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PubMedDate not supplied

[Cross resistance to pyrethroids in Aedes aegypti from Cuba induced by the selection with organophosphate malathion].

A strain from Aedes aegypti (L) collected in the municipality of Santiago de Cuba with low levels of resistance to malathion (1.79x) was subjected to selection pressure aimed at evaluating the evolution of the resistance to this organophosphate and its usefulness for control. After 5 generations of selection (SAN-F5) with malathion, it was not possible to increase the resistance and it was obtained a value of resistance factor (FR50) of 2.22x. None or little cross resistance to the following organophosphate insecticides was observed: fenthion, temephos and fenitrotion; however, it was found an elevated cross resistance to deltamethrin pyrethroid, with a value of 287.5x in the third generation of selection. It was also observed cross resistance to other pyrethroids (lambda-cyhalothrin, cypermethrin and ciflutrine). The mechansim of elevated esterases did not generate resistance to pyrethroids, which was corroborated through inhibition gel studies and through the calculation of the frequency in microtitering plaques. Nevertheless, there was an increase in the frequency of the glutathione-s-transferase mechanism from 0.049 in Santiago de Cuba to 0.42 in SAN-F5, which may be associated with the resistance to pyrethroids. The cross resistance to pyrethroids, mainly to deltamethrin, resulting from the selection with malathion may limit the use of these insecticides in the control unless a good strategy for their use is laid down.

Aedes↗
PubMed2004

Surveillance of dengue vector at thiruvananthapuram (Kerala) International Airport.

A survey of Aedes (Stegomyia) mosquitoes was undertaken in and around the International airport at Thiruvananthapuram during premonsoon season. An attempt has been made in this paper to elaborate on the presence of risk potential for Dengue /yellow fever at the airport with the detection of Aedes breeding. The entomological indices have also been discussed with regard to presence of potential wet containers and rate of infestation by Aedes mosquitoes. The airport area was searched for Aedes (Stegomyia) breeding where 20% of the premises were found positive for Aedes aegypti breeding and one premise (6.6%) was found positive with Aedes albopictus breeding. In the 400 meters (perimeter) of airport, four municipal wards namely Chakka, Sankumugam, Valiyathura and Vettucadu were surveyed. The house index ranged from 5.8% to 11.7% for Aedes aegypti while, it was between 9.8% to 19.2% with regard to Aedes albopictus. The container index ranged between 4.4% to 9.9% for Aedes aegypti and 7.1% to 15.3% for Aedes albopictus. Breteau index was found to be between 23.5% to 51.9% for both the species. The susceptibility test conducted against different insecticides showed that the immature stages of Ae. aegypti and Ae. albopictus were found to be susceptible to the commonly used larvicides in public health viz. Temephos (0.02 ppm), Fenthion (0.05 ppm), Malathion (1.0 ppm) and Fenitrothion (0.06 ppm).

Aedes↗
PubMed2004

Study on susceptibility status in aquatic and adult stages of Aedes aegypti and Ae. albopictus against insecticides at international airports of south India.

A study on susceptibility status in aquatic and adult stages of Aedes aegypti and Ae. albopictus was undertaken at International Airports of Thiruvananthapuram and Cochin located in southern India. WHO standard test kits were used to conduct insecticide susceptibility tests against various organophosphates, organochlorines, carbamates and synthetic pyrethroids. The results indicate that adult Aedes aegypti and Ae. albopictus were resistant to DDT and dieldrin, but susceptible to propoxur, fenitrothion, malathion, deltamethrin, permethrin and lambdacyhalothrin. The susceptibility test conducted on immature stages of Ae. aegypti and Ae. albopictus revealed that they are susceptible to the larvicides commonly used under the National Vector Borne Diseases Control Programme viz. Temephos (0.02 ppm), Fenthion (0.05 ppm) Malathion (1.0 ppm) and Fenitrothion (0.06 ppm).

Aedes↗
PubMed1991

Tralomethrin (OMS-3048), a new synthetic pyrethroid against vector mosquitoes.

Tralomethrin (OMS-3048) a synthetic pyrethroid, was tested for its insecticidal properties in the laboratory against normal strains of Culex quinquefasciatus, Cx. tritaeniorhynchus, Cx. sitiens, Anopheles stephensi, An. culicifacies, Aedes aegypti and Armigeres subalbatus and against strains of Cx. quinquefasciatus resistant to fenthion and malathion. Tralomethrin showed good larvicidal activity against all the species tested. LC50 ranged between 7.00 x 10(-6) and 9.10 x 10(-3) mg (ai)/l. Resistant strains of Cx. quinquefasciatus showed higher tolerance than the normal strain. Tralomethrin was more effective against adults of An. culicifacies (LD50 0.18 micrograms/cm2) than the other species. Residual activity of this compound lasted for 15 weeks on thatch surface at a dosage of 50 mg (ai)/m2 against all the mosquito species tested. In the field, this compound was effective for a period of 1-2 days in polluted water viz., cesspits and drains and 10-24 days in less polluted water as in cement tanks, when applied at the rate of 0.002-2.0 mg (ai)/l against immatures of Cx. quinquefasciatus.

Aedes↗
PubMedDate not supplied

Postharvest-applied agrochemicals and their residues in fresh fruits and vegetables.

Many agrochemicals are applied postharvest on fruits and vegetables to extend their lives and preserve quality during storage, transport, and marketing. Persistence and distribution of residues on the edible portions of produce have been reported for citrus fruits, pome fruits, stone fruits, mangos, strawberries, bananas, kiwi fruits, avocados, some minor fruit commodities, and bell peppers and tomatoes. Data on the persistance and residues of the fungicides benomyl, biphenyl, sec-butylamine, captan, carbendazim, dicloran, fosetyl-aluminum, guazatine, imazalli, iprodione, metalaxyl, o-phenylphenol, prochloraz, thiabendazole, thiophanate-methyl, triadimeton, and vinclozolin, the fumigants ethylene dibromide, methyl bromide, and sulfur dioxide, the insecticides dimethoate and fenthion, the antiscald compounds diphenylamine and ethoxyquin, and the growth regulators 2,4-D and daminozide are presented and discussed.

Agrochemicals↗
PubMed1991

Acute toxicity of certain organochlorine, organophosphorus, synthetic pyrethroid and microbial insecticides to the mosquito fish Gambusia affinis (Baird and Girard).

Acute toxicity of certain organochlorine, organophosphorus, synthetic pyrethroid and microbial insecticides to the mosquito fish Gambusia affinis were determined to collect baseline data for selecting the resistant strains of the fish. The synthetic pyrethroid, Lambdacyhalothrin was most toxic to the fish (LC50 = 0.0022 ppm), followed by deltamethrin, cypermethrin and fenvalerate. Organochlorine insecticides, DDT and gamma-HCH, were less toxic than the pyrethroids, and these were followed by organophosphorus insecticides, malathion, fenthion, monocrotophos and temephos. The last two insecticides were least toxic among the different chemical insecticides (LC50 greater than 80 ppm ai). The microbial insecticide ABG-6262 (Vectolex 2.5 AS), a Bacillus sphaericus preparation, was totally harmless to the fish at 2500 microliters/l up to one week.

Animals↗
PubMed1990

Comparative organophosphorus insecticide susceptibility in Caribbean populations of Aedes aegypti and Toxorhynchites moctezuma.

Aedes aegypti larvae from Antigua, Jamaica, Puerto Rico, St. Lucia, Trinidad and Union Island and predatory larvae, Toxorhynchites moctezuma, from Trinidad were tested for susceptibility to temephos, malathion, fenthion, fenitrothion and chlorpyrifos. There was some organophosphorus resistance in all strains of Ae. aegypti, in the approximate order: Antigua greater than Jamaica greater than Puerto Rico greater than St. Lucia greater than Trinidad greater than Union Island. Toxorhynchites moctezuma was much less susceptible to temephos than the Ae. aegypti strain, indicating its possible usefulness in an integrated management program.

Aedes↗
PubMed1985

Current status on the Florida Abate Monitoring program--susceptibility levels of three species of mosquitoes during 1984.

During 1984, larval susceptibility tests of temephos were performed on Aedes taeniorhynchus and Culex nigripalpus collected from the same general areas as in 1980-82, and the results compared to the susceptible laboratory strains. No resistance was detected against these two species. When strains of Culex quinquefasciatus from some new areas were tested against temephos, malathion, naled, fenthion and chlorpyrifos, their tolerance varied according to the insecticide tested and the origin of the strain. Some strains ranged from 1.6 to 43.0X more tolerant to temephos when compared to the West Florida Arthropod Research Laboratory strain (WFARL strain).

Aedes↗
PubMed1989

Insecticide tolerance of Culex nigripalpus in Florida.

Larval susceptibility tests of Culex nigripalpus populations from various areas of Florida have shown resistance to several organophosphorus insecticides since 1984. Although the degree of resistance is low (2 to 7 times), it can be termed tolerance and appears to be the greatest for fenthion, followed by temephos, naled and malathion. It is suggested that pesticide runoff from lawns, golf courses and agricultural and urban areas may play a role in developing resistance in Florida mosquito populations.

Animals↗
PubMed1987

Nuisance midges (Diptera: Chironomidae) and their control in Japan.

In recent years, adult Chironomidae (particularly Chironomus yoshimatsui and Tokunagayusurika akamushi) emerging from polluted natural and man-made aquatic habitats in urban areas of Japan have become intolerable because they pose severe nuisance and economic problems. Several organophosphorus (OP) insecticides and insect growth regulators (IGRs) including methoprene and diflubenzuron were tested in the laboratory against C. yoshimatsui and several other midge species. The OP insecticides were effective against the midge larvae except for Procladius sp. Both IGRs were highly effective against C. yoshimatsui at concentrations less than 0.001 ppm; diflubenzuron showed superior activity over methoprene. In field studies, temophos has been successfully used at rates ranging from 0.1 to 2 ppm against C. yoshimatsui and several other species in a variety of habitats. Diflubenzuron at 1 ppm rate of treatment provided excellent control of C. yoshimatsui in polluted rivers while methoprene at the same rate was less effective. Frequent field use of temephos and fenthion has led to increased tolerance of these insecticides (particularly the latter) by C. yoshimatsui.

Animals↗
PubMed1986

Studies on insecticide susceptibility of Anopheles gambiae s.1. and Culex quinquefasciatus in the area of Ouagadougou, Burkina Faso (west Africa).

Tests to evaluate the susceptibility level in Anopheles gambiae s.1. and Culex quinquefasciatus from Ouagadougou and two nearby villages have been carried out. Anopheles gambiae s.1. larvae from Ouagadougou showed complete susceptibility to organophosphates and carbamates, and adults showed low level resistance to DDT. Nine percent survival of adult An. gambiae s.1. to one hour exposure of 4% DDT was observed in samples from Zaghtouli village while in those from Koubri village, where dieldrin also was tested, resistance to both organochlorine insecticides was detected. Culex quinquefasciatus showed susceptibility to fenthion, malathion, fenitrothion, and chlorpyrifos, whereas incipient resistance to temephos was detected. Electrophoretic analysis showed polymorphism of high and low active esterases (Est-2 + Est-3) confirming the association between OP resistance and enhanced esterase activity in this species.

Animals↗
PubMed1986

[Cutaneous absorption of chemicals].

Chemicals have become indispensible for the maintenance of health in animals and man. The route of administration of each medicament is decided by factors such as site of desired action, chemistry of the active ingredient, age and species of the patient, and frequency of administration (or desired duration of activity). In situations where the oral and hypodermic routes, which are used most frequently, are inadequate or unsatisfactory, dermal application can provide a valuable alternative method to achieve systemic activity. Examples of formulations currently available for dermal application contain diverse chemicals and are intended for a variety of purposes, such as crufomate against cattle grubs, fenthion against cattle lice, levamisole against gastrointestinal nematodes, nitroglycerine for angina pectoris, and scopolamine for motion sickness. The skin acts as a barrier to penetration by chemicals and micro-organisms by virtue of its morphology and chemical composition. Chemicals which do penetrate, do not necessarily pass through the appendages (hair follicles and gland ducts), but mostly penetrate through the interjacent epidermis, either through the cells, or via the intracellular spaces. These spaces have recently been shown by electron microscopy to be filled by an amorphous substance which exudes on the skin surface in convex ridges. This substance has a lipid nature, but is not hydrophobic as is often accepted. For a chemical to be able to penetrate the skin, it must be partially water and lipid soluble, polar, and weakly ionizing. A variety of factors can possibly affect the permeability of skin for a chemical. These include species differences in morphology (skin thickness, tightness of intercellular junctions, density of hair follicles and other appendages), biochemistry, and physiology; seasonal and climatic variations; and differences between breeds and genders. Species differences in skin permeability are largely unpredictable and inconsistent. An observed difference between two species for one chemical cannot necessarily be extrapolated to another.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗
PubMedDate not supplied

Simplified cleanup and gas chromatographic determination of organophosphorus pesticides in crops.

A simple and efficient cleanup method for gas chromatographic determination of 23 organophosphorus pesticides in crops including onion is described. The sample was extracted with acetone. The extract was purified with coagulating solution, which contained ammonium chloride and phosphoric acid, and then filtered by suction. The filtrate was diluted with NaCl solution and reextracted with benzene. The organic layer was evaporated and injected into a gas chromatograph equipped with a flame photometric detector (FPD) and fused silica capillary columns (0.53 mm id) coated with silicone equivalent to OV-1701, OV-1, and SE-52. Onion extract, which contained FPD interferences, was cleaned up on a disposable silica cartridge. Recoveries of most organophosphorus pesticides from spiked crops: mandarin orange, tomato, spinach, sweet pepper, broccoli, lettuce, and onion at levels of 0.02-0.28 ppm, exceeded 80%, but the water-soluble pesticides dichlorvos and dimethoate gave poor recoveries in all crops; the nonpolar pesticides disulfoton, chlorpyrifos, fenthion, prothiophos, and leptophos were not recovered quantitatively in spinach, sweet pepper, broccoli, and lettuce. IBP, edifenphos, phosmet, and pyridaphenthion were not recovered from onion because of adsorption to the silica cartridge. The detection limits ranged from 1.25 to 17.5 ppb on a crop basis.

Charcoal↗
PubMed1985

A chironomid (Diptera: Chironomidae) midge population study and laboratory evaluation of larvicides against midges inhabiting the lagoon of Venice, Italy.

Chironomid larval densities in the saltwater lagoon of Venice, Italy, were assessed in the spring of 1984. Four organophosphates; chlorpyrifos, temephos, fenthion and fenitrothion, and three pyrethroids; cypermethrin, permethrin and deltamethrin, were tested in the laboratory against field-collected larvae. Three industrial formulations of Bacillus thuringiensis var. israelensis (B.t.i.) were also tested as midge larvicides. Only Chironomus salinarius occurred in the benthic samples taken from different sections of the lagoon. The densities of this species ranged from 0 to 38,976 larvae/m2. The highest mean larval density of 15,673/m2 was encountered in a section of the lagoon adjacent to Venice airport and receiving large quantities of raw sewage. The lowest mean density (less than 1 larva/m2) existed in another area of the lagoon receiving discharge from chemical industry. Cypermethrin and permethrin were 21-233X more active against the larvae than the four organophosphates. Chlorpyrifos was the most active organophosphate. Formulations of B.t.i. were economically ineffective against the larvae.

Animals↗
PubMedDate not supplied

Disappearance of organochlorine residues from abdominal and egg fats of chickens, Ontario, Canada, 1969-1982.

Abdominal fats were collected from 8-week old broilers slaughtered at provincially inspected abattoirs across Ontario between 1969 and 1982. Domestically produced hen eggs were collected from either egg grading stations or producers over the same period. Composite samples were analyzed for organochlorine insecticides and industrial chemicals. Between 1979 and 1982, organophosphorus insecticides were routinely included in these analyses. Sigma DDT and PCB residues declined rapidly between 1969 and 1982 in extractable lipids of both abdominal and egg fats, while dieldrin declined less markedly over the same period. Declines in residues followed first order logarithmic regression equations. Chlordane and heptachlor epoxide were rarely observed above the detection limit of 1 microgram/kg in egg fat; however, the incidence of these residues in abdominal fat increased after 1973 following the removal of aldrin, dieldrin, and heptachlor in 1969 and the subsequent increased use of chlordane for soil insect control until 1977. Lindane residues were rarely observed above the detection limit. In 1979, when the detection limit was reduced, both alpha-BHC and lindane were identified, but at levels below 1 microgram/kg. Endosulfan, methoxychlor, and fenthion were identified on one or 2 occasions over the 13-year period.

Adipose Tissue↗
PubMed1968

Ecological considerations in scrub typhus. 3. Methods of area control.

The best of the known methods for control of the chigger vectors of scrub typhus is the application of dieldrin to the ground and low-lying vegetation as a fog or spray at the rate of 2.5 lb to the acre (28 kg/hectare). This has produced a more than 91% reduction in the numbers of Leptotrombidium (L.) akamushi (Brumpt, 1910) and L. (L.) deliense (Walch, 1922) for at least 2 years. Aldrin applied at the rate of 2.25 lb per acre (2.5 kg/hectare) is also highly effective, but less so than dieldrin. Lindane at the rate of about 5 lb per acre (5.7 kg/hectare) ranks third, but offers protection for only about 2 months. Because of the potential hazards to wildlife when such long-acting compounds are used, application of organophosphorous or carbamate insecticides may be used instead in areas where reapplication every few weeks is feasible. Fenthion and arprocarb are promising compounds for this purpose.

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↗
PubMed1970

Summary of field trials in 1964-69 in Rangoon, Burma, of organophosphorus larvicides and oils against Culex pipiens fatigens larvae in polluted water.

In tests in Rangoon, Burma, of the larvicidal activity of various organophosphorus compounds against C. p. fatigans, it was found that the activity usually lasted much longer in septic tanks and pit latrines than in open drains. Dursban, Abate, fenthion and several other emulsifiable concentrates caused high larval mortality at a concentration of 0.05 ppm but 0.5 ppm was normally required to obtain a minimum of 1-2 weeks of complete larval control. For the desired residual activity, dosages about 40-400 times the laboratory LC(95) values were normally required, depending on the compound used.The most effective formulation was Dursban emulsifiable concentrate, which, at a concentration of 0.5 ppm, was effective for 3, 7 and 12 weeks in concrete drains, pit latrines and septic tanks, respectively. Petroleum oils applied at rates of 25-40 US gal/ac (approx. 237 l/ha-380 l/ha) and a pyrethrum derivative at a concentration of 1.0 ppm were toxic to larvae but not highly residual. Some emulsifiable-concentrate/oil mixtures appeared to be outstandingly effective, although inconsistent results also occurred. Granular formulations were normally less effective than the emulsifiable concentrates.

Animals↗