Iprodione Research Articles

Developmental Toxicity and Teratogenic Effects of Dicarboximide Fungicide Iprodione on Zebrafish (Danio rerio) Embryos

Iprodione (IDN) is a broad-spectrum fungicide used to treat various fungal infections in plants. Despite its extensive use, assessment of its toxicity in aquatic organisms remains incomplete. This study investigated the deleterious effects of IDN using zebrafish (ZF) as a model organism. ZF embryos, beginning at 2 h post-fertilization (hpf), were exposed to IDN (3.75–40 mg/L), and both mortality and deformities were assessed. The impact of IDN on mortality was concentration-dependent and significant from 14 mg/L. Importantly, IDN induced several deformities at sublethal concentrations, including abnormal somites, reduced retinal pigment accumulation, yolk sac edema, hatching failure, abnormal swim bladders, and spinal curvature. The EC50 values for IDN-induced deformities were 3.44 ± 0.74 to 21.42 ± 6.00 mg/L. The calculated teratogenic index values for all deformities were above 1, indicating that IDN is teratogenic to ZF. IDN-exposed ZF also displayed abnormalities in touch-evoked escape responses. IDN significantly affected heart rate and blood flow, and induced pericardial edema and hyperemia in a concentration-dependent manner, suggesting its influence on cardiac development and the function of ZF. In conclusion, these results suggest that IDN exerts toxic effects on ZF embryos, affecting mortality, development, and behavior.

Acidity-activated degradable Mn-engineered silicon nanohybrids coordinated with iprodione for high-efficiency management of Sclerotinia sclerotiorum and nutrient enhancement to crops

Nanocarriers that respond to environmental stimuli are highly desirable in optimizing the bioavailability of pesticides while minimizing side effects. Manganese-engineered nanomaterials hold promising prospects in agriculture as versatile carriers for both intelligent controlled pesticide delivery and crop nutrient enhancement. Here, Mn-engineered hollow silicon nanospheres (Mn-HSNs) with a bubble-like structure were synthesized for encapsulating iprodione (IPR) to obtain IPR-loaded Mn-HSNs (IPR@Mn-HSNs). Due to its high surface area of 261.28 m2/g and surface-enriched active sites, Mn-HSNs demonstrated a commendable loading capacity of 56.4 % for IPR. Results indicated that the -Si-O-Mn- hybrid framework of IPR@Mn-HSNs not only facilitated acidity-triggered IPR release capability but also served as a plentiful source of Mn ion and orthosilicic acid (Si(OH)4) to promote crop growth. The release amount of IPR in an acidic environment generated by Sclerotinia sclerotiorum of oilseed rape was 3.14 times higher than that under neutral conditions. In vitro experiments demonstrated that the antibacterial activity of IPR@Mn-HSNs was about 1.2 times higher than that of commercial IPR suspension concentrate. Appreciably, IPR@Mn-HSNs could be effectively transported to different parts of rapeseed plants through foliar spray, thereby enhancing the effectiveness of pesticide utilization. More importantly, IPR@Mn-HSNs had no discernible impact on the survival of Harmonia axyridis and were relatively safe for HL-7702 and HK-2 cells. Therefore, this work offers valuable insights into the development of an efficient and environmentally friendly pesticide nanoformulation for sustainable and eco-friendly plant protection in agriculture.

Potential Antifungal Effect of Copper Oxide Nanoparticles Combined with Fungicides against Botrytis cinerea and Fusarium oxysporum.

Copper oxide nanoparticles (NCuO) have emerged as an alternative to pesticides due to their antifungal effect against various phytopathogens. Combining them with fungicides represents an advantageous strategy for reducing the necessary amount of both agents to inhibit fungal growth, simultaneously reducing their environmental release. This study aimed to evaluate the antifungal activity of NCuO combined with three fungicide models separately: Iprodione (IPR), Tebuconazole (TEB), and Pyrimethanil (PYR) against two phytopathogenic fungi: Botrytis cinerea and Fusarium oxysporum. The fractional inhibitory concentration (FIC) was calculated as a synergism indicator (FIC ≤ 0.5). The NCuO interacted synergistically with TEB against both fungi and with IPR only against B. cinerea. The interaction with PYR was additive against both fungi (FIC > 0.5). The B. cinerea biomass was inhibited by 80.9% and 93% using 20 mg L-1 NCuO + 1.56 mg L-1 TEB, and 40 mg L-1 NCuO + 12 µg L-1 IPR, respectively, without significant differences compared to the inhibition provoked by 160 mg L-1 NCuO. Additionally, the protein leakage and nucleic acid release were also evaluated as mechanisms associated with the synergistic effect. The results obtained in this study revealed that combining nanoparticles with fungicides can be an adequate strategy to significantly reduce the release of metals and agrochemicals into the environment after being used as antifungals.

Metabolic Profiling and Comparative Proteomic Insight in Respect of Amidases during Iprodione Biodegradation.

The fungicide iprodione (IPR) (3-(3,5-dichlorophenyl) N-isopropyl-2,4-dioxoimidazolidine-1-carboxamide) is a highly toxic compound. Although IPR has been restricted, it is still being applied in many places around the world, constituting an environmental risk. The biodegradation of IPR is an attractive option for reducing its residues. In this study, we isolated thirteen IPR-tolerant bacteria from a biopurification system designed to treat pesticides. A study of biodegradation using different strains was comparatively evaluated, and the best degradation rate of IPR was presented by Achromobacter sp. C1 with a half-life (T1/2) of 9 days. Based on a nano-LC-MS/MS analysis for the strains, proteins solely expressed in the IPR treatment were identified by highlighting the strain Achromobacter sp. C1, with 445 proteins primarily involved in the biosynthesis of secondary metabolites and microbial metabolism in diverse environments. Differentially expressed protein amidases were involved in six metabolic pathways. Interestingly, formamidase was inhibited while other cyclases, i.e., amidase and mandelamide hydrolase, were overexpressed, thereby minimizing the effect of IPR on the metabolism of strain C1. The dynamic changes in the protein profiles of bacteria that degrade IPR have been poorly studied; therefore, our results offer new insight into the metabolism of IPR-degrading microorganisms, with special attention paid to amidases.

Neurobehavioral Responses and Toxic Brain Reactions of Juvenile Rats Exposed to Iprodione and Chlorpyrifos, Alone and in a Mixture.

Herein, male juvenile rats (23th postnatal days (PND)) were exposed to chlorpyrifos (CPS) (7.5 mg/kg b.wt) and/or iprodione (IPD) (200 mg IPD /kg b.wt) until the onset of puberty (60th day PND). Our results demonstrated that IPD and/or CPS exposure considerably reduced locomotion and exploration. However, CPS single exposure induced anxiolytic effects. Yet, neither IPD nor IPD + CPS exposure significantly affected the anxiety index. Of note, IPD and/or CPS-exposed rats showed reduced swimming time. Moreover, IPD induced significant depression. Nonetheless, the CPS- and IPD + CPS-exposed rats showed reduced depression. The individual or concurrent IPD and CPS exposure significantly reduced TAC, NE, and AChE but increased MDA with the maximum alteration at the co-exposure. Moreover, many notable structural encephalopathic alterations were detected in IPD and/or CPS-exposed rat brain tissues. The IPD + CPS co-exposed rats revealed significantly more severe lesions with higher frequencies than the IPD or CPS-exposed ones. Conclusively, IPD exposure induced evident neurobehavioral alterations and toxic reactions in the brain tissues. IPD and CPS have different neurobehavioral effects, particularly regarding depression and anxiety. Hence, co-exposure to IPD and CPS resulted in fewer neurobehavioral aberrations relative to each exposure. Nevertheless, their simultaneous exposure resulted in more brain biochemistry and histological architecture disturbances.

Biodegradation of Iprodione and Chlorpyrifos Using an Immobilized Bacterial Consortium in a Packed-Bed Bioreactor.

This work provides the basis for implementing a continuous treatment system using a bacterial consortium for wastewater containing a pesticide mixture of iprodione (IPR) and chlorpyrifos (CHL). Two bacterial strains (Achromobacter spanius C1 and Pseudomonas rhodesiae C4) isolated from the biomixture of a biopurification system were able to efficiently remove pesticides IPR and CHL at different concentrations (10 to 100 mg L-1) from the liquid medium as individual strains and free consortium. The half-life time (T1/2) for IPR and CHL was determined for individual strains and a free bacterial consortium. However, when the free bacterial consortium was used, a lower T1/2 was obtained, especially for CHL. Based on these results, an immobilized bacterial consortium was formulated with each bacterial strain encapsulated individually in alginate beads. Then, different inoculum concentrations (5, 10, and 15% w/v) of the immobilized consortium were evaluated in batch experiments for IPR and CHL removal. The inoculum concentration of 15% w/v demonstrated the highest pesticide removal. Using this inoculum concentration, the packed-bed bioreactor with an immobilized bacterial consortium was operated in continuous mode at different flow rates (30, 60, and 90 mL h-1) at a pesticide concentration of 50 mg L-1 each. The performance in the bioreactor demonstrated that it is possible to efficiently remove a pesticide mixture of IPR and CHL in a continuous system. The metabolites 3,5-dichloroaniline (3,5-DCA) and 3,5,6-trichloro-2-pyridinol (TCP) were produced, and a slight accumulation of TCP was observed. The bioreactor was influenced by TCP accumulation but was able to recover performance quickly. Finally, after 60 days of operation, the removal efficiency was 96% for IPR and 82% for CHL. The findings of this study demonstrate that it is possible to remove IPR and CHL from pesticide-containing wastewater in a continuous system.

Iprodione Removal by UV-Light-, Zero-Valent Iron- and Zero-Valent Aluminium-Activated Persulfate Oxidation Processes in Pure Water and Simulated Tertiary Treated Urban Wastewater

The degradation of iprodione (IPR), a once frequently used but recently banned dicarboximide fungicide, by UV-C light-, zero-valent iron- (ZVI), and zero-valent aluminium (ZVA)-activated persulfate (PS) oxidation processes was comparatively studied in distilled (pure) water (DW) and simulated, tertiary treated urban wastewater (SWW). The performance of PS-activated oxidation processes was examined by following IPR (2–10 mg/L) removal, PS (0.01–1.00 mM) consumption, metal ion release (for the two heterogeneous catalytic oxidation processes), dissolved organic carbon (DOC) removal as well as hydroxylated aromatic and low molecular weight aliphatic degradation products. The effect of pH and PS concentrations on IPR removal was examined in DW. While the experiments in DW highlighted the superior performance of UV-C/PS treatment (with 78% DOC removal after 120 min at pH = 6.2), the performance of UV-C/PS treatment decreased sharply (to 24% DOC removal after 120 min at pH = 6.8) in the complex wastewater matrix (in SWW). Complete IPR (in 20 min) and 40% DOC (in 120 min) removals were obtained with ZVI/PS treatment (1 g/L ZVI, 1.5 mM PS, pH = 3.0), which was the most effective oxidation process in SWW. The treatment performance was strongly influenced by the SWW constituents, and UV-C/PS treatment appeared to be the most sensitive to it.

Iprodione and/or chlorpyrifos exposure induced testicular toxicity in adult rats by suppression of steroidogenic genes and SIRT1/TERT/PGC-1α pathway.

There is cumulative evidence that iprodione (IPR) fungicide and chlorpyrifos (CPF) insecticide are endocrine disruptors that can evoke reproductive toxicity. Yet, the underlying mechanisms are still unclear. Besides, the outcomes of their co-exposure to male sexual behavior and male fertility are still unknown. The effects of IPR (200 mg/kg b.wt) and CPF (7.45 mg/kg b.wt) single or mutual exposure for 65 days on sexual behavior, sex hormones, testicular enzymes, testis, and accessory sex gland histomorphometric measurements, apoptosis, and oxidative stress biomarkers were investigated. In addition, expression of nuclear receptor subfamily group A (NR5A1), 17β-hydroxysteroid dehydrogenase (HSD17B3), silent information regulator type-1 (SIRT1), telomerase reverse transcriptase (TERT), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) genes has been assessed. Our results revealed that the individual or concurrent IPR and CPF exposure significantly disturb the sexual behavior, semen characteristics, testicular enzymes, and male hormones level. Oxidative stress caused by IPR and CPF activates apoptosis by inducing Caspase-3 and reducing Bcl-2. Downregulation of HSD17B3, NR5A1, and SIRT1/TERT/PGC-1α pathway was evident. Of note, most of these disturbances were exaggerated in rats co-exposed to IPR and CPF compared to IPR or CPF alone. Conclusively, our findings verified that IPR and CPF possibly damage the male reproductive system, and concurrent exposure should be avoided.

Iprodione and chlorpyrifos induce testicular damage, oxidative stress, apoptosis and suppression of steroidogenic- and spermatogenic-related genes in immature male albino rats.

The fungicide iprodione (IPR) and the insecticide chlorpyrifos (CPF) are concurrently applied for early disease control in fruits and other crops. However, there are no available data about the impacts of their co-exposure. Additionally, IPR and CPF are known as endocrine disruptors that can cause reproductive toxicity. The outcomes of their co-exposure on the development of male reproductive organs are still unknown. Therefore, this study aimed to assess the risk of exposure to these pesticides, particularly on the postnatal development of the male albino rat reproductive system from postnatal days 23-60. The results revealed that a single IPR or CPF exposure has harmful consequences on the reproductive development and function manifested by reduced testicular weight, serious changes in sperm characteristics, reproductive hormone level imbalance, testicular enzymes, oxidative stress and apoptosis-related enzymes, which correlated with transcription levels of steroidogenic- and spermatogenic-related genes. Histopathologically, both compounds caused severe damage in the testis and accessory glands architecture. Notably, co-exposure to IPR and CPF in rats caused more serious damage, indicative of an additive effect than individual exposure, so concurrent exposure should be avoided as it is more hazardous, especially on male fertility.

N-acetylcysteine reduced the immunotoxicity effects induced in vitro by azoxystrobin and iprodione fungicides in mice.

Azoxystrobin (AZO) and Iprodione (IPR) fungicides are extensively used worldwide, and therefore, contaminate all environmental compartments. The toxicity and the mechanisms by which they affected immune cells are complex and remain unknown. This study investigated the impact of AZO and IPR on the in vitro function of mice peritoneal macrophages including lysosomal enzyme activity and tumor necrosis factor (TNF)α and nitric oxide (NO) production in response to lipopolysaccharide (LPS) stimulation, the proliferation of mice splenocytes stimulated by concanavalin (Con)A and LPS, and the production of the Th1cytokine interferon-gamma (IFNγ) and the Th2 cytokine interleukin (IL)-4 and IL-10 by ConA-activated splenocytes. This is the first report indicating that AZO and IPR fungicides dose-dependently inhibited mice macrophage lysosomal enzyme activity and LPS-stimulated production of TNFα and NO. Mitogen-induced proliferation of mice splenocytes was also suppressed by AZO and IPR in a dose-dependent manner. More pronounced impact was observed on ConA-induced response. The production of IFNγ by ConA-stimulated splenocytes was dose-dependently inhibited; however, the production of IL-4 and IL-10 increased in the same conditions. These results suggested that AZO and IPR polarized Th1/Th2 cytokine balance towards Th2 response. Overall, marked immunosuppressive effects were observed for AZO. The immunomodulatory effects caused by AZO and IPR were partially reversed by the pharmacological antioxidant N-acetylcysteine (NAC), suggesting that both fungicides exerted their actions through, at least in part, oxidative stress-dependent mechanism. Collectively, our data showed that AZO and IPR fungicides exerted potent immunomodulatory effects in vitro with eventually strong consequences on immune response and immunologically based diseases.

Construction of EVA/chitosan based PEG-PCL micelles nanocomposite films with controlled release of iprodione and its application in pre-harvest treatment of grapes.

A novel nanocomposite poly(ethylene-co-vinyl acetate) (EVA) film with controlled in vitro release of iprodione (ID) was prepared. Chitosan (CS) was used as the reinforcement which enhances the water and oxygen permeability of films. ID loaded poly(ethylene glycol)-poly(ε-caprolactone) (PEG-PCL) (IPP) micelles were used as the drug carrier which endows the films with antifungal and controlled release ability. IPP micelles with spherical shape and uniform size were obtained, and the maximum encapsulation efficacy (EE) was 91.17±5.03% by well controlling the feeding amount of ID. Incorporation CS could improve the oxygen and moisture permeability of films, and the maximum oxygen permeability (OP) and water vapor transmission rate (WVTR) were 477.84±13.03cc/(m2·d·0.1MPa) and 8.60±0.25gm-2 d-1, respectively. After loading IPP micelles, the films showed an improved antifungal ability and temperature-sensitive drug release behavior, and were found to enhance the quality of grapes by pre-harvest spraying.

UV-C-activated persulfate oxidation of a commercially important fungicide: case study with iprodione in pure water and simulated tertiary treated urban wastewater.

Recently, the European Food Safety Authority (EFSA) has banned the use of iprodione (IPR), a common hydantoin fungicide and nematicide that was frequently used for the protective treatment of crops and vegetables. In the present study, the treatment of 2mg/L (6.06μM) aqueous IPR solution through ultraviolet-C (UV-C)-activated persulfate (PS) advanced oxidation process (UV-C/PS) was investigated. Baseline experiments conducted in distilled water (DW) indicated that complete IPR removal was achieved in 20min with UV-C/PS treatment at an initial PS concentration of 0.03mM at pH = 6.2. IPR degradation was accompanied with rapid dechlorination (followed as Cl- release) and PS consumption. UV-C/PS treatment was also effective in IPR mineralization; 78% dissolved organic carbon (DOC) was removed after 120-min UV-C/PS treatment (PS = 0.30mM) compared with UV-C at 0.5W/L photolysis where no DOC removal occurred. LC analysis confirmed the formation of dichloroaniline, hydroquinone, and acetic and formic acids as the major aromatic and aliphatic degradation products of IPR during UV-C/PS treatment whereas only dichloroaniline was observed for UV-C photolysis under the same reaction conditions. IPR was also subjected to UV-C/PS treatment in simulated tertiary treated urban wastewater (SWW) to examine its oxidation performance and ecotoxicological behavior in a more complex aquatic environment. In SWW, IPR and DOC removal rates were inhibited and PS consumption rates decreased. The originally low acute toxicity (9% relative inhibition towards the photobacterium Vibrio fischeri) decreased to practically non-detectable levels (4%) during UV-C/PS treatment of IPR in SWW.

Exploring the interaction mechanism of a dicarboxamide fungicide, iprodione with bovine serum albumin

Binding of iprodione (IPR), a dicarboxamide fungicide, to the carrier protein in bovine circulation, bovine serum albumin (BSA) was characterized with the help of fluorescence, absorption, circular dichroism and Fourier transform infrared (FTIR) spectral measurements in combination with computational analysis. The increase in the KSV (Stern–Volmer constant) value with temperature and absorption spectral results characterized the IPR-induced quenching of BSA fluorescence as dynamic quenching. On the other hand, higher value (> 1011 M−1 s−1) of the bimolecular quenching rate constant (kq) suggested complex formation between IPR and BSA. In view of it, increase in KSV value with temperature can be considered as an indication of the involvement of endothermic apolar (hydrophobic) interactions in stabilizing the IPR–BSA complex, as these forces are maximized at higher temperature. A weak binding affinity was anticipated from the values of the binding constant (Ka = 0.83–2.69 × 103 M−1) for IPR–BSA association. Thermodynamic analysis of the binding data further supported contribution of hydrophobic interactions in the IPR–BSA association process. This result was validated by the computational docking analysis. Spectral results from three-dimensional fluorescence and circular dichroism demonstrated microenvironmental changes around BSA fluorophores and protein’s structural (secondary and tertiary) alterations, respectively, upon IPR binding to the protein. Slight variation in the secondary structures of BSA in the presence of IPR was also verified from FTIR spectral results. IPR was found to bind to both site I (subdomain IIA) and site II (subdomain IIIA) of BSA, showing more preference toward site II, as identified by the competitive drug displacement results and supported by the computational analysis.

Toxicological effects of comercial formulations of fungicides based on procymidone and iprodione in seedlings and root tip cells of Allium cepa.

In this study the phytotoxic, cytotoxic, genotoxic and mutagenic effects of two commercial fungicide-active compounds, procymidone (PR) and iprodione (IP), were determined. The parameters evaluated were germination and root growth, mitotic index, chromosomal and nuclear aberrations, and molecular analyses were also performed in the model plant Allium cepa L. The results demonstrated that the active compounds PR and IP were phytotoxic, delaying germination and slowing the development of A. cepa seedlings. Moreover, PR and IP showed cytogenotoxicity towards A. cepa meristematic cells, inducing chromosomal changes and cell death. The mutagenic activity of the active compounds was demonstrated by the detection of DNA changes in simple sequence repeat (SSR) and inter-simple sequence repeat (ISSR) markers in the treated cells compared to the negative control. Together, these results contribute to a better understanding of the damage caused by these substances in living organisms and reveal a promising strategy for prospective studies of the toxic effects of environmental pollutants.

Rapid detection of iprodione in cucumber and apple using an immunochromatographic strip test

ABSTRACT In recent years, fungicides have been frequently detected in soil, water, and air because of their extensive use, with detrimental effects on the environment. Therefore, the screening of foods for iprodione (IPRO) has become mandatory. A rapid, specific and sensitive method based on an immunochromatographic strip test has been developed for the determination of IPRO residues in cucumber and apple. The antigen IPRO-ovalbumin and a goat anti-mouse IgG antibody were drawn onto a nitrocellulose membrane as the test and control lines, respectively. Under optimal conditions, the cut-off limits of the semi-quantitative strip test for IPRO was as low as 10 ng/mL in 0.01 M PBS pH 7.4, 20 ng/mL in cucumber juice, and 25 ng/mL in apple juice and the results were obtained within 5 min. Our data suggests that this immunochromatographic assay can be used for the sensitive, rapid, and specific on-site screening of IPRO in cucumber and apple.

Cyto(geno)toxicity of Commercial Fungicides Based on the Active Compounds Tebuconazole, Difenoconazole, Procymidone, and Iprodione in Lactuca sativa L. Meristematic Cells

The present work aimed to evaluate the effects of commercial fungicides containing the active compounds from the triazole group—tebuconazole (TBZ) and difenoconazole (DFZ)—and dicarboximide group—procymidone (PRD) and iprodione (IPD) on the mitotic cycle of the plant model Lactuca sativa L. These active compounds have been present in foods sampled at different Brazilian’s states and amounted higher than recommended by law. The bioassay with L. sativa was applied to access the toxicity and better understand the mechanisms of action of these compounds in living beings. The active principles IPD and DFZ presented mitodepressive effect, statistically reducing the MI at all applied concentrations in comparison to the negative control. TBZ was the most cytotoxic active compound tested inhibited in 77% mitotic active in the lowest concentration applied. PRD alter the frequency of mitotic cells only in the concentration above that recommended by the manufacture. C-metaphase and adherent chromosomes were the most frequent cell cycle alteration observed on the treated cells, followed by bridges and lost chromosomes. Therefore, the mechanism of action was mainly aneugenic (70%). For TBZ, the frequency of condensed nucleus was very expressive (313 higher than the negative control).

Characterization and evaluation of fungicide resistance among Lasiodiplodia theobromae isolates associated with mango dieback in Oman

Dieback is one of the most common diseases of mango in different parts of the world, including Oman. Despite efforts to control the disease using different fungicides, disease incidence is still high in some farms in the country. This study involved in-depth analysis of the causal agents of the disease in two farms in Oman and the degree of sensitivity of fungal isolates to four common fungicides. The survey showed the association of dieback symptoms with 100% of mango cultivars in the first farm and 47% of mango cultivars in the second farm, with some cultivars having higher disease incidence (e.g. cvs Rothana and Zafran). Isolations from 40 mango trees showing dieback symptoms revealed the association of Lasiodiplodia spp. with 95% of the trees. Alternaria and Fusarium spp. were isolated from only 10% and 8% of the trees, respectively. Further identification of 67 Lasiodiplodia isolates using sequences of the internal transcribed spacer region of the ribosomal RNA gene (ITS rRNA) and sequence of the translation elongation factor gene (TEF) revealed that all isolates belong to Lasiodiplodia theobromae. Pathogenicity test of two randomly selected isolates of L. theobromae on cvs Amerbally and Omani showed that inoculated seedlings started showing dieback symptoms 2 within two weeks post inoculation. Testing sensitivity of 28 randomly selected L. theobromae isolates to four common fungicides showed that the EC50 levels of the isolates were in the range of 0.01-8.75 (avg. 0.54 mg l-1 ) for iprodione, 0.1-242.8 (111.6 mg l-1 ) for copper oxychloride, 40.3-738.1 (avg. 229.3 mg l-1 ) for copper hydroxide and 0.1 to over 1000 (avg.˃1000 mg l-1 ) for thiophanate-methyl. The current study showed the development of resistance to some fungicides, especially thiophanate-methyl. Development of resistance to fungicides could be one of the main reasons behind the reduction in the efficacy of managing dieback in the studied farms.

Effects of low doses of carbendazim or iprodione either separately or in mixture on the pubertal rat seminiferous epithelium: An ex vivo study

It has been shown that non-cytotoxic doses of Carbendazim (CBZ), a broad-spectrum benzimidazole fungicide, possess endocrine-disrupting (androgen-like) actions, ex vivo, on the pubertal rat seminiferous epithelium. Iprodione (IPR), a dicarboximide fungicide, is also known to be an endocrine-disrupter (anti-androgen). The effect of a mixture of these two pesticides was investigated in the validated rat seminiferous tubule culture model. Cultures were performed in the absence or presence of CBZ 50nM or IPR 50nM either alone or in mixture (Mix), over a 3-week period. Mix exerted a dramatic effect on two proteins (Connexin 43 and Claudin-11) of the blood-testis barrier and possessed similar effects to IPR on some germ cell populations. The presence of IPR together with CBZ (Mix) cancelled the effect of CBZ on the increase of the androgen-dependent TP1 and TP2 mRNAs and on the decrease of ERα, ERβ mRNAs. Nevertheless, CBZ alone or IPR alone or Mix induced toxicity on spermatogenesis resulting in a decrease of round spermatids (the precursors of spermatozoa). These results strongly suggest that, even at these low concentrations, the effects of IPR and of CBZ are not solely dependent on their respective anti-androgenic and androgen-like effects and should involve several mechanisms of action.

بررسی شاخص تأثیر زیست‌محیطی (EIQ) آفت کش های مصرفی در محصول گندم و جو در مشهد

شاخص تأثیر زیست‌محیطی (EIQ) یک روش محاسبه مخاطرات زیست‌محیطی آفت کش ها است. با اندازه گیری شاخص می‌توان به پر مخاطره ترین آفت‌کش استفاده شده از لحاظ زیست‌محیطی در یک منطقه پی برد و با جایگزینی آن با آفت‌کش دیگر، سلامت زیستی جامعه‌ای خاص را تأمین نمود و همچنین می‌توان با معرفی آفت‌کش‌های جایگزین و کم خطر یک محصول خاص، پایداری محصول در جامعه را سبب شد. برای ارزیابی مخطره زیست‌محیطی ناشی از کاربرد آفت‌کش‌ها در این تحقیق شاخص تأثیر زیست‌محیطی (EIQ) و اجزای آن (جز کارگر مزرعه، جز مصرف کننده و جز اکولوژیک) و شاخص تأثیر زیست محیطی مزرعه (EIQ-FUR) مورد استفاده قرار گرفت. مقدار این شاخص برای ماده مؤثره آفت‌کش‌های مصرفی در محصول گندم و جو در شهرستان مشهد تعیین شد و برای مقایسه آفت‌کش‌ها و روش‌های مدیریت آفت، شاخص EIQ-FUR محاسبه گردید. طبق نتایج به دست آمده، بیشترین خطر در جزء مصرف کننده و آبشویی و کارگر مزرعه، مربوط به قارچکش کاربندازیم بود. دیازینون کمترین خطر را در جزء کارگر مزرعه دارا بود. کمترین خطر در جزء مصرف‌کننده و آبشویی مربوط به حشره کش دلتامترین بود. در جزء اکولوژی بیشترین تخریب زیست‌محیطی توسط حشره‌کش دیازینون ایجاد می‌شد. قارچ‌کش کاربندازیم پرمخاطره‌ترین سم مصرفی در بین سموم مورد استفاده در مزارع گندم و جو در شهرستان مشهد شناخته شد. کمترین مقدار میانگین وزنی شاخص EIQ-FUR در کاربرد علف کش‌ها و بیشترین مقدار این شاخص در کاربرد قارچ کش‌ها دیده شد.

Rhizosphere effect on pesticide degradation in biobeds under different hydraulic loads

Interactions between microorganisms and root exudates in a biobed system with vegetal (grass) cover could enhance pesticide degradation. Otherwise, a high water load may generate high concentrations of pesticides in lixiviates. We studied the effect of the vegetal cover on the degradation of a mixture of atrazine (ATZ), chlorpyrifos (CHL) and iprodione (IPR) (35 mg L -1 each) in a biobed system operated with two different hydraulic loads (0.6 and 1.2 L of tap water per day). The concentration of the pesticides and their main metabolites were measured in the lixiviates during 60 days, as well as in the biomixtures at the end of the study. Dehydrogenase activity in the biomixtures and organic acid exudation from the vegetal cover were also analysed. The vegetal cover diminished the lixiviation of pesticides and their metabolites mainly at the lower hydraulic load used. The degradation of the pesticides was high (>95%) and increased in biobeds with vegetal cover and low hydraulic load. Degradation metabolites of CHL and IPR were formed during pesticide degradation; however they were degraded in the biobed and were not detected in lixiviates at the end of the study. In general, an increase in organic acid exudation by vegetal cover was observed caused by chemical stress after pesticide application. The increase was similar at both hydraulic loads. Efficient colonisation of wheat straw by fungi was observed by confocal microscopy.