Application Of Chlorpyrifos Research Articles

Foliar Spraying of Chlorpyrifos Triggers Plant Production of Linolenic Acid Recruiting Rhizosphere Bacterial Sphingomonas sp.

Plants have developed an adaptive strategy for coping with biotic or abiotic stress by recruiting specific microorganisms from the soil pool. Recent studies have shown that the foliar spraying of pesticides causes oxidative stress in plants and leads to changes in the rhizosphere microbiota, but the mechanisms by which these microbiota change and rebuild remain unclear. Herein, we provide for the first-time concrete evidence that rice plants respond to the stress of application of the insecticide chlorpyrifos (CP) by enhancing the release of amino acids, lipids, and nucleotides in root exudates, leading to a shift in rhizosphere bacterial community composition and a strong enrichment of the genus Sphingomonas sp. In order to investigate the underlying mechanisms, we isolated a Sphingomonas representative isolate and demonstrated that it is both attracted by and able to consume linolenic acid, one of the root exudates overproduced after pesticide application. We further show that this strain selectively colonizes roots of treated plants and alleviates pesticide stress by degrading CP and releasing plant-beneficial metabolites. These results indicate a feedback loop between plants and their associated microbiota allowing to respond to pesticide-induced stress.

Assessing phytotoxicity and cyto-genotoxicity of two insecticides using a battery of in-vitro biological assays.

Intensive use of chemical pesticides in agriculture poses environmental risks and may have negative impacts on agricultural productivity. The potential phytotoxicity of two chemical pesticides, chlorpyrifos (CPS) and fensulfothion (FSN), were evaluated using Cicer arietinum and Allium cepa as model crops. Different concentrations (0-100 μgmL-1) of both CPS and FSN decreased germination and biological attributes of C. arietinum. High pesticide doses significantly (p≤0.05) caused membrane damage by producing thiobarbituric acid reactive substances (TBARS) and increasing proline (Pro) content. Pesticides elevated ROS levels and substantially increased the superoxide anions and H2O2 concentrations, thus aggravating cell injury. Plants exposed to high pesticide dosages displayed significantly higher antioxidant levels to combat pesticide-induced oxidative stress. Ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) increased by 48%, 93%, 71%, 52% and 94%, respectively, in C. arietinum roots exposed to 100 µgFSNmL-1. Under CLSM, pesticide-exposed C. arietinum and 2',7'-dichlorodihydrofluorescein diacetate (2'7'-DCF) and 3,3'-diaminobenzidine stained roots exhibited increased ROS production in a concentration-dependent manner. Additionally, enhanced Rhodamine 123 (Rhd 123) and Evan's blue fluorescence in roots, as well as changes in mitochondrial membrane potential (ΔΨm) and cellular apoptosis, were both associated with high pesticide dose. Allium cepa chromosomal aberration (CAs) assay showed a clear reduction in mitotic index (MI) and numerous chromosomal anomalies in root meristematic cells. Additionally, a-dose-dependent increase in DNA damage in root meristematic cells of A. cepa and conversion of the super-coiled form of DNA to open circular in pBR322 plasmid revealed the genotoxic potential of pesticides. The application of CPS and FSN suggests phytotoxic and cyto-genotoxic effects that emphasize the importance of careful monitoring of current pesticide level in soil before application and addition at optimal levels to soil-plant system. It is appropriate to prepare both target-specific and slow-release agrochemical formulations for crop protection with concurrent safeguarding of agroecosystems.

Field efficacy of some newer chemical insecticides against stem borer, Nupserha sp. near vexator (Pascoe) in sunflower (Helianthus annuus L.)

A field experiment was conducted to evaluate the efficacy of some newer chemical insecticides viz., thiodicarb75WSP, indoxacarb 14.5SC, spinosad 45SC, profenophos 50EC, dichlorovos 76EC and chlorpyrifos 20EC againststem borer Nupserha sp. near vexator in sunflower at Oilseeds Research Station, Latur, Maharashtra. Resultsrevealed that all the treatments were significantly superior in reducing the population of stem borer over untreated control. Among the insecticides, indoxacarb @ 1ml/l was most effective and was found on par with spinosad @ 0.3ml/l, profenophos @ 2ml/l and thiodicarb @ 2gm/l. Highest seed yield was recorded with spinosad (1416 kg/ha) and found on par with indoxacarb (1401 kg/ha) whereas the lowest yield was observed in untreated control (1010 kg/ha). The maximum incremental benefit cost ratio was obtained with application of chlorpyrifos (4.96) followed by indoxacarb (4.27), profenofos (3.43), and spinosad (3.09).

An ultra-sensitive photoelectrochemical sensor for chlorpyrifos detection based on a novel BiOI/TiO2 n-n heterojunction

Due to widespread application of chlorpyrifos for controlling pests in agriculture, the continuous accumulation of chlorpyrifos residue has caused serious environmental pollution.The detection of chlorpyrifos is of great significance for humans and environment because it can arise a series of diseases by inhibiting acetylcholinesterase (AChE) activity. Photoelectrochemical sensing, as an emerging sensing technology, has great potential in the detection of chlorpyrifos. It is urgent that find a suitable photoelectric sensing strategy to effectively monitor chlorpyrifos. Herein, an n-n heterojunction was constructed by uniformly immobilizing n-type 3DBiOI, which had loose porous structure composed of numerous small and thin nanosheets, on the surface of TiO2 with anatase/rutile (AR-TiO2) heterophase junction. Under light irradiation, the proposed BiOI/AR-TiO2 n-n heterojunction exhibited excellent optical absorption characteristics and photoelectrochemical activity. Additionally, the photoelectrochemical sensing platform demonstrated excellent analytical performance in monitoring chlorpyrifos. Under optimized conditions, it showed a wide detection range of 1 pg mL−1- 200 ng mL−1 and a detection limit (S/N = 3) as low as 0.24 pg mL−1, with superior selectivity and stability. The ultra-sensitivity and great specificity for detection of chlorpyrifos can be ascribed to chelation between Bi (Ⅲ) and C=N and P=S bonds in chlorpyrifos, which had been confirmed in this work. Meanwhile, the PEC sensor also had potential application value for monitoring chlorpyrifos in water samples, lettuce and pitaya, which the recoveries of samples ranged from 96.9% to 104.7% with a relative standard deviation (RSD) of 1.11%–5.93%. This sensor provided a novel idea for constructing heterojunctions with high photoelectric conversion efficiency and had a high application prospect for the detection of chlorpyrifos and other structural analogues.

Ecological safety evaluation of chlorpyrifos on agricultural soil: Effects on soil microbes

The health of farmland soils is directly related to the proper application of pesticides. Chlorpyrifos is a widely used broad-spectrum organophosphorus insecticide, and its ecological security risk to farmland soils requires evaluation. A trial was conducted to study the effects of chlorpyrifos on soil microbes in a wheat–maize rotation field. A 45 % chlorpyrifos emulsion was sprayed at the recommended and dual doses, after which the chlorpyrifos residue, soil microbial content, bacterial community structure, functional microbial abundance, and enzyme activities were measured. The results showed that chlorpyrifos had a half-life of 8.94–9.88 and 2.17–2.18 days in soil for wheat and maize, respectively. Although the final chlorpyrifos residues in the crop grains were lower than the maximum residue limit recommended by the Chinese government, soil fungal abundance was significantly inhibited, and the structure and function of soil bacterial communities were disturbed. Furthermore, the quantities of nitrification-related genera (Acidobacteria GP4 and Acidobacteria GP6) and functional genes (AOB-amoA and AOA-amoA) decreased, whereas those of denitrification-related functional genes (nirS and nirK) and urease activity increased. Gemmatimonas and alkaline phosphatase involved in phosphorus cycling were activated, and the abundance of cbbLR and cbbLG genes involved in carbon fixation decreased. The integrated biomarker response index showed that nirK and β-glucosidase were the most sensitive indicators in wheat and maize stages. The present study provides toxicological data and theoretical guidance for the ecological safety evaluation and rational application of chlorpyrifos in soil.

Evaluating combined effects of pesticide and crop nutrition (with N, P, K and Si) on weevil damage in East African Highland Bananas.

Banana weevil (Cosmopolites sordidus, Germar) is a major pest in East African Highland Banana. The influence of crop nutritional status on weevil damage is poorly understood. Nutrient availability affects the nutritional quality of plants for weevils and may affect weevil damage. Here, we evaluate the effect of insecticides alone and in combination with fertilisers (N, P, K and Si) on weevil damage using data from two experiments in central and southwest Uganda. In the first experiment, we varied chlorpyrifos and application rates of N, P and K. In the second experiment, we varied the application rates of K and Si. Treatment effects were analysed using generalised linear mixed models with a negative binomial distribution. In the first experiment, chlorpyrifos reduced and N increased weevil damage, while P and K had no significant effect. In the K or Si application rates reduced weevil damage compared with the control. We conclude that the combined application of chlorpyrifos with K and Si fertilisers can contribute to weevil damage control on sites with low nutrient availability and should form part of integrated weevil management in bananas. Future studies should assess how much reduction in insecticide use is possible in EAHB with judicious input rates.

Oxidative stress in Arthrospira platensis by two organophosphate pesticides.

Although it is known that organophosphate insecticides are harmfull to aquatic ecosystems, oxidative damages caused by Dimethoate and Chlorpyrifos are not studied on Arthrospira platensis Gomont. In this study, various Chlorpyrifos (0-150 µg mL-1) and Dimethoate (0-250 µg mL-1) concentrations were added to the culture medium in laboratory to evaulate growth rate, chlorophyll-a content and antioxidant parameters of A. platensis. Optical Density (OD560) and chlorophyll-a decreased compared to the control for seven days in both pesticide applications. Superoxide dismutase (SOD) activity increased at 50 µg mL-1 Chlorpyrifos concentration but it decreased at all concentrations. Although Ascorbate peroxidase (APX) and glutathione reductase (GR) activities increased with Chlorpyrifos application, they did not change with Dimethoate application. Malondialdehyde (MDA) amount decreased at 150 µg mL-1 Chlorpyrifos concentration but it increased in Dimethoate application. The H2O2 content were increased in both applications. Proline decreased in 50 and 75 µg mL-1 Chlorpyrifos concentrations and increased at 150 µg mL-1 concentration, while it increased at 25 µg mL-1 Dimethoate concentration. The results were tested at 0.05 significance level. These pesticides inhibit A. platensis growth and chlorophyll-a production and cause oxidative stress. The excessive use may affect the phytoplankton and have negative consequences in the aquatic ecosystem.

New insights into the effects of chlorpyrifos on soil microbes: Carbon and nitrogen cycle related microbes in wheat/maize rotation agricultural field

Chlorpyrifos, a broad−spectrum organophosphorus insecticide, has been widely detected worldwide and is a potential neurotoxin and endocrine disruptor. Besides, chlorpyrifos has been proven that have a negative effect on soil microbes. In the present study, chlorpyrifos formulation (LORSBAN®, 45% emulsifiable concentrate) was applied in an agricultural field at the recommended dose (R dose, 270.0 and 337.5 g a.i. ha−1 for wheat and maize respectively) and double recommended (DR) dose. Chlorpyrifos residue level and effect on soil microbes related to soil carbon and nitrogen cycle function were analyzed. Results showed that the half−lives of chlorpyrifos in wheat and maize field soil were 7.23–8.23 and 1.45–1.77 d, respectively. Application of chlorpyrifos at even DR dose did not result in unacceptable residual chlorpyrifos, where the final residual chlorpyrifos in wheat/maize (leaf, stem, and grain) was meet the requirement of the maximum residual limit (0.5 mg kg−1 for wheat and 0.05 mg kg−1 for maize) in China. Chlorpyrifos enhanced the activity of β−glucosidase by increasing the relative abundance of Sphingosinicella and promoted the carbon cycle in wheat field. The changes of cbbLR and cbbLG gene abundance also confirmed that chlorpyrifos could affect the import and export of soil carbon pool. The effect of chlorpyrifos on soil N cycle was determined by changes in the abundance of the bacterial genus Gemmatimonas, which is associated with denitrification. Further analysis of N−cycle functional genes and urease activity showed that chlorpyrifos inhibited nitrogen fixation in wheat field, but promoted nitrogen fixation in maize field. In general, bacterial abundance, urease, and AOA−amoA gene could be early warning markers of chlorpyrifos contamination. The results demonstrated the negative effects of chlorpyrifos on soil microbes especially on soil C and N cycle in actual agricultural field. It provides new insights about chlorpyrifos environmental pollution and its effect on soil ecosystems.

Acute Toxicity of Chlorpyrifos on Histological Alterations in the Anomuran Crab, Emerita asiatica (H. Milne Edwards, 1837)

Acute toxicity of Chlorpyrifos on histological alterations in the different organs like gills, hepatopancreas and ovary of anomuran crab, Emerita asiatica was studied. Though Emerita asiatica is not a commercially viable crab, but it plays a vital role in the environment to maintain a stable marine ecosystem. Several steps and precautions measures should be taken to conserve these members of the marine food chain to have a stable ecosystem and also to protect this species from extinction. Thus, it can be concluded that the use of Chlorpyrifos which has been legally banned in India is justified. It has been proved by several workers and has been conformed in present investigation that use of this Chlorpyrifos causes serious damage to the vital organ of sand crabs gill, hepatopancreas and ovary. The application of Chlorpyrifos could be reduced in the agricultural field to nearby coastal regions.

Evaluation of chemical and microbial control options for Pangaeus bilineatus (Say) (Hemiptera: Cydnidae) infesting peanut crop.

The peanut burrower bug, Pangaeus bilineatus is a major crop pest of peanuts in the southern United States. Peanuts infested by P.bilineatus exhibit weight and quality losses and could be discounted by ≤50% of the prevailing market price. Control of this pest is difficult because it attacks peanut pods underground, thus rendering foliar pesticide applications ineffective. Integration of entomopathogenic fungi and nematodes (EPF/EPNs) with chemical insecticides in the management of P.bilineatus was investigated as a potential integrated pest management containment tool. The nymphs were less susceptible than adults of P.bilineatus to EPNs. Comparison of six strains of both Heterorhabditis spp. and Steinernema spp. demonstrated that Steinernema carpocapsae (All) was the most virulent EPN, causing 75.54% mortality of P.bilineatus adults after 7 days postinoculation (dpi), whereas the mortality generated by the application of the rest of the nematodes ranged between 17.03% (H.bacteriophora - Lewis) and 50% (H.bacteriophora VS). Application of imidacloprid by itself at ½FR (field rate) did not result in any significant mortality of P.bilineatus adults but application of chlorpyrifos at 1/8FR caused significant mortality (27.41-61.35%) at 7-14 dpi. However, combined applications of S.carpocapsae and imidacloprid resulted in significant mortality starting at 3dpi. The interactions between S.carpocapsae and imidacloprid were synergistic at 3-5dpi, but became additive at 7-14 dpi. Both chlorpyrifos and imidacloprid did not negatively impact the reproduction of S.carpocapsae. The compatibility between S.carpocapsae and imidacloprid makes a case for the combination to be used for the management of P.bilineatus. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Remediation of chlorpyrifos in soil using immobilized bacterial consortium biostimulated with organic amendment

Pesticides released into the environment have become a danger to the mother earth arousing a worldwide alert to initiate remediation at the point sources of contamination in an ecofriendly way. The recent advances in bioremediation technology using microbial consortium have been found effective for the treatment of pesticides in soil. In this context, the present study evaluates and compares the ability of an assembled bacterial consortium C5 (Staphylococcus warneri CPI 2, Pseudomonas putida CPI 9 and Stenotrophomonas maltophilia CPI 15) to remove chlorpyrifos in soil in its free cells state and immobilized state on wood chips. Chlorpyrifos degradation by C5 was studied via a pot study experiment with completely randomized block design. A comparative analysis of degradation, total microbial count and dehydrogenase activity was performed in soils with and without chlorpyrifos application history and under amendment with a mix of cow dung and mushroom spent as biostimulant. Based on ANOVA results, the treatments T3 and T7, both received immobilized C5 and biostimulant were found to be the best giving complete degradation of 125 mg kg−1 of chlorpyrifos in 30 days. All the studied factors – degradation, microbial count and dehydrogenase activity were higher in the soil with chlorpyrifos exposure history. The results presented here highlight the potential use of wood chip immobilized consortium C5 biostimulated with a mix of cow dung and mushroom spent for remediating chlorpyrifos effectively in contaminated soil.

3-Indolepropionic acid prevented chlorpyrifos-induced hepatorenal toxicities in rats by improving anti-inflammatory, antioxidant, and pro-apoptotic responses and abating DNA damage.

The application of chlorpyrifos (CPF), an organophosphorus pesticide to control insects, is associated with oxidative stress and reduced quality of life in humans and animals. Indole-3-propionic acid (IPA) is a by-product of tryptophan metabolism with high antioxidant capacity and has the potential to curb CPF-mediated toxicities in the hepatorenal system of rats. It is against this background that we explored the subacute exposure of CPF and the effect of IPA in the liver and kidney of thirty rats using five cohort experimental designs (n = 6) consisting of control (corn oil 2mL/kg body weight), CPF alone (5mg/kg), IPA alone (50mg/kg), CPF + IPA1 (5mg/kg + 25mg/kg), and CPF + IPA2 (5mg/kg + 50mg/kg). Subsequently, we evaluated biomarkers of hepatorenal damage, oxidative and nitrosative stress, inflammation, DNA damage, and apoptosis by spectrophotometric and enzyme-linked immunosorbent assay methods. Our results showed that co-treatment with IPA decreased CPF-upregulated serum hepatic transaminases, creatinine, and urea; reversed CPF downregulation of SOD, CAT, GPx, GST, GSH, Trx, TRx-R, and TSH; and abated CPF upregulation of XO, MPO, RONS, and LPO. Co-treatment with IPA decreased CPF-upregulated IL-1β and 8-OHdG levels, caspase-9 and caspase-3 activities, and increased IL-10. In addition, IPA averts CPF-induced histological changes in the liver and kidney of rats. Our results demonstrate that co-dosing CPF-exposed rats with IPA can significantly decrease CPF-induced oxidative stress, pro-inflammatory responses, DNA damage, and subsequent pro-apoptotic responses in rats' liver and kidneys. Therefore, supplementing tryptophan-derived endogenous IPA from exogenous sources may help avert toxicity occasioned by inadvertent exposure to harmful chemicals, including CPF-induced systemic perturbation of liver and kidney function.

Bioremediation Potential of Plant-Bacterial Consortia for Chlorpyrifos Removal Using Constructed Wetland

The extensive and unchecked application of chlorpyrifos against crop insects has caused contamination of various ecosystems, such as soil, sediments, and water, posing harm to plants, animals, useful arthropods, and humans. The present study aimed at evaluating the ability of proto-type constructed wetland to biodegrade chlorpyrifos and its major metabolites especially 2-hydroxy-3, 5, 6-trichloropyridine/ol (TCP) using chlorpyrifos-degrading indigenous bacterial strains, namely, Acinetobacter baumanni and Bacillus cibi with Canna spps. and indigenous Mentha spps. as a bacterial–plant consortium. Soil and plant samples were collected at regular time intervals for 12 weeks; analytes were extracted using the toluene method and evaluated through gas chromatography–mass spectrometry (GC-MS). In case of wetland vegetation with Canna and Mentha, 2-hydroxy-3, 5, 6-trichloropyridine (TCP, m/z = 198) and 2- hydroxypyridine (m/z = 97) with deprotonated molecular ions at m/z = 69 (M-H)−were detected as the intermediate metabolites, while in the bacterial–plant consortium, instead of TCP, 3, 5, 6-trichloro-2-methoxypyridine (TMP, m/z = 212) was formed along with di-ethylthiophosphate (DETP, m/z = 169). Based on the metabolite analysis using GC-MS, the biodegradation pathway for chlorpyrifos degradation through bacterial–plant consortia is predicted. The constructed wetland with the bacterial–plant consortium showed its potential to either bypass TCP generation, or TCP may have been immediately biodegraded by the plant part of the consortium. The designed constructed wetland provided a novel remedial measure to biodegrade chlorpyrifos without producing harmful metabolites.

Residues and degradation dynamics of pymetrozine and chlorpyrifos in rice field ecosystem

Field trials were conducted in Guangzhou, Nanning, and Nanjing in two consecutive years to evaluate the terminal residue levels and dissipation trend of pymetrozine and chlorpyrifos in rice ecosystem. Analyses were carried out by high-performance-liquid-chromatography for pymetrozine and gas-chromatography-mass-spectrometry for chlorpyrifos, achieved good linear relationship over range from 0.01 to 5.0 mg·kg−1 for both (r > 0.9998). Average recoveries were 86.0% to 106.0% for pymetrozine, and 79.7% to 102.3% for chlorpyrifos at the spiking levels of 0.01, 0.1 and 1.0 mg·kg−1. Half-lives of pymetrozine in paddy water, paddy soil and rice plant were 0.35–2.81, 2.69–6.95 and 1.22–3.70 days, while that of chlorpyrifos were 0.86–1.88, 3.09–6.86 and 0.58–2.84 days. Final residues of pymetrozine and chlorpyrifos in brown rice ranged from less than 0.6 to 26.0 μg·kg−1 and 14.3 to 191.6 μg·kg−1, respectively. It is recommended that 25% pymetrozine and chlorpyrifos suspension be sprayed twice at the intervals of 10 days with dosages ranging from 375 (maximum recommended dosage) to 562.5 g a.i.·ha−1 (1.5 times of the maximum recommended dosage). The rice can be harvested safely 15 days after the last application of pymetrozine and chlorpyrifos. The research results help ensures the safe application of pymetrozine and chlorpyrifos in rice ecosystem.

Combined toxicity of chlorpyrifos, abamectin, imidacloprid, and acetamiprid on earthworms (Eisenia fetida).

Mixed pesticides have been broadly used in agriculture. However, assessing the combined effects of pesticides in the environment is essential for potential risk assessment, though the task is far from complete. Median lethal concentrations of pesticides as well as acetylcholinesterase (AChE) levels and cellulose activities were measured in earthworms (Eisenia fetida) individually and jointly exposed to pesticides imidacloprid (IMI), acetamiprid (ACE), chlorpyrifos (CRF), and abamectin (ABM)). A 3:1 mixture of CRF and IMI had additive effects, while a 3:1 mixture of CRF and ACE had synergic effects. The joint effects of ABM with IMI or with ACE were synergistic. As CRF concentration increased, AChE activities were significantly decreased. For high concentrations of IMI, AChE activities under combined CRF and IMI applications were significantly inhibited following increased exposure time. Moreover, the cellulase activities under combined applications of CRF with IMI or with ACE had similar effects. This study provides basic data for scientifically evaluating the environmental risk and safety of combined uses of pesticides.

Environmental Distribution, Metabolic Fate, and Degradation Mechanism of Chlorpyrifos: Recent and Future Perspectives.

Pesticides play a significant role in crop production and have become an inevitable part of the modern environment due to their extensive distribution throughout the soil ecosystem. Prophylactic applications of chlorpyrifos (CP) affect soil fertility, modify soil microbial community structure, and pose potential health risks to the nontarget organisms. Bioremediation through microbial metabolism is found to be an ecofriendly and cheaper process for CP removal from the environment. So far, various bacterial and fungal communities have been reported for CP and its metabolites degradation. Organophosphorus hydrolase (OPH) and methyl parathion hydrolase (MPH) are crucial bacterial enzymes for CP degradation as they efficiently hydrolyze the unbreakable P-O and P = S bond. This review discusses the prospects of toxicity level, persistency, and harmful effects of CP on the environment. CP degradation mechanisms, metabolic pathways, and key enzymes, along with their structural details, are also featured. The highlights on molecular docking with OPH and MPH enzyme for CP show the best binding affinity with OPH; hence, it is an essential part of CP degradation. Simultaneously, metagenomic analysis of soil from contaminated agricultural lands and wastewater was analyzed with the goal to identify the dominant CP degraders and enzymes. The identification of potent degraders, key enzymes, and evaluation of microbial community dynamics upon pesticide exposure can be used as a warning for its dissemination and biomagnification into the food chain.

Ecological performance of multifunctional pesticide tolerant strains of Mesorhizobium sp. in chickpea with recommended pendimethalin, ready-mix of pendimethalin and imazethpyr, carbendazim and chlorpyrifos application.

The present study was designed to screen the Mesorhizobium strains (50) for tolerance with four recommended pesticides in chickpea. In-vitro, robust pesticide tolerant strains were developed in pesticides amended media over several generations. Further, verification of the multifunctional traits of pesticide tolerant mesorhizobia under pesticide stress was conducted in-vitro. Among different pesticides, significantly high tolerance in Mesorhizobium strains was observed with recommended doses of pendimethalin (37%) and ready-mix (36%) followed by chlorpyrifos (31%) and carbendazim (30%), on an overall basis. Based on multifunctional traits, Mesorhizobium strains viz. MR2, MR17 and recommended MR33 were the most promising. Ecological performance of the potential Mesorhizobium strains alone and in dual-inoculation with recommended PGP rhizobacterium strain RB-1 (Pseudomonas argenttinensis JX239745.1) was subsequently analyzed in field following standard pesticide application in PBG-7 and GPF-2 chickpea varieties for two consecutive rabi seasons (2015 and 2016). Dual-inoculant treatments; recommended RB-1 + MR33 (4.1%) and RB-1 + MR2 (3.8%) significantly increased the grain yield over Mesorhizobium alone treatments viz MR33 and MR2, respectively. Grain yield in PBG7 variety was significantly affected (7.3%) by the microbial inoculant treatments over GPF2 variety. Therefore, the potential pesticide tolerant strains MR2 and MR33 can be further explored as compatible dual-inoculants with recommended RB-1 for chickpea under environmentally stressed conditions (pesticide application) at multiple locations. Our approach using robust multifunctional pesticide tolerant Mesorhizobium for bio-augmentation of chickpea might be helpful in the formulation of effective bio-inoculants consortia in establishing successful chickpea-Mesorhizobium symbiosis.

Comparative Study on Effect of Pesticides and Vermicompost on the Growth of Eisenia foetida

Earthworms are important soil invertebrates and play an important role in improving soil quality. They act as nature´s best fertilizers and have beneficial role in the process of vermicomposting which is very useful in crop production. The Indiscrete use of chemical fertilizers and pesticides poses a threat to soil quality, crop production and also hampered the growth of earthworms. In the present study the impact of pesticides and vermicompost in potato crops field and on Eisenia foetida was evaluated. The study aimed to understand the effect of chemical and biological fertilizers on the life table attributes of earthworm, Eisenia foetida. Laboratory adapted Eisenia foetida were reared on artificial soil supplemented with chemical fertilizers and vermicompost. Changes in number and biomass of Eisenia foetida were monitored four times in various applications of pesticides and in vermicompost. Four pesticides that are commonly used in potato crops are Chlorpyrifos, Malathion, Carbofuran and Cypermethrin. Thus, the negative impact of these pesticides on Eisenia foetida and Potato crops has been reported when compared to the control (Vermicompost). The effect of Pesticides was noted in following order: Chlorpyrifos ˃ Malathion ˃ Cabofuran ˃ Cypermethrin. Application of Chlorpyrifos to the potato crop field harboring earthworms reduced the number of earthworms from 200 in the control group to 20 after 60 days of the application. The effect was more pronounced on the total biomass of the culture owing to the high toxicity of Chlorpyrifos. The Pesticides treatment decreased the percent survival of the earthworms by 70% and 40%, respectively. The number and biomass of Earthworm decreased on increasing the application of pesticides thus, reduces crop production. On the other hand, the vermicompost had a positive effect on the earthworm’s biology.

English

In this study, the impact of insecticides on the chlorophyll and carotenoid contents in peach leaves was assessed. Applied insecticides are registered in Republic of Serbia and some EU countries for the control of the oriental fruit moth (Grapholita molesta Busck) in peach orchards. The experiments were set up in peach orchards (variety “Royal gem”) at the localities of Čelarevo and Šišatovac (northern region of the Republic of Serbia). The applied spray liquids from different chemical groups based on cyantraniliprole (a.i. 100 g/l), chlorantraniliprole (a.i. 200 g/l), spinetoram (a.i. 250 g/l), indoxacarb (a.i. 150 g/l), acetamiprid (a.i. 200 g/kg), deltamethrin (a.i. 25 g/l), pyriproxyfen (a.i. 100 g/l) and chlorpyrifos (a.i. 250 g/l), were foliar applied at a concentrations of 0.06, 0.02, 0.02, 0.05, 0.025, 0.05, 0.1 and 0.25%, respectively. Leaves were sampled 3 and 7 days after treatment and analysed for the contents of photosynthetic pigments. Results showed the most adverse impact on the total chlorophyll; their content decreased after application of chlorantraniliprole (32.6-52.7%), indoxacarb (31.1-47.5%), chlorpyrifos (32.4-36.9%), pyriproxyfen (19.5-37.7%) and cyantraniliprole (22.8-33.4%). However, the carotenoid content was increased (16.3 to 117.1%) in the analyzed samples three and seven days after the treatment at both localities, except spinetoram which reduced carotenoids content by 2%. In general, the tested pigments in peach leaves showed a different biochemical reaction depending on the applied insecticides.

Reducing environmental risks of chlorpyrifos application in typical soils by adding appropriate exogenous organic matter: Evidence from a simulated paddy field experiment

Chlorpyrifos (CPF), as an organophosphate insecticide extensively used in the modern agricultural system, has been gradually banned in many countries due to its reported health risks to organisms, including humans. This study used simulated paddy field experiments and carbon-14 tracing to explore the possibility of reducing environmental risks of chlorpyrifos application through appropriate agronomic practice. Results showed 14C-CPF concentration in rice plants planted in the red soil (RS) was significantly higher than that in black soil (BS) and fluvo-aquic soil (FS). The application of biochar and chicken manure in RS reduced 14C-CPF accumulation in rice plants, and the content of 14C-CPF in rice grains decreased by 25% and 50%, respectively. Adding biochar to all three soils reduced the migration of 14C-CPF, especially in FS with the highest risk of 14C-CPF migration. The addition of chicken manure in FS reduced the migration of 14C-CPF and the total residual amount of 14C-CPF in the soil. In addition, chicken manure treatment increased the formation of 14C-bound residues (BRs) in soils and changed the distribution 14C-BRs in humus. The results indicated that the degree of environmental risks associated with the CPF application varies with soil types and could be reduced by introducing suitable exogenous organic matter into different soils, which is of great significance for guiding the scientific application of chlorpyrifos in agronomic practices.