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PubMed1996

Use of a new rapid bioluminescence method for screening organophosphate and N-Methylcarbamate insecticides in processed baby foods.

An enzyme with high specific affinity for organophosphate and N-methylcarbamate insecticides has been incorporated into a new test for detection of these insecticides at the level of parts per billion (ppb) (commercially available as the Charm Pesticide Test). To measure the extent of insecticide inhibition of the enzyme, a specific bioluminescent substrate is used. The signal is counterproportional to the amount of insecticides. Random sampling of four baby food brands and testing for the cumulative levels of organophosphate and N-methylcarbamate insecticides found carbaryl to be the most common residue. Out of the 155 samples tested there were 132 negative samples (85.2%) and 23 suspected positive samples (14.2%). The suspected positive samples were further analyzed by high-performance liquid chromatography (HPLC) and gas chromatography/mass spectrometry (GC/MS). Carbaryl was confirmed in 18 of the samples. One of the samples contained an active metabolite of tetrachlorvinphos and in 3 of the positive samples an insecticide could not be identified by GC/MS. One positive sample was not processed for confirmation due to high fat content.

Carbamates↗
PubMed1988

A case-referent study of soft-tissue sarcoma and Hodgkin's disease. Farming and insecticide use.

A population-based case-referent study in Kansas examined the relationship between exposure to insecticides and the development of soft-tissue sarcoma (STS) and Hodgkin's disease (HD). Data from telephone interviews for 133 STS cases, 121 HD cases, and 948 referents indicated that STS was associated with use of insecticides on animals, but not on crops. HD was not significantly associated with either use. STS risk was higher among the farmers who themselves mixed or applied insecticides to animals than among farmers who did not. Farmers who failed to use any protective equipment to reduce insecticide exposure were at a significantly elevated risk of STS. Risk rose with early calendar year of first use. The excess risk appeared to be primarily among fibrous and myomatous sarcomas with little association seen for lipomatous or other STS neoplasms. Myomatous sarcomas increased significantly with duration and time since first use of insecticides on animals. If the reported association between STS and insecticides is causal, the data suggest that exposure to the agent(s) responsible may have been reduced in the mid-1950s or the agent(s) have an average latency period for STS of at least 20 years.

Aged↗
PubMed1999

Control of dengue fever with active surveillance and the use of insecticidal aerosol cans.

An interventional study was conducted in southern Vietnam to evaluate the feasibility and effectiveness of a new approach to control dengue fever. The approach consisted of active surveillance of dengue patients and the use of insecticidal aerosol cans. Febrile patients were tested serologically at local health centers and insecticidal aerosol cans were given to the family and employed in the neighborhood of dengue patients instead of ultra low volume (ULV) fogging with insecticide. The number of dengue IgM antibody positive cases among febrile patients, the number of reported dengue hemorrhagic fever patients and the total cost were compared in the 2 approaches (prompt focal ULV fogging and the use of insecticidal aerosol cans) in 1997. The aerosol cans were employed 5 times (in June, July, August, September and October) in the study area. ULV fogging in the control area was performed 5 times (in March, May, July, August and September). Twenty-two serologically positive cases were found in the study area which was about half that found in the control area (43 cases). A total of 16 dengue hemorrhagic fever patients was reported in the study area and 43 in the control area. Compared with the reported numbers of the previous year, the reduction rate in the number of dengue hemorrhagic fever cases was 71.4% in the study area and 51.7% in the control area. There were statistically significant differences in the morbidity of dengue fever and the reduction rate of dengue hemorrhagic fever. The cost of the insecticidal aerosol cans was US$393 which was lower than the cost of US$553 for ULV fogging. The findings suggest that insecticidal aerosol cans were effective and feasible for dengue fever control.

Aerosols↗
PubMedDate not supplied

Determination of insecticides in honey by matrix solid-phase dispersion and gas chromatography with nitrogen-phosphorus detection and mass spectrometric confirmation.

A multiresidue method was developed for the determination of 12 organophosphorus insecticides (diazinon, parathion methyl, fenitrothion, pirimiphosmethyl, malathion, fenthion, chlorpyrifos, quinalphos, methidathion, ethion, azinphosmethyl, coumaphos), one carbamate (pirimicarb), and one amidine (amitraz) in unifloral and multifloral honeys. The analytical procedure was based on the matrix solid-phase dispersion of honey on a mixture of Florisil and anhydrous sodium sulfate in small glass columns and subsequent extraction with a low volume of hexane-ethyl acetate (90 + 10, v/v), assisted by sonication. The insecticide residues were determined by capillary chromatography with nitrogen-phosphorus detection and confirmed by mass spectrometry. Average recoveries at the 0.05-0.5 microg/g levels were >80% for organophosphorus insecticides and about 60% for the other insecticides, pirimicarb and amitraz, with relative standard deviations <10%. The detection limit for the different insecticides ranged between 6 and 15 microg/kg. The main advantages of the proposed method are that extraction and cleanup are performed in a single step with a low volume of organic solvent. The method is simple, rapid, and less laborious than conventional methods. Several Spanish honeys were analyzed with the proposed method and no residues of the studied insecticides were found.

Gas Chromatography-Mass Spectrometry↗
PubMed2003

[Study on the degradation of residual insecticides on and in the vegetables and washing off method].

The degradation of residual insecticide in the vegetables is according to the first order of chemical dynamitic reaction. The half-life of insecticide on/in the vegetable can be calculated through a series sampling and analysis the residual amount to obtain a regression equation or by a simplified equation. Although the total amount of residual insecticide degraded according to the first order of chemical dynamitic reaction, the lost of the partial insecticide which absorbed in the leaves seems likely according to a more complicated exponent curve which has been described. The adsorbed residual insecticide (on the leaves) was easy washed away. The non-ionic detergent is more effect than water. But the absorbed insecticide (in the plant tissue) is hard to wash out.

Dimethoate↗
PubMed2004

Investigation on the optimal term of one-fold insecticide application for decreasing onion thrips ( Thrips tabaci Lindeman, Thysanoptera, Thripidae) damage on early white cabbage.

An impact of the term of one-fold insecticide application to reduce the damage of the onion thrips in early white cabbage was established. During the growing season plants were treated with insecticide (abamectin) in three different terms (treatment 1: 9 June, treatment 2: 16 June, treatment 3: 23 June, and treatment 4: untreated). On the exterior leaves of cabbage heads, treated with the insecticide, statistically significantly lower mean index of damage was determined as compared to the untreated plants. No significant differences were found between three different terms of application. The majority of the economically important damages in all of the treatments was found between the 3rd and 6th exterior leaf in the head. The highest mean weight of heads (1517.3 g) and mean net weight of heads I = mean weight of heads - weight of damaged and removed leavesl (1166.3 g) were established in plants which were treated the last. These parameters were the lowest in untreated plants (1083.3 g / 805.6 g). The yield loss due to damaged leaves removal amounted from 22.9% (treatment 2) to 25.6% (treatment 4). Based on the results obtained in this research we concluded that yield loss due to onion thrips attack in plants with one-fold insecticide application is not substantially lower as in untreated plants (though statistically significant differences between them were established), because insecticide cannot reach the interior leaves in the head. Substantial differences in the total and net weight of heads between the treatments and especially between the treated and untreated plants are explained by the fact that feeding of numerous thrips populations in the heads and on the exterior cabbage leaves negatively affects plant physiology and yield. The highest average yield in plants which were treated the last indicates a possibility that insecticide also inhibits plant growth and development to a certain extent.

Animals↗
PubMed2004

[Effects of Bacillus thuringiensis transgenic rice and chemical insecticides on arthropod communities in paddy-fields].

This paper assessed the effects of cry1Abl/cry1Ac-carrying transgenic Bacillus thuringiensis rice (Bt rice) and chemical insecticides on the arthropod communities under paddy-field conditions in terms of arthropod guild dominance, family composition and dominance distribution of each guild, individuals of each guild, some common indices of arthropod communities, and community dissimilarity. In most cases, no significant differences were found between the Bt and control rice plots without any chemical insecticide spray in such arthropod community specific parameters as guild dominance, family composition and dominance distribution, temporal dynamics of the individuals of each guild or all arthropod, as well as some common community indices (including species richness, Shannon-Wiener diversity index, evenness index and dominant index) and their temporal dynamics. The similarity of arthropod community between the Bt and control rice plots were apparently higher. It was clear that Bt rice generally showed no marked negative effect on the arthropod community in paddy field. In contrast, some arthropod community specific parameters such as guild dominances in the control plot with chemical insecticide spray were in some cases markedly and even significantly different from those in the control plot without any chemical insecticide spray. The similarity of arthropod community between the control plots with and without chemical insecticide spray was relatively lower. It could be concluded that the effect of Bt rice on the arthropod community was apparently lower than that of chemical insecticides.

Animals↗
PubMed1991

Neurotoxicology of pyrethrin and the pyrethroid insecticides.

Natural pyrethrin and synthetic pyrethroid insecticides have been considered among the safest classes of insecticides available. Pyrethrins and pyrethroids are classified on the basis of their chemical structures and their toxicologic, neurophysiologic and pharmacologic effects. Cellular effects of pyrethrin and pyrethroid insecticides have been postulated to involve interactions with sodium channels, receptor-ionophore complexes, neurotransmitters, and ATPases. Toxicity is a function of chemical structure, metabolism, route of exposure, and the presence or absence of synergists. Pyrethroid insecticides are neurotoxic, and the development and severity of clinical signs is proportional to the nervous tissue pyrethroid concentration. Type I pyrethroid poisoning in mice and rats produces a syndrome characterized by tremors, prostration and altered startle reflexes. Type II pyrethroid poisoning in mice and rats causes ataxia, convulsions, hyperactivity, choreoathetosis and profuse salivation. A presumptive diagnosis of pyrethrin/pyrethroid poisoning is based upon history of exposure, development of appropriate clinical signs, and chemical analysis for insecticide residues. Treatment of pyrethrin and pyrethroid toxicosis involves basic life support, seizure control when needed, and the prevention of further insecticide absorption.

Animals↗
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↗
PubMed1993

Studies on the effect of translocation of chemical insecticides in Eicchornia host plant on Mansonia mosquitos--a potential control method.

A novel method for the control of Mansonia larvae was developed and tested. In this method, foliar absorption and translocation of a chemical insecticide, monocrotophos, a known systemic insecticide was studied in the Eicchornia plant. Acetone solution of the insecticide was painted onto leaves of the plant. At daily intervals, stems were severed and divided into equal sections which were introduced into bowls. Larvae of Aedes aegypti were tested for the presence of monocrotophos. It was found that translocation of the insecticide occurred at different rates in the stems and in some plants the chemical was also released into the surrounding water. Based on these results, 2 insecticides namely, monocrotophos and temephos were painted onto leaves of the host plant and their translocation to the root and water environment was examined by testing with Mansonia and Aedes aegypti larvae. The results again confirmed the translocation process and it was found that the insecticides were secreted into the surrounding water, thereby killing the larvae. However, in leaves painted with permethrin (synthetic pyrethroid) or flufenoxuron (chitin synthesis inhibitor), such a process was not detected. The potential of this new concept in Mansonia larval control is examined.

Aedes↗
PubMed1996

[Effects of 3 insecticide formulations in the removal and hatching of oothecae of Blatella germanica (Dictyoptera: Blattellidae)].

Different insecticide formulations used for the control of German Cockroach, Blatella germanica (L.) were studied to know their effects on the gravid females of this species. The insecticides assayed were baygon 20% EC, diazinon 60 EC, and licon 2.5% EC. Exposure to each insecticide showed an effect on the oothecal drop (p < 0.001). Gravid females treated with baygon had the highest percent of oothecae detached (71%); whereas diazinon caused the lowest percent (33.5%). Doses of baygon, diazinon, and icon used showed that among the oothecas detached hatching occurred only in 19.01%; 34.2% and 39.11%, respectively. Of the oothecas retained by treated females, the lowest hatching percent was produced by baygon (13.79%) compared with diazinon and icon insecticides, which presented the highest hatching percentages with 39.84 and 47.82, respectively. Therefore, the effects of insecticides on females bearing oothecas may be considered at the time of selecting an insecticide to control the German cockroach.

Animals↗
PubMed2006

Enhancing insecticidal efficacy of baculovirus by early expressing an insect neurotoxin, LqhIT2, in infected Trichoplusia ni larvae.

LqhIT(2), an insect specific neurotoxin from the venom of Leiurus quinquestriatus hebraeus, has been demonstrated to improve insecticidal efficacy of Autographa californica nuclear polyhedrosis virus (AcMNPV). A polyhedrin-positive recombinant AcMNPVvAcP(hsp70)EGFP/P(pag90)IT(2) was engineered for larvae to express the enhanced green fluorescence protein (EGFP) and LqhIT(2) under the control of P(hsp70) and P(pag90) promoters, respectively. This would allow a visual observation of the viral infection and an improvement of the insecticidal efficacy. The insecticidal activity of this recombinant baculovirus, a wild type AcMNPV and four other recombinant baculoviruses, was evaluated and compared in terms of mortality, body weight, median lethal time (LT(50)), and median lethal concentration (LC(50)). Insecticidal efficacy was unaltered when treated with vAcP(hsp70)EGFP, moderately improved when infected by vAcP(10)IT(2) (a P(10)-promoted LqhIT ( 2 ) gene), and significantly elevated when treated with vAcP(pag90)IT(2) or vAcP(hsp70)EGFP/P(pag90)IT(2). No apparent difference was observed in insecticidal efficacy when additional EGFP was expressed as a visible marker. These results suggest that recombinant AcMNPV vAcP(hsp70)EGFP/P(pag90)IT(2) may be used as an effective insecticide against Trichoplusia ni and other lepidopterous insect pests.

Animals↗
PubMed1996

Vip3A, a novel Bacillus thuringiensis vegetative insecticidal protein with a wide spectrum of activities against lepidopteran insects.

A novel vegetative insecticidal gene, vip3A(a), whose gene product shows activity against lepidopteran insect larvae including black cutworm (Agrotis ipsilon), fall armyworm (Spodoptera frugiperda), beet armyworm (Spodoptera exigua), tobacco budworm (Heliothis virescens), and corn earworm (Helicoverpa zea) has been isolated from Bacillus thuringiensis strain AB88. VIP3-insecticidal gene homologues have been detected in approximately 15% of Bacillus strains analyzed. The sequence of the vip3A(b) gene, a homologue of vip3A(a) isolated from B. thuringiensis strain AB424 is also reported. Vip3A(a) and (b) proteins confer upon Escherichia coli insecticidal activity against the lepidopteran insect larvae mentioned above. The sequence of the gene predicts a 791-amino acid (88.5 kDa) protein that contains no homology with known proteins. Vip3A insecticidal proteins are secreted without N-terminal processing. Unlike the B. thuringiensis 5-endotoxins, whose expression is restricted to sporulation, Vip3A insecticidal proteins are expressed in the vegetative stage of growth starting at mid-log phase as well as during sporulation. Vip3A represents a novel class of proteins insecticidal to lepidopteran insect larvae.

Amino Acid Sequence↗
PubMed1994

The effect of multiple soil applications of disulfoton on enhanced microbial degradation in soil and subsequent uptake of insecticidal chemicals by potato plants.

Potatoes were grown during 1992 in 2 m2 plots of loam which had received 1, 2 or 3 annual treatments of Di-Syston 15G, equivalent to 3.36 kg AI/ha, in furrow at planting. The presence of enhanced degradative activity to the sulfoxide and sulfone metabolites of disulfoton in the soil treated in the previous two years was confirmed by laboratory tests prior to the 1992 treatments. Soil, seed potato and foliage from the three treatments were analyzed for disulfoton and its sulfoxide and sulfone metabolites for 12 wk following planting/treatment. Disulfoton was the major insecticidal component of the soil, a minor component of the seed piece and was not detected (< 0.02 ppm) in potato foliage. Disulfoton concentrations in each of the three substrates sampled were similar for the three treatments. Disulfoton sulfoxide and sulfone were the major insecticidal components of the seed piece and foliage. Their maximum concentrations in 1st year soil, seed pieces and foliage were ca. 2x, 2x and 6x, respectively, those measured in the 2nd and 3rd year treatments. The results demonstrate that enhanced microbial degradation of relatively minor insecticidal compounds in the soil can profoundly affect insecticide levels in the plant when these compounds are the major insecticidal components accumulated. The broader implications for crop protection using soil-applied systemic insecticides are discussed.

Biodegradation, Environmental↗
PubMed2004

Bacterial insecticidal toxins.

Over the years it has been important for humans to control the populations of harmful insects and insecticides have been used for this purpose in agricultural and horticultural sectors. Synthetic insecticides, owing to their various side effects, have been widely replaced by biological insecticides. In this review we attempt to describe three bacterial species that are known to produce insecticidal toxins of tremendous biotechnological, agricultural, and economic importance. Bacillus thuringiensis (BT) accounts for 90% of the bioinsecticide market and it produces insecticidal toxins referred to as delta endotoxins. The other two bacteria belong to the genera Photorhabdus and Xenorhabdus, which are symbiotically associated with entomopathogenic nematodes of the families Heterorhabditidae and Steinernematidae respectively. Whereas, Xenorhabdus and Photorhabdus exist in a mutualistic association with the entomopathogenic nematodes, BT act alone. BT formulations are widely used in the field against insects; however, over the years there has been a gradual development of insect resistance against BT toxins. No resistance against Xenorhabdus or Photorhabdus has been reported to date. More recently BT transgenic crops have been prepared; however, there are growing concerns about the safety of these genetically modified crops. Nematodal formulations are also used in the field to curb harmful insect populations. Resistance development to entomopathogenic nematodes is unlikely due to the physical macroscopic nature of infection. Xenorhabdus and Photorhabdus transgenes have not yet been prepared; but are predicted to be available in the near future. In this review we start with an overview of the synthetic insecticides and then discuss Bacillus thuringiensis, Xenorhabdus nematophilus, and Photorhabdus luminescens in greater detail.

Agriculture↗
PubMed1981

Persistence of four pyrethroid insecticides in a mineral and an organic soil.

Permethrin, cypermethrin, fenpropanate and fenvalerate (emulsifiable concentrates) were applied at 280 g AI/ha and incorporated into mineral and organic soil contained in small field plots. Radishes and carrots were grown to serve as indicators of insecticide uptake. Similar plots were treated with the same insecticides at 140 g AI/ha and the soil surface was left undisturbed following application. Soil cores were removed at appropriate intervals and the crops were harvested when mature. The insecticide concentration in all samples was determined by gas-liquid chromatography. The amount of insecticide in the soil declined rapidly to less than 50% of the initial value in 1 month or less for most material-soil-treatment combinations and within 2 months for all cases. Concentrations remained in excess of 0.01 ppm in the organic soil for at least six months for all material-treatment combinations but fell below this level over 2-5 months in the mineral soils. Organic soil incorporated fenvalerate was the most persistent combination overall with 25, 17 and 7% remaining at 6, 18 and 28 months respectively. The trans-isomers of permethrin and cypermethrin disappeared more quickly than the cis-isomers but the insecticidally active IR isomers were not preferentially degraded relative to the inactive 1S. No residues (less than 0.01 ppm) were found in the radish or carrot crops. First order disappearance rates were not constant for any of the combinations. A comparison of partial rate constants showed: 1) 0-1 mo rates were generally greater in mineral than organic soil, 2) 1-6 mo rates in organic soil were lower than 0-1 mo rates, 3) 1-6 mo rates for surface applications to organic soil were generally less than for incorporated applications. In laboratory experiments, 0-1 mo rates for fenvalerate disappearance in a mineral soil were 2-3x greater for 0.5 ppm than for 10 ppm while 1-6 mo rates were independent of insecticide concentration but were 1.5x greater for 0.5% moisture than for 5%.

Biodegradation, Environmental↗
PubMed2001

[N-terminal analysis and antibody preparation of insecticidal protein form Pseudomonas pseudoalcaligenes].

The insecticidal protein from Pseudomonas pseudoaligenes was and exotoxin which had toxicity on locusts. In order to elucidate its molecular properties an amino acid sequence, the insecticidal protein was purified from the culture supernatant by ultrafiltration, ion-exchange chromatography and gel filtration, and showed a single band on SDS-PAGE. Analysis of the purified insecticidal protein dentified N-terminal sequence of ten amino acid residues. Its polyclonal antibody was also obtained by immunizing rabbit with the insecticidal protein recovered form SDS-PAGE gel. The antibody titer determined by ELISA method was 1:12,800, indicating that it has high reactivity. Western blot analysis revealed that the antibody was spectific to 26 kD insecticidal protein, and did not cross-react with other proteins produced by the bacterium, suggesting that a specific antibody with high titer was obtained and could be used for further investigations of the gene cloning and expression of insecticidal protein.

Amino Acid Sequence↗
PubMed1992

[Modification and expression of insecticidal protein structural gene of Bacillus thuringiensis var. aizawai 7-29].

The regulative region (181bp) and the fifth toxic active domain (217bp) were removed from the insecticidal protein gene of Bacillus thuringiensis var. aizawai 7-29. After the synthesis of the adaptor (15bp) that contains initiation codon (ATG) and the PCR synthesis of the fifth toxic active domain (229bp) that contains stop codon (TAA), were inserted into on 5' truncated and 3' truncated of the coding fod N-terminal peptid's DNA fragment, that to become a modified structural gene. The modified structural gene can be play initiatic translation-function and stop translation-function during translation of insecticidal protein. The insecticidal protein was determined by western blotting, showed the expression of modified structural gene in Escherichia coli JM 103. The bioassay of insecticidal proteins showed the 3' truncated and 5' truncated of insecticidal gene was higher toxic active than the 3' truncated of insecticidal gene in Escherichia coli JM 103.

Bacillus thuringiensis↗