-stage larvae per test, following the World Health Organization standard protocol with minor modifications. Among algal extracts, only D. dichotoma was active against the larvae of Ae. albopictus. Ethanolic extracts of that species showed LC₉₀ (the concentration that kills 90% of larvae) and LC₅₀ (the concentration that kills 50% of larvae) values at 44.32 and 85.92 mg/liter, respectively. Based on the data obtained, D. dichotoma biometabolic extracts could be potential candidates as larvicide compounds to control Ae. albopictus, encouraging the use of macroalgae as natural resources in integrated vector management strategies.

Larvicidal oils can be used to control immature Aedes aegypti and other pestiferous mosquitoes. To test whether oil-based larvicides also act as oviposition deterrents, indoor and semi–field trials were conducted at the Navy Entomology Center of Excellence in Jacksonville, FL. In both studies, treatment cages consisted of oviposition cups lined with seed germination paper as an oviposition substrate and filled with 1-wk-old southern live oak (Quercus virginiana) leaf litter–infused water. Treatment cages consisted of 2 cups treated with CocoBear™ Mosquito Larvicidal Oil, while 2 cups were untreated. Control cages contained oviposition cups with only oak leaf litter–infused water. Gravid Ae. aegypti were released into cages and allowed to oviposit for 24 h, after which eggs were counted. The number of eggs deposited in treatment and control cages was not significantly different (indoor P = 0.0865; outdoor P = 0.9765). However, the number of eggs deposited in untreated cups was significantly greater than that deposited in treated cups within treatment cages (indoor P < 0.0001; outdoor P = 0.0050). These results suggest that the presence of the larvicidal oil CocoBear may cause gravid female Ae. aegypti to seek alternative oviposition sites.

We compared the efficacy of the Biogents Gravid Aedes Trap (BG-GAT) and Biogents-2 Sentinel (BG2S) trap to assess differences in adult mosquito collection rates between these 2 mosquito surveillance methods in northeastern Florida. Species diversity of trap collections was significantly greater for BG2S than for BG-GAT, with 14 mosquito species collected from the former trap and 4 species from the latter. Aedes aegypti and Culex quinquefasciatus were the 2 predominant species collected in both traps. Overall, BG2S traps collected significantly more mosquitoes (in some instances nearly 5 times) than the BG-GAT, regardless of species. There was no significant difference between the 2 traps with respect to gravid status when total species and number of mosquitoes collected were compared. However, at the species level, 8% of Ae. aegypti were gravid from the BG-GAT collections compared with 1% from the BG2S. The number of gravid Cx. quinquefasciatus was also considerably greater (59%) for the BG-GATs than for BG2S traps (2%), but these relationships were not statistically significant due to high variability in collections between traps.