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PubMed1990

Impact of selected pesticides on field population dynamics of parasitic Hymenoptera (Pteromalidae) in caged-layer poultry manure in southern California, U.S.A.

Field studies were conducted at caged-layer poultry facilities in southern California, U.S.A., to determine the effect of selected pesticides on beneficial Pteromalidae. Weekly parasite sampling was conducted using sentinel Musca domestica L. pupae to assess changes in parasitization in relation to pesticide treatment. Sites were sampled weekly for 5 weeks before treatment and for 8-10 weeks post-treatment. Treatments were applied twice to six hen houses (four treated plus two controls) at each of two sites. Treatments were: (1) dimethoate (0.5%), spot-treatment to wet areas only (approximately 5-10% of manure surface); (2) dimethoate (0.5%), entire manure surface; (3) cyromazine (0.1%), entire manure surface; and (4) permethrin (0.05%) applied to all hens in the house for northern fowl mite [Ornithonyssus sylviarum (Canestrini and Fanzago)]. The two discrete pesticide applications during an 8-day period had no significant effect on activity of Muscidifurax spp. and Spalangia spp. at either site.

Animals↗
PubMed2005

Stimulus frequency dependence of the central and peripheral somatosensory evoked activity in rats treated with various pesticides.

Rats were treated with a combination of insecticide agents in different timing schemes. In acute administration, 1/5 LD50 of the three insecticides: dimethoate, propoxur and cypermethrin, or their combination, was given once by gavage. In the developmental model, female rats received oral doses of 1/25 LD50 of the above insecticides in combination in three timing schemes including pregnancy and lactation. Responses in the somatosensory cortex and in the tail nerve, evoked by peripheral electric stimulation, were recorded in acute preparation under urethane anesthesia. It was tested whether the parameters of the cortical and peripheral evoked response are dependent on the frequency and whether this dependence is different in control and treated animals. The latency increase of the cortical responses with increasing stimulation frequency was significantly stronger in rats treated acutely with cypermethrin and the combination, and in rats receiving the combination during both intra- and extrauterine development. On the duration, the effects were less clear. Frequency dependent increase of the tail nerve action potential latency was significantly intensified by cypermethrin, and the amplitude decrease, by cypermethrin and dimethoate. Fatigue of this response during a stimulation series was also altered by the insecticides. Frequency dependence and fatigue possibly reflect the actual state of the nervous system and may have the potency to be developed to functional biomarkers.

Action Potentials↗
PubMed1976

[Elimination of alkyl phosphates by means of haemoperfusion: experimental results and findings from human casuistics (author's transl)].

We examined the possibility that haemoperfusion with coated activated charcoal might be used in the therapy of alkyl phosphate intoxications. The criterion used was the effect of haemoperfusion on the elimination of alkyl phosphates from the blood. Clearance values for haemoperfusion of nitrostigmine, demeton-S-methyl sulfoxide and dimethoate were determined in vitro. Very good clearance values were ascertained at a blood flow rate of 100ml/min (mitrostigmine 59.20ml/min, demeton-S-methyl sulfoxide 83.70 ml/min, dimethoate 87.84 ml/min). Measurements of the nitrostigmine clearance as a function of various nitrostigmine concentrations in plasma showed that haemoperfusion is effective over a concentration range covering two powers of ten. A 7-h haemoperfusion with coated activated charcoal was performed on a suicide patient with severe nitrostigmine intoxication (Folidol-öl). Clearance values were obtained which were to be expected on the basis of the in vitro investigations. The nitrostigmine concentrations in the extracorporeal blood plasma fell as a result of haemoperfusion to a mid-value of 55 per cent of the initial level. In the patient the level of nitrostigmine in the blood rose showing that there had been a redistribution of nitrostigmine from the tissue or a subsequent absorption from the gastrointestinal tract into the vessels. The results support the use of haemoperfusion with coated activated charcoal in very severe cases of alkyl phosphate intoxication or where standard therapy fails.

Adult↗
PubMed2002

Influence of organic acids on the mobility of heavy metals in soil amended with some insecticides.

The mobility (Rf value) of some heavy metals, such as: Co, Zn, Ag, Cu, and Pb was measured through soil amended with some insecticides, such as: endosulfan, chlorpyrifos, dimethoate and methyl demeton using distilled water, formic, acetic and oxalic acids as mobile phase. The enhancement in the mobility of metal ions in all the amended soils formic, acetic and oxalic acids as mobile phase. The enhancement in the mobility of metal ions in all the amended soils followed the order: Co > Zn > Ag > Cu > Pb. On the otherhand the mobility followed the order: endosulfan > chlorpyrifos > dimethoate > methyl dementon for the amended insecticides and the order: formic > acetic > oxalic acids for the mobile phase in natural as well as amended soils. Mobility of ions increased upto a concentration of 0.25 mg 100 g-1 of soils thereafter it was decreased in all the systems. The results have been explained on the basis of the nature of heavy metals, insecticides, organic acids and the solubilities of the salts formed in the soil-insecticide-amended systems.

Chlorpyrifos↗
PubMed1985

The environmental impacts of four insecticides on non-target organisms in the Gezira Irrigation Scheme canals of Sudan.

The toxic effects of the insecticides endosulfan, decamethrin, dimethoate and dursban on the aquatic fauna of some of the Gezira irrigation canals were studied. The animal groups selected were fishes, arthropods and snails. Endosulfan was found to be highly toxic, particularly to Gambusia affinis, under field and laboratory conditions. All animals proved to be less sensitive to decamethrin in the field probably because this insecticide reacted with the organic matter and hence its toxicity was reduced. However in the laboratory it proved to be the most toxic chemical to all organisms probably because of the presence of the solvent in the emulsifiable concentrate formulation. The third insecticide, dimethoate had a very low toxicity to all organisms in the field or in the laboratory. Similarly dursban had a lower toxicity to fish than endosulfan under laboratory conditions, but higher toxicity to arthropods and snails. In the field the highest mortality among fish was obtained when dursban was mixed with endosulfan. For all insecticides, fish were the least tolerant of all animals tested, followed by arthropods and then molluscs.

Agriculture↗
PubMed1987

[Orienting resistance tests on the population of Musca domestica in the East German district of Rostock].

In 1984-1986 we examined the insecticide resistance in 33 populations of Musca domestica. The average sensibility amounted to 21% with Trichlorfon, to 66% with Dimethoate and to 63% with Trichlorphenidine. For the moment, Dimethoate is the most successful insecticide in problematic stables, compared with it Trichlorfon often fails. Pest control operators have reported on first cases of inefficacy of Pyrethrum.

Animals↗
PubMed1978

[The effect of organic phosphoric esters on the experimental peptic ulcer (author's transl)].

The authors have investigated some organic phosphoric esters such as dimethoate, malatione, and trichlorphone in order to see whether they influence the genesis of the reserpine ulcer induced in rats or whether they act on the existing ulcer. Another objective of the investigation was to determine whether the aggravating effect of these compounds on the experimental gastric ulcer can be mitigated or prevented with isopropamide and gastrixon, two compounds known to be used in the therapy of ulcers. It was found that 1. dimethoate and trichlorphone considerably aggravate the genesis of the experimental peptic ulcer in rats, and that also malathione exercises this exacerbating effect still to some extent, 2. that the already existing experimental ulcer is aggravated by all three organic phosphoric esters and that 3. the severe experimental damage to the stomach can be reduced or prevented with Isopropamide and even more effectively with Gastrixon. As to the interpretation of the phenomena observed the authors take the view that--provided the effects mentioned apply also to man--with this a new risk was detected in the field of the chemical plant protection which may well gain importance for the health of a population.

Adult↗
PubMed2001

The status and development of insecticide resistance in Danish populations of the housefly Musca domestica L.

Samples of housefly (Musca domestica) field populations were collected from Danish livestock farms in 1997. The tolerance of the first-generation offspring was determined for a number of insecticides. Dose-response values were obtained by topical application for the pyrethroids bioresmethrin and pyrethrum, both synergised with piperonyl butoxide, and the organophosphate dimethoate. The organophosphates azamethiphos and propetamphos and the carbamate methomyl were tested in discriminating dose feeding bioassays. Resistance was low to moderate in most of the populations for most of the compounds tested, but this study also revealed the existence of high resistance to pyrethroid, organophosphate and carbamate insecticides in some populations. The resistance factors at LD50 for bioresmethrin/piperonyl butoxide ranged between 2 and 98, and for pyrethrum/piperonyl butoxide between 2 and 29. Our results indicate that pyrethroid resistance in Denmark is increasing, since four of the 21 farms showed more than 100-fold resistance at LD95, a level of resistance only observed once before. Resistance factors at LD50 for dimethoate ranged from 9 to 100, and showed two distinct trends: populations with either decreasing or increasing resistance. Resistance to azamethiphos was found to be widespread and high. Although two strains with high methomyl and propetamphos resistance were observed, methomyl and propetamphos resistance is moderate and appears not to be increasing.

Animals↗
PubMed2006

The effect of indoxacarb and five other insecticides on Phytoseiulus persimilis (Acari: Phytoseiidae), Amblyseius fallacis (Acari: Phytoseiidae) and nymphs of Orius insidiosus (Hemiptera: Anthocoridae).

A laboratory study assessed the contact toxicity of indoxacarb, abamectin, endosulfan, insecticidal soap, S-kinoprene and dimethoate to Amblyseius fallacis (Garman), Phytoseiulus persimilis Athias-Henriot and nymphs of Orius insidiosus (Say). Amblyseius fallacis is a predacious phytoseiid mite and an integral part of integrated pest management (IPM) programmes in North American apple orchards. The other two beneficials are widely used in greenhouses to manage various arthropod pests infesting vegetable and ornamental crops. Indoxacarb is a slow-acting insecticide, so toxicity data were recorded 7 days post-treatment when the data had stabilised. It showed no toxicity to O. insidiosus nymphs or to A. fallacis or P. persimilis adults. The LC50 values for O. insidiosus nymphs and P. persimilis could not be estimated with their associated confidence limits, because the g values were greater than 0.5 and under such circumstances the lethal concentration would lie outside the limits. The LC50 for A. fallacis was 7.6x the label rate. The fecundity of P. persimilis was reduced by 26.7%. The eclosion of treated eggs from both species of beneficial mites was not affected adversely. Among the other pest control products, S-kinoprene and endosulfan affected adversely at least one species of the predators, whereas dimethoate, abamectin and insecticidal soap were very toxic to all three beneficials. Indoxacarb should be evaluated as a pest control product in IPM programmes.

Animals↗
PubMed1994

Relationship of carcinogenicity and cellular proliferation induced by mutagenic noncarcinogens vs carcinogens. III. Organophosphate pesticides vs tris(2,3-dibromopropyl)phosphate.

Our laboratory has been examining the mechanisms whereby chemicals produce mutagenicity in short-term in vitro assays yet fail to produce carcinogenesis in 2-year rodent bioassays. Previous studies indicated that some mutagenic hepatocarcinogens increased cell proliferation in the target organ, the liver, while other structurally related mutagens that were noncarcinogenic failed to do so. We demonstrate in this report that another mutagenic carcinogen, tris(2,3-dibromopropyl phosphate), increased cell proliferation that was localized in the outer medulla of the kidney. This was also the target site for carcinogenesis in a 2-year bioassay and is another example of the association between chemically induced cell proliferation and carcinogenesis. This study also reports the absence of increased cell proliferation in the liver or kidney after exposure in the diet to the mutagenic organophosphate insecticides dimethoate, dioxathion, and dichlorvos following dietary exposure for 2 weeks at the same dose levels and routes of exposure that did not increase the tumor incidence in either organ in 2-year carcinogenesis assays. The present studies support the tenet that chemically induced cell proliferation may be a necessary prerequisite for chemical carcinogenesis, since in rat liver and kidney there was neither cell proliferation after 2 weeks nor tumor development after 2 years dietary exposure to the mutagenic organophosphate insecticides dimethoate, dioxathion, and dichlorvos.

Animals↗
PubMed1999

Fungal utilization of organophosphate pesticides and their degradation by Aspergillus flavus and A. sydowii in soil.

Fungal species were isolated which utilize organophosphate pesticides, viz. phosphorothioic (pirimiphos-methyl and pyrazophos), phosphorodithioic (dimethoate and malathion), phosphonic (lancer) and phosphoric (profenfos) acid derivatives. Pesticide degradation was studied in vitro and in vivo (soil). Aspergillus flavus, A. fumigatus, A. niger, A. sydowii, A. terreus, Emericella nidulans, Fusarium oxysporum and Penicillium chrysogenum were isolated from pesticide-treated wheat straw. The number of A. sydowii colonies was significantly promoted by 1 mmol/L pirimiphos-methyl, pyrazophos, lancer, dimethoate and malathion when used as phosphorus sources and by pirimiphos-methyl and pyrazophos when used as carbon sources. The number of A. flavus colonies increased with 0.5 mmol/L lancer and malathion used as the only carbon sources. A. sydowii, A. niger, A. flavus, E. nidulans and F. oxysporum grew on, and utilized, 5 pesticides as phosphorus source and showed more than 50% mass growth. A. sydowii, A. flavus and F. oxysporum phosphatase hydrolyzed the pesticides suggesting that these species are important pesticide degraders. A. sydowii produced higher amounts of the phosphatase than A. flavus and F. oxysporum. The enzyme was highly active against pyrazophos, lancer and malathion used as the only sources of organic phosphate. A. flavus and A. sydowii phosphatases efficiently hydrolyzed pesticides at 300 ppm in soil, the degradation at 1000 ppm was lower. Mineralization of 1000 ppm pesticides in soil amended with wheat straw was higher than in nonamended soil. All added pesticides except profenfos were degraded within 3 weeks. Lyophilized adapted biomass of A. flavus and A. sydowii could thus be used for field biodegradation of these pesticides.

Aspergillus↗
PubMed2006

The status of pesticide residues in the drinking water sources in Meiliangwan Bay, Taihu Lake of China.

The study was carried out to assess the levels of pesticide residues in the water of Meiliangwan Bay, Taihu Lake of China. The most commonly employed organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs) and herbicide atrazine were analyzed. The water samples were collected seasonally from Meiliangwan Bay within a period of one year. The pesticides were analyzed by gas chromatography (GC) with microECD or NPD after solid-phase extraction (SPE), which was confirmed by GC with an ion trap mass spectrometry (MS). The mean concentrations were 1.98 ng/l for lindane, 0.378 ng/l for heptachlor epoxide, 0.367 ng/l for p,p'-DDE, 0.496 ng/l for p,p'-DDD, 1.06 ng/l for p,p'-DDT and 51.6 ng/l for dichlorvos, 39.0 ng/l for demeton, 346 ng/l for dimethoate, 4.12 ng/l for methyl parathion, 11.6 ng/l for malathion, 2.17 ng/l for parathion and 217 ng/l for atrazine. Generally, low concentrations of OCP were found, whereas the concentrations of the OPPs and atrazine in the water of Taihu Lake were relatively high. Heptachlor epoxide and lindane were the two most commonly encountered OCPs while dichlorvos, demeton and dimethoate were found to have much higher concentrations and occurrences than other OPPs.

Atrazine↗
PubMed1991

Impact of insecticides on nontarget microarthropod fauna in agricultural soil.

Ecologically important soil microarthropods were used to evaluate the direct and residual toxicities of some insecticides under field and laboratory conditions. The density of total microarthropods and major groups, namely Acarina and Collembola, suffered a statistically significant and persistent decline in the aldrin 30 EC (0.25%)- and endosulfan 35 EC (0.33%)-treated soil of wheat fields. But dimethoate 30 EC (0.125%) and phosphamidon 85 EC (0.03%) applied in mustard fields produced only a temporary decline. Laboratory studies showed that all the above insecticides and monocrotophos 36 EC (0.2%), methyl parathion 50 EC (0.05%), chlordane 20 EC (0.125%), and carbaryl 50 WP (0.625%) had a direct knockdown effect on Cyphoderus sp. but another collembolan species, Xenylla sp., appeared to be somewhat resistant. Only endosulfan was toxic to a common soil Acarina species, Lancetoppia sp. Among four soil media, toxicity was maximum in pure sand, followed by sandy loam, clay, and organic soil. The residual toxicity of phosphamidon, dimethoate, methyl parathion, and endosulfan was more prolonged for Cyphoderus sp. than for Xenylla sp. Only the larval stage of Lancetoppia sp. was susceptible to the residual effect of endosulfan. LD50 and bioassay studies showed that Cyphoderus sp. can be employed as a potential biomonitor of insecticide pollution in soil.

Animals↗
PubMed1984

Evaluation of the mutagenic potential of four commercial mixtures of insecticides.

Male mice (Q strain) were given a single ip injection at the maximum tolerated dose of one of four commercial mixtures of insecticides: Luxan Tue-Taons (150 g dimethoate and 150 g fenitrothion/litre), Metadipterex (210 g trichlorfon and 270 g methyldemeton/litre), Dynafos (155 g malathion, 60 g dichlorvos and 75 g carbaryl/litre) and Phosan Plus (95 g dimethoate, 100 g malathion and 100 g methoxychlor/litre). At the maximum tolerated doses, Luxan Tue-Taons (60 mg/kg), Metadipterex (15 mg/kg), Dynafos (50 mg/kg) and Phosan Plus (100 mg/kg) did not induce chromosome aberrations in bone-marrow cells, spermatogonia or primary spermatocytes of the mice. No evidence of potential genetic effects was obtained in a dominant lethal mutation assay.

Animals↗
PubMed2006

Is prochloraz a potent synergist across aquatic species? A study on bacteria, daphnia, algae and higher plants.

Fungicides inhibiting the biosynthesis of ergostrol, such as the triazoles and imidazoles, have been shown to enhance the effect of insecticides on birds, mammals and invertebrates in the terrestrial environment. The synergy is proposed to be due to an effect on P450 monooxygenase enzymes active in pesticide metabolism in these organisms. Fungicides often enter the aquatic environment jointly with other pesticides. It is therefore possible that they could act as synergists also in the aquatic environment. In this study we tested the joint effect of the imidazole fungicide prochloraz together with the herbicides acifluorfen, diquat and terbuthylazine, the fungicide azoxystrobin and the insecticides chlorfenvinphos, dimethoate, and pirimicarb on the bacteria Vibrio fischeri (six binary mixtures), the crustacean Daphnia magna (four binary mixtures), the algae Pseudokirchneriella subcapitata (four binary mixtures) and the floating plant Lemna minor (three binary mixtures). All the binary mixtures were evaluated both in relation to the model of concentration addition (CA) and independent action (IA) using isobolograms. The study showed strong synergy in relation to CA between prochloraz and azoxystrobin, diquat and esfenvalerat on D. magna with sums of toxic units for the 50:50% effect mixture ( summation TU(50:50)) as low as 0.25. The mixture with dimethoate was however antagonistic with summation TU(50:50) of 2.04. Four out of the six mixtures testes on V. fisheri showed synergy in relation to CA, but for three of the mixtures the response could be explained by IA. Only the mixture with diquat showed synergy in relation to both IA and CA with summation TU(50:50) around 0.50. There was no significant synergy for any of the combinations tested on the plant and the algae species in relation to CA and only for diquat in the algae-test in relation to IA. Hence, prochloraz does synergise the effect of some pesticides in the aquatic environment, but not consistently across species. The organism most susceptible to synergy by prochloraz in this study was D. magna. Especially the combination with insecticides such as esfenvalerate, where the concentration needed to immobilize 50% of the daphnia was reduced from >3microgL(-1) to less than 0.5microgL(-1) when prochloraz was added, could be problematic as these concentrations are environmentally realistic. Furthermore, insecticides and ergostrol-biosynthesis-inhibitors (EBI-fungicides) are often applied together, and are therefore likely to co-exist in surface waters, enhancing the problem of the already very potent insecticides.

Animals↗
PubMed2005

A comparative analysis of the toxicity of eight common soil contaminants and their effects on drought tolerance in the collembolan Folsomia candida.

Previous exposure to contaminants can increase the susceptibility to drought stress in soil invertebrates. In the present study, the effects of eight common environmental contaminants on drought tolerance and reproduction were investigated using the collembolan Folsomia candida as a model organism. Four classes of chemicals were considered: polycyclic aromatic hydrocarbons (pyrene and fluorene), detergents (linear alkylbenzene sulfonate (LAS) and nonylphenol), insecticides (dimethoate and cypermethrin), and heavy metals (copper and cadmium). Previous exposure to nonylphenol, pyrene, and fluorene had significant effects on drought tolerance. LAS had a weak effect on drought tolerance, whereas the remaining chemicals had no such effects even at concentrations at which reproduction was considerably reduced. Reproduction and adult survival in F. candida were equally sensitive to dimethoate. However, for all other chemicals, reproduction was a considerably more sensitive parameter than adult survival. The results suggest that toxicants whose effects are associated with cell membrane function are the most potent with respect to effect on drought tolerance.

Adaptation, Physiological↗
PubMed1996

Selective, solid-matrix dispersion extraction of organophosphate pesticide residues from milk.

A rapid procedure has been developed that allows a single-step, selective extraction and cleanup of organophosphate (OP) pesticide residues from milk dispersed on solid-matrix diatomaceous material filled into disposable cartridges by means of light petroleum saturated with acetonitrile and ethanol. Recovery experiments were carried out on homogenized commercial milk (3.6% fat content) spiked with ethanolic solutions of 24 OP pesticides, viz., ethoprophos, diazinon, dimethoate, chlorpyrifos-methyl, parathion-methyl, chlorpyrifos-ethyl, malathion, isofenphos, quinalphos, ethion, pyrazophos, azinphosethyl, heptenophos, omethoate, fonofos, pirimiphos-methyl, fenitrothion, parathion, chlorfenvinphos, phenthoate, methidathion, triazophos, phosalone, azinphos-methyl, at levels ranging for the different OP pesticides from 0.02 mg/kg to 1.11 mg/kg. Average recoveries of four replicates were in the range 72-109% for the different OP pesticides, with relative standard deviations (R.S.D.) from ca. 1 to 19%, while dimethoate and omethoate were not recovered. Coextracted fatty material amounted to an average of about 4.0 mg/ml of milk. The extraction procedure requires about 30 min. The main advantages are that extraction and cleanup are carried out in a single step, emulsions do not occur, several samples can be run in parallel by a single operator, reusable glassware is not needed and simple operations are required.

Animals↗
PubMed2001

Time to death response in carabid beetles exposed to multiple stressors along a gradient of heavy metal pollution.

We investigated the responses of invertebrates inhabiting polluted environments to multiple stressors. Carabid beetles (Pterostichus oblongopunctatus F.) were subjected to food deprivation and insecticide treatment (dimethoate) to resolve trends associated with a gradient of heavy metal pollution. Metal concentrations along the gradient of five sites ranged from approximately 150 to 10,500 mg/kg Zn, 136 to 2600 mg/kg Pb, and 0.84 to 81.9 mg/kg Cd. There was no difference in body mass along the pollution gradient. However, the beetles originating from the most contaminated sites were significantly less tolerant to food deprivation than beetles from the reference site. Median survival time was 120 h for the two most polluted sites, compared with 168 h at the reference site. Beetles from the two most polluted sites were also significantly more susceptible to dimethoate at 0.1 microgram active ingredient/beetle. Median survival times were 12 and 123 h for beetles from the two most polluted sites and 359 h for the reference site. Carabid beetles exposed to chronic pollution, therefore, exhibit elevated susceptibility to additional stressors.

Adaptation, Physiological↗