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At least 55 records · Page 3Linked to original sources
PubMed1998

A critical review of ultralow-volume aerosols of insecticide applied with vehicle-mounted generators for adult mosquito control.

This review of ultralow-volume (ULV) ground aerosols for adult mosquito control includes discussion on application volume, aerosol generators, droplet size, meteorology, swath, dispersal speed, assay methods, insecticide efficacy, and nontarget effects. It summarizes the efficacy of ULV insecticidal aerosols against many important pest and disease-bearing species of mosquitoes in a wide range of locations and habitats in the United States and in some countries of Asia and the Americas. Fourteen conclusions were drawn from the review. 1) ULV ground aerosol applications of insecticide are as efficacious against adult mosquitoes as high- or low-volume aerosols. 2) ULV aerosols with an optimum droplet size spectrum can be produced by several types of nozzles including vortex, pneumatic, and rotary. Droplet size of a particular insecticide formulation is dependent primarily on nozzle air pressure or rotation speed and secondarily on insecticide flow rate. 3) Label flow rates of insecticide for ULV aerosol application can be delivered accurately during routine operations with speed-correlated metering systems within a calibrated speed range, usually not exceeding 20 mph. 4) The most economical and convenient method of droplet size determination for ULV aerosols of insecticide is the waved-slide technique. 5) The efficacy of ULV ground aerosols against adult mosquitoes is related to droplet size because it governs air transport and impingement. The optimum droplet size for mosquito adulticiding is 8-15 microns volume median diameter (VMD) on the basis of laboratory wind-tunnel tests and field research with caged mosquitoes. 6) In general, ULV aerosols should be applied following sunset when mosquitoes are active and meteorological conditions are favorable for achieving maximum levels of control. Application can be made during daytime hours when conditions permit, but rates may have to be increased. The critical meteorological factors are wind velocity and direction, temperature, and atmospheric stability and turbulence. 7) Maximum effective swaths are obtained with aerosols in the optimum VMD range during favorable meteorological conditions in open to moderately open terrain. The insecticide dosage must be increased in proportion to increased swath to maintain the same level of mosquito control. 8) Dispersal speed within a range of 2.5-20 mph is not a factor affecting efficacy if insecticide rate and optimum droplet size are maintained. 9) The results of caged mosquito assays are comparable with reductions in free-flying natural populations. 10) The field efficacies of mosquito adulticides applied as ULV ground aerosols are predictable from the results of laboratory wind-tunnel tests. 11) Results of field tests in open to moderately open terrain during favorable meteorological conditions indicated that ULV insecticidal aerosol application rates producing 90% or more control of Anopheles, Culex, and Psorophora spp. are below or approximately equal to maximum United States Environmental Protection Agency label rates. Against some Aedes spp., some pyrethroid insecticides must be synergized to produce 90% control at label rates. 12) Results of field tests in residential areas with moderate to dense vegetation and in citrus groves or other densely wooded areas showed that insecticide rates of ULV ground aerosols must be increased 2-3-fold to obtain 90% or more control of adult mosquitoes. However, the maximum rates on some insecticide labels would have to be increased to allow higher application rates. 13) Applications of ULV ground aerosols of insecticide in accordance with label directions following sunset do not pose a serious threat to humans, nontarget beneficial animals, or automotive paints. 14) Some aerosol generators operated at high RPM levels exceed the OSHA 8-h hearing hazard criteria of 90 dBA and may require hearing protectors for operators.

Aedes↗
PubMed2005

Human exposure to mosquito-control pesticides--Mississippi, North Carolina, and Virginia, 2002 and 2003.

Public health officials weigh the risk for mosquito-borne diseases against the risk for human exposure to pesticides sprayed to control mosquitoes. Response to outbreaks of mosquito-borne diseases has focused on vector control through habitat reduction and application of pesticides that kill mosquito larvae. However, in certain situations, public health officials control adult mosquito populations by spraying ultra-low volume (ULV) (<3 fluid ounces per acre [oz/acre]) mosquito-control (MC) pesticides, such as naled, permethrin, and d-phenothrin. These ULV applications generate aerosols of fine droplets of pesticides that stay aloft and kill mosquitoes on contact while minimizing the risk for exposure to persons, wildlife, and the environment. This report summarizes the results of studies in Mississippi, North Carolina, and Virginia that assessed human exposure to ULV naled, permethrin, and d-phenothrin used in emergency, large-scale MC activities. The findings indicated ULV application in MC activities did not result in substantial pesticide exposure to humans; however, public health interventions should focus on the reduction of home and workplace exposure to pesticides.

Environmental Exposure↗
PubMed1987

Ecological mapping to support mosquito control on the French Mediterranean coast.

Less than a century ago on the French Mediterranean coast, mosquitoes were responsible for a high rate of mortality from malaria. Today, mosquitoes are no more than a nuisance, but mosquito control is carried out actively to protect local residents and the economically important tourist trade. Along the Mediterranean coast, mosquito control makes use of environmental management:, biological control and insecticides. However, by use of detailed ecological maps, these control activities can be accurately targeted, leading to efficient control, reduced costs and minimal likelihood of insecticide resistance. In this article, Andre Gobinoud explains these techniques.

Journal Article↗
PubMed1996

Adverse assessments of Gambusia affinis: an alternate view for mosquito control practitioners.

Adverse opinions on the introduction of Gambusia affinis for the control of larval mosquitoes are reviewed. The sources span a period of some 59 years and come from a variety of sources. The principal opposition to the introduction of G. affinis comes from ichthyologists, although some mosquito researchers have expressed concerns about the environmental impact of placing the fish in habitats to which it is not native. Questions concerning the appropriateness of using the fish are presented.

Animals↗
PubMed1986

Mosquito control by plankton management: the potential of indigestible green algae.

Most kinds of phytoplankton are good food for mosquito larvae. However, Culex, Aedes and Anopheles larvae fail to develop successfully in water where certain species of closely related green algae in the order Chlorococcales are the main source of food; apparently because the larvae are unable to digest them. Many species of Scenedesmus, Kirchneriella, Dactylococcus, Elakotothrix, Tetrallantos, Coelastrum, Selenastrum and Tetradesmus have this effect. These algae may offer a practical possibility for mosquito control when introduced into mosquito breeding habitats. Introduction of these algae could be assisted by simultaneous introduction of select filter-feeding zooplankton such as Daphnia.

Animals↗
PubMed1999

Interruption of chemical mosquito control and evolution of insecticide resistance genes in Culex pipiens (Diptera: Culicidae).

Within the Llobregat Delta (Barcelona, Spain), Culex pipiens L. has been the target of organophosphate insecticide (OP) control for 10 yr (1982-1992). Between 1991 and 1992, OPs were replaced by Bacillus-based toxins in all the mosquito control programs within > 150 km of this area. The distribution of several OP-resistance genes was surveyed within the Llobregat Delta and neighboring populations (< 25 km) during the 2 yr following this regional pesticide change to investigate how the change in selection pressure affected the dynamics of OP-resistance genes. The immigration failure of the A2-B2 resistant esterases and the observed difference in OP-resistance dynamics between isolated and nonisolated populations may indicate fitness disadvantages associated with OP-resistance genes, hence a tendency for a decrease in OP-resistance. In contrast, one OP-resistance gene further increased in frequency, whereas the frequencies of some others were maintained. These unexpected results question the importance of pesticides from sources other than mosquito control, and the variability of pleiotropic fitness costs among pesticide resistance genes.

Animals↗
PubMed1988

An evaluation of Gambusia affinis and Bacillus thuringiensis var. israelensis as mosquito control agents in California wild rice fields.

The mosquito control potential of the mosquitofish and Bacillus thuringiensis var. israelensis (Bti) were evaluated in experimental wild rice fields in Lake County, California. Fields were assigned one of six treatment: control, 1.1 kg/ha G. affinis, 3.4 kg/ha G. affinis, Bti only (6 kg/ha Vectobac granules), 1.1 kg/ha G. affinis plus Bti and 3.4 kg/ha G. affinis plus Bti. Gambusia affinis, at both release rates, significantly reduced the mosquito population at densities exceeding 100 fish/minnow trap. Treatments with Bti significantly reduced larval population; however, the populations in the fields without fish rebounded to pretreatment levels within two weeks. In fields stocked with G. affinis and treated with Bti, populations remained low after Bti treatment. Nontarget populations of arthropods were significantly lower in fields stocked with G. affinis than in fields without fish on one or more sampling dates.

Agriculture↗
PubMed2006

Aquatic effects of aerial spraying for mosquito control over an urban area.

In an effort to combat West Nile Virus, planes dispersed insecticide over Sacramento, CA, treating nearly 50,000 hectares with pyrethrins and the synergist piperonyl butoxide (PBO). Widespread dispersal of insecticide over a metropolitan area, coupled with extensive pretreatment data on the area's urban creeks, provided a unique opportunity to study effects of mosquito control agents on aquatic habitats within an urban setting. There was no evidence of aquatic toxicity from the two active ingredients in the product applied. However, PBO concentrations were high enough to enhance toxicity of pyrethroids already existing in creek sediments from general urban pesticide use. PBO concentrations of 2-4 microg/L were high enough to nearly double the toxicity of sediments to the amphipod Hyalella azteca. Though the increase in toxicity was modest, it was unexpected to find environmental synergy at all. Risk assessments for mosquito control agents have focused on the active ingredients but have failed to recognize the potential for interactions with pesticides previously existing in the environment, which in this case appeared to represent a risk to aquatic life greater than that of the active ingredients themselves.

Amphipoda↗
PubMed1995

Biological and physicochemical properties of fenitrothion microcapsules as a residual spraying formulation for mosquito control.

Insecticidal properties of fenitrothion microcapsules (MC3) as a new residual spraying formulation for mosquito control were studied. Adult female Anopheles albimanus were confined so as to contact several surfaces treated with fenitrothion MC or wettable powder (WP) for 10 and 30 min. Residual efficacy of MC at the rate of 1 g/m2 was almost equivalent to that of WP at the rate of 2 g/m2 on a plywood surface and was superior to that on an unglazed pottery surface. Greater than 50% mortality was maintained for more than 28 wk after treatment by fenitrothion MC on a mud surface with 10 min of contact at the rate of 2 g/m2. The effective duration on a mud surface treated with WP was less than 44 wk with 30 min of contact and was less than 12 wk with 10 min of contact at the rate of 2 g/m2. Microcapsule particles were observed to be mechanically broken (trampled) by mosquito contact, and the amount of fenitrothion released from MC increased as contact time increased. Comparison of MC with WP and emulsifiable concentrate formulations in this study indicates that the increased residual activity results from protection from evaporation and decomposition afforded by capsule walls of the MC formulation.

Animals↗
PubMed2002

Presidential address given at the 68th annual meeting of the American Mosquito Control Association, February 2002. State of the Association 2001-2002.

The members of the American Mosquito Control Association (AMCA) faced 3 major challenges during the 2001-02 presidential term of Sammie Dickson. The 1st challenge was the unprecedented spread of West Nile virus (WN) across the eastern half of the USA. Second, the terrorist attacks of September 11, 2001, caused a shift away from the spread of WN investigations to a patriotic effort to control terrorism. The terrorist attacks had a rippling effect through the U.S. economy. This downturn in the economy has forced some changes in the way AMCA will plan its Annual Meetings. Third, legislative issues on a national scale have forced AMCA members to become proactive on legislation that affects the way public health is protected in this country.

Legislation as Topic↗
PubMed1992

Comparison of people who request mosquito control services and their non-requesting neighbors.

The personal profiles of people who called to request mosquito control services were compared with their neighbors who did not call. Demographically, callers were generally representative of their neighbors. Callers considered the mosquito problem to be greater than did their non-calling neighbors, tended to do more things outdoors, tended to be home more, and considered themselves more attractive to mosquitoes and more allergic to mosquito bites than non-callers. There were also more newer (less than 1 year) residents among the callers than non-callers. Callers were almost exclusively from year-round-resident homeowners in long-term-resident neighborhoods.

Age Factors↗
PubMed2000

Evaluating mosquito control pesticides for effect on target and nontarget organisms.

Recent requirements for biomonitoring of urban stormwater runoff have raised the issue of toxic contributions from mosquito control products. A comparison of seven pesticides for their toxicity to target and nontarget organisms was conducted in field and laboratory trials to determine relative impacts in and around Craighead County, Arkansas. Twenty-four and forty-eight-hour acute toxicity tests using Ceriodaphnia dubia, Daphnia magna, Daphnia pulex, and Pimephales promelas were employed with U.S. Environmental Protection Agency (U.S. EPA) suggested procedures as standard test organisms. Additional tests with resident mosquito fish, Gambusia affinis, and mosquito larvae, Anopheles quadrimaculatus, included ditch-receiving waters to compare the somewhat sterile laboratory exposures to actual field conditions. Exposure to as much as 31.4 microg/L of the pesticides Dursban(R), malathion, Permanone(R), Abate(R), Scourge(R), B.t.i, and Biomist(R) were required for effective control of An. quadrimaculatus, whereas as little as 2.7 microg/L resulted in substantial mortality of some nontarget organisms. These data suggest that prevailing application rates for effective mosquito control not only affect nontarget organisms but may also confound stormwater and nonpoint toxicity evaluations that utilize sensitive indicator species.

Animals↗
PubMed1994

Laboratory evaluation of fenitrothion microcapsules as a new residual spraying formulation for mosquito control.

Physicochemical and insecticidal properties of fenitrothion microcapsule (MC) as a new residual spraying formulation for mosquito control were studied. The wall staining after treatment with MC at the rate of 1-2 g AI/m2 was not noticeable as compared with that of wettable powder (WP). Covering rate with MC on a vertical wall was almost the same as WP and emulsifiable concentrate (EC) when the wall material was absorptive plywood and mud, and was relatively higher than WP and EC when the wall material was nonabsorptive overlaid plywood. Residual efficacy of MC at the rate of 1 g/m2 was almost equivalent or superior to that of WP at the rate of 2 g/m2. Fenitrothion MC also has had an "airborne" effect, which is sort of a vapor killing effect of insecticides under high vapor pressure. This suggested a difference in mode of action in mosquitoes from that for cockroach control.

Animals↗
PubMed2006

Prospects for the mosquito baculovirus CuniNPV as a tool for mosquito control.

CuniNPV is a pathogen of Culex mosquitoes, vectors of West Nile virus and other forms of encephalitis. Successful development of CuniNPV requires an efficient production system and formulated product that incorporates magnesium, an essential component for transmission. It may be possible to develop mosquito baculoviruses as a new type of biopesticide by microencapsulating the virus and magnesium into formulations that would be effective regardless of the water quality. In addition, this new insight on transmission may facilitate the discovery and development of additional baculoviruses for the control of other important mosquito vectors. Biological mining of the CuniNPV genome and investigations to understand virus-mosquito interactions at the molecular level offer exciting possibilities for the development of novel mosquito control strategies and tools. Understanding the molecular mechanisms of infection will provide the opportunity to devise new control strategies, for example, compromising the defensive systems of the mosquito (proteases for the peritrophic matrix) or exploiting receptors used by the virus to specifically deliver toxins to mosquito larvae via the midgut. As additional baculovirus genomes become available, comparative genomics could lead to a more informed understanding of how the virus exploits its host as well as the factors responsible for the genus-specific host range of most known mosquito baculoviruses.

Animals↗
PubMed1995

Mosquito control in Dar es Salaam. I. Assessment of Culex quinquefasciatus breeding sites prior to intervention.

In preparation for a trial polystyrene beads and pyriproxyfen for the control of Culex quinquefasciatus mosquitoes, surveys of their breeding were carried out in two contrasting areas of Dar es Salaam, Mikocheni and Ilala, during the dry season. Sanitation structures (latrines, soakage pits, septic tanks and cess pits) were the most profilic breeding places, totalling 780 in Mikocheni and 1544 in Ilala. Those in Mikocheni were estimated to contain about 1.4 times more mosquito pupae, per site, than in such structures in Ilala. This was both because a higher proportion of sites contained visible water and because sites with water were more likely to contain pupae in Mikocheni. The relative importance of the different types of structure, in terms of productivity, was the same in both areas. Although septic tanks and cess pits made up only 10.5% of the on-site sanitation structures in Ilala, they contained 53% of the total number of pupae in enclosed sites; they were therefore particularly important targets for treatment with polystyrene beads. A survey during the rainy season of sites in Ilala revealed little change in the proportion that were wet, or in the frequency of breeding in those with visible water. The number, type and area of open breeding sites varied greatly between the two study areas. In Mikocheni the area of open breeding sites was 100 times greater than in Ilala, with 97% of the 13,000 m2 being flooded grassland. In Ilala all but four of the sixty-six open breeding sites were puddles of sullage water derived from bathrooms.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗