Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “INSECTICIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,153 records · Page 64Linked to original sources
PubMed1959

Insecticide resistance in Anopheles sacharovi.

A series of observations is presented on the susceptibility or resistance to insecticides of Anopheles sacharovi in Greece, Iran, Italy, Romania and Turkey. High physiological resistance to DDT was observed in the Tarsus area of southern Turkey. In Greece very marked physiological resistance to dieldrin was found in all the areas examined and was associated, at least in the Peloponnese, with similar resistance to DDT, affecting, however, only a part of the sacharovi population. In Italy and Romania, after 10 years' use of DDT, sacharovi is still susceptible to it; long use of BHC in Romania has not resulted in the development of resistance to dieldrin or to BHC. Further investigation of the situation in Iran is considered necessary.The fact that the use of DDT in Greece, after the development of resistance to this insecticide in 1951, has not resulted in the formation of a highly resistant mosquito population is considered to be due to the irritant effect of the DDT on susceptible mosquitos, causing them to leave sprayed surfaces before they have picked up a lethal dose.The information to date points to the existence in A. sacharovi of two independent mechanisms of physiological resistance-one to DDT and another to dieldrin and BHC-which may or may not be present together.

Animals↗
PubMed1962

The susceptibility of Culex pipiens fatigans Wiedemann larvae to insecticides in Malaya.

The levels of susceptibility of C. p. fatigans larvae from four different localities in Malaya to DDT, dieldrin, malathion, fenthion, diazinon and Sevin have been studied; their toxicity was: diazinon > fenthion > malathion > dieldrin > DDT > Sevin.Larvae from different localities showed a wide range of susceptibility to the chlorinated hydrocarbon insecticides, dieldrin (40x) and DDT (10x), but the organophosphorus compounds and the carbamate compound, Sevin, gave consistent results from all localities. One strain from a rural area (Lamir) was the most susceptible to all insecticides and has been used as a reference strain for related studies on the development of resistance.

Animals↗
PubMed1964

THE STABILITY OF RESISTANCE TO CARBAMATE INSECTICIDES IN THE HOUSEFLY AFTER CESSATION OF SELECTION PRESSURE.

Two housefly strains selected for maximal resistance for 30 generations with Isolan (1-isopropyl-3-methyl-5-pyrazolyl dimethylcarbamate) and m-isopropylphenyl methylcarbamate, respectively, were released from insecticidal pressure and their responses to these two carbamates were studied through 62 further generations.In the Isolan-selected strain, resistance to both carbamates remained virtually unchanged up to the 41st generation; it regressed gradually thereafter, and by the 62nd generation the strain contained approximately 28% susceptible individuals. Resistance in the strain selected with m-isopropylphenyl methylcarbamate regressed rapidly, especially between the 11th and 19th generations; by the 54th generation the strain was almost as susceptible to both carbamates as before selection.The author concludes that insecticidal pressure with Isolan resulted in the development of a relatively stable resistant phenotype, while similar selection pressure with m-isopropylphenyl methylcarbamate on the same parental stock and for the same length of time produced an equally resistant but unstable phenotype. This differential stability of resistance is attributed to the incorporation of dissimilar modifying genes in the two strains during the process of selection for the character of resistance.

Animals↗
PubMed1963

CHROMOSOME CHANGES AND INSECTICIDE RESISTANCE IN ANOPHELES QUADRIMACULATUS.

Certain insecticide-resistant strains of anopheline mosquitos found in the field or developed in the laboratory are known to contain a high proportion of heterozygotes for chromosomal inversions, but up till now it has not been clear how this could be causally related to resistance. In the present investigation, 2 resistant strains and 2 susceptible strains of Anopheles quadrimaculatus, and the hybrids between them, were examined for the frequency of inversions. It was found that neither the resistant nor the susceptible strains were characterized by inversion buckles. Moreover, no new inversions appeared in the hybrids between them. It was therefore concluded that where heterozygosity for inversions has been observed in anophelines, it is a characteristic of hybrids due to parental differences resulting from geographic separation, and has no relation to specific insecticide resistance.

Animals↗
PubMed1964

ASSESSMENT OF THE KILL OF ANOPHELES GAMBIAE BY THE FUMIGANT INSECTICIDE DICHLORVOS IN EXPERIMENTAL HUTS.

As part of the World Health Organization's programme for the evaluation and testing of new insecticides, different types of dichlorvos dispenser were installed in experimental huts in Tanganyika for study of their effectiveness in killing Anopheles gambiae. It was found that satisfactorily high mosquito mortalities of 75% or more were maintained for one to two months after installation of a dispenser. Mortalities were about 10% higher in huts with grass roofs than in those with mud-lined roofs. The vapour toxicity was similar in the two types of hut, but the results of bio-assay tests on different types of surface showed that there was a residual contact effect of the insecticide as well as the fumigant effect; the lower mortalities in the mud-roofed huts may be due in part to removal or decomposition of the dichlorvos by the mud surface.Measurements of blood pseudo-cholinesterase levels in persons who slept in the experimental huts gave no indication that the dichlorvos had any harmful effect on them.

Animals↗
PubMed2003

Susceptibility of Italian populations of Aedes albopictus to temephos and to other insecticides.

We evaluated larval and adult susceptibility to 5 insecticides commonly used for control of Aedes albopictus, by using 15 field-collected populations from northern and central Italy, and we compared these data, collected in 2002, with those from evaluations conducted in 1992-93, 1996, and 1998-99. Larvae were tested for susceptibility to temephos and to the conventional diagnostic dosages of chlorpyrifos and fenthion proposed by the World Health Organization for Aedes aegypti. Adults were exposed to the diagnostic dosages of deltamethrin and permethrin. Overall, all of the populations tested in 2002 were still susceptible to temephos: median lethal concentration (LC50) values ranged from 0.0026 to 0.0085 mg/liter, and LC99 values ranged from 0.0093 to 0.023 mg/liter. These populations were also fully susceptible to chlorpyrifos and fenthion, and adults were susceptible to deltamethrin and permethrin. When comparing these data with those from previous evaluations, we observed a slight yet progressive increase in the LC50 and LC99 values of susceptibility to temephos, and these values are approaching the diagnostic dosage of 0.02 mg/liter proposed for Ae. aegypti. However, the implications of these findings need to be considered in light of the results of previous studies that have shown that larval Ae. albopictus are less susceptible than Ae. aegypti to organophosphate insecticides.

Aedes↗
PubMed2004

Diagnostic dose of synergized d-phenothrin for insecticide susceptibility testing by bottle bioassay.

The diagnostic dose of d-phenothrin synergized 1:1 with piperonyl butoxide for testing insecticide susceptibility of mosquitoes by bottle bioassay is reported for 2 mosquito species, Culex quinquefasciatus and Ochlerotatus taeniorhynchus. The diagnostic dose was defined as 2 times the 95% lethal concentration (LC95). LC50, LC90, and LC95 were estimated by probit analysis of dose response data. Procedures for diluting the commercial-grade off-the-shelf pesticide in acetone, treating the bottles, and calculating baseline data for insecticide-susceptible mosquito populations are described. The advantages and disadvantages of testing off-the-shelf commercial-grade pesticides that are maintained on premises by mosquito control programs, in contrast to using reagent-grade chemicals purchased from a chemical supply house, are also discussed. Data obtained by this method can be invaluable in making timely management decisions about the choice of pesticides in a control program.

Animals↗
PubMed1950

Toxicology of organic phosphate insecticides.

The development of effective new insecticides has created potential industrial health hazards to people engaged in their manufacture and application, as well as to those with casual exposures. A group of these insecticides known as the organic phosphates is extremely toxic, destroying the enzyme cholinesterase and exerting a cholinergic action on the mammalian animal. A discussion of the origin, chemistry, and pharmacology of these compounds, along with a description of symptoms, diagnosis and treatment of poisoning is presented. Methods of prevention of poisoning and control measures for the safe use of these compounds are described.

Cholinesterases↗
PubMedDate not supplied

[Resistance to insecticides in larvae and adults of Aedes aegypti, Havana City: prevalence of A4 esterasa associated with resistance to temephos].

2 strains of Aedes aegypti from 2 people's councils with high indexes of infestation of this vector were studied due to the need of carrying out an effective control of larvae and adults in the municipality of Guanabacoa. The levels of susceptibility and/or resistance to organophosphate insecticides, pyrethroids and a carbamate were determined. The results of the bioassays in larvae showed a complete susceptibility to organophosphate insecticides, malathion, clorpirifos, methyl-pyrimifos and propoxur carbamate in both people's councils. However, it was observed a high resistance to temephos and fenthion. No resistance to fenitrothion was found in one of the people's councils. At the adult stage and at the dose recommended by the World Health Organizaton or by the product manufacturers, it was observed resistance to malathion, fenitrothion and propoxur; nevertheless, better results were obtained with the pyrethroids, with mortality percentages over 90%. According to the results obtained, by using the SSS tributyl phosphotritiade sinergist (DEF) and piperonyl butoxide, it was demonstrated that the multiple function esterases and oxidases played an important role in the resistance to temephos and fenthion. It was proved that he amplified activity of these enzymes was at an elevated frequency in both people's councils, the same as the glutathione transferase (GST) in one of the 2 people's councils. It was observed that in both people's councils prevailed the amplified activity of A4 esterases by polyacrylamide gel electrophoresis.

Aedes↗
PubMedDate not supplied

[Status of resistance to insecticides and resistance mechanisms in larvae from Playa municipality collected during the intensive campaign against Aedes aegypti in Havana City, 2001-2002].

The levels of susceptibility and/or resistance to inseciticides in Aedes aegypti larvae collected at the municipality of Playa during the intensive campaign against the mosquito Aedes aegypti, in Havana City, in the present year, were determined. In larvae, it was found a high resistance to the organophosphate insecticides phention and temephos and moderate to fenitrothion. A high resistance to propoxur carbamate was also detected. The larvae proved to be susceptible to clorpirifos, malathion and methylpyrimifos. The results obtained through the use of sinergists indicated that esterases play an important role in the detected resistance to organophosphate insecticides, but not in the resistance to propoxur. However, the monooxigenases take part only in the resistance to fenitothrion. These mechanisms were found at an elevated frequency in the larvae from this municipality. It was confirmed the role played by esterases in the resistance to temephos by polyacrilamide gel inhibition tests.

Aedes↗
PubMedDate not supplied

Anopheles arabiensis: abundance and insecticide resistance in an irrigated area of eastern Sudan.

The abundance of Anopheles arabiensis and its susceptibility to insecticides was studied in New Halfa, eastern Sudan, from March 1999 to June 2000. Of 4854 females anophelines collected, 4847 (99.9%) were An. arabiensis and 7 (0.1%) An. pharoensis. Female An. arabiensis were breeding throughout the year, with 2 peak densities, during the rainy (158.4 females/room/day and 84.7 larvae/10 dips) and irrigated seasons (136.8 females/room/day and 44.8 larvae/10 dips). The mean biting activity was 28.8 bites/person/ night, found throughout the night, mainly outdoors. Susceptibility of An. arabiensis to insecticides dichloro-diphenyl-trichloroethane (DDT), malathion and fenitrothion was 97.8%, 96.3% and 100% respectively. An. arabiensis is the sole malaria vector in the area and is perennial rather than seasonal.

Agriculture↗
PubMed1992

Acetylcholinesterase. Two types of modifications confer resistance to insecticide.

Quantitative and qualitative changes in acetylcholinesterase confer resistance to insecticides. We have constructed several Drosophila melanogaster strains producing various amounts of enzyme by P-mediated transformation. Toxicological analysis of these strains demonstrates that resistance to organophosphorus insecticides is correlated with the amount of acetylcholinesterase in the central nervous system. Resistance may also be qualitatively determined. Comparison of the Drosophila acetylcholinesterase gene between a resistant strain caught in the wild and a wild type susceptible strain only revealed one nucleotide transition resulting in the replacement of a phenylalanine by a tyrosine. Flies mutant for acetylcholinesterase and rescued with a minigene mutagenized for this same transition produced an altered enzyme which renders flies resistant to pesticides.

Acetylcholinesterase↗
PubMed1991

Insecticide susceptibility of Aedes aegypti from Santo Domingo, Dominican Republic.

The insecticide susceptibility of Aedes aegypti adults and larvae from Santo Domingo, Dominican Republic, was investigated using World Health Organization standard procedures. A field strain was more resistant to insecticides than a colony strain that originated from the same place. Larvae produced from ovitrap-collected eggs were resistant to temephos (78.2% mortality on exposure to 0.025 mg/liter). Mortality rates after exposure of adults to discriminating concentrations showed that wild populations were resistant to DDT, malathion, propoxur, permethrin and deltamethrin. The problem of resistance was considered serious enough to warrant consideration of control measures other than the use of chemicals.

Aedes↗
PubMed1978

Resistant level of houseflies to seven kinds of synthetic insecticides and effect of synergists to the Malathion resistant strain in Singapore.

The resistant level of the houseflies to the seven kinds of insecticides, Malathion, Sumithion, Baytex, Diazinon, DDVP, DDT and Chrysron, was examined on the 3 strains collected in Singapore. It was found that most housefly colonies in Singapore showed a higher susceptibility to those insecticides than that of the Takatsuki strain of Japan, especially to DDT. However, the resistant level to Malathion was remarkably higher than that of the Takatsuki strain. The synergists, piperonyl butoxide, Safroxane and S-421, mixed with Malathion were effective for lowering the resistant level of the Malathion-resistant strain.

Animals↗
PubMed1967

The susceptibility of Culex pipiens fatigans larvae to insecticides in Rangoon, Burma.

Since April 1963, the susceptibility to insecticides of larvae of Culex pipiens fatigans has been extensively studied by the WHO Filariasis Research Unit in Rangoon, Burma, as part of a programme of research aimed at establishing which compound or group of compounds could be used to control the vector of filariasis.Larvae from various localities in Rangoon showed wide variations in susceptibility to chlorinated hydrocarbons. There were also seasonal variations and it was difficult to standardize test conditions. Nevertheless, resistance to this group of compounds, especially DDT, sufficient to prevent control has been clearly demonstrated. As C. p. fatigans has never been subjected to intensive control by insecticides in Rangoon, the results confirm the findings made elsewhere that this mosquito is naturally resistant to chlorinated hydrocarbons.The larvae are, however, susceptible to organophosphorus compounds, especially fenthion and parathion.

Animals↗
PubMed1965

Toxicity of certain new compounds to insecticide-resistant houseflies.

Houseflies in poultry ranches in certain areas of California are now resistant to most insecticides licensed for use in these establishments, and this resistance problem appears likely to spread to other areas in the future. The authors have therefore studied the contact and oral toxicity of 19 new compounds that have shown interesting properties against resistant flies. These compounds were selected from among several hundred submitted by various laboratories for evaluation under a co-operative programme sponsored by the World Health Organization.Five compounds were found to be as toxic to three insecticide-resistant strains as to a susceptible strain, and showed strikingly steep log-dosage/probit mortality lines against the resistant strains. The authors suggest that these compounds be further studied for fly control in field trials.

California↗
PubMed1969

Aerial applications of insecticides for tsetse fly control in East Africa.

Since 1948, research has progressed in East Africa on the control of tsetse flies by aeria, applications of insecticides. Initial experiments proved that residual spray treatments were ineffective while repeated applications of coarse aerosols gave promising fly mortalities.In recent years, with the development of more toxic insecticides used in conjunction with improved thermal exhaust equipment and modified rotary atomizers, sprays with fine aerosol characteristics have been produced at considerably reduced cost. Aerial applications of aerosols are confined to early morning and late afternoon when weather conditions are stable, but large areas can be treated during these short intervals, and the technique is efficient and economical. Control of tsetse flies has been good; where complete isolation of an area has been possible, eradication has been achieved.It would be economically worth while to assess the possibility of increasing spray swath widths, and also to continue with research into the biological effectiveness of pyrethrum, primarily because of its absolute safety in use. There is a need for a simple method for the determination of tsetse fly populations in woodland and savanna habitats. Finally, it is recommended that the results of research to date should be brought more forcefully to the attention of government bodies and commercial airspray operators so that the techniques be more fully exploited.

Aerosols↗
PubMed1980

Recent developments of insecticide resistance in some Turkish anophelines.

Susceptibility tests carried out since 1974 in both the field and the laboratory with Anopheles sacharovi, A. hyrcanus and A. maculipennis from Turkey have revealed resistance to organophosphate and carbamate insecticides in all three species, in the first two in the southern Chukurova plain and in the third in the northern area around Osmanjik. Resistance was indicated by significant survivals when exposed to dosages killing presumed susceptible strains of these and other anopheline species. The temperature at which the susceptibility tests were carried out had a marked influence on mortalities. Broad spectra of resistance were shown by all three species, though with interspecific differences, and are attributed to the extensive and intensive use of a wide range of chemicals for agricultural pest control. Of the insecticides readily available for house-spraying for malaria control, malathion would appear to be the one with the greatest potential usefulness.

Animals↗