RESUMO
Gravid traps are commonly used by mosquito control agencies to collect local populations of Culex pipiens, which are then tested for the presence of West Nile virus. Culex pipiens adults disperse a relatively short distance (~2.5 km) from their breeding site, so it can be challenging to position a sufficient number of gravid traps to accurately monitor these mosquitoes in large urban areas. As placement of these traps is often limited to locations out of public?view, the potential for placing these traps belowground in commonly found storm-water catch basins was investigated. We compared the numbers of mosquitoes isolated in the Centers for Disease Control and Prevention (CDC) gravid traps placed aboveground with various types of CDC gravid traps placed in nearby catch basins. We found that the gravid traps placed in catch basins collected significantly fewer Culex pipiens females as compared to the aboveground traps. However, the 2 types of catch basin traps continued to function and collect mosquitoes despite heavy rainfall and runoff, demonstrating their utility for sample collection in an urban setting. The potential advantages and disadvantages of using catch basins for the placement of CDC gravid traps are discussed.
Assuntos
Culex/fisiologia , Controle de Mosquitos/métodos , Animais , Centers for Disease Control and Prevention, U.S. , Feminino , Fatores de Tempo , Estados UnidosRESUMO
Because it is often logistically impossible to monitor all catch basins within an operational area, local mosquito control programs will preemptively treat catch basins with larvicides each season. However, these larvicides can, ostensibly, be considered water quality pollutants. To experimentally reduce the use of larvicides toward improving water quality, 30 basins within a small 0.7-km(2) residential area were monitored weekly for the presence of larvae and pupae for 14 wk in the summer of 2013. Once a basin was found to reach a threshold of 12 mosquitoes per dip sample, it received a FourStar® Briquet (a 180-day briquet formulation of 6% Bacillus sphaericus and 1% B. thuringiensis israelensis). Each week a FourStar-treated basin surpassed this threshold, it was treated with an application of CocoBear™ oil (10% mineral oil). By the end of trials, all but one basin received a briquet and 13 required at least 4 treatments of CocoBear, suggesting that preemptive treatment is appropriate for the study area.
Assuntos
Bacillus , Culicidae , Óleo Mineral , Controle de Mosquitos/métodos , Controle Biológico de Vetores , Qualidade da Água , Animais , Bacillus/fisiologia , Bacillus thuringiensis/fisiologia , Chicago , Culicidae/crescimento & desenvolvimento , Larva , Óleo Mineral/farmacologia , Estações do AnoRESUMO
The North Shore Mosquito Abatement District applies extended release larvicides including methoprene-based Altosid® XR Extended Residual Briquets to approximately 40,000 catch basins in the southern half of the District's operational area at the beginning of each season. Treatments begin in May and typically again 9 to 10 wk later when larvicide efficacy appears to wane. In 2013 spinosad-based Natular™ XRT tablets were applied to basins, and a subset were monitored for larvae and pupae weekly with a standard dipper. When setting the threshold for retreatment as 12 juveniles per dip sample it was observed that basins required a second application 9 wk after the initial application, a time period similar to Altosid despite utilizing a different active ingredient. Average counts of weekly larval samples appeared to be positively associated with average numbers of Culex pipiens collected the following week in a gravid trap located among catch basins, highlighting the importance of basins as sources of these mosquitoes.
Assuntos
Distribuição Animal , Culex , Inseticidas , Macrolídeos , Controle de Mosquitos , Animais , Chicago , Culex/crescimento & desenvolvimento , Culex/fisiologia , Combinação de Medicamentos , Larva/crescimento & desenvolvimento , Larva/fisiologia , Controle de Mosquitos/métodos , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Estações do AnoRESUMO
Stormwater catch basins are the primary source of mosquitoes targeted by the North Shore Mosquito Abatement District, in the northern suburbs of Chicago. Over a 17-wk period (June to September 2011), 3 clusters of catch basins located within a 0.7-km2 area were monitored weekly with dipper samples of immature mosquitoes. During the 2nd week of monitoring, Natular XRT tablets (6.25% spinosad) were applied to northernmost cluster and FourStar Briquets (6% Bacillus û, 1% Bacillus thuringiensis israelensis) were applied to the southernmost cluster; the remaining middle cluster was kept untreated. Following 15 wk of monitoring in 20 basins in each cluster, both Natular and FourStar reduced immature numbers in treated catch basins for 8 consecutive weeks. These results suggest, if effectively timed, a single application of either larvicide may last an entire season.
Assuntos
Bacillus , Culicidae , Inseticidas , Macrolídeos , Controle de Mosquitos/métodos , Animais , Chicago , Culicidae/crescimento & desenvolvimento , Combinação de Medicamentos , Larva/crescimento & desenvolvimento , Fatores de TempoRESUMO
Over the course of three years, 200 ft to 0.75 mi (60 m to 1.2 km) sections of 3 larger (>6 ft [1.8 m] diam) belowground storm sewer conveyance pipes in the northwestern Chicago suburbs were inspected for the presence of adult mosquitoes. Culex mosquitoes were by far the most common (555 of 556 [99.8%] total mosquitoes) collected within pipes during all four meteorological seasons (i.e. during months of October, January, May, August). These observations support prior work elsewhere, suggesting storm sewer pipes are consistent sites of refuge for adult Culex mosquitoes.
Assuntos
Culex , Culicidae , Animais , Chicago , Estações do AnoRESUMO
Over the course of three years, 200 ft to 0.75 mi (60 m to 1.2 km) sections of 3 larger (>6 ft [1.8 m] diam) belowground storm sewer conveyance pipes in the northwestern Chicago suburbs were inspected for the presence of adult mosquitoes. Culex mosquitoes were by far the most common (555 of 556 [99.8%] total mosquitoes) collected within pipes during all four meteorological seasons (i.e. during months of October, January, May, August). These observations support prior work elsewhere, suggesting storm sewer pipes are consistent sites of refuge for adult Culex mosquitoes.
RESUMO
In the northern suburbs of Chicago, stormwater catch basins are the primary source of vector mosquitoes targeted by the local mosquito abatement district, and therefore effective catch basin larvicides are needed. From June to September 2011, Natular XRT was applied at label rate to a cluster of 20 catch basins and compared to a cluster of 20 untreated basins all within a small 0.21 km2 area of catch basins known historically to have high levels of mosquitoes. All monitored basins held immature stages of mosquitoes at least once; however, significantly fewer immatures overall were observed from Natular-treated basins than in untreated basins during 14 wk of monitoring. During the study a portion of Natular-treated catch basins was cleaned as part of scheduled maintenance, and this appeared to remove both the larvicide and any control effects. Better timing of catch basin maintenance events is suggested, particularly if, as the results of this study suggest, a single larvicide treatment may be effective for an entire season.
Assuntos
Culicidae , Insetos Vetores , Inseticidas/administração & dosagem , Macrolídeos/administração & dosagem , Controle de Mosquitos , Animais , Chicago , Combinação de Medicamentos , Insetos Vetores/efeitos dos fármacos , Controle de Mosquitos/métodosRESUMO
West Nile virus remains the leading cause of arboviral neuroinvasive disease in the United States, despite extensive efforts to control the mosquito vectors involved in transmission. In this study, we evaluated the effectiveness of Altosid SR-20 (active ingredient, S-methoprene 20%) larvicide applications using truck-mounted ultra-low volume (ULV) dispersal equipment to target Culex pipiens Linnaeus (Diptera: Culicidae) and Cx. restuans (Theobald)larvae. A combination of emergence bioassays, open-field measurements of deposited S-methoprene and spray distribution using gas chromatography-mass spectrometry, and assessments of adult Culex spp. populations in response to applications were conducted over the summer of 2020 within the North Shore Mosquito Abatement District (IL, USA). Open-field applications revealed that dispersed Altosid SR-20 using ULV equipment was effective (75% emergence inhibition in susceptible lab strain Cx. pipiens larvae) up to 53 m. In suburban neighborhood applications, we found that S-methoprene deposition and larval emergence inhibition (EI) in front yards did not differ significantly from backyards. An overall EI of 46% and 28% were observed for laboratory strain Cx. pipiens and wild Cx. restuans larvae respectively, and both had an EI significantly higher than the untreated control group. The EI of exposed wild Cx. pipiens larvae did not differ from the untreated controls, suggesting an increased tolerance to S-methoprene. No difference in abundance of gravid or host-seeking adult Culex spp. post-application was detected between treated and untreated sites. These results document the ability of area-wide application to distribute S-methoprene, but this strategy will need further modifications and evaluation for Culex spp. management.
Assuntos
Culex , Febre do Nilo Ocidental , Vírus do Nilo Ocidental , Animais , Metoprene , Chicago , Mosquitos Vetores , Estações do Ano , Culex/fisiologia , Larva , Febre do Nilo Ocidental/prevenção & controleRESUMO
Culex quinquefasciatus Say mosquitoes flourish in belowground stormwater systems in the southern United States. Recent evidence suggests that oviposition-site-seeking females may have difficulties locating, entering, and ovipositing inside permanent water chambers when surface entry through pickholes in manhole covers are sealed. It remains unknown, however, if newly emerged adults are able to detect cues necessary to exit these partly sealed systems via lateral conveyance pipes or if they perish belowground. Fourth instar Cx. quinquefasciatus were placed within proprietary belowground stormwater treatment systems to determine the percentage of newly emerged adults able to escape treatment chambers via a single lateral conveyance pipe. Overall, 56% of deployed mosquitoes were captured in adult exit traps with an 1:1 male:female ratio. The percentage of adults captured varied significantly among chambers, but was not associated with structural site characteristics such as the chamber depth or the length and course of conveyance pipe to the exit trap. Empirical observations suggested that longbodied cellar spiders, Pholcus phalangioides (Fuesslin), ubiquitous in these structures, may have reduced adult trap capture. Findings demonstrate that newly emerged Cx. quinquefasciatus can exit subterranean chambers under potentially difficult structural conditions but suggest that a portion may perish in the absence of surface exit points in manhole shafts.
Assuntos
Culex , Drenagem Sanitária , Controle de Mosquitos , Animais , FemininoRESUMO
To increase the effectiveness of adult mosquito control, more frequent ultra-low volume (ULV) applications have been suggested. In the Chicago area, weather may be a limiting factor to more frequent applications. To investigate this, ULV adulticidal application dates from the Northwest Mosquito Abatement District during June 2011 to September 2020 were compared to historical weather data-wind and rain patterns to determine optimum conditions for conducting ULV treatments. During the 85 applications performed during 2011-20, there would have been an opportunity, based on weather conditions, for an additional consecutive night for about half (48.2%) of the time. These opportunities diminished with each additional application. The most intensive response possible would have been a spray of 5 consecutive nights, which occurred once in 3 of the 10 years investigated.
Assuntos
Inseticidas , Chicago , Controle de Mosquitos , Veículos Automotores , Tempo (Meteorologia)RESUMO
Stormwater treatment systems (STS) intended to mitigate the potentially negative public health and environmental impact caused by urban runoff are highly conducive to mosquito production. Thirty-one STS, 15 aboveground extended detention basins (EDBs) and 16 proprietary belowground systems newly installed along State Route 125 in San Diego County, CA, were inspected monthly between July 2008 and June 2009 for presence of standing water and mosquitoes. During the 12-mo study, standing water was observed in 66% of the 180 total inspections to EDBs and at least once in each of the 15 basins, whereas belowground systems held water year-round in permanent-water sumps. With the exception of one EDB, immature mosquitoes were observed in all STS, during every month of the year in EDBs and all months except December in belowground systems. Cumulatively, mosquitoes were noted in 44% of the 372 total site inspections, with a nearly equal number of positive observations from EDBs and belowground systems. Four species were identified from EDBs, Culex tarsalis Coquillett, Cx. quinquefasciatus Say, Anopheles hermsi Barr and Guptavanij, and Culiseta incidens (Thompson). Cx. quinquefasciatus was the sole species identified from belowground systems. Results derived from this study provide additional evidence for mosquito production in STS because of structural design or persistent inflows, or both, of dry-weather urban runoff. Interagency collaboration is needed to ensure that STS are designed and maintained in a way that minimizes their potential to produce mosquitoes that can negatively affect public health.
Assuntos
Culicidae , Drenagem Sanitária , Insetos Vetores , Animais , CaliforniaRESUMO
Over the course of 2019 and 2020, 7 larvicide formulations for use in catch basins were evaluated using a standardized pass/fail protocol. A comparison between 1- and 2-pouch doses of VectoLex® water-soluble pouches (WSP; 10 g per pouch) and 20 g of VectoLex FG (loose granules) suggests that the WSP formulation may have a shorter duration than the FG formulation. Results also suggest that 20 g doses of each of 2 larvicides, Duplex™-G and Sumilarv® 0.5G, may have a minimum effective duration in basins for approximately 40 days. A 20 g dose of Altosid® XR-G and a single briquet Altosid XR each had an observed minimum effective duration of 20 days. Sustain MBG had an observed duration of only 7 wk posttreatment. These observations provide evidence that, in some locations, 20 g granular applications may have a longer effective duration than a single briquet. This work highlights the utility of applying a standardized protocol for routine quality control assessments of the thousands of catch basin larvicide applications performed seasonally by mosquito abatement districts.
Assuntos
Culex , Inseticidas , Animais , Illinois , Larva , Controle de MosquitosRESUMO
Belowground stormwater treatment devices referred to as Best Management Practices (BMPs) can be persistent sources of Culex quinquefasciatus Say (Diptera: Culicidae) mosquitoes and in urban environments necessitate routine monitoring and insecticide treatment for control. The design of certain structural features of BMPs may discourage mosquito entry and oviposition, potentially reducing the need for control measures. From August 2007 to November 2008, 29 BMPs were intermittently monitored for the presence of mosquitoes and compared against selected structural features. A bucket ovitrap was developed to estimate entry of oviposition-site-seeking females into BMPs via egg raft counts. The number of egg rafts collected was positively associated with larger diameters and shorter lengths of conveyance pipe from the nearest inlet or outlet and with increasing number of pickholes in BMP manhole covers. In contrast, the number of days pickholes were sealed against adult mosquito entry was negatively associated with eggs rafts. Findings suggest that the design of belowground BMPs and their conveyance systems can influence mosquito oviposition inside these structures. Specific design criteria with the greatest potential to minimize mosquito production and provide safe access for monitoring and control activities are discussed.
Assuntos
Culex/fisiologia , Controle de Mosquitos/métodos , Chuva/parasitologia , Animais , California , Processos Climáticos , Desenho de Equipamento , Feminino , Controle de Mosquitos/instrumentação , Oviposição , Estações do AnoRESUMO
Efforts to improve water quality increasingly rely on structural stormwater best management practices (BMPs) to remove pollutants from urban runoff. These structures can unintentionally produce mosquitoes and may play a role in the spread of mosquito-borne diseases. A questionnaire was distributed to over 300 stormwater and mosquito control agencies in the United States to assess the prevalence of BMPs and associated mosquito production, identify current measures to control mosquitoes within BMPs, and elucidate the extent of collaboration between these agencies. Responses suggest that agencies often lack basic information relevant to minimizing mosquitoes in BMPs, such as the number of structures within an agency's jurisdiction and the frequency of their maintenance, and that greater interagency collaboration could improve control efforts. Approximately 40% of agencies reported regular collaboration to minimize mosquito production in BMPs; however, barriers to such collaborative work included confusion over roles and responsibilities and a lack of interest. The rapid increase of BMPs in urban environments resulting from increasingly stringent water-quality regulations provides justification for increased collaboration between stormwater and mosquito control sectors of government to aid and strengthen public health efforts.
Assuntos
Culicidae/efeitos dos fármacos , Órgãos Governamentais/organização & administração , Controle de Mosquitos/métodos , Controle de Mosquitos/organização & administração , Eliminação de Resíduos Líquidos , Animais , Culicidae/fisiologia , Coleta de Dados , Inquéritos e Questionários , Estados UnidosRESUMO
Belowground proprietary stormwater treatment devices can produce mosquitoes, including vectors of West Nile virus. Elimination of vertical entry points such as pick holes in manhole covers may reduce the number of mosquitoes entering and reproducing in these structures. Plastic manhole dish inserts were evaluated as structural barriers against mosquito entry through pick holes in a simulated stormwater treatment device. Inserts were 100% effective at preventing mosquito entry through covers when no other openings existed. In devices configured with an open lateral conveyance pipe, the addition of an insert under the cover reduced mosquito oviposition significantly. Subsequent trials to further elucidate mosquito entry through manhole covers found a significant positive correlation between increasing number of pick holes and mosquito oviposition. Results of the study suggest the potential for manhole dish inserts to decrease the number of mosquitoes entering belowground structures. The different available stormwater treatment systems and site-specific installations may, however, provide a much greater variety of possible alternate entry points for mosquitoes than was addressed in the current study. Further work is needed in field installations to quantify the significance of pick holes to mosquito entry and determine under what conditions, if any, manhole dish inserts would be most effective and appropriate.
Assuntos
Culicidae/fisiologia , Controle de Mosquitos/instrumentação , Controle de Mosquitos/métodos , Animais , Comportamento Animal/fisiologia , Engenharia , Feminino , OviposiçãoRESUMO
During June through September 2018, the North Shore Mosquito Abatement District evaluated a quality control protocol for larvicide-treated catch basins that allowed for comparisons of larvicides with different modes of action. Results suggest that when applied at a rate of 2 tablespoons (approximately 20 g of product) per basin, these larvicides (VectoLex® FG Lysinibacillus sphaericus, Natular™ G30 Spinosad, and Altosid® Pellets Methoprene) could reduce the need for retreatment for up to 4 wk or longer. Using this same protocol, Spheratax® SPH (50G) L. sphaericus was applied to a subset of approximately 900 basins and met the threshold for retreatment 1.1 wk postapplication. Despite these larvicide applications, pupae continued to be observed in non-Altosid® treated basins, suggesting 100% mortality may not be attainable.
Assuntos
Culicidae , Inseticidas , Controle de Mosquitos , Animais , Chicago , Culicidae/crescimento & desenvolvimento , LarvaRESUMO
Simulated stormwater management devices baited with alfalfa infusion were constructed to test conveyance pipe dimension and orientation as a potential deterrent to mosquito oviposition. Various configurations of pipe diameter, length, and orientation were evaluated based on egg raft counts. Field trials tested pipes of 1.3-, 5-, and 10-cm diam and 0-, 90-, or 270-cm lengths, in both horizontal and vertical orientations. Additional trials of 10-cm-diam horizontal pipe evaluated the effects of a 90 degrees bend, single or dual entry points, and lengths greater than 270 cm. Significantly fewer egg rafts were collected in pipes of smaller diameter and longer length in both horizontal and vertical orientations. A 90 degrees bend or removal of an entry point to pipes of fixed length had no significant effect on oviposition. A maximum tested length of 24.4 m did not preclude oviposition. The results of this study suggest that manipulating diameter and length of conveyance pipe in stormwater management devices may not be an effective strategy to deter oviposition. The need for integrating improved, novel, nonchemical mosquito control measures into designing and operating stormwater management structures is discussed.
Assuntos
Culicidae/fisiologia , Oviposição/fisiologia , Animais , Comportamento Animal/fisiologia , Engenharia , Feminino , Água DoceRESUMO
A widely recommended strategy to minimize mosquito production in structural stormwater Best Management Practices (BMPs) is to ensure they hold captured water for no more than 72 h. However, this standard may be overly conservative for many mosquito species found in urban environments and may impede or prevent the capacity of BMPs to fulfill more stringent water quality standards in environmentally sensitive areas. Egg-to-pupa development of Culex tarsalis, Cx. pipiens, and Cx. quinquefasciatus were examined during July, August, and September 2006 in stormwater management basins and in water collected from these basins in 3 climatically distinct regions of California: the Lake Tahoe Basin, Sacramento Valley, and Los Angeles Basin. The observed minimum times to pupal development were 6 days for Cx. tarsalis and Cx. quinquefasciatus and 8 days for Cx. pipiens. Multiple linear regression models were used to estimate minimum predicted development times under optimal conditions for each region. The results suggest that water residence times of up to 96 h will not significantly increase the potential for Culex mosquito production in stormwater BMPs in the 3 regions included in this study.
Assuntos
Culex/crescimento & desenvolvimento , Animais , California , Ecossistema , Engenharia , Água Doce , Temperatura , Fatores de TempoRESUMO
Effectiveness in controlling mosquitoes in storm water catch basins in the North Shore Mosquito Abatement District (northeastern Cook County, Illinois) was determined for 3 formulations of methoprene-based larvicides (Altosid XR 150-day Briquets, Altosid 30-day Pellets, Altosid 30-day Granules) in 2017 using a pass/fail evaluation criterion, in which emergence of a single adult from pupae collected from the basin constituted a control failure. Over the course of the 16-week study, basins receiving the 150-day briquets were treated once and basins receiving the pellet and granular formulations were treated every 4 weeks, with the first treatment occurring during the last week of May. Untreated basins were also observed for comparison with the treated basins. Over the course of the study, adult mosquitoes emerged from pupae collected in 94.2% of the untreated basins that contained pupae. All of the formulations evaluated in the study demonstrated some degree of control compared with the untreated basins, with pupae successfully emerging as adults in 64.6%, 55.5%, and 21.8% of samples from 150-day briquet, 30-day tablet, and 30-day pellet-treated basins that contained pupae, respectively. Pellets reapplied every 28 days provided significantly more effective control than the other formulations. The simple pass/fail criterion for evaluating control effectiveness proved to be a useful procedure for comparing effectiveness to untreated basins and among treatments.
RESUMO
During June to September 2017, 7 mosquito control programs in the midwestern United States evaluated a total of 9 catch basin larvicide formulations using similar protocols. Treated basins were monitored among study sites to observe when larvicides failed to control mosquitoes in 25% or more basins within a site. Overall, when monitoring occurred within the maximum label duration of the larvicides, sites treated with a single larvicide tablet or briquet surpassed the 25% fail threshold more often than pellet and granular larvicide formulations. In 438 of the study basins, the depth from sump bottom to catch basin lid was measured. In basins that were deeper than 5 ft (1.5 m), larvicides failed to control mosquitoes significantly more often than those 5 ft or shallower.