Effects Of Different Pesticides Research Articles

An optical sensor for pesticide determination based on the autoindicating optical properties of peroxidase

During the enzymatic reaction of the heme-protein Horseradish peroxidase (HRP) with hydrogen peroxide there are changes in the molecular absorption spectra of HRP and its different oxidation states which can be used for quantitative determination of the substrate. One of these intermediate oxidation states is the HRPII, with iron as an oxyferryl. This compound is assumed to be responsible for the organophosphate pesticide degradation in the Fenton reaction. In this work, the enzymatic HRP-H₂O₂ reaction has been studied, based on the effect of different pesticides on the mechanism reaction; these modifications have been used for the quantitative determination of pesticides. A mathematical model has been developed relating to the analytical signal with the pesticide concentration. Three organophosphate pesticides (diazinon, trichlorfon and tetrachlorvinphos) and one sulfamide (dichlofluanid) have been used to demonstrate the viability of the methodology and the accomplishment fulfillment of the model. Tetrachlorvinphos was chosen as the pesticide model to develop the optical sensor film for continuous pesticide determination, consisting of HRP immobilized in a polyacrylamide gel. The sensor can be used for at least 15 days and responds linearly to tetrachlorvinphos concentrations in the range from 4.0 × 10(-7) to 4.0 × 10(-6)mol L(-1). The main advantage of the methodology is its reversibility in contrast to the irreversible Fenton reaction. The HRP-H2O2 methodology has been used to measure the pesticides in a waste water sample spiked with tetrachlorvinphos.

Evaluation of effect of different pesticides on pigeon pea using statistical tools in field experiment

Evaluation of effect of different pesticides on pigeon pea using statistical tools in field experiment

Side effects of different pesticides used in citrus on the adult stage of the parasitoid Aphytis melinus DeBach (Hymenoptera Aphelinidae) and its progeny

Twelve pesticides commonly used in citrus in Spain were tested on adults of Aphytis melinus DeBach to determine their effects on parasitoid survival and fecundity, and the duration of the residue of each pesticide. Six of these pesticides were found to be harmless to moderately harmful to this parasitoid in a laboratory assay in closed Petri dishes: spinosad (bait formulation), azadirachtin, fenbutatin, fosetyl-Al, copper oxichloride, and mancozeb, with their scores on the reduction of beneficial capacity (RBC) index being between 21.4 and 94.6% after one week. The other six pesticides classified as harmful were tested on citrus plants to study their persistence over time under greenhouse conditions: Pirimicarb, pyriproxifen, paraffinic oil, abamectin, chlorpyrifos, and lambda-cyhalothrin. Most of these products reduced their negative effect on adults of A. melinus between one and six weeks after treatment, although lambda-cyhalothrin was still harmful to parasitoids 11 weeks after application. This information can help growers and consultants to make decisions about pesticide selection and application timing in citrus in order to support IPM implementation when A. melinus is present.

The effect of different pesticides on reproduction of entomopathogenic nematodes

Entomopathogenic nematodes (EPNs) in the families Steinernematidae and Heterorhabditidae are generally considered beneficial nematodes. These beneficial nematodes can serve in integrated pest management (IPM) in agro-ecosystems. The effect of chemical insecticides (11 different pesticides) on Steinernema sp. (EBN-1e), and Heterorhabditis bacteriophora (EBN-10k) was determined under laboratory conditions. Generally, EBN-1e Steinernema strain was more tolerant to different tested insecticides than Heterorhabditis strain. The survival of IJs was more than 90% after treatement with Captan, Methomyl, Mancozeb, Benomyl, Trimiltox forte and Diafenthiuron, for EBN-1e nematode strain, while Chlorfluazuron decreased its survival to less than 5%. In contrast, the survival of Heterorahbditis strain was less than the Steinernema strain. There were significant differences in reproduction rates between EBN-1e and EBN-10k exposed to different chemical insecticides. The EBN-1e strain had higher reproduction rate than EBN-10k in all treatments. In general, there was significant difference in reproductive rates between the species concentrations (500 IJs and 1000 IJs) exposed to different chemicals or between exposure times (48 h. and 96 h.)

SELETIVIDADE DE PRODUTOS FITOSSANITÁRIOS UTILIZADOS NA CULTURA DA SOJA PARA PUPAS DE TRICHOGRAMMA PRETIOSUM RILEY, 1879 (HYMENOPTERA: TRICHOGRAMMATIDAE)

RESUMO O objetivo do trabalho foi avaliar o efeito de produtos fitossanitários sobre pupas de Trichogramma pretiosum. Foram conduzidos três bioensaios em delineamento inteiramente casualizado com 11 tratamentos e cinco repetições. Em cada repetição, ovos de Anagasta kuehniella (Zeller, 1879) (Lepidoptera: Pyralidae) foram utilizados como hospedeiro alternativo, sendo aderidos em cartelas de cartolina de 1 cm2 com solução de goma arábica à 40% e oferecidos para o parasitismo por 24h. Após 168-192h do parasitismo, quando os parasitoides estavam na fase de pupa, as cartelas foram mergulhadas por cinco segundos nos tratamentos testados. Avaliou-se a sobrevivência dos indivíduos tratados e a redução na emergência dos parasitoides foi classificada segundo as normas da IOBC. Os inseticidas flufenoxurom (Cascade®) 10, diflubenzurom (Dimilin®) 20 e metoxifenozide (Intrepid 240SC®) 21,6 e 36 g i.a. ha-1 foram classificados como inócuos. Permetrina (Valon 384 CE®) 49,92; betaciflutrina 12,5 + imidacloprido 100 (Connect®) e gama-cialotrina (Stallion 150SC®) 3,75 g i.a. ha-1 foram levemente nocivos. Clorpirifós (Lorban 480BR®) 384 e espinosade (Tracer®) 24 g i.a. ha-1 foram moderadamente nocivos. Os herbicidas glifosato 720 + imazetapir 90 (Alteza®); s-metolacloro (Dual Gold®) 1920; flumioxazina (Flumyzin 500®) 60; clomazona (Gamit®) 1000; glifosato 2880 (Gliz 480SL®); dicloreto de paraquate 600 + diurom 300 (Gramocil®); glifosato 1200 (Roundup Ready®); foram classificados como inócuos e os herbicidas 2,4-D (DMA 806BR®) 1209; dicloreto de paraquate (Gramoxone®) 600; glifosato (Roundup Transorb®) 2592 g i.a. ha-1 classificados como levemente nocivos. Os fungicidas tiofanato-metílico (Cercobin 500 SC®) 400; flutriafol 60 + tiofanato-metílico 300 (Celeiro®); carbendazin (Derosal 500SC®) 250; tebuconazole (Folicur EC®) 150; flutriafol (Impact®) 125; tebuconazole 120 + trifloxistrobina 60 (Nativo®); epoxiconazole 30 + piraclostrobina 79,8 (Opera®); epoxiconazole (Opus SC®) 12,5; azoxistrobina (Priori®) 50; azoxistrobina 60 + ciproconazole 24 (Priori Xtra®) g i.a. ha-1 foram classificados como inócuos aT. pretiosumna fase de desenvolvimento avaliada (pupa). Dentre os produtos avaliados, aqueles classificados como inócuos devem ser priorizados no manejo integrado de pragas (MIP) por compatibilizar o uso do controle químico sem prejudicar o controle biológico. Do mesmo modo, os produtos classificados como moderadamente nocivos devem ser evitados sempre que possível ou substituídos por outro de menor impacto.

Development and validation of a cellular biosensor detecting pesticide residues in tomatoes

Two of the most important categories of pesticides used in agricultural practice are organophosphates and dithiocarbamates. Their extensive and inappropriate use has rendered their reliable monitoring at trace levels more and more necessary. This study presents the construction of a rapid and sensitive cellular biosensor test based on the measurement of changes of the cell membrane potential of immobilized cells, according to the working principle of the Bioelectric Recognition Assay (BERA). The cells were immobilized by entrapment in a sodium alginate bead and directly applied in different pesticide dilutions and agricultural samples. The pesticides used were the organophosphate insecticide diazinon and the dithiocarbamate fungicide propineb. Two different cell types, N2a (neuroblastoma) and Vero (fibroblast) were used as the biosensory elements in order to investigate their differential response against the pesticides. In this way, we hoped to increase the selectivity of the assay. Based on the observed patterns of response, we demonstrate that the sensor can be used for the qualitative and, in some concentrations, quantitative detection of the pesticides with a high degree of reproducibility. The lowest detected concentration was 3nM. Finally, for the investigation of the effects of different pesticides on the accumulation of cytosolic Ca(2+), we conducted a fluorescent assay on N2a cells treated with tomato sample extracts, which were replicates of the E.U. proficiency test sample. The tomato samples were either organically grown or contained 14 different pesticides. The experimental results showed a higher increase of the intracellular Ca(2+) concentration in cells treated with non-organic samples compared to the cells treated with organic samples.

Comet assay in phytoplankton as biomarker of genotoxic effects of environmental pollution

The alkaline comet assay was tested on different microalgae: the dinoflagellates, Karenia mikimotoi and Alexandrium minutum, and the diatom, Chaetoceros gracilis. The microalgae were exposed during their exponential growth to the model direct genotoxicant, hydrogen peroxide (1h, 5 and 100muM H2O2). Following H2O2 exposure, the comet assay was validated only for K. mikimotoi for which genotoxicity was observed from the lowest tested concentration of 5 microM with a concentration-dependent effect. C. gracilis was too small in size (4 microm) to be correctly analysed. For A. minutum, our lysis buffer was not strong enough to digest the cellulosic thecal plates. For K. mikimotoi, the comet assay was thus applied for the study of the genotoxic effects of different pesticides: epoxiconazole (as Opus formulation), chlorpyriphos-ethyl (as Dursban formulation) and endosulfan at 1, 10 and 100 microg of active substance/L for 24h. Exposure to epoxiconazole in formulation resulted in an increase in the extent of DNA strand breaks at the highest tested concentration icro/L. Endosulfan exposure resulted in DNA damage for K. mikimotoi nuclei. Genotoxicity was observed from 1 microg/L of endosulfan and was not concentration dependent.

Detection of carbamic and organophosphorous pesticides in water samples using a cholinesterase biosensor based on Prussian Blue-modified screen-printed electrode

In the present paper, a comparative study using Co-phthalocyanine and Prussian Blue-modified screen-printed electrodes, has been performed. Both the electrodes have demonstrated an easiness of preparation together with high sensitivity towards thicoholine (LOD = 5 × 10 −7 and 5 × 10 −6 M for Co-phthalocyanine and Prussian Blue, respectively) with high potentialities for pesticide measurement. Prussian Blue-modified screen-printed electrodes were then selected for successive enzyme immobilization due to their higher operative stability demonstrated in previous works. AChE and BChE enzymes were used and inhibition effect of different pesticides was studied with both the enzymes. AChE-based biosensors have demonstrated a higher sensitivity towards aldicarb (50% inhibition with 50 ppb) and carbaryl (50% inhibition with 85 ppb) while BChE biosensors have shown a higher affinity towards paraoxon (50% inhibition with 4 ppb) and chlorpyrifos-methyl oxon (50% inhibition with 1 ppb). Real samples were also tested in order to evaluate the matrix effect and recovery values comprised between 79 and 123% were obtained.

Influence of pesticides on the growth rate and plant-growth promoting traits of Gluconacetobacter diazotrophicus

The in vitro study to examine the effect of different pesticides on the growth and survival of Gluconacetobacter diazotrophicus strain PAL5 was carried out. Monocrotophos, Lindane and Dichlorvos had the most lethal actions against Gluconacetobacter grown on LGIP medium, while Endosulphan, Chlorpyriphos, and Malathion effects were intermediate. Herbicides generally appeared to have no adverse effect on the growth and survival of Gluconacetobacter in the medium except for the concentrations exceeding recommended rates. Fungicides, except Ridomil, had a slight effect on the growth of Gluconacetobacter at recommended dose. With the various pesticides used, the cell morphology was affected to a larger extent resulting in larger number of pleomorphic cells. Further their influence on the physiological traits like nitrogenase activity, indole-3-acetic acid, gibberellin A 3 production, and phosphate and zinc solubilizing activity are discussed.

Soil fungi as indicators of pesticide soil pollution

Soil fungi, with their pronounced enzymic activity and high osmotic potential, represent a significant indicator of negative effects of different pesticides on the agroecosystem as a whole. In that respect, a trial was set up on the alluvium soil type with the aim to investigate the effect of different herbicides (Simazine, Napropamid, Paraquat), fungicides (Captan and Mancozeb) and insecticides (Fenitrothion and Dimethoate) on a number of soil fungi under apple trees. The number of soil fungi was determined during four growing seasons by an indirect method of dilution addition on the Czapek agar. The study results indicate that the fungi belong to the group of microorganisms that, after an initial sensible response to the presence of pesticides in the soil, very rapidly establish normal metabolism enabling them even to increase their number. The fungicides and insecticides applied were found to be particularly effective in that respect.

Effects of pesticides on the acute phase proteins in fishes: an experimental study

The acute phase response is a nonspecific reaction of fish to disturbances in homeostasis. The acute phase proteins (APPs) are mainly glycoproteins released by hepatocytes following specific stimulation by the cytokines. The function of APP is to modulate an immune response. We have recently isolated several different APPs from fishes including ceruloplasmine (Cp), fibrinogen (Fg), serum amyloid A and C-reactive protein (CRP). The aim of the present study was to evaluate the effects of different pesticides on the APP responses in fishes and to investigate the utility of applying APP measurements for monitoring of aquatic environmental contamination. We analyzed the kinetics of different APP levels after intoxication. Cp and CRP exhibited a three- to five-fold elevation following intoxication suggesting that APP may be sensitive and highly effective biomarkers.

Soil fumigation with methyl bromide as a means of increasing the occurrence of the inoculum strain in peanut nodules

A field experiment was carried out on sandy loam soil to determine the effect of different pesticides on the nodulation activity of peanut-specific local rhizobia and the recovery rate of the inoculum applied. The experiment included a pesticide-untreated control and the following six treatments: methyl bromide, Edabrom, Edigan (metham-sodium), ethoprophos, fenamiphos and a combination of Edabrom and Edigan. The ELISA (enzyme-linked immunosorbent assay) reactions of nodule antigens (38, 64, 86 and 128 days after planting) showed that despite the pesticides applied, the indigenous peanut Rhizobium population was active in nodulation. However, methyl bromide substantially decreased the number of nodules containing native rhizobial strains. The amount of nodules reacting with antibodies specific to the inoculum strain ranged from 47 to 63%, as compared with 25 to 40% in the control plots and other treatments tested. The positive effect of soil fumigation with methyl bromide on the occurrence of the introduced strain was confirmed in an additional field experiment. Serological evaluation by ELISA showed that 48% of the nodules formed on plants derived from inoculated + methyl bromide-treated plots contained the inoculum strain, as compared with 11 % in the inoculated but non-fumigated plots. The highest values of nitrogenase activity and top dry weight were recorded in the inoculated but non-fumigated plots. Although this treatment produced the maximal yield of pods, the differences between inoculated and non-inoculated methyl bromide-treated plots did not reach the threshold of significance. Seed- and pod-weights in the fumigated and inoculated plots were significantly higher than in the other treatments.

Effect of different pesticides on plant root nodules and rhizosphere microflora in cowpea (Vigna sinensis).

Summary The effect of different pesticides (insecticide, nematicide and fungizide) on the efficiency of inoculated rhizobia and rhizosphere microflora was studied in cowpea plants (Vigna sinensis). It was found that the application of an insecticide (Temik) in different concentrations generally affected formation of efficient nodules, whereas the number of nodules was reduced. It was also found that dry weight of plant and symbiotic nitrogen fixation were increased at a certain concentration. On the other hand, the numbers of nodules indicate no inite relation to nematicide (Terracure) concentrations. The fungicide (Thiram) otherwise showed no inhibitory effect at any of the concentrations tried. Moreover an increase in numbers of nodules, dry weight of plant, and symbiothic nitrogen fixation was observed. Concerning rhizosphere microflora insecticide (Temik) and nematicide (Terracure) indicate dropping by the first samples and increase by the late ones.This may be due to the degradation of pesticides by soil microorganisms. The fungicide (Thiram) on the other hand showed an increase in numbers of bacteria and actinomycetes compared to fungi by sampling date. This can be attributed to the conversion of Thiram into dimethyldithiocarbamate, likely the metabolites influence the stimulation of bacteria and actionomycetes ( Murthy and Raghu 1976).

Changes in selected biochemical parameters in the kidney and blood of the fish, Tilapia mossambica (Peters), exposed to heptachlor.

Pesticides used in pest control programs seem to produce many physiological and biochemical changes in fresh water organisms by influencing the activities of several enzymes. Alterations in the chemical composition of the natural aquatic environment usually effect behavioral and physiological systems of the inhabitants, particularly of the fish. Although some data are available on the effects of different pesticides on the biochemical aspects of fish gill, data on heptachlor toxicity on T. mossambica kidney are lacking. Therefore, an attempt has been made to observe certain biochemical paramets of fish, T. mossambica under heptachlor intoxication. Investigation of this nature is useful in understanding the orientation of biochemical changes during sublethal toxicity to ascertain the degree of intensity of the toxicity of heptachlor on the kidney.

Individual and Combined Effects of Certain Pesticides on Rhizoctonia solani, Sheath Blight Pathogen of Rice

AbstractThe effect of different pesticides (fungicide, herbicide and insecticide) on the mycelial growth and formation and germination of sclerotia of sheath blight pathogen of rice, Rhizoctonia solani Kühn was studied in nutrient medium and in natural soil. Among the herbicides and insecticides, fenitrothion (insecticide) and thiobencarb (herbicide) were the most effective in inhibiting the mycelial growth and sclerotial formation. These pesticides effected significant inhibition of both mycelialgrowth and sclerotial formation at 7.5 to 10μg/ml concentration while fungicides carbendazim and tolclofosmethyl effected almost complete inhibition at 2.5 μg/ml. Interestingly, a synergistic increase in the toxicity to mycelial growth, sclerotial formation and sclerotial germination was noticed when the fungicide, mancozeb and the herbicide, thiobencarb were applied at subtoxic concentration in combination. Such synergistic interactions between pesticides in a combination leading to increased toxicity suggest that under the current practice of applying fungicides, herbicides and insecticides either simultaneously or in rotation, certain combinations may help in reducing the dose of a fungicide in disease control.

Prevention of reaginic antibody production and anaphylactic gastric ulcer by pesticides and by a polychlorinated biphenyl

The effects of different pesticides, lindane, phosalone, and carbaryl, and of one polychlorinated biphenyl, pyralene, were studied on the development of reaginic antibody production and the formation of allergic gastric ulceration in Mastomys natalensis following prior sensitization and subsequent challenge with ovalbumin. The results indicate that lindane, phosalone, and pyralene have a pronounced suppressive effect on type 1 hypersensitivity reaction when ingested orally. These results give further cause for concern about the hazards to health which might result from continued indiscriminate use of such substances.

Título en español.

Se estudió el efecto de las aplicaciones de insecticidas a pepinillos, habichuelas tiernas, maíz dulce y tomates, para determinar sus efectos sobre la calidad y rendimientos de estas cosechas. Los resultados fueron los siguientes: 1. Pepinillos: Las aspersiones foliares con Parathion, a razón de 1% libras por acre, no causaron aumentos significativos ni en el peso ni en el número de frutas. Cuando se trató la semilla con Guthion, a razón de 6 libras por acre, y también se aplicó una aspersión foliar a los 21 días después de la siembra, esto no surtió efecto significativo alguno sobre el rendimiento y número de frutas. 2. Habichuelas tiernas: Las aspersiones foliares con DDT, a razón de 2 libras por acre cada 14 días, aumentaron significativamente la produción. Las aplicaciones de Guthion a razón de 6 libras por acre a los 14 y 28 días después de la siembra, sumentaron significativamente la producción. 3. Maíz dulce: El DDT, a razón de 4 libras por acre, asperjado al follaje cada 7 días redujo en forma muy significativa el daño del gusano cogolleroí por lo que estas plantas se desarrollaron más vigorosas que las que no se trataron. El maíz de las parcelas tratadas con DDT en la forma arriba mencionada, produjo mayor número de mazorcas que el de las que no se trataron. Cuando se trataron las barbas de las mazorcas con DDT y Dylox, esto causó un aumento significativo en el número de mazorcas comerciales producidas sobre las que no se trataron. 4. Tomates: Las aspersiones foliares con Parathion y DDT y las aplicaciones granulares con Di-Syston a la base de las plantas, no causaron efecto alguno sobre el rendimiento en peso o sobre el número de frutas.