MOF-based Ag NPs/Co3O4 nanozyme for colorimetric detection of thiophanate-methyl based on analyte-enhanced sensing mechanism.

Silver nanoparticles supported on metal-organic framework (ZIF-67)-derived Co3O4 nanostructures (Ag NPs/Co3O4) were synthesized via a facile in situ reduction strategy. The resulting materials exhibited pH-switchable peroxidase/catalase-like catalytic activity. Ag NP doping greatly enhanced the catalytic activity of Ag NPs/Co3O4 towards 3,3',5,5'-tetramethylbenzidine (TMB) oxidation and H2O2 decomposition which were 59 times (A652 of oxTMB) and 3 times (A240 of H2O2) higher than that of ZIF-67, respectively. Excitingly, thiophanate-methyl (TM) further enhanced the peroxidase-like activity of Ag NPs/Co3O4 nanozyme due to the formation of Ag(I) species in TM-Ag NPs/Co3O4 and generation of more radicals resulting from strong interaction between Ag NPs and TM. The TM-Ag NPs/Co3O4 nanozyme exhibited lower Km and higher Vmax values towards H2O2 when compared with Ag NPs/Co3O4 nanozyme. A simple, bioelement-free colorimetric TM detection method based on Ag NPs/Co3O4 nanozyme via analyte-enhanced sensing strategy was successfully established with high sensitivity and selectivity. Our study demonstrated that hybrid noble metal NPs/MOF-based nanozyme can be a class of promising artificial nanozyme in environmental and food safety applications.

Research Progress on Benzimidazole Fungicides: A Review.

Benzimidazole fungicides are a class of highly effective, low-toxicity, systemic broad-spectrum fungicides developed in the 1960s and 1970s, based on the fungicidal activity of the benzimidazole ring structure. They exhibit biological activities including anticancer, antibacterial, and antiparasitic effects. Due to their particularly outstanding antibacterial properties, they are widely used in agriculture to prevent and control various plant diseases caused by fungi. The main products of benzimidazole fungicides include benomyl, carbendazim, thiabendazole, albendazole, thiophanate, thiophanate-methyl, fuberidazole, methyl (1-{[(5-cyanopentyl)amino]carbonyl}-1H-benzimidazol-2-yl) carbamate, and carbendazim salicylate. This article mainly reviews the physicochemical properties, toxicological properties, disease control efficacy, and pesticide residue and detection technologies of the aforementioned nine benzimidazole fungicides and their main metabolite (2-aminobenzimidazole). On this basis, a brief outlook on the future research directions of benzimidazole fungicides is presented.

Smartphone-assisted carbon dots fluorescent sensing platform for visual detection of Thiophanate-methyl in fruits and vegetables.

Trimesic acid and o-phenylenediamine (OPD) were employed as precursors to synthesize yellow-green fluorescent carbon dots (Y-G-CDs) by solvothermal synthesis for the sensitive detection of Thiophanate-methyl (TM) in real agricultural products. The Y-G-CDs probe could specifically recognize the TM primarily through π-π stacking. Moreover, the fluorescence quenching of the probe was ultimately dominated by the PET effect, based on the interaction between the abundant carboxyl groups on the surface of the Y-G-CDs and the amino group of TM. A strong linear relationship between the fluorescence quenching of the probe and TM concentration in the range of 0-10 µmol/L was observed and the limit of detection (LOD) was calculated to be 50.7 nmol/L. Compared to the interference pesticides, the Y-G-CDs probe demonstrated exceptional selectivity toward TM, with satisfactory recoveries of 96.3 % - 104.2 % in spiked food samples. The Y-G-CDs probe enables simple pretreatment, cost-effective, and on-site detection of TM in fruits and vegetables with visual detection of the TM employing a smartphone-assisted sensing platform.

Fungicide Sensitivity of Fusarium oxysporum f. sp. lentis and Fusarium acuminatum Affecting Lentil in the Northern Great Plains.

Fusarium oxysporum f. sp. lentis and F. acuminatum cause wilting and root rot in pulse crops including lentil. Fungicide seed treatments are widely used, but information about Fusarium spp. sensitivity in lentils is limited. Here, 30 F. oxysporum f. sp. lentis and 30 F. acuminatum isolates from Montana, southern Canada, North Dakota, and Washington were identified, tested for pathogenicity, and assayed for in vitro sensitivity to pyraclostrobin, prothioconazole, ipconazole, and thiophanate-methyl. F. oxysporum f. sp. lentis and F. acuminatum differed in their sensitivity to all fungicides. No resistant isolates were identified, but F. oxysporum f. sp. lentis had lower EC50 values in pyraclostrobin (averaging 0.47 µg a.i./ml) than F. acuminatum (averaging 0.89 µg a.i./ml) for mycelia assays. Both species had lower EC50 values in prothioconazole, averaging EC50 0.23 in F. oxysporum f. sp. lentis and 0.53 µg a.i./ml in F. acuminatum. F. oxysporum f. sp. lentis isolates had the lowest EC50 values on ipconazole compared to F. acuminatum (0.78 and 1.49 µg a.i./ml). The pathogens were least sensitive to thiophanate-methyl (1.74 µg a.i./ml for F. oxysporum f. sp. lentis and 1.91 µg a.i./ml for F. acuminatum). Overall sensitivity to the fungicides was higher in F. oxysporum f. sp. lentis than F. acuminatum. This study provides reference EC50 values while pointing to the possibility of differential fungicide efficacies on Fusarium spp. This will be helpful to monitor shifts in sensitivity of Fusarium spp. and devise robust root rot/wilt management approaches.

Low frequency of resistance to thiophanate-methyl in Monilinia fructicola populations from southeastern United States peach orchards.

Methyl benzimidazole carbamate (MBC) fungicides were once widely used for brown rot (Monilinia fructicola) control of peach (Prunus persica (L.) Batsch) in the southeastern US, but their use was substantially reduced and often eliminated due to widespread resistance. In this study, 233 M. fructicola isolates were collected from major peach production areas in Alabama, Georgia, and South Carolina, and sensitivity to thiophanate-methyl was examined. Isolates were also collected from one organic and two experimental peach orchards. A discriminatory dose of 1 µg/ml was used to distinguish sensitive (S) and moderately sensitive (S-LR) isolates from low resistant phenotypes, while 50 and 500 µg/ml thiophanate-methyl concentrations were used to determine high resistant (HR) phenotypes. Sequence analyses were performed to identify mutations in the ß-tubulin target gene and detached fruit assays were performed to determine the efficacy of a commercial product against isolates representing each phenotype. Results indicated 55.7%, 63.5%, and 75.9% of isolates from Alabama, Georgia, and South Carolina, respectively, were S to thiophanate-methyl; 44.3%, 36.5%, and 21.4% were S-LR; no isolates were LR; and only 3 isolates (1.3%) from South Carolina were HR. No mutations in S or S-LR isolates were found, but HR isolates revealed the E198A mutation, an amino acid change of glutamic acid to alanine conferring high resistance. The high label rate of a commercial product containing thiophanate-methyl controlled brown rot caused by S and S-LR isolates in detached fruit studies but was ineffective against HR isolates. The combinations of thiophanate-methyl with azoxystrobin or isofetamid, when mixed together and applied in an experimental orchard 14 days preharvest, significantly reduced brown rot incidence on pre and postharvest commercially ripe fruit and efficacy was comparable to that of a grower standard fungicide. These results indicate that thiophanate-methyl may again be useful to peach growers in the southeastern US for brown rot and fungicide resistance management.

Unveiling the Impact of Thiophanate-Methyl on Arthrospira platensis: Growth, Photosynthetic Pigments, Biomolecules, and Detoxification Enzyme Activities.

BACKGROUND: The intensive and injudicious use of pesticides in agriculture has emerged as a major concern due to its detrimental impact on aquatic ecosystems. However, the specific impact of broad-spectrum fungicides, such as Thiophanate-methyl (TM), on cyanobacteria remains a subject of ongoing research and debate. METHODS: In order to fill this knowledge gap, The present study aimed to comprehensively investigate the toxicological effects of TM (10-30 µg/L) on the growth, photosynthetic pigments, oxidative stress, and biochemical composition of the non-nitrogen-fixing cyanobacterium Arthrospira platensis. RESULTS: Our findings unequivocally demonstrated that TM exposure significantly inhibited the growth of A. platensis. Moreover, the decrease in chlorophyll content indicated a pronounced negative impact on the photosynthetic system of A. platensis caused by TM exposure. Notably, TM induced oxidative stress in A. platensis, as substantiated by a significant increase in lipid peroxidation (MDA) within the culture. Furthermore, the intracellular generation of hydrogen peroxide (H2O2) exhibited a positive correlation with higher TM dosages, while the levels of vital antioxidant enzymes, such as catalase (CAT) and ascorbate peroxidase (APX), exhibited a discernible decrease. This suggests that TM compromises the antioxidant defense mechanisms of A. platensis. Additionally, TM was found to enhance the activity of a plethora of enzymes involved in the detoxification of pesticides, including peroxidase (POD) and glutathione-S-transferase (GST), thereby indicating a robust detoxification response by A. platensis. Interestingly, exposure to TM resulted in a general suppression of biocomponent production, such as total proteins and total carbohydrates, which exhibited a diminishing trend with increasing TM concentration. Conversely, the lipid content witnessed a significant increase, possibly as an adaptive response to TM-induced stress. CONCLUSIONS: These findings contribute to a deeper understanding of the ecological implications of pesticide usage and emphasize the urgent need for the adoption of sustainable and environmentally-friendly agricultural practices to safeguard aquatic ecosystems.

Efficacy and Profitability of Fungicides for Managing Frogeye Leaf Spot on Soybean in the United States: A 10-Year Quantitative Summary.

Frogeye leaf spot (FLS), caused by Cercospora sojina, is an economically important disease of soybean in the United States. Data from 66 uniform fungicide trials (UFTs) conducted from 2012 to 2021 across eight states (Alabama, Arkansas, Illinois, Iowa, Kentucky, Louisiana, Mississippi, and Tennessee) were gathered and analyzed to determine the efficacy and profitability of the following fungicides applied at the beginning pod developmental stage (R3): azoxystrobin + difenoconazole (AZOX + DIFE), difenoconazole + pydiflumetofen (DIFE + PYDI), pyraclostrobin (PYRA), pyraclostrobin + fluxapyroxad + propiconazole (PYRA + FLUX + PROP), tetraconazole (TTRA), thiophanate-methyl (TMET), thiophanate-methyl + tebuconazole (TMET + TEBU), and trifloxystrobin + prothioconazole (TFLX + PROT). A network meta-analytic model was fitted to the log of the means of FLS severity data and to the nontransformed mean yield for each treatment, including the nontreated. The percent reduction in disease severity (%) and the yield response (kg/ha) relative to the nontreated was the lowest for PYRA (11%; 136 kg/ha) and the greatest for DIFE + PYDI (57%; 441 kg/ha). A significant decline in efficacy over time was detected for PYRA (18 percentage points [p.p.]), TTRA (27 p.p.), AZOX + DIFE (18 p.p.), and TMET + TEBU (19 p.p.) by using year as a continuous covariate in the model. Finally, probabilities of breaking even were the greatest (>65%) for the most effective fungicide DIFE + PYDI and the lowest (<55%) for PYRA. Results of this meta-analysis may be useful to support decisions when planning fungicide programs.

Self-assembled thiophanate-methyl/star polycation complex prevents plant cell-wall penetration and fungal carbon utilization during cotton infection by Verticillium dahliae.

No effective fungicides are available for the management of Verticillium dahliae, which causes vascular wilt disease. In this study, a star polycation (SPc)-based nanodelivery system was used for the first time to develop a thiophanate-methyl (TM) nanoagent for the management of V. dahliae. SPc spontaneously assembled with TM through hydrogen bonding and Van der Waals forces to decrease the particle size of TM from 834 to 86 nm. Compared to TM alone, the SPc-loaded TM further reduced the colony diameter of V. dahliae to 1.12 and 0.64 cm, and the spore number to 1.13 × 108 and 0.72 × 108 cfu/mL at the concentrations of 3.77 and 4.71 mg/L, respectively. The TM nanoagents disturbed the expression of various crucial genes in V. dahliae, and contributed to preventing plant cell-wall degradation and carbon utilization by V. dahliae, which mainly impaired the infective interaction between pathogens and plants. TM nanoagents remarkably decreased the plant disease index and the fungal biomass in the root compared to TM alone, and its control efficacy was the best (61.20 %) among the various formulations tested in the field. Furthermore, SPc showed negligible acute toxicity toward cotton seeds. To the best of our knowledge, this study is the first to design a self-assembled nanofungicide that efficiently inhibits V. dahliae growth and protects cotton from the destructive Verticillium wilt.

Processes involved in biochemical response to pesticides by lizard Podarcis siculus (Rafinesque-Schmaltz, 1810) - A field study.

Although reptiles are non-target organisms of pesticide applications, their ecological niche and trophic role suggest that the use of these compounds in agriculture can have toxicological effects on them. Our recent field study on Italian wall lizard Podarcis siculus in hazelnut orchards evidenced that the use of pesticides-mixtures, consisting of thiophanate-methyl (TM), tebuconazole (TEB), deltamethrin (DM), lambda-cyhalothrin (LCT), besides copper sulphate, induced an increase of the total antioxidant capacity toward hydroxyl radicals and caused DNA damage; however, it did not cause neurotoxicity, and did not induce the glutathione-S-transferases' activities. These results raised some questions which were answered in this study by carrying out analyses on 4 biomarkers and 5 chemical substances in the tissues of non-target organisms coming from treated fields: cytochrome P450, catalase, total glutathione, and malondialdehyde, TM, TEB, DM, LCT and Cu. Our results highlighted a partial accumulation of different chemicals, the involvement of two important mechanisms of defence, and some cellular damages after exposure to the considered pesticides. In details, 1) LCT and DM were not accumulated in lizard muscle, copper remained at basal levels, whereas TM and TEB were uptaken with a partial metabolization of TM; 2) the cytochrome P450 and the catalase were involved in lizard biochemical responses to pesticides-mixtures used for "conventional" farming treatment; 3) "conventional" treatment with pesticides caused damage to lipids, besides DNA, probably related to the excess of hydroxyl radicals.

Thiophanate-methyl induces notochord toxicity by activating the PI3K-mTOR pathway in zebrafish (Danio rerio) embryos.

Thiophanate-methyl (TM), a typical pesticide widely used worldwide, was detected in rivers, soil, fruits, and vegetables. Thus, it is urgent to identify the potential harm of TM residual to non-target organisms and its molecular mechanisms. We used zebrafish (Danio rerio) in this study to evaluate TM toxicity. TM exposure induced developmental toxicity, including inhibited hatchability, reduced heart rates, restrained spontaneous locomotion, and decreased body length. Furthermore, we observed obvious toxicity in the notochord and detected increased expression levels of notochord-related genes (shha, col2a, and tbxta) by in situ hybridization in zebrafish larvae. In addition, calcein staining, alkaline phosphatase (ALP) activity analysis, and anatomic analysis indicated that TM induced notochord toxicity. We used rescue experiments to verify whether the PI3K-mTOR pathway involved in the notochord development was the cause of notochord abnormalities. Rapamycin and LY294002 (an inhibitor of PI3K) relieve notochord toxicity caused by TM, including morphological abnormalities. In summary, TM might induce notochord toxicity by activating the PI3K-mTOR pathway in zebrafish.

Prevalence of H6Y mutation in ß-tubulin causing thiophanate-methyl resistant in Monilinia fructicola from Fujian, China.

Brown rot disease broke out in stone fruit orchards of Fujian, China in 2019, despite pre-harvest application of methyl benzimidazole carbamate (MBC). To determine the reason, a total of 44 Monilinia fructicola strains were collected from nectarine, plum and peach fruits in this study, among which 79.5% strains were resistant to thiophanate-methyl, indicated by discriminatory dose of 5 µg/mL. The resistance of these strains was confirmed by treating detached peach fruit with label rates of formulated thiophanate-methyl which only completely inhibit infection of the sensitive strains, but not the resistant strains. Further analysis of the mechanism of MBC resistance revealed that all resistant strains carry a H6Y mutation in ß-tubulin protein Tub2, which was only reported previously in the M. fructicola strains from California, USA, and do not display obvious fitness penalties, as no significant defects in mycelial growth rate, sporulation, conidia germination, aggressiveness on detached peach fruit and temperature sensitivity was detected. In addition, we found that diethofencarb, the agent for managing MBC-resistance strains, was unable to inhibit growth of the H6Y strains. Taken together, our study, for the first time, identified a mutation form of H6Y in the ß-tubulin protein of M. fructicola in China, rendering the strains wide resistance to thiophanate-methyl. This mechanism of M. fructicola gaining resistance to MBC fungicides needs to be fully considered, when designing management strategies to control brown rot disease in stone fruit orchards.

Allicin-Inspired Heterocyclic Disulfides as Novel Antimicrobial Agents.

In this work, a series of derivatives with disulfide bonds containing pyridine, pyrimidine, thiophene, thiazole, benzothiazole, and quinoline were designed and synthesized based on the various biological activities of allicin disulfide bond functional groups. The antimicrobial activities of the target compounds were determined, and the structure-activity relationships were discussed. Among them, compound S8 demonstrated the most potent antifungal activity in vitro against Monilinia fructicola (M. fructicola), with an EC50 value of 5.92 µg/mL. Furthermore, an in vivo bioassay revealed that compound S8 exhibited equivalent curative and higher protective effects as the positive drug thiophanate methyl at a concentration of 200 µg/mL. The preliminary mechanism experiments showed that compound S8 could inhibit the growth of M. fructicola' s hyphae in a time- and concentration-dependent manner, and compound S8 could induce the shrinkage of hyphae, disrupt the integrity of the plasma membrane, and cause the damage and leakage of cell contents. More than that, compound S5 also demonstrated an excellent antibacterial effect on Xanthomonas oryzae (X. oryzae), with a MIC90 value of 1.56 µg/mL, which was superior to the positive control, thiodiazole copper.

Carbon dots@Cu metal-organic frameworks hybrids for ratiometric fluorescent determination of pesticide thiophanate-methyl.

A dual-emission fluorescent (FL) probe was constructed by coordinating Cu2+ of copper metal-organic frameworks (Cu-MOFs) with - COO- group of carbon dots (CDs) for pesticide thiophanate-methyl (TM) determination. TM was recognized by organic ligands (H2BDC and H2BDC-NH2) of Cu-MOFs via π stacking. Due to the higher affinity of Cu2+ to TM than ligands and CDs, TM chelated with Cu2+ to form TM-Cu complex. Thus coordination of Cu-MOFs was damaged and the ligands were released resulting in the FL intensity increase of Cu-MOFs (F430). And also CDs were released from CDs@Cu-MOFs hybrids and electron transfer from CDs to CuMOFs was inhibited, leading to the FL intensity increase of CDs (F600). The FL intensity ratio (F430/F600) showed a good linear relationship with TM concentrations of 0.0307-0.769 µmol L-1 with a limit of detection (LOD) of ~ 3.67 nmol L-1. The probe was successfully applied to detect TM in spiked food samples with satisfactory recoveries of 93.1-113%. Additionally, visual detection of TM was achieved according to the fluorescence color variation from blue to carmine, indicating promising application of CDs@Cu-MOFs probe.

Under Pressure: A Comparative Study of Botrytis cinerea Populations from Conventional and Organic Farms in Cyprus and Greece.

The highly heterogeneous nature of Botrytis cinerea provides adaptive benefits to variable environmental regimes. Disentangling pathogen population structure in anthropogenic agroecosystems is crucial to designing more effective management schemes. Herein, we studied how evolutionary forces exerted in different farming systems, in terms of agrochemicals-input, shape B. cinerea populations. In total, 360 B. cinerea isolates were collected from conventional and organic, strawberry and tomato farms in Cyprus and Greece. The occurrence and frequency of sensitivities to seven botryticides were estimated. Results highlighted widespread fungicide resistance in conventional farms since only 15.5% of the isolates were sensitive. A considerable frequency of fungicide-resistant isolates was also detected in the organic farms (14.9%). High resistance frequencies were observed for boscalid (67.7%), pyraclostrobin (67.3%), cyprodinil (65.9%), and thiophanate-methyl (61.4%) in conventional farms, while high levels of multiple fungicide resistance were also evident. Furthermore, B. cinerea isolates were genotyped using a set of seven microsatellite markers (simple sequence repeat [SSR] markers). Index of association analyses (Ia and rBarD) suggest asexual reproduction of the populations, even though the mating-type idiomorphs were equally distributed, indicating frequency-dependent selection. Fungicide resistance was correlated with farming systems across countries and crops, while SSRs were able to detect population structure associated with resistance to thiophanate-methyl, pyraclostrobin, boscalid, and cyprodinil. The expected heterozygosity in organic farms was significantly higher than in conventional, suggesting the absence of selective pressure that may change the allelic abundance in organic farms. However, genetic variance among strawberry and tomato populations was high, ranking host specificity higher than other selection forces studied.

Evaluation of Fungicide Soil Drench Treatments to Manage Black Root Rot Disease of Avocado.

Four common fungicidal products were evaluated for their effect on symptoms caused by two nectriaceous black root rot fungi, Calonectria ilicicola and Dactylonectria macrodidyma, when applied as pot drenches to avocado (Persea americana) seedlings in the greenhouse. Applications of fludioxonil, thiophanate-methyl + etridiazole, prochloraz, and prochloraz MnCl at 2 and 4 weeks after inoculation with C. ilicicola significantly reduced root necrosis and improved root and aboveground plant biomass compared with water-treated controls. Fludioxonil reduced necrosis by 60% and had a significantly lower frequency of reisolation of C. ilicicola than the other three fungicide treatments. D. macrodidyma inoculation caused less severe symptoms in seedlings than C. ilicicola despite the longer duration of the trial. Pot drenches with fludioxonil, thiophanate-methyl + etridiazole, and prochloraz MnCl, but not prochloraz alone, significantly reduced root necrosis caused by D. macrodidyma. Prochloraz MnCl was the only fungicide treatment to increase root and plant biomass compared with water-treated controls. Both fludioxonil and prochloraz MnCl reduced the frequency of reisolation of D. macrodidyma from necrotic roots by about 50% compared with the other fungicides or water controls. The results indicated that drenches with these fungicides may suppress existing low to moderate black root rot infection, allowing new root growth and improved establishment in the orchard. Fungicide drenching must not replace best-practice disease management strategies in nurseries but may be a useful tool in crisis situations.

Effect of fungicides on spike characteristics in winter wheat inoculated with Fusarium culmorum.

The impact of fungicides on the head blight (FHB) development disease index, percent spike harvest index (SHI), and deoxynivalenol (DON) accumulation in wheat kernels under field conditions was evaluated after artificial spike inoculation with Fusarium culmorum (S-14). The trial was carried out using commercially available fungicides and a sensitive cultivar of bread wheat (Flamura-85) in a field of a wheat producer located in the Trakya region of Turkey. Fungicides were applied at the beginning of anthesis (ZGS 61), 48 hours after the inoculation with the pathogen. Disease index was determined 10 days and 14 days post-inoculation. The application of fungicides containing tebuconazole, thiophanate methyl plus tetraconazole and prothioconazole plus trifloxystrobin reduced the FHB disease and increased kernel number, spike weight, and kernel weight, as compared to the inoculated/non-fungicide control. The efficacy of tebuconazole and of prothioconazole plus trifloxystrobin was higher than that of thiophanate methyl plus tetraconazole on FHB disease severity, percent spike harvest index (SHI), and DON accumulation in wheat kernels.

Differential immunomodulatory effects of six pesticides of different chemical classes on human monocyte-derived macrophage functions.

Exposure to pesticides through eyes, skin, ingestion and inhalation may affects human health by interfering with immune cells, such as macrophages. We evaluated, in vitro, the effect of six pesticides widely used in apple arboriculture on the functions of human monocyte-derived macrophages (hMDMs). hMDMs were cultured for 4 or 24 h with or without pesticides (0.01, 0.1, 1, 10 µmol.L-1). We showed that chlorpyrifos, thiacloprid, thiophanate, boscalid, and captan had little toxic effect at the tested concentrations, while dithianon had low-cytotoxicity at 10 µmol.L-1. While boscalid showed no effect on hMDMs function, thiophanate (0.01 µmol.L-1) stimulated with TPA and thiacloprid (1, 10 µmol.L-1) stimulated with zymosan activated ROS production. Chlorpyrifos, dithianon, and captan inhibited ROS production and TNF-α, IL-1ß pro-inflammatory cytokines. We established that dithianon (0.01-1 µmol.L-1) and captan (0.1, 1 µmol.L-1) induced mRNA expression of NQO1 and HMOX1 antioxidant enzymes. Dithianon also induced the mRNA expression of catalase, superoxide dismutase-2 at 10 µmol.L-1. Together, these results show that exposure to chlorpyrifos, dithianon, and captan induce immunomodulatory effects that may influence the disease fighting properties of monocytes/macrophages while pesticides such as thiacloprid, thiophanate and boscalid have little influence.

Chemical seed treatment and mycorrhizal inoculation provide better development and nutrition of common bean plants.

BACKGROUND: Chemical seed treatment is an established practice in agriculture to protect crops from soil-borne pathogens and pests. Arbuscular mycorrhizal fungi (AMF) benefit plants by extending soil exploration as well as water and nutrient uptake. The objective of this work was to analyze the effects of combinations of seed treatments with doses of inoculant containing Rhizoglomus intraradices on vegetative development, root colonization and nutrition of Phaseolus vulgaris plants and soil microbiota. RESULTS: Seed treatment benefited the vegetative development and nutrition of beans, with the treatments metalaxyl + fludioxonil + tiabendazole and pyraclostrobin + thiophanate methyl + fipronil standing out regarding the contents of nitrogen (N), phosphorus (P), iron (Fe) and zinc (Zn) of the aerial parts. Mycorrhizal inoculation linearly increased dehydrogenase activity, root biomass and total plant biomass, with increments reaching 27%. There was an interaction between seed treatment and inoculation dose for aboveground biomass and the contents of potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), manganese (Mn) and root colonization, with expressive results for the combination of the two highest doses of inoculant with metalaxyl + fludioxonil + tiabendazole or pyraclostrobin + methylthiophanate + fipronil in the seeds. CONCLUSION: Chemical seed treatment and mycorrhizal inoculation benefited bean plants and their nutritional status. The best combinations for the bean crop were metalaxyl + fludioxonil + tiabendazole with 41.4 mg of the inoculant per 100 seeds and pyraclostrobin + thiophanate methyl + fipronil with 62.1 mg of the inoculant per 100 seeds. © 2022 Society of Chemical Industry.

Molecular Diagnosis of Thiophanate-Methyl-Resistant Strains of Fusarium fujikuroi in Japan.

Fusarium fujikuroi is the pathogen of rice bakanae disease and is subclassified into gibberellin and fumonisin groups (G and F groups). Thiophanate-methyl (TM), a benzimidazole fungicide, has been used extensively to control F. fujikuroi. Previous investigation showed that F-group strains are TM sensitive (TMS), whereas most G-group strains are TM resistant (TMR) in Japan. The minimum inhibitory concentration in TMS strains was 1 to 10 µg ml-1, whereas that in TMR strains was >100 µg ml-1. E198K and F200Y mutations in ß2-tubulin were detected in TMR strains. A loop-mediated isothermal amplification-fluorescent loop primer method was developed for diagnosis of these mutations and applied to 37 TMR strains and 56 TMS strains. The results indicated that 100% of TMR strains were identified as having either the E198K mutation (41%) or the F200Y mutation (59%), whereas none of the TMS strains tested showed either mutation. We found one remarkable TMR strain in the F group that had an F200Y mutation. These results suggest that E198K and F200Y mutations in ß2-tubulin contribute to TM resistance in F. fujikuroi.

Evaluation of the cytotoxic and genotoxic potential of the captan-based fungicides, chlorothalonil-based fungicides and methyl thiophanate-based fungicides in human fibroblasts BJ.

The objectives of this study were to examine cytotoxic and genotoxic damage in human BJ fibroblasts caused by three pesticides used worldwide by trypan blue dye exclusion assays and to measure the relative level of phosphorylated histone H2A.X by flow cytometry at different concentrations. Captan-based fungicide and methyl thiophanate-based fungicide (100 and 1000 µΜ) showed immediate cytotoxic effects; furthermore, after 24 h, captan-based fungicide, chlorothalonil-based fungicide and methyl thiophanate-based fungicide caused cytotoxic effects in the concentration ranges of 40-100 µM, 30-100 µM and 150-1000 µM, respectively. All fungicides generated DNA damage in the treated cells by activating ATM and H2A.X sensor proteins. The three fungicides tested generated DNA double-stranded breaks and showed cytotoxicity at concentrations 33, 34, and 5 times lower (captan, chlorothalonil and thiophanate-methyl respectively) than those used in the field, as recommended by the manufacturers.