Search

In order to clarify resistance of Corynespora cassiicola to commonly used fungicides such as boscalid, trifloxystrobin and procymidoneoxime and screen effective fungicides, the sensitivity of C. cassiicola in Tangshan and Handan area of Hebei Province from 2020 to 2021 was detected by mycelium growth rate method, CcSdh and CcCytb resistant mutant genotypes were analyzed by PCR technique, the control efficacy of 10 commonly used fungicides against the local main resistant mutant SdhB-I280V&Cytb-G143A was evaluated by pot experiment, and the efficacy of the alternate use of highly effective alternative fungicides was carried out. According to the test results, the C. cassiicola in the main producing areas of cucumber in Tangshan and Handan of Hebei Province developed different degrees of resistance to boscalid, trifloxystrobin and procymidoneoxime. The average EC50 value of boscalid against the 280 strains of C. cassiicola was 8.12 μg/mL, with the resistance frequency was 27.43%. The average EC50 value of trifloxystrobin against the 144 strains of C. cassiicola was 62.6 μg/mL, with the resistance frequency against the 162 strains (including the 18 strains with EC50 value greater than 200 μg/mL) was 99.49%. The average EC50 of procymidoneoxime against the 163 strains of C. cassiicola was 6.95 μg/mL, with the resistance frequency was 52.76%. Eleven kinds of CcSdh resistance mutant types were detected in total, and the mutation frequency reached 56.86%. Six of them were single mutations, four of them were double mutations, and one of them was triple mutation. CcCytb carried only G143A mutation, and the frequency was 100%. In the pot experiment, the two mixed fungicides 75% chlorothalonil WP + 50% procymidone WP and 50% iprodione WP + 75% (pyraclostrobin + propineb) WP had the highest control efficacy on cucumber target leaf spot, with the control efficacy of 71.52% and 70.52%, respectively. The second was the compound fungicide 75% (pyraclostrobin + propineb) WP, and the control efficacy was 57.90%. 75% chlorothalonil WP + 50% procymidone WP and 50% iprodione WP + 75% (pyraclostrobin + propineb) WP were used alternately to control cucumber target leaf spot with 71.53% effect and 94.64% efficacy in pot experiment and field experiment, respectively. This showed that the mixing and alternate use of fungicides with different action mechanisms have broad application prospects for the control of cucumber target leaf spot. [ABSTRACT FROM AUTHOR]

Chlorothalonil (2,4,5,6-tetrachloro-1,3-benzenedicarbonitrile, TPN, CAS: 1897-45-6) is a halogenated fungicide currently widely applied to a large variety of crops. Its carcinogenicity, embryo lethality, and high chronic oral toxicity in mammals, among other effects on a variety of organisms, has made its biodegradation of great interest. Chlorothalonil dehalogenase (Chd) from the bacterium Pseudomonas sp. CTN-3 offers a potential solution by catalyzing the first step in the degradation of chlorothalonil. Reported herein are active biomaterials of Chd when encapsulated in tetramethylorthosilicate (TMOS) gels using the sol–gel method (Chd/sol), alginate beads (Chd/alginate), and chitosan-coated alginate beads (Chd/chitosan). Both Chd/sol and Chd/chitosan increased protection from the endopeptidase trypsin as well as imparted stability over a pH range from 5 to 9. Chd/sol outperformed Chd/alginate and Chd/chitosan in long-term storage and reuse experiments, retaining similar activity to soluble Chd stored under similar conditions. All three materials showed a level of increased thermostability, with Chd/sol retaining >60% activity up to 70 °C. All materials showed activity in 40% methanol, suggesting the possibility for organic solvents to improve TPN solubility. Overall, Chd/sol offers the best potential for bioremediation of TPN using Chd. [ABSTRACT FROM AUTHOR]

Several fungicide products with metalaxyl-chlorothalonil as the active ingredients are available in the Mexican market. Applying products containing this mixture of molecules is a common method that farmers choose to prevent damage caused to crops by Phytophthora capsici. Despite the efficacy of the mixture of metalaxyl-chlorothalonil in controlling the growth of this pathogen, their intensive use could contribute to the development of multidrug-resistant strains. Additionally, the dynamics of resistance to commercial metalaxyl-chlorothalonil-based fungicides and the virulence of P. capsici during continuous exposure are yet to be studied in detail. In this study, four continuous generations of P. capsici were exposed to two concentrations (5 and 100 μg·mL−1) of a commercial fungicide containing metalaxyl-chlorothalonil as the active ingredients. Changes in morphology, growth, and virulence were observed after the first interaction with the fungicide. However, in further generations exposed to the same amount of the product, the morphology and growth of P. capsici were partially restored, whereas its virulence was completely re-established. These results indicate a rapid adaptation to the metalaxyl-chlorothalonil mixture and highlight the importance of using different methods to control P. capsici and prevent the development of more virulent and multidrug-resistant strains. [ABSTRACT FROM AUTHOR]

Objective) To establish a method for simultaneous determination of chlorothalonil and its metabolite 4-hydroxychlorothalonil residues in animal-derived food by ultra-high performance liquid chromatography-tandem mass spectrometry. (Methods) The samples were extracted by oscillating with acetonitrile solution of 1% acetic acid, defatted with n-hexane, purified by matrix dispersible solid phase extractant (PSA, anhydrous magnesium sulfate), separated by Waters BEH C18 column under a gradient elution program using 0.1% formic acid aqueous solution and acetonitrile as the mobile phases. The anion multiple reaction monitoring model (MRM) of atmospheric pressure chemical ionization source (APCI) was used for the determination, and the matrix matching external standard method was used for quantitative determination. (Results) The linear relationships of chlorothalonil and 4-hydroxychlorothalonil were good in the range of 5- 500 μg/L, and the limits of quantitation were 0.005 mg/kg. The average recoveries of chlorothalonil and 4-hydroxychlorothalonil were 69.3%-111.0% and 65.3%-117.9%, respectively. The relative standard deviations of chlorothalonil and 4-hydroxychlorothalonil were 1.6%- 10.8% and 1.1%-9.0%, respectively. (Conclusion) The method is simple, rapid, sensitive, accurate and reliable for simultaneous determination of chlorothalonil and its metabolite 4-hydroxychlorothalonil in animal-derived food. [ABSTRACT FROM AUTHOR]

Metasurface structures have proven to be effective in enhancing terahertz sensing signals and can thus be used as sensors to improve terahertz detection sensitivity. However, the sensitivity is limited by the poor spatial overlap between the analytes and the local electric field of the metasurface. In this work, a novel design of a floating bilayer metasurface structure for terahertz sensing is proposed and investigated. This structure supports a sharp toroidal dipole resonance and can concentrate near‐field energy on the analyte and metal atoms rather than on the substrate surface by floating the metal atoms. Consequently, the sensitivity is significantly improved to as high as 362 GHz RIU−1; theoretically, this is approximately 2.6 times higher than that of the common metasurface. The ability of the floating bilayer metasurface to quantitatively detect chlorothalonil is experimentally demonstrated. The resonance peak shows a significant frequency shift of 7 GHz for a change of 0.0001 mg dL−1 in chlorothalonil concentration, reaching up to 86 GHz when the change in chlorothalonil concentration is 100 mg dL−1; this is approximately 6.6 times higher than that of the common metasurface. This work provides opportunities for metasurface to realize ultrasensitive sensing in the terahertz regime. [ABSTRACT FROM AUTHOR]

Rationale: Chlorothalonil (CHT), a broad-spectrum fungicide, has been employed widely to control foliar diseases, whereas with a major metabolite of polar 4-hydroxychlorothalonil (CHT-4-OH), only an acceptable nonpolar CHT residue is allowed by most countries. This study involves the method development for CHT residue in vegetables/fruits using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with a novel modified discharge-adaptor (DA) interface. Methods: CHT residue was analyzed using LC-MS/MS with DA interface (LC-DAMS/MS), developed in our previous works. A DA was placed on the electrospray tip to switch the ionization modes. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was applied to extract CHT residue of vegetables/fruits efficiently with less sample preparation time and analysis cost. Results: CHT and CHT-4-OH spiked in four different vegetables/fruits were extracted using the modified QuEChERS method. After LC with isocratic elution, CHT and CHT-4-OH were separated within 3 min. Using LC-DA-MS/MS, the ion signals of CHT were improved two to three times, and the limit of quantification of 5 ng/g and linearity (r2 > 0.99) in the range of 5-200 ng/g were achieved using 10 g of vegetables/fruits. The precision and accuracy were within 15% each. The modified QuEChERS and LC-DA-MS/MS were applied to examine eight field-grown vegetables/fruits; 9.5 and 2588.9 ng/g of CHT were detected in two vegetables/fruits. Conclusion: LC-DA-MS/MS combined with modified QuEChERS was successfully applied to determine CHT residue <10 ng/g in vegetables/fruits and with satisfied validation results. The developed method could reduce both analysis cost and time, attributing to simplifications in modified QuEChERS, isocratic elution, and DA interface in LC-DA-MS/MS. [ABSTRACT FROM AUTHOR]

Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile; TPN) is an environmentally persistent fungicide that sees heavy use in the USA and is highly toxic to aquatic species and birds, as well as a probable human carcinogen. The chlorothalonil dehalogenase from Pseudomonas sp. CTN-3 (Chd, UniProtKB C9EBR5) degrades TPN to its less toxic 4-OH-TPN analog making it an exciting candidate for the development of a bioremediation process for TPN; however, little is currently known about its catalytic mechanism. Therefore, an active site residue histidine-114 (His114) which forms a hydrogen bond with the Zn(II)-bound water/hydroxide and has been suggested to be the active site acid/base, was substituted by an Ala residue. Surprisingly, ChdH114A exhibited catalytic activity with a kcat value of 1.07 s−1, ~ 5% of wild-type (WT) Chd, and a KM of 32 µM. Thus, His114 is catalytically important but not essential. The electronic and structural aspects of the WT Chd and ChdH114A active sites were examined using UV–Vis and EPR spectroscopy on the catalytically competent Co(II)-substituted enzyme as well as all-atomistic molecular dynamics (MD) simulations. Combination of these data suggest His114 can quickly and reversibly move nearly 2 Å between one conformation that facilitates catalysis and another that enables product egress and active site recharge. In light of experimental and computational data on ChdH114A, Asn216 appears to play a role in substrate binding and preorganization of the transition-state while Asp116 likely facilitates the deprotonation of the Zn(II)-bound water in the absence of His114. Based on these data, an updated proposed catalytic mechanism for Chd is presented. [ABSTRACT FROM AUTHOR]

Abstract Pesticides are indispensable tools in modern agriculture for enhancing crop productivity. However, the inherent toxicity of pesticides raises significant concerns regarding human exposure, particularly among agricultural workers. This study investigated the exposure and associated risks of two commonly used pesticides in open-field pepper cultivation, namely, chlorothalonil and flubendiamide, in the Republic of Korea. We used a comprehensive approach, encompassing dermal and inhalation exposure measurements in agricultural workers during two critical scenarios: mixing/loading and application. Results revealed that during mixing/loading, dermal exposure to chlorothalonil was 3.33 mg (0.0002% of the total active ingredient [a.i.]), while flubendiamide exposure amounted to 0.173 mg (0.0001% of the a.i.). Conversely, dermal exposure increased significantly during application to 648 mg (chlorothalonil) and 93.1 mg (flubendiamide), representing 0.037% and 0.065% of the total a.i., respectively. Inhalation exposure was also evident, with chlorothalonil and flubendiamide exposure levels varying across scenarios. Notably, the risk assessment using the Risk Index (RI) indicated acceptable risk of exposure during mixing/loading but raised concerns during application, where all RIs exceeded 1, signifying potential risk. We suggest implementing additional personal protective equipment (PPE) during pesticide application, such as gowns and lower-body PPE, to mitigate these risks.

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Autoclaving eliminates microbial contamination during micropropagation, but the process is complex, time-consuming and expensive. Chemical sterilisation also effectively disinfects culture media and is relatively simple and cost-effective. Prior studies have focused on the effects of chemical sterilisation on bud induction, but the effects of sterilant on proliferation and rooting are unknown. We investigated the effect of sterilant on Acacia mangium × A. auriculiformis bud induction, rooting and subculture rooting. The optimal bud induction medium comprised 1/8 Murashige and Skoog medium $ + $ + 7 g l−1 agar $ + $ + 0.2 g l−1 chlorothalonil $ + $ + 0.5 mg l−1 6-benzylaminopurine. The maximum bud induction rate (99.54%) with zero contamination was achieved using the third to fifth stem segments collected in October and treated with 0.8 g l−1 carbendazim for 3 min. The maximum rooting rate (97.62%) was attained using a rooting medium consisting of 7 g l−1 agar $ + $ + 0.2 g l−1 chlorothalonil $ + $ + 1.5 mg l−1 indolebutyric acid $ + $ + 0.5 mg l−1 naphthaleneacetic acid. Proliferation ratio and subculture duration were positively correlated. The maximum proliferation rate (3.58%) was realised in the fourth subculture rooting. Chlorothalonil can effectively replace autoclaving of A. mangium × A. auriculiformis bud induction and rooting media. The present study provides insights for improving the rapid propagation method of Acacia sp. and a new direction for the development of micropropagation technology. [ABSTRACT FROM AUTHOR]

Chlorothalonil (CTL) is widely used in agricultural production and antifoulant additive globally due to its broad spectrum and non-systemic properties, resulting in its widespread existence in foods, soil and water. Extensive evidence demonstrated that exposure to CTL induced adverse effects on organisms and in particular its reproductive toxicity has been attracted public concern. However, the influences of CTL on oocyte maturation is mysterious so far. In this study, we documented the toxic effects of CTL on oocyte in vitro maturation and the related underlying mechanisms. Exposure to CTL caused continuous activation of spindle assembly checkpoints (SAC) which in turn compromised meiotic maturation in mouse oocyte, featured by the attenuation of polar body extrusion (PBE). Detection of cytoskeletal dynamics demonstrated that CTL exposure weakened the acetylation level of α-tubulin and impaired meiotic spindle apparatus, which was responsible for the aberrant state of SAC. Meanwhile, exposure to CTL damaged the function of mitochondria, inducing the decline of ATP content and the elevation of reactive oxygen species (ROS), which thereby induced early apoptosis and DNA damage in mouse oocytes. In addition, exposure to CTL caused the alteration of the level of histone H3 methylation, indicative of the harmful effects of CTL on epigenetic modifications in oocytes. Further, the CTL-induced oxidative stress activated mitogen-activated protein kinase (MAPK) pathway and injured the maturation of oocytes. In summary, exposure to CTL damaged mouse oocyte in vitro maturation via destroying spindle assembly, inducing oxidative stress and triggering MAPK pathway activation.

Peanut (Arachis hypogaea L.) is susceptible to leaf spot diseases caused by the fungi Nothopassalora personata and Passalora arachidicola, which can decrease yield substantially. Chlorothalonil is one of the most widely used fungicides to control these diseases but was recently banned in the European Union due to toxicity to amphibians and fish. Dodine is an alternative fungicide with a similar range of activity. However, information about its impact on the peanut physiology is lacking. The objectives of this study were to assess the effect of dodine on leaf photosynthesis, yield, and pod quality of peanut and evaluate the potential of dodine as a replacement of chlorothalonil in the control of leaf spot diseases. A 3‐year field experiment was conducted using Georgia‐06G. Treatments consisted of chlorothalonil at 0.86 kg a.i. ha−1 (high rate), chlorothalonil at 0.43 kg a.i. ha−1 (low rate), dodine at 0.68 kg a.i. ha−1 (high rate), and dodine at 0.34 kg a.i. ha−1 (low rate). Photosynthetic efficiency was altered by fungicide in only a few instances, and a clear trend was not observed. The high rate of dodine resulted in the least defoliation caused by leaf spot of all fungicide treatments. Pod maturity, yield, and grading parameters were not affected by fungicide. Overall, dodine did not impact negatively the photosynthetic activity, pod quality, and yield of peanut. Moreover, this chemistry was efficient in controlling leaf spot diseases under heavy disease pressure; therefore, dodine is a potential replacement of chlorothalonil in the control of leaf spot diseases in peanut. Core Ideas: Leaf photosynthetic efficiency was generally not impacted by chlorothalonil or dodine application.Pod maturity profile, pod yield, and grading parameters did not differ among the fungicide treatments.The selection between chlorothalonil or dodine did not impact the quality and value of peanut pods.High rate of dodine resulted in the lowest defoliation caused by leaf spot diseases of all fungicide treatments.Dodine is a potential alternative to chlorothalonil in the control of leaf spot diseases in peanut. [ABSTRACT FROM AUTHOR]

A mechanistic model was developed to simulate one-dimensional pesticide transport in two-stage vertical flow constructed wetland. The two pesticides taken under study were carbendazim and chlorothalonil. The water flow patterns within the constructed wetland were simulated using the Richards equation. Water content and vertical flux, which are the outputs of the substrate water flow model, were used to calculate the substrate moisture-related parameters and advection term in the solute transport model. The governing solute transport equation took into account a total of six processes: advection, molecular diffusion, dispersion, adsorption to the solid surface, degradation and volatilization. A total of 14 simulation cases, corresponding with available experimental data, were used to calibrate the model, followed by further simulations with standardized influent pesticide concentrations. The simulations indicated that the constructed wetland reached a steady state of pesticide removal after 7 days of operation. Two distinct water flow patterns emerged under saturated and unsaturated conditions. The patterns observed while varying the hydraulic loading rates were similar for each individual saturation condition. Two-factor ANOVA of the simulated data further revealed that the carbendazim and chlorothalonil removal was dependent on the hydraulic loading rates, but it was independent of the influent pesticide concentration. Analysis of the simulated pesticide removal showed that degradation emerged as the predominant removal process over time for both the pesticides. The model developed in this study can be an important tool for the design and construction of treatment wetlands for pesticide removal from wastewater. [ABSTRACT FROM AUTHOR]

It is very important to evaluate the immunotoxicity and molecular mechanisms of pesticides. In this study, difenoconazole and chlorothalonil were evaluated for immunotoxicity by using the human Jurkat T-cell line, and the EC50 were 24.66 and 1.17 mg/L, respectively. The joint exposure of difenoconazole and chlorothalonil showed a synergistic effect at low concentrations (lower than 10.58 mg/L) but an antagonistic effect at high concentrations (higher than 10.58 mg/L). With joint exposure at a concentration of EC10, the proportion of late apoptotic cells was 2.26- and 2.91-fold higher than that with exposure to difenoconazole or chlorothalonil alone, respectively. A transcriptomics analysis indicated that the DEGs for single exposure are associated with immunodeficiency disease. Single exposure to chlorothalonil was mainly involved in cation transportation, extracellular matrix organization, and leukocyte cell adhesion. Single exposure to difenoconazole was mainly involved in nervous system development, muscle contraction, and immune system processes. However, when the joint exposure dose was EC10, the DEGs were mainly involved in the formation of cell structures, but the DEGs were mainly involved in cellular processes and metabolism when the joint exposure dose was EC25. The results indicated that the immunotoxicological mechanisms underlying joint exposure to difenoconazole and chlorothalonil are different under low and high doses. [ABSTRACT FROM AUTHOR]

Glutathione plays a critical role in plant growth, development and response to stress. It is a major cellular antioxidant and is involved in the detoxification of xenobiotics in many organisms, including plants. However, the role of glutathione-dependent redox homeostasis and associated molecular mechanisms regulating the antioxidant system and pesticide metabolism remains unclear. In this study, endogenous glutathione levels were manipulated by pharmacological treatments with glutathione synthesis inhibitors and oxidized glutathione. The application of oxidized glutathione enriched the cellular oxidation state, reduced the activity and transcript levels of antioxidant enzymes, upregulated the expression level of nitric oxide and Ca2+ related genes and the content, and increased the residue of chlorothalonil in tomato leaves. Further experiments confirmed that glutathione-induced redox homeostasis is critical for the reduction of pesticide residues. RNA sequencing analysis revealed that miRNA156 and miRNA169 that target transcription factor SQUAMOSA-Promoter Binding Proteins (SBP) and NUCLEAR FACTOR Y (NFY) potentially participate in glutathione-mediated pesticide degradation in tomato plants. Our study provides important clues for further dissection of pesticide degradation mechanisms via miRNAs in plants.

Chlorothalonil is an organochlorine fungicide that blocks the respiratory process of cells and persists in agricultural products because it is used extensively to prevent fungal diseases. An analytical method of chlorothalonil using the modified QuEChERS method and gas chromatography– mass spectrometry (GC-MS/MS) was developed to analyze the residue in agricultural commodities distributed in Republic of Korea. Acetonitrile, including acetic acid and formic acid, was used to compare the extraction efficiency. The extraction and purification processes were established by comparing three versions of the QuEChERS method and various dispersive solid-phase extraction (d-SPE) combinations. Ultimately, 1% formic acid in acetonitrile with QuEChERS original salts and d-SPE (PSA, C18) were selected for the extraction and clean-up procedures for method validation and establishment. Five agricultural commodities, viz., brown rice, mandarin, soybean, pepper, and potato, were examined to validate the established method, which displayed excellent linearity, with a coefficient of determination of R2 = 0.9939–0.997 in the calibration curve range of 0.002–0.1 mg/kg. The limits of detection (LOD) and quantification (LOQ) were calculated to be 0.003 mg/kg and 0.01, respectively, for the method. The LOQ value satisfied the suitable level for the Positive List System (PLS). The mean recovery of chlorothalonil was 79.3–104.1%, and the coefficient of variation was <17.9% for intra- and inter-day precision at 0.01, 0.1, and 0.5 mg/kg. The matrix effects in the five commodities were confirmed by the ion suppression effects, except for brown rice, in which a medium enhancement effect was observed at 21.4%. Chlorothalonil was detected in eight apples, one watermelon, and one cucumber. Ultimately, chlorothalonil was detected in ten agricultural products. Thus, this analytical method could be used for the routine detection of chlorothalonil in agricultural products, and the data may be used to inform and improve current food policies. [ABSTRACT FROM AUTHOR]

The photodegradation behavior of the mixture of chlorothalonil and profenofos in water was investigated under high pressure mercury lamp (HPML). The results showed that the half-life of chlorothalonil at 3 μmol/L was 122.46 min under the HPML irradiation, and the half-lives of chlorothalonil were 64.54, 38.25 and 33.05 min in the presence of 1, 2 and 3 equivalent of profenofos. The half-lives of 3, 6, and 9 μmol/L profenofos were 87.85, 86.11 and 87.63 min, while they were 85.57, 83.51 and 84.32 min in the presence of chlorothalonil, respectively. This indicates that profenofos promoted the photodegradation of chlorothalonil in water and the promotion effect was increased as the concentration of profenofos increased. Chlorothalonil did not affect the photodegradation of profenofos. The main photodegradation product of chlorothalonil was 4-hydroxyl chlorothalonil with and without profennofos. Five photodegradation products of profenofos were detected, namely, 4-bromo-2-chlorophenyl hydrogen phosphate ethyl ester, O-(4-bromo-2- chlorophenyl)-O-ethyl-S-hydrogen phosphate, O-(2-chlorophenyl)-O-ethyl-S-propyl phosphorothioate, (2-chloro-4-hydroxyphenyl)-O-ethyl-S-propyl phosphorothioate, and 2-chloro-4-bromophenol. Profenofos promoted the degradation of chlotothalonil via the generation of more hydroxyl radicals. This study provides important theoretical support for the evaluation of the environmental ecotoxicity of combined pollution of chlorothalonil and profenofos [ABSTRACT FROM AUTHOR]

The Ethiopian floriculture industry produces large amounts of wastewater, which requires treatment systems with lower retention times, higher hydraulic flow, and higher hydraulic loading rates (HLRs). Unsaturated vertical flow constructed wetlands (UVF-CWs), which represent these characteristics, have not been studied in depth for chlorothalonil remediation from wastewater. In this study, six UVF-CWs and nine pumping stations were organized into three experimental groups as three independent two-stage CW systems. The influent was pumped into the first vertical-flow stage, after which the effluent was collected and pumped into the second vertical-flow stage. The stage A and stage B effluents were tested for chlorothalonil removal at three different HLR of 50, 200, and 400 L d−1 m−2 and two influent chlorothalonil concentrations of 100 and 500 µg L−1. The chlorothalonil levels for the stage A effluent at an HLR of 50 L d−1 m−2 for both influent chlorothalonil concentrations were below the detection limit of 0.08 µg L−1. A maximum chlorothalonil concentration of 7.9 and 196 µg L−1 was observed in the stage A effluent for influent concentrations of 100 and 500 µg L−1, respectively. The chlorothalonil levels for the stage B effluent were all below the detection limit of 0.08 µg L−1. A final chlorothalonil removal efficiency of at least 99.9% was observed for both influent chlorothalonil concentrations at the three HLRs used. These results demonstrated that UVF-CWs represent a viable solution for chlorothalonil remediation in the Ethiopian floriculture industry. [ABSTRACT FROM AUTHOR]

This study investigated the degradation of two chlorothalonil formulations [Chlorcal 70% Wettable Powder (WP) and Open 72% Suspension Concentrate 72% (SC)]. The tested fungicides were stored at 54 ± 2°C for 14 days. During the different storage periods, samples were taken after 1, 3, 7, and 14 days to determine physical properties, evaluate the chemical stability of the active ingredient: Hexachlorobenzene as impurities by HPLC and fingerprint (GC/MS and IR), as well as the evaluation of their efficacy, by testing them against the mycelial growth of Fusarium solani and Botrytis cinerea under in vitro condition. The results indicated that Open 72% SC was the most effective fungicide against F. solani and B. cinerea it recorded the lowest EC50 value of 28.4 and 46.8 ppm respectively, followed by Chlorcal 70%WP with EC50 values of 42.9 and 59.4 ppm respectively. On the other hand, the effectiveness of tested fungicides deteriorated as the result of storage at 54 ± 2 ºC for 14 days with EC50 values increased from 28.4 to 130.9 and 46.8 to 278.1 in the case of Open 72% SC against F. solani and B. cinerea respectively, while the degradation efficiency of Chlorcal 70%WP was decreased at storage with EC50 values from 42.9 to 89.4 and 59.4 to 145.3 against these two fungi respectively. Chlorcal 70%WP was more stable at during storage and less effective against fungal pathogens and determination of chemical content (total soluble sugar; total protein; free amino acids) and some enzymes (amylase and catalase) activities of mycelium fungi. Potato dextrose (PD) media treated with chlorothalonil formulations induced a significant decrease in all components in each fungus except the catalase enzyme in the case of B. cinerea. The obtained results showed that active ingredients were 69.82%, 71.9% and reached 69.3%, and 70.75% after 14 days of storage at 54 ± 2 ºC for Chlorcal 70% WP, Open 72% SC, respectively. Also calculated half-life (T0.5) values for Chlorcal 70% WP, Open 72% SC were 1382.07 days and 614.035 days, respectively. This result refers that Chlorcal 70% WP is more stable than Open 72% SC after storage at 54 ± 2 oC for 14 days, whereas the amount of hexachlorobenzene was within the FAO limits for all sources before and after storage. Then the other tested GC / MS was used for the degradation of chlorothalonil fungicide, the two major degradation products in chlorothalonil were 2,5,6-trichloro- 4- hydroxyisophthalonitrile and 2,4,6-trichloroisophthalonitrile.

Wet bubble disease (WBD) is globally becoming a major problem in mushroom crops. The effectiveness of the application of different chemical (chlorothalonil, metrafenone and prochloraz-Mn) and Bacillus (B. subtilis and B. amyloliquefaciens strains) -based products for the control of WBD in artificially inoculated mushroom crops was studied. Six trials were carried out, with three different inoculum rates. The effect of fungicides on mushroom productivity and disease incidence was assessed. The effectiveness of the treatments is statistically related to the harshness of the disease. The greatest reductions in disease incidence were achieved after treatments with chemical fungicides, notably prochloraz-Mn. When the outbreak was strong, the low calculated incidence reduction values for metrafenone treatments advised against their application. The results also indicated the low effect of both bio-fungicides, at the doses and timing evaluated, for the control of this mushroom disease. [ABSTRACT FROM AUTHOR]

Postharvest senescence and disease development can reduce the nutritional value of fresh jujube fruit. Herein, four different disease-controlling agents (chlorothalonil, CuCl2, harpin and melatonin) were separately applied to fresh jujube fruit, and all improved postharvest quality (evaluated by disease severity, antioxidant accumulation and senescence) relative to controls. Disease severity was drastically inhibited by these agents, in the order chlorothalonil > CuCl2 > harpin > melatonin. However, chlorothalonil residues were detected even after storage for 4 weeks. These agents increased the activities of defense enzymes including phenylalanine ammonia-lyase, polyphenol oxidase, glutathione reductase and glutathione S-transferase, as well as accumulation of antioxidant compounds such as ascorbic acid, glutathione, flavonoids and phenolics, in postharvest jujube fruit. The enhanced antioxidant content and antioxidant capacity (evaluated by Fe3+ reducing power) was ordered melatonin > harpin > CuCl2 > chlorothalonil. All four agents significantly delayed senescence (evaluated by weight loss, respiration rate and firmness), with the effect ordered CuCl2 > melatonin > harpin > chlorothalonil. Moreover, treatment with CuCl2 also increased copper accumulation ~ threefold in postharvest jujube fruit. Among the four agents, postharvest treatment with CuCl2 could be considered most appropriate for improving postharvest jujube fruit quality under low temperature conditions without sterilization. [ABSTRACT FROM AUTHOR]

Direct and indirect effects of the fungicide chlorothalonil on aquatic plankton community structure were investigated by exposing plankton to chlorothalonil concentrations of 0.010, 0.025, 0.100, 0.250 and 1.000 mg/L over 20 days in 18 microcosms (glass tanks having 8 L of pond water). Each treatment was executed in three replicates. Total phytoplankton and zooplankton abundance and chlorophyll-a concentrations in microcosms were measured 5, 10 and 20 days after pesticide exposure. Plankton community and taxa response to pesticide concentrations were analyzed using the similarity of percentages procedure (SIMPER) and one-way ANOVA test. The results of the study indicated that highest concentration levels of chlorothalonil exposure had a significant impact on phytoplankton and zooplankton taxa. Phytoplankton taxa Amphora sp. and Staurastrum sp. and zooplankton taxa Moina sp. and copepod Nauplius were highly sensitive to chlorothalonil exposure. Phytoplankton taxa Mougeotia sp. increased with increased chlorothalonil (0.1–1.0 mg/L) concentrations, and zooplankton taxa of Aeolosoma sp. showed no significant reduction of individuals in response to pesticide exposure. Results showed that pesticide residues have a direct and rapid impact on phytoplankton and zooplankton community structure. Changes in diversity and species composition induced by pesticides indicate the importance of considering indirect effects of pesticides on the ecological food chain in the aquatic environment. [ABSTRACT FROM AUTHOR]

In order to establish a rapid screening method for chlorothalonil residues in blueberry samples, the pesticide chlorothalonil was used as the target analyte in this study, and the effects of colloidal gold labeling parameters and sample preparation methods on colloidal gold immunochromatographic assay (GICA) were systematically studied. Firstly, 25 nm colloidal gold nanoparticles labelled with anti-chlorothalonil monoclonal antibody was used as the detection probe. ChlorothalonilBSA (1 mg/mL) conjugate and goat anti-mouse IgG antibody (0.1 mg/mL) were coated on nitrocellulose filter membrane (NC) to form the test line (T) and quality control line (C), respectively. Then the blueberry samples were extracted with acidic acetonitrile and diluted with double distilledwater (dd H2O), and were detected by the assembled immuno-chromatographic test strip. The qualitative and semi-quantitative analysis of chlorothalonil in blueberries could be accomplished within 15 minutes, and the limit of detection (LOD) observed by naked eyes was 0.1 mg/kg. The crossreactivity for the detection of 4-hydroxy-chlorothalonil, quintozene, carbendazim and procymidone was negligible. The recovery results of chlorothalonil in blueberry using the colloidal gold immunochromatographic test strip were consistent with those of the UPLC-MS/MS method. Both methods could be successfully applied to the detection of chlorothalonil in blueberries. The immunochromatographic test strip is helpful for on-site detection, while the UPLC-MS /MS method can provide accurate quantification. [ABSTRACT FROM AUTHOR]

Fungicide usage has increased globally in response to the rise in fungal pathogens, especially in the agricultural sector. However, research examining the toxicity of fungicides is still limited for many aquatic species. In this study, we examined the acute toxicity of two widely used fungicides, chlorothalonil and pyraclostrobin, on six North American larval amphibian species across multiple families using 96-h LC50 tests. We found that pyraclostrobin was approximately 3.5x more toxic than chlorothalonil; estimated LC50 values ranged from 5–18 µg/L for pyraclostrobin and 15–50 µg/L for chlorothalonil. Comparing across amphibian groups, we found that salamanders were 3x more sensitive to pyraclostrobin than anuran species and equally as sensitive to chlorothalonil. Notably, our estimated LC50 values within the range of the expected environmental concentration for these fungicides suggesting environmental exposures could lead to direct mortality in these species. Given the widespread and increasing usage of fungicides, additional work should be conducted to assess the general risk posed by these chemicals to amphibian and their associated aquatic habitats. [ABSTRACT FROM AUTHOR]

Background: Chlorothalonil and acetamiprid are chemical pesticides commonly used in agricultural production and have been shown to have negative effects on bee’s fitness. Despite many studies have revealed that honey bee (Apis mellifera L.) larvae are posting a high risk on exposure to pesticides, but the toxicology information of chlorothalonil and acetamiprid on bee larvae remain limited. Results: The no observed adverse effect concentration (NOAEC) of chlorothalonil and acetamiprid for honey bee larvae were 4 μg/mL and 2 μg/mL, respectively. Except for CarE, the enzymic activities of GST and P450 were not influenced by chlorothalonil at NOAEC, while chronic exposure to acetamiprid slightly increased the activities of the three tested enzymes at NOAEC. Further, the exposed larvae showed significantly higher expression of genes involved in a series of different toxicologically relevant process following, including caste development (Tor (GB44905), InR-2 (GB55425), Hr4 (GB47037), Ac3 (GB11637) and ILP-2 (GB10174)), immune system response (abaecin (GB18323), defensin-1 (GB19392), toll-X4 (GB50418)), and oxidative stress response (P450, GSH, GST, CarE). Conclusion: Our results suggest that the exposure to chlorothalonil and acetamiprid, even at concentrations below the NOAEC, showed potentially effects on bee larvae’s fitness, and more important synergistic and behavioral effects that can affect larvae fitness should be explored in the further. [ABSTRACT FROM AUTHOR]

Quantitative detection of pesticide residues in food and environmental samples using an improved lateral flow immunoassay (LFIA) is of considerable importance for real-time analysis. This paper proposes a highly sensitive LFIA platform based on a hierarchical magneto-colorimetric compact. This compact serves as both the target magnetic enrichment substrate and a photosensitive label. Initially, a large porous dendritic silica template is prepared and doped with superparamagnetic ferric oxide nanoparticles (Fe 3 O 4 NPs) and colloidal gold nanoparticles (AuNPs) at high densities within its vertical channels. The sequential assembly of central–radial channels allow for the three-dimensional integration of these two components, enabling independent control of their discrete functions without mutual interference. Following alkyl organosilicon encapsulation and silica sealing, the composite spheres are then applied in LFIA to detect chlorothalonil residues. Fe 3 O 4 NPs enhance the binding efficiency to target analytes, while AuNPs amplify the signal, leveraging their high loading densities and robust optical properties. The developed LFIA platform exhibited a detection limit of 0.34 ng/mL for chlorothalonil and a linear range of 0.0085–824 ng/mL. The recoveries varied between 85.1 % and 103.1 %, and the relative standard deviations were 1.25%–8.84 %. This LFIA approach demonstrates high sensitivity, specificity, reproducibility and flexible detection modes, making it highly suitable for the on-site monitoring of pesticide residues. [Display omitted] • Dear Sir/Madam: • A sensitive LFIA platform was constructed using hierarchical magnetic substrates. • This study is the first to examine how SFAS enhance antigen-antibody binding. • Integrating two materials speeds up sample preparation and improves sensitivity. • The method presented a much lower LOD with stable than another detection. [ABSTRACT FROM AUTHOR]

It is very important to evaluate the immunotoxicity and molecular mechanisms of pesticides. In this study, difenoconazole and chlorothalonil were evaluated for immunotoxicity by using the human Jurkat T-cell line, and the EC50 were 24.66 and 1.17 mg/L, respectively. The joint exposure of difenoconazole and chlorothalonil showed a synergistic effect at low concentrations (lower than 10.58 mg/L) but an antagonistic effect at high concentrations (higher than 10.58 mg/L). With joint exposure at a concentration of EC10, the proportion of late apoptotic cells was 2.26- and 2.91-fold higher than that with exposure to difenoconazole or chlorothalonil alone, respectively. A transcriptomics analysis indicated that the DEGs for single exposure are associated with immunodeficiency disease. Single exposure to chlorothalonil was mainly involved in cation transportation, extracellular matrix organization, and leukocyte cell adhesion. Single exposure to difenoconazole was mainly involved in nervous system development, muscle contraction, and immune system processes. However, when the joint exposure dose was EC10, the DEGs were mainly involved in the formation of cell structures, but the DEGs were mainly involved in cellular processes and metabolism when the joint exposure dose was EC25. The results indicated that the immunotoxicological mechanisms underlying joint exposure to difenoconazole and chlorothalonil are different under low and high doses.

Among different novel technologies, sonochemistry is a sustainable emerging technology for food processing, preservation, and pesticide removal. The study aimed to probe the impact of high-intensity ultrasonication on chlorothalonil fungicide degradation, reduction pathway, and bioactive availability of spinach juice. The chlorothalonil fungicide-immersed spinach juice was treated with sonication at 360 W, 480 W, and 600 W, 40 kHz, for 30 and 40 min at 30 ± 1 °C. The highest reduction of chlorothalonil fungicide residues was observed at 40 min sonication at 600 W. HPLC-MS (high-performance liquid chromatography-mass spectroscopy) analysis revealed the degradation pathway of chlorothalonil and the formation of m-phthalonitrile, 3-cyno-2,4,5,6-tetrachlorobenamide, 4-dichloroisophthalonitrile, trichloroisophtalonitrile, 4-hydoxychlorothalonil, and 2,3,4,6-tetrachlorochlorobenzonitrile as degradation products. High-intensity sonication treatments also significantly increased the bioavailability of phenolic, chlorophyll, and anthocyanins and the antioxidant activity of spinach juice. Our results proposed that sonication technology has excellent potential in degrading pesticides through free radical reactions formation and pyrolysis. Considering future perspectives, ultrasonication could be employed industrially to reduce pesticide residues from agricultural products and enhance the quality of spinach juice.

This study investigated the degradation of two chlorothalonil formulations [Chlorcal 70% Wettable Powder (WP) and Open 72% Suspension Concentrate 72% (SC)]. The tested fungicides were stored at 54 ± 2°C for 14 days. During the different storage periods, samples were taken after 1, 3, 7, and 14 days to determine physical properties, evaluate the chemical stability of the active ingredient: Hexachlorobenzene as impurities by HPLC and fingerprint (GC/MS and IR), as well as the evaluation of their efficacy, by testing them against the mycelial growth of Fusarium solani and Botrytis cinerea under in vitro condition. The results indicated that Open 72% SC was the most effective fungicide against F. solani and B. cinerea it recorded the lowest EC50 value of 28.4 and 46.8 ppm respectively, followed by Chlorcal 70%WP with EC50 values of 42.9 and 59.4 ppm respectively. On the other hand, the effectiveness of tested fungicides deteriorated as the result of storage at 54 ± 2 °C for 14 days with EC50 values increased from 28.4 to 130.9 and 46.8 to 278.1 in the case of Open 72% SC against F. solani and B. cinerea respectively, while the degradation efficiency of Chlorcal 70%WP was decreased at storage with EC50 values from 42.9 to 89.4 and 59.4 to 145.3 against these two fungi respectively. Chlorcal 70%WP was more stable at during storage and less effective against fungal pathogens and determination of chemical content (total soluble sugar; total protein; free amino acids) and some enzymes (amylase and catalase) activities of mycelium fungi. Potato dextrose (PD) media treated with chlorothalonil formulations induced a significant decrease in all components in each fungus except the catalase enzyme in the case of B. cinerea. The obtained results showed that active ingredients were 69.82%, 71.9% and reached 69.3%, and 70.75% after 14 days of storage at 54 ± 2 °C for Chlorcal 70% WP, Open 72% SC, respectively. Also calculated half-life (T0.5) values for Chlorcal 70% WP, Open 72% SC were 1382.07 days and 614.035 days, respectively. This result refers that Chlorcal 70% WP is more stable than Open 72% SC after storage at 54 ± 2 oC for 14 days, whereas the amount of hexachlorobenzene was within the FAO limits for all sources before and after storage. Then the other tested GC / MS was used for the degradation of chlorothalonil fungicide, the two major degradation products in chlorothalonil were 2,5,6-trichloro-4-hydroxyisophthalonitrile and 2,4,6-trichloroisophthalonitrile. [ABSTRACT FROM AUTHOR]

Powdery mildew is one of the most important diseases that causes significant economic losses in melon. Chemical fungicides and tolerant melon varieties, which may reduce pathogen severity and encourage positive plant responses, are viable techniques for controlling this disease. The study objectives were to investigate the effectiveness of contact fungicides, systemic fungicides and a combination of both in four commercial fields at various sampling times [30, 90 and 120 days after the first fungicide application (DAFA)]. Both fungicide mixture azoxystrobin + chlorothalonil and fungicide thiophanate-methyl reduced the disease index of powdery mildew on melon varieties compared to the untreated control (disease index 1.70–2.13 and 0.83–1.75, respectively at 120 DAFA), reduced the disease severity (24.79–31.5% and 19.06–21.88%, respectively at 120 DAFA) and the percentage of leaf area covered by powdery mildew (27–43.75% and 8.25–39%, respectively at 120 DAFA). Furthermore, melon plants treated with azoxystrobin + chlorothalonil showed a larger yield increase (63.31–71.40%), polar (15.43–17.59 cm) and equatorial (24.71–29.61 cm) diameter, yield (2.23–3.18 fruits number/plant; 27.67–52.22 t/ha) and mean weight (2411.25–3289.5 g). Azoxystrobin + chlorothalonil and thiophanate-methyl not only reduced the disease index and disease severity index, but also promoted a yield increase of all melon varieties. More attention should be given to the effectiveness of chemical fungicide control in view of expected climate changes. But fungicides continuous application following a fixed schedule is unsustainable and could lead to high resistance development in PM fungi. [ABSTRACT FROM AUTHOR]

A series of simulated rainfall experiments were conducted to determine the interception effects of grass filter strip（GFS） established by bermuda, tall fescue and white clover on atrazine with weaker absorbability and chlorothalonil with stronger absorbability in surface runoff by comparison with control system（CS）, while the migration characteristics of the two kinds of pesticides with different absorbability were discussed. The results show that the outflow concentrations of dissolved and adsorbed atrazine are higher than that of chlorothalonil both from CS and GFS; compared with CS, the concentrations of dissolved atrazine and dissolved chlorothalonil from GFS are decreased by more than 60% and 6% respectively. The reduction of suspended particles amount from GFS is more than 94.70%, and the load reductions of adsorbed atrazine and chlorothalonil from GFS are more than 80% by comparison with CS. The study evidences that GFS can effectively intercept the pesticide carried both in solid and liquid phases, and vegetation is more important to atrazine interception. [ABSTRACT FROM AUTHOR]

Pesticides are extensively used in agriculture to prevent infestation of crops, control plant-associated diseases and pests, and increase crop productivity. With regards to typical agricultural practice, tank mixing of two or more plant protection products or the subsequent applications of herbicides, fungicides, and insecticides are common application strategies to improve pest control. Our study provides evidence that the fungicide mixture consisting of mancozeb, metalaxyl-M, and chlorothalonil, each applied according to their recommended field rates, retarded the degradation of the phenoxy herbicide 4-chloro-2-methylphenoxyacetic acid (MPCA) in soil. MCPA dissipation times were between 1.6 and 1.9 days without and 2.5–3.5 days with co-applied fungicides. Furthermore, the proportions of extractable residues, non-extractable residues, mineralization, volatile organic compounds, and MPCA metabolism were altered by the fungicide mixture, i.e., considerably lower amounts of the main transformation product of MCPA, 4-chloro-2-methylphenol, were formed. The effects induced by the fungicides persisted throughout the experiment. Our results demonstrate that the current situation of considering individual active substances in the authorization process for plant protection products could lead to a discrepancy in the exposure assessment for humans and the environment. For specifically these cases, this calls into question whether the legally required level of protection is provided. [ABSTRACT FROM AUTHOR]

Copyright of Food Hygienic & Safety Science / Shokuhin Eiseigaku Zasshi is the property of Japanese Society for Food Hygiene & Safety and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pesticide residues have been a focus of attention of food safety. Different varietal pakchoi plants grown in open fields were studied to understand effects of morphology, leaf wax content, and vitamin C on the deposition, dissipation, and metabolism of chlorothalonil. The loose pakchoi plants and flat leaves were conducive to pesticide deposition, but not plants with erect leaves. Chlorothalonil on nine varieties of pakchoi dissipated in the first-order kinetic with T1/2 s of 1.4 ~ 2.0 days. Vitamin C in pakchoi could promote the dissipation of chlorothalonil. Carbendazim could significantly promote the dissipation of chlorothalonil on pakchoi. Interestingly, four metabolites of chlorothalonil were identified in the pakchoi and the metabolic pathway was predicted by DFT calculations. The risk assessment showed that pakchoi were safe for consumption after 10 days of application of the recommended dose. This work provides important information for the understanding of deposition, dissipation, and metabolism of chlorothalonil in pakchoi. [ABSTRACT FROM AUTHOR]

Copyright of Coatings & Protection / Tuceng yu Fanghu is the property of Coating & Protection Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work aimed to evaluate the efficacy of fungicides for controlling anthracnose (Colletotrichum gloeosporioides) on peach palm (Bactris gasipaes var. gasipaes) seedlings in nursery beds and in newly planted peach palms in the field. The nursery experiment included two fungicide combinations: [thiophanate-methyl + chlorothalonil (TM + C) and pyraclostrobin + epoxiconazole (P + E)], three application intervals (7, 14, and 21 days), and an additional nontreated control. The two field experiments with newly planted peach palms tested the fungicide combinations TM + C at 15-day intervals for 12 months after transplanting, comparing to the control without fungicide application. The severity of anthracnose was assessed, and it was used for calculating the area under the disease progress curve (AUDPC). The fungicides TM + C and E + P applied at 7-days intervals were effective in the control of anthracnose in peach palm seedlings, resulting in the lowest severities and AUDPC. The fungicide TM + C reduced the maximum disease severity and AUDPC under field conditions. However, differences in the final severity of anthracnose and stem diameter were not significant compared to the control. Therefore, the use of fungicides for control of anthracnose in the field is not necessary. [ABSTRACT FROM AUTHOR]

The rapid sulfhydrylation of chlorothalonil (CHT) in sulfur-rich vegetable matrices was observed in our previous study. However, the formation pathway, residual behavior, and toxicity of sulfhydrylated CHT remain unclear. In this study, we reveal that 4-sulfhydryl chlorothalonil (4-SH-CHT) can be formed by the reaction of CHT with H 2 S species. CHT sulfhydrylation mainly occurs in tissue-destroyed pak choi, as H 2 S and various H 2 S donors are released along with tissue destruction. Over 50 % of CHT was transformed during pak choi homogenization at room temperature (25 °C). Liquid nitrogen with solvent acidification has been proposed to inhibit rapid sulfhydrylation during the analysis of CHT and its degradation products. The analytical method developed to simultaneously detect CHT, 4-SH-CHT, and 4-hydroxy chlorothalonil demonstrated good accuracy, high sensitivity, and satisfactory repeatability. At the maximum recommended dose of CHT, the terminal concentration of CHT in pak choi was higher than the maximum residue level, suggesting a potential chronic risk. The acute toxicity of 4-SH-CHT was higher than that of CHT, and the main target organs were the liver and heart. The consumption of 4-SH-CHT in several tissue-destroyed pak choi samples was higher than the threshold level. This study provides valuable information for further comprehensive safety evaluations of CHT in sulfur-rich vegetables and related foods., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Chlorothalonil is an organochlorine fungicide that blocks the respiratory process of cells and persists in agricultural products because it is used extensively to prevent fungal diseases. An analytical method of chlorothalonil using the modified QuEChERS method and gas chromatography– mass spectrometry (GC-MS/MS) was developed to analyze the residue in agricultural commodities distributed in Republic of Korea. Acetonitrile, including acetic acid and formic acid, was used to compare the extraction efficiency. The extraction and purification processes were established by comparing three versions of the QuEChERS method and various dispersive solid-phase extraction (d-SPE) combinations. Ultimately, 1% formic acid in acetonitrile with QuEChERS original salts and d-SPE (PSA, C18) were selected for the extraction and clean-up procedures for method validation and establishment. Five agricultural commodities, viz., brown rice, mandarin, soybean, pepper, and potato, were examined to validate the established method, which displayed excellent linearity, with a coefficient of determination of R2 = 0.9939–0.997 in the calibration curve range of 0.002–0.1 mg/kg. The limits of detection (LOD) and quantification (LOQ) were calculated to be 0.003 mg/kg and 0.01, respectively, for the method. The LOQ value satisfied the suitable level for the Positive List System (PLS). The mean recovery of chlorothalonil was 79.3–104.1%, and the coefficient of variation was

Vanilla planifolia is attacked by the fungus F. oxysporum f. sp. vanillae. Since there are no resistant genotypes available to producers, they opt for the use of synthetic fungicides to control the disease, however, there is no information on a possible resistance of the pathogen to these commercial fungicides. The goal of the work was to analyze the response of F. oxysporum strains, pathogenic (nine) and non-pathogenic (three) of V. planifolia, to three fungicides of the benzimidazole family and to chlorothalonil, as well as the genetic bases by studying the target proteins of these active ingredients, β-tubulin and GPDH. It was observed that the 12 strains studied were susceptible to the fungicides benomyl and carbendazim, while 11 of them were resistant to thiophanate methyl and nine to chlorothalonil. No relationship was found between the pathogenic character or the origin of the strains and the susceptibility to fungicides. It was found that resistance to thiophanate methyl is not conferred by a point mutation of the β-tubulin coding sequence, as previously hypothesized; apparently, it could be more related to the absence of protein motifs. No relationship was observed between variation in the gene GPDH with the resistance or susceptibility of the strains. [ABSTRACT FROM AUTHOR]

A liquid crystal (LC)-based assay was developed to detect chlorothalonil (CHL). The detection principle is based on (i) the electrostatic interaction between the positively charged protein protamine (PRO) with the negatively charged phospholipid dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DOPG) and (ii) the CHL-mediated inhibition of papain (PAP) activity. The aqueous/LC interface was decorated with a monolayer of DOPG and PRO that self-assembled via electrostatic interactions. PAP can hydrolyze PRO, resulting in the realignment of an LC by DOPG, inducing a shift in the LC response from bright to dark. The addition of CHL can inhibit the activity of PAP, leading to the attraction of PRO to DOPG and the consequent disruption of the LC orientation. The orientation change of the LC in the presence or absence of CHL can be observed from the changes in its optical appearance using a polarized light microscope. Under optimal conditions, the developed assay achieved a detection limit of 0.196 pg mL−1 within a range of determination of 0.65–200 pg mL−1. The selectivity of the assay was verified in the presence of carbendazim and imidacloprid. The practical application of the proposed assay was demonstrated by its use to determine the levels of CHL in food extracts and environmental samples, which yielded recoveries and relative standard deviations (RSD) in the ranges of 87.39–99.663% and 1.03–6.32%, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Sublethal concentrations of β-endosulfan reduced tadpoles weight, neutrophil and lymphocyte count, while CORT levels increased. • Tadpoles exposed to chlorothalonil show an increase in counts of monocytes and lymphocytes; and accelerated the larval development. • A combination of stress factors increases the number of lymphocytes in the blood due to synergistic cytotoxicity. • Chlorothalonil has non-monotonic effects on various immune cells at low concentrations. • Predators produce variation in weight and length of the tadpoles. Pesticide exposure and its interaction with other natural stressors can play a role in amphibian population declines because disruptions in stress hormone regulatory mechanisms may inhibit immune responses during metamorphosis. Here, we determined the interactive effects of predation risk and sublethal concentration of two pesticides on immunological and physiological responses in tadpoles of the tropical frog Lithobates taylori. Using mesocosms, we used chronic exposure to three levels of chlorothalonil and β-endosulfan in the presence or absence of Odonate larvae. Our results show that β-endosulfan in high concentrations reduced the weight of the tadpoles and increased the neutrophil count and corticosterone (CORT) levels. Larval development was accelerated by high concentrations of chlorothalonil. Also, this pesticide in low and high concentrations increases the absolute values of lymphocytes. Tadpoles exposed to chlorothalonil increased the numbers of monocytes (in low concentrations), and lymphocytes (in high and low concentrations). The interactions of the low concentrations of both pesticides with and without the predator's presence also increased the number of lymphocytes. A combination of pesticides increases the number of lymphocytes in the blood due to synergistic cytotoxicity. This study proves that β- endosulfan elevates circulating CORT and thus generates physiological stress in tadpoles. Given that both pesticides are widely used within the distribution of L. taylori in Costa Rica, it is likely that tadpoles' development and immune function are altered by pesticide use. In combination with stressors such as emerging diseases and altered precipitation regimes, widespread agrochemical uses likely caused this species enigmatic decline in recent decades. [ABSTRACT FROM AUTHOR]