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At least 73 records · Page 4Linked to original sources
PubMed1992

Beta-cyfluthrin, a synthetic pyrethroid for mosquito control.

Beta-cyfluthrin (OMS 3051), a new synthetic pyrethroid and one of the stereoisomers of cyfluthrin, was studied for insecticidal activity against eight mosquito species. Its larvicidal activity with LC50 values of 5.62 x 10(-5) and 1.19 x 10(-4) mg/l respectively for Culex quinquefasciatus and Aedes aegypti was comparable with that of deltamethrin. This pyrethroid was more effective against the larvae of Armigeres subalbatus (LC50 - 7.76 x 10(-7)) and the adults of Anopheles culicifacies LT50 - 27.76 min at 2.0 mu/cm2) than the other species tested. Residual efficacy at 50 mg(ai)/m2 was more persistent (for 14-25 weeks) on thatch and asbestos among the four treated surfaces. This compound also elicited oviposition deterrent activity at 0.001 mg/l against Cx.quinquefasciatus. beta-cyfluthrin is a good insecticide for mosquito control. However, care should be exercised while using it as a larvicide in breeding habitats considering its toxicity to fish.

Adult↗
PubMedDate not supplied

Esterases as biomarkers in Nereis (Hediste) diversicolor exposed to temephos and Bacillus thuringiensis var. israelensis used for mosquito control in coastal wetlands of Morbihan (Brittany, France).

Since 1998, a biomonitoring programme has been implemented to assess the potential impact of chemical mosquito control on macroinvertebrates of the coastal wetlands of Morbihan (Brittany, France). Acetylcholinesterase and carboxylesterases were used as biomarkers to assess the effects of Abate 500e (a.i. temephos) and Vectobac 12 AS (a.i. endotoxins of Bacillus thuringiensis var. israelensis, Bti) in Nereis (Hediste) diversicolor. Esterase inhibition revealed a marked impact of temephos, suggesting preferential contamination of the worms through the food. In Bti-exposed N. diversicolor, random variations of esterase activities were observed, that could not be attributed to the larvicide. However, esterases only reflected indirect physiological effects of Bti, and further investigations are needed to identify biomarkers more specific of Bti endotoxins.

Animals↗
PubMed1980

Health risks in ultra-low-volume (ULV) aerial spray of malathion for mosquito control.

A field study was undertaken to evaluate health risks in persons engaged in ultra-low-volume (ULV) aerial application of technical malathion for mosquito control. No specific toxicity signs and symptoms were observed except nausea and irritation of eyes in a few cases. Observations on the ChE activity has revealed a significant depression in plasma at the end of spray operation in labourers employed in loading and unloading of insecticide and in field workers. Red blood cells ChE activity was not affected in any group of subjects. At the end of spray operation the insecticide residue on the grass used as cattle feed were about 315 ppm, which are much above the permissible level. However, 4 days after the application normal levels of the insecticide residues were detected.

Agriculture↗
PubMed1989

Conceptual model for the use of aerial color infrared photography by mosquito control districts as a survey technique for Psorophora columbiae oviposition habitats in Texas ricelands.

Two photographic missions per year are recommended to provide information on land-use and mosquito oviposition habitats. A winter mission, following a rain, will-provide a view of low areas within fields which may be obscured by summer vegetation. A summer mission will provide current land-use and crop distribution information and may show plant stress conditions due to excessive soil moisture. An aerial color infrared photographic survey with directed ground verification should result in a substantial savings in cost and increased efficiency in surveillance of mosquito producing habitats over ground survey techniques currently employed by mosquito control districts.

Animals↗
PubMed2002

Operational studies with Valent VectoLex WDG, Bacillus sphaericus, in three Florida Mosquito Control Districts.

VectoLex WDG, Bacillus sphaericus (Valent BioSciences Corporation), was evaluated in 3 Florida Mosquito Control Districts under operational conditions. Application rates were 0.5 and 1.0 lb/acre and an untreated control in each district. Study sites included woodland ponds, residential areas such as catch basins, and commercial business retention ponds. Pretreatment and posttreatment assessments were made with a standard dipper at designated dipping stations. The most prevalent mosquitoes included Culex quinquefasciatus, Culex nigripalpus, Culex erraticus, Ochlerotatus infirmatus, Anopheles crucians, Anopheles quadrimaculatus, and Psorophora spp. VectoLex WDG was effective for 24-35 days posttreatment with one application.

Animals↗
PubMed2004

[Mosquito control based on larvicides in the State of Rio Grande do Sul, Brazil: choice of the control agent].

A comparison between chemical and biological larvicides in routine operations against mosquitoes in Rio Grande do Sul State was carried out in this study. In laboratory bioassays against Culex quinquefasciatus, biological formulations Vectobac 12 AS and Teknar 3000 (Bacillus thuringiensis israelensis) as well as ABG 6262 (B. sphaericus 2362), both in liquid and powder form, were highly effective. Locally produced B. thuringiensis israelensis, formulations also yielded good results. Among chemical larvicides, pyrethroid compounds Pirisa and K-Othrine yielded better results than the organophosphates Lebaycid and Abate. These last formulations yielded responses ten weaker than predicted in other studies. Under field conditions, a dose of 1250 mg/m2 for biological formulations was considered adequate for routine application because at this level it is possible to overcome physical influences on results. Only B. sphaericus preparations caused important disruption of mosquito colonization in active breeding sites. Up to 39 weeks were tabulated without complete colonization in natural conditions and one month in artificially colonized tanks. This study suggests that biological alternatives should be considered in mosquito control programs. They may be a solution to such problems as resistance to larvicides, elimination of natural enemies, and short-lasting effects of applications.

Journal Article↗
PubMed1992

Fishes of District Sundargarh, Orissa, with special reference to their potential in mosquito control.

An extensive fish fauna survey was carried out in Sundargarh, a malaria-endemic district in Orissa, during 1988 to 1990 to identify and evaluate the indigenous larvivorous fishes for mosquito control. In all, 57 species belonging to 19 families under 6 orders were found in the local water bodies. On laboratory evaluation against anopheline and culicine larvae, six potential larvivorous fishes, viz. Aplocheilus panchax, Oryzias melastigma, Oreochromis mossambicus, Gambusia affinis, Danio (B.) rerio and Esomus danricus were selected. Feasibility of mass multiplication of these fishes in village ponds for operational use is being studied.

Animals↗
PubMed2001

Isolation of bacterial strains colonizable in mosquito larval guts as novel host cells for mosquito control.

We screened for microorganisms that can be utilized as new host cells for mosquito larvicides. As long persistence in the environment is required of host cells, we examined the bacterial populations in the guts of mosquito larvae collected from natural breeding habitats. Larvae of Aedes aegypti and Culex quinquefasciatus were examined, and Bacillus species, particularly Bacillus cereus, were found to be the dominant bacterial species in their guts. To investigate the relationship between these Bacillus strains and the mosquito larvae, we re-introduced the bacteria into larvae of Aedes aegypti, C. quinquefasciatus and another common mosquito strain, Anopheles dirus. The cell numbers of Bacillus cereus strains Ae10 and Cx5 in the guts were consistent throughout a 7-d period without food supplementation, suggesting that these strains were able to colonize in the guts of the larvae. To confirm this, we introduced a plasmid containing a kanamycin resistance marker into Ae10 and Cx5 and fed these recombinant strains to C. quinquefasciatus larvae. Even when food was supplemented for 7 d, the recombinant strains, particularly Ae10, were still found in the guts. Under similar conditions, B. thuringiensis serovar israelensis c4Q2-72 was hardly detectable after 2 d, while Escherichia coli could not be detected at all. Their stable retention in mosquito larvae guts and the feasibility of genetic manipulation indicates these strains possess high potential as novel host cells for application in mosquito control.

Journal Article↗
PubMed2003

Recombinant bacteria for mosquito control.

Bacterial insecticides have been used for the control of nuisance and vector mosquitoes for more than two decades. Nevertheless, due primarily to their high cost and often only moderate efficacy, these insecticides remain of limited use in tropical countries where mosquito-borne diseases are prevalent. Recently, however, recombinant DNA techniques have been used to improve bacterial insecticide efficacy by markedly increasing the synthesis of mosquitocidal proteins and by enabling new endotoxin combinations from different bacteria to be produced within single strains. These new strains combine mosquitocidal Cry and Cyt proteins of Bacillus thuringiensis with the binary toxin of Bacillus sphaericus, improving efficacy against Culex species by 10-fold and greatly reducing the potential for resistance through the presence of Cyt1A. Moreover, although intensive use of B. sphaericus against Culex populations in the field can result in high levels of resistance, most of this can be suppressed by combining this bacterial species with Cyt1A; the latter enables the binary toxin of this species to enter midgut epithelial cells via the microvillar membrane in the absence of a midgut receptor. The availability of these novel strains and newly discovered mosquitocidal proteins, such as the Mtx toxins of B. sphaericus, offers the potential for constructing a range of recombinant bacterial insecticides for more effective control of the mosquito vectors of filariasis, Dengue fever and malaria.

Animals↗
PubMedDate not supplied

A small scale field trial with expanded polystyrene beads for mosquito control in septic tanks.

A field trial of the use of expanded polystyrene beads (EPSB) to control the breeding of mosquito larvae in household septic tanks was conducted in Sarawak. One week after treatment, the breeding of Culex quinquefasciatus and Aedes albopictus was reduced by 100% and 68.7% respectively. For both species combined, a 57.25% reduction in the adult emergence rate was achieved. No adult was caught in the emergence trap one month after treatment. A reduction in mosquito biting rates was reported by 87.3% of respondents. All households regarded the EPSB treatment as effective. This study has reduced the relatively high infestation rate of A. albopictus in the septic tanks to 16-20%. The EPSB treatment is feasible and practical. Post-treatment assessment using adult emergence traps and the implications for the vector control programme of the local authority are discussed.

Aedes↗
PubMed1993

Availability and utility of local fishes of Shahjahanpur for mosquito control.

A survey of fishes in Shahjahanpur in different aquatic habitats revealed 35 indigenous fish species. Out of 35 fish species, 24 were found feeding on mosquito larvae of which 6 species, viz. Chela bacaila, Puntius stigma, Rasbora daniconius, Esomus danricus, Colisa fasciatus and Danio sp., had good larvivorous potential. Most of the fish species preferred to feed on III and IV instar larvae. In the presence of planktonic food, the consumption capacity of fishes for mosquito larvae was lesser on third day (D3) of observation than on first day (D1). The difference in the consumption of mosquito larvae between D1 and D3 was significant (P < 0.01). Similarly, difference in the feeding capacity of fishes in the months of September and January was highly significant (P < 0.001). But there was no seasonal variation in the preference of instar-wise consumption. Indigenous fish species such as C. fasciatus, E. danricus, P. stigma, R. daniconius and Danio sp. could therefore play a significant role in controlling mosquito breeding in this area.

Animals↗