Effect of terbutryn at environmental concentrations on early life stages of common carp (Cyprinus carpio L.)

The aim of this study was to assess the toxicity of terbutryn to early developmental stages of common carp (Cyprinus carpio). Based on accumulated mortality in the experimental groups, lethal concentrations of terbutryn were estimated at 36 day LC50 = 3.06 mg l⁻¹ terbutryn. Based on inhibition of growth in the experimental groups, lowest observed-effect concentration (LOEC) = 0.005 mg l⁻¹ terbutryn; and no observed-effect concentration (NOEC) = 0.0007 mg l⁻¹ terbutryn. Fulton’s condition factors were significantly lower in fish exposed to 2 mg l⁻¹ compared with controls. By day 30, fish exposed to 0.00002 mg l⁻¹ - real environmental concentration in Czech rivers - 0.02, 0.2, and 2 mg l⁻¹ terbutryn showed significantly lower mass and total length compared with controls. No significant negative effects on hatching or embryo viability were demonstrated at the concentrations tested, but significant differences in early ontogeny among groups were noted. Fish from the two highest tested concentrations (0.2 and 2 mg l⁻¹) showed a dose-related delay in development compared with the controls. At concentrations of 0.02, 0.2, and 2 mg l⁻¹ damage to caudal kidney tubules when compared to control fish was found.     

Acute toxicity of diazinon on the common carp (Cyprinus carpio L.) embryos and larvae

In the present study, the toxic effects on the embryos and larvae of the common carp were used as a model to investigate the organophosphorus pesticide, diazinon, which contaminates aquatic ecosystems. Data obtained from the diazinon acute toxicity tests were evaluated using the Probit Analysis Statistical Method. The control and six test experiments were repeated five times. The number of dead embryos significantly increased in response to diazinon concentrations 0.25, 0.5, 1, 2, 4, and 8 mg L⁻¹ (p < 0.05 for each case). The 48 h LC₅₀ value (with 95% confidence limits) of diazinon for common carp embryos was estimated at 0.999 (0.698-1.427) mg L⁻¹. Dose-response decreases in hatching success were recorded as 84.60, 75.2, 54.1, 31.0, 6.0, and 0.0%, respectively (p < 0.05). The number of dead larvae significantly increased with increasing diazinon concentrations exposed for 24-96 h (p < 0.05). The 24, 48, 72, and 96 h LC₅₀ values (with 95% confidence limits) of diazinon for common carp larvae were estimated at 3.688 (2.464-8.495), 2.903 (2.019-5.433), 2.358 (1.672-4.005), and 1.530 (1.009-3.948) mg L⁻¹, respectively. There were significant differences in the LC₅₀ values obtained at different exposure times (p < 0.05). The results of the study suggest that low levels (0.25 mg L⁻¹) of diazinon in the aquatic environment may have a significant effect on the reproduction and development of carp.     

The toxic effects of pyrethroid deltamethrin on the common carp (Cyprinus carpio L.) embryos and larvae

Deltamethrin, a synthetic pyrethroid pesticide contaminating aquatic ecosystems as a pollutant, was investigated in the present study for toxic effects on embryos and larvae of common carp, Cyprinus carpio as a model. The control and five test experiments were repeated five times. The water temperature in the experimental units was kept at 24 ± 1 °C. The number of dead embryos significantly increased in response to deltamethrin concentrations 0.005, 0.05, 0.5, 5, 25, and 50 μg L⁻¹ (p<0.05 for each cases). Dose-response decreases in hatching success were recorded as 75.2, 64.6, 47.4, 26.0, 14.4, and 9.0%, respectively. The lowest concentration of deltamethrin (0.005 μg L⁻¹) produced a significantly decrease in number of dead larvae compared to control group (p<0.05). With increasing deltamethrin concentrations, the larvae exposed duration 1-48 h significantly increased the number of dead larvae (p<0.05 for each cases). The 48 h LC₅₀ values (with 95% confidence limits) of deltamethrin for common carp embryos and larvae were estimated as 0.213 (0.103-0.404) and 0.074 (0.011-0.260) μg L⁻¹, respectively. The results provide evidence that deltamethrin pollution may have an adverse effect on the reproduction and development of carp, which should be considered when this chemical is used in agricultural areas near aquatic ecosystems.     

Effect of atrazine and chlorpyrifos exposure on heat shock protein response in the brain of common carp (Cyprinus carpio L.)

Atrazine (ATR) and chlorpyrifos (CPF) are the most common pesticides found in freshwater ecosystems throughout the world. In the present study, the common carps were exposed to ATR, CPF and their mixture as describe in Table 1. Then we investigated the HSPs (HSP60, HSP70 and HSP90) expression in the brain of common carp by western blot and real-time PCR. Results indicated that HSP60 and HSP70 were significantly increased as compared to corresponding controls after 40 d exposure (P < 0.05). While the increased expression levels of HSP90 in exposure groups was only observed at 4.28 μg/L ATR group and 1.16 μg/L CPF group, and after 40 d recovery, the expression levels of HSP90 were higher than most of exposure groups (P < 0.05). It was suggested that the increased gene expression of HSPs was possible to protect injured cell mass caused by ATR, CPF and their mixture exposure. The present results provided new insights into the mechanisms used by fish to adapt to stressful environments.     

Ameliorative effect of lycopene on antioxidant status in Cyprinus carpio during pyrethroid deltamethrin exposure

The aim of the present study was to investigate the ameliorative properties of lycopene against the toxic effects of deltamethrin (DM) by examining oxidative damage markers such as lipid peroxidation and the antioxidant defense system components in carp (Cyprinus carpio). The fish were divided into seven groups of 15 fish each and received the following treatments: Group 1, no treatment; Group 2, orally administered corn oil; Group 3, oral lycopene (10 mg/kg body weight); Group 4, exposure to 0.018 μg/L DM; Group 5, exposure to 0.018 μg/L DM plus oral administration of 10 mg/kg lycopene; Group 6, exposure to 0.036 μg/L DM; and Group 7, exposure to 0.036 μg/L DM plus oral administration of 10 mg/kg lycopene. Treatment was continued for 14 days, and at the end of this period, blood and tissue (liver, kidney, and gill) samples were collected. Levels of malondialdehyde (MDA) and reduced glutathione (GSH) as well as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were determined in blood and tissues for measurement of oxidant-antioxidant status. A significant elevation in the level of MDA, as an index of lipid peroxidation, and reductions in antioxidant enzyme activities (SOD, CAT, and GSH-Px) and low molecular weight antioxidant (GSH) levels were observed in DM-exposed fish. Treatment with lycopene attenuated the DM-induced oxidative stress by significantly decreasing the levels of MDA. In addition, lycopene significantly increased the SOD, CAT, and GSH-Px activities and the level of GSH. The present results suggest that administration of lycopene might alleviate DM-induced oxidative stress.     

Effects of the herbicide LASSO MTX (alachlor 42% W/V) on biometric parameters and liver biomarkers in the common carp (Cyprinus carpio)

The aim of the study was to evaluate the effect of subchronic exposure to the herbicide LASSO MTX (alachlor 42% W/V) on biometric parameters and important liver biomarkers in the common carp (Cyprinus carpio). One year old fish were exposed for 28 days to LASSO MTX added to the tank water at concentrations of 240 and 2400 μg L⁻¹. The exposure did not affect fish biometric parameters. Glutathione-S-tranferase (GST) activity in liver (hepatopancreas) remained unchanged in exposed fish when compared to controls. However, significant induction of total cytochrome P 450 (CYP 450), ethoxyresorufin-O-deethylase (EROD) activity and elevated glutathione (GSH) in liver of exposed fish were detected.     

Effects of N-acetylcysteine on oxidative responses in the liver of fenthion exposed Cyprinus carpio

The aim of this study was to evaluate the effects of different N-acetylcysteine doses on the tolerance to fenthion-induced oxidative stress, alterations in glutathione metabolism and cholinesterase specific activities in the liver by using freshwater fish Cyprinus carpio (Cyprinidae) as a model organism. An acute toxicity study was carried out to determine 96-h median lethal concentration of fenthion for this species (2.16 mg/L) and 80% of this concentration was applied in toxicity studies. Four groups, each containing eight fish were constituted as follows: Control group, fenthion treated group, 0.5 or 400 mg/kg NAC-injected + fenthion-treated groups. Biochemical analyses were carried out spectrophotometrically. Fenthion treatment significantly decreased total glutathione and glutathione levels, glutathione/glutathione disulfide ratio together with glutathione reductase and γ-glutamylcysteine synthetase specific enzyme activities. The higher dose of N-acetylcysteine increased the toxic effects of fenthion and γ-glutamyl transpeptidase specific activity while decreasing glutathione S-transferase specific activity. However, injection of the lower dose provided a limited protection against fenthion toxicity. In all exposure groups, lipid peroxidation increased and total protein levels decreased, while protein depletion was prevented by low dose of N-acetylcysteine application. Acetylcholinesterase and butyrylcholinesterase activities were at similar levels in the liver of C. carpio. A dose-dependent inhibition was observed in butyrylcholinesterase activity by N-acetylcysteine application. The results showed that fenthion had a significant oxidative stress inducing potential through the reduction of glutathione redox capacity. The critical point for overcoming oxidative stress by N-acetylcysteine in fenthion toxicity was the selection of the dose; N-acetylcysteine exerted its toxic effects by means of oxidative stress in fish liver at the higher dose.     

毒死蜱对稀有鮈鲫不同生命阶段的毒性效应

为探明毒死蜱对鱼类不同生命阶段的毒性效应,以稀有鮈鲫Gobiocypris rarus为测试生物,评价了毒死蜱对其的急性毒性及对胚胎生长发育的毒性效应。结果表明:毒死蜱对稀有鮈鲫胚胎、仔鱼、幼鱼和成鱼的96 h-LC50值分别为7.59(5.14~9.86)、0.393(0.326~0.447)、0.047 8(0.038 2~0.054 9)和0.027 2(0.021 9~0.041 9)mg/L,毒死蜱对稀有鮈鲫4个生命阶段的毒性大小依次为成鱼幼鱼仔鱼胚胎;稀有鮈鲫暴露于毒死蜱后最明显的中毒症状是脊柱畸形;此外,质量浓度为6.13~35.8 mg/L的毒死蜱在48 h时可明显促进稀有鮈鲫胚胎的孵化。     

Biotransformation of clomazone in rice (Oryza sativa) and early watergrass (Echinochloa oryzoides)

Rice (Oryza sativa), a relatively tolerant species, and early watergrass (Echinochloa oryzoides; EWG), a relatively susceptible species, were exposed to ¹⁴C-labeled clomazone to determine accumulation, biotransformation, and mass balance. On a total mass basis, rice absorbed more clomazone than EWG (p < 0.05), but on a nmol/g basis, there was no significant difference between the two species (p > 0.05). Rice contained more extractable ¹⁴C residues (7.7 ± 0.5 vs. 4.8 ± 0.5 nmol in rice vs. EWG, respectively; p < 0.5), but the concentration in EWG was significantly higher (4.2 ± 0.5 vs. 1.8 ± 0.1 nmol/g in EWG vs. rice, respectively; p < 0.01). More metabolized residue was measured in EWG compared to rice (84.1% vs. 67.9%; p < 0.01). Both species produced hydroxylated forms, β-d-glucoside conjugates, and several other unidentified polar metabolites, but EWG generally produced higher metabolite concentrations. The concentration of the suspected active metabolite, 5-ketoclomazone, was significantly higher in EWG vs. rice (21 ± 2 vs. 5.7 ± 0.5 pmol/g, respectively; p < 0.01). Differences in sensitivity to clomazone between rice and EWG appear to be due to differential metabolism, but in this case the more susceptible EWG qualitatively and quantitatively metabolized more clomazone than the more tolerant rice. This is consistent with the action of a metabolically activated herbicide. This metabolic difference could be exploited to develop herbicide safeners for use with clomazone.     

Impacts of hypersaline water on the biotransformation and toxicity of fenthion on rainbow trout (Oncorhynchus mykiss), striped bass (Morone saxatilis X Morone chrysops) and tilapia (Oreochromis mossambicus)

Hypersaline water derived from agricultural practices primarily in arid landscapes can impact fisheries in streams receiving run-off from fields. Previous studies have indicated significant elevation in the toxicity of thio-ether pesticides by hypersaline water in certain species of euryhaline fish due to enhanced formation of sulfoxide metabolites which may be more toxic than the parent compounds. The objectives of this study were to evaluate the effects of salinity on the toxicity of the thio-ether organophosphate pesticide, fenthion in three species of euryhaline fish: rainbow trout (Oncorhynchus mykiss), striped bass (Morone saxatilis X Morone chrysops), tilapia (Oreochromis mossambicus) and determine whether a relationship was observed between toxicity and enantioselective sulfoxidation. Stereochemical formation and total sulfoxide formation did not mirror acute toxicity in the three species exposed in fresh or hypersaline conditions. Mortality of striped bass and rainbow trout due to fenthion exposure was enhanced by hypersaline treatments and a trend towards increased toxicity was observed in tilapia. In liver microsomes of rainbow trout, inhibition of cytochrome P450 (CYP) caused a respective 7- and 3-fold increase in sulfoxide formation in liver microsomes fresh and saltwater fish, and a significant increase in the formation of the (+)R-sulfoxide. CYP inhibition also caused a significant elevation of the (+)R-sulfoxide in freshwater striped bass, but not in hypersaline-treated bass. The results indicated contribution by CYP in the sulfoxidation of fenthion as well as the formation of other metabolites in all three species. In summary, hypersaline conditions impacted fenthion toxicity under conditions that appeared to be independent of fenthion sulfoxide formation indicating a much more complex mechanism of action for compounds with phosphorothioate and thio-ether structural features potentially involving multiple oxidative pathways.     

新烟碱类等杀虫剂对葱蝇的毒力及其对生长发育和繁殖的影响

采用定量滴加法和浸渍法测定了8种药剂对葱蝇1龄和3龄幼虫的毒力,用噻虫胺和噻虫嗪等新烟碱类杀虫剂的亚致死浓度分别处理葱蝇1龄和3龄幼虫,观察其对葱蝇生长发育和繁殖的影响,并进行了田间药效试验。结果表明,噻虫胺和噻虫嗪对3龄幼虫48 h的LC₅₀分别为14.7839 mg/L和13.3055 mg/L,毒力为毒死蜱的0.41倍和0.50倍。但LC_30-40剂量处理葱蝇3龄幼虫后,第6天存活幼虫体重分别较对照降低35.47%和36.34%,幼虫发育历期延长3.68天和3.98天,化蛹率降低71.91%和78.65%,雌蛹重降低13.36%和14.72%,雄蛹重降低15.97%和18.32%,羽化率降低12.50%和17.86%,单雌产卵量降低47.71%和51.68%。噻虫胺和噻虫嗪处理1龄幼虫,对其生长发育也有显著不利影响。田间药效试验结果显示,1 200 g/hm²噻虫胺和噻虫嗪处理后7天防效分别达98.16％和92.46％,表明这两种药剂对葱蝇防治效果高、推广应用价值大。     

Impact of sodium cyanide on catalase activity in the freshwater exotic carp, Cyprinus carpio (Linnaeus)

The Cyprinus carpio fingerlings on exposure to lethal (1 mg/L) and sub lethal concentrations (0.066 mg/L) of sodium cyanide showed inhibition in the activity of catalase. The disruption of catalase activity in freshwater fish, C. carpio is demonstrated in the present study using UV–visible spectrophotometer at 240 nm using hydrogen peroxide as a substrate. It suggests toxic effects of sodium cyanide and consequent accumulation of hydrogen peroxide in the functionally different tissues namely, liver, gill, muscle and brain. This might lead to cellular damages, and create widespread physiological disturbance. The results suggest that catalase activity can be a good diagnostic tool for sodium cyanide toxicity in biomonitoring programme.     

四种羧酸酰胺类杀菌剂对辣椒疫霉菌三个不同发育阶段的毒力比较

室内离体条件下测定了4种羧酸酰胺类(CAAs)杀菌剂双炔酰菌胺、烯酰吗啉、丁吡吗啉和氟吗啉对辣椒疫霉3个不同生长发育阶段的抑制活性。结果表明:4种杀菌剂抑制辣椒疫霉菌丝生长的EC50值分别为1.95×10-2、1.41、1.85、2.31 μ g/mL;对病菌孢子囊形成的抑制效果最好,其EC50值分别为2.00×10-4、1.50×10-3、2.60×10-3、4.30×10-3 μ g/mL;抑制游动孢子萌发的EC50值分别为4.60×10-3、0.373、0.494、0.635 μ g/mL。4种CAAs杀菌剂对辣椒疫霉的抑制作用均高于对照药剂甲霜灵、吡唑醚菌酯及嘧菌酯。     

Individual and combined effects of dimecron-ziram on the levels of serum prolactin and selected minerals of an edible freshwater fish, Oreochromis mossambicus (Peters)

The individual and combined effects of dimecron (an organophosphate pesticide) and ziram (a carbamate fungicide) on the levels of serum prolactin and selected minerals (Ca, P, and Mg) are studied in an edible freshwater fish, Oreochromis mossambicus (Peters) exposed to sub-lethal concentrations of individual dimecron (0.002 mL L⁻¹) and ziram (0.008 mL L⁻¹) and combined 1:4 mixture of dimecron-ziram (0.01 mL L⁻¹) for 24, 48, and 72 h. Exposure of fish to sub-lethal concentration of individual and mixture of dimecron and ziram caused changes in the levels of serum prolactin and minerals studied compared to control fishes. Based on the results obtained, it was concluded that the individual exposures of dimecron and ziram comparatively manifested higher toxic effects (than the combined exposure) by reducing prolactin levels and loss of mineral contents. These changes may result in a severe osmoregulatory problem.     

噻虫胺等药剂对韭菜迟眼蕈蚊的致毒效应

为了明确新烟碱类药剂对韭菜迟眼蕈蚊的毒力,采用管测药膜法和药液定量滴加法测定了噻虫胺等6种药剂对韭菜迟眼蕈蚊不同虫态的毒力,并研究了噻虫胺、甲氨基阿维菌素苯甲酸盐和辛硫磷亚致死浓度对其4龄幼虫生长发育和繁殖的影响。结果表明,新烟碱类杀虫剂噻虫胺、吡虫啉和噻虫嗪对成虫的击倒毒力均较高,分别是阿维菌素的5.75、3.86和3.51倍;6种药剂对韭菜迟眼蕈蚊卵的毒力均较低;对2龄和4龄幼虫的毒力,均以噻虫胺最高,LC₅₀分别为0.339 mg/L和1.020 mg/L,分别是阿维菌素的27.00倍和25.23倍。用噻虫胺亚致死剂量处理韭菜迟眼蕈蚊4龄幼虫,其发育历期和蛹期延长,蛹重、化蛹率、成虫羽化率、单雌产卵量和卵孵化率均降低。     

An in vitro assay for the assessment of the effects of an organophosphate, paraoxon, and a triazine, atrazine, on the heart of the gilthead sea bream (Sparus aurata)

The effects of paraoxon and atrazine on the spontaneously beating auricle, isolated from the heart of Sparus aurata, were assessed. Paraoxon, 5 μM, eliminated the atria contraction within 28.4 ± 2.8 min, an effect which was fully reversed by 15 μM atropine, an antagonist of muscarinic cholinergic receptors. The IC₅₀ was estimated to be 3.2 ± 1.5 μΜ. Atrazine, 50 and 100 μM, induced a 22.5 ± 3.2 and 32.9 ± 2.3% increase in the force of auricle contraction, caused by excitation of sympathetic synaptic terminals releasing adrenaline. This effect was reversed by 50 μM propranolol, a blocker of β-adrenoreceptors. The results have shown that both sympathetic and parasympathetic nerve terminals are activated by atrazine. Also, the auricle contraction is mainly under sympathetic control, while the frequency is dominated by cholinergic system. Finally, the detailed parameters of the auricle contraction estimated during exposure to specific pesticides, force, frequency, time-response curves and electromechanical coupling can be further used to assess and compare the toxic effects of other compounds, anticholinesterases for example, on the heart of the fish.     

五种昆虫生长调节剂对韭菜迟眼蕈蚊的致毒作用

为明确昆虫生长调节剂对韭菜迟眼蕈蚊幼虫的毒力差异、作用特点和田间控制效果,采用药液定量滴加法比较了5种昆虫生长调节剂对其不同龄期幼虫的毒力、LC50对4龄幼虫生长发育和繁殖的影响,以及药剂致毒的温度效应和盆栽防效。结果表明:5种昆虫生长调节剂对韭菜迟眼蕈蚊2龄和4龄幼虫的毒力均以虱螨脲最高,LC50分别为0.173 mg/L和0.295 mg/L,氟铃脲和氟啶脲次之,均高于对照药剂辛硫磷;而吡丙醚和灭蝇胺低于辛硫磷。5种昆虫生长调节剂以LC50处理4龄幼虫后,虱螨脲、氟铃脲和氟啶脲对其存活幼虫后续发育历期、成虫羽化率和繁殖力的影响较大,尤其是单雌产卵量较清水对照分别降低72.6%、57.8%和58.1%;灭蝇胺也可使成虫产卵量降低;吡丙醚可引起卵孵化率下降。该类药剂对其幼虫的毒力基本不受环境温度的影响;虱螨脲、氟铃脲和氟啶脲7.5、15 g a.i./667 m2处理对当代4龄幼虫的防效较低,但对下一代幼虫的防效可达93%以上;虱螨脲、氟铃脲和灭蝇胺与新烟碱类的噻虫胺混用,可显著提高药剂的速效性,且持续控制作用好。     

Mutagenic, genotoxic and enzyme inhibitory effects of carbosulfan in rainbow trout Oncorhynchus mykiss

Rainbow trout (Oncorhynchus mykiss; 116.88 ± 21.69 g) were exposed to sublethal concentrations (25 μg/L) of carbosulfan for 60 days to test if the long term exposure of fish to carbosulfan affects red blood cells acetylcholinesterase (AChE), δ-aminolevulinic acid dehydratase (ALA-D) and paraoxonase (PON) enzyme activity and induces genotoxic and/or mutagenic effects. The exposure resulted in inhibition of AChE and ALA-D activity of rainbow trout when compared to control fish. The activity of PON was not affected by carbosulfan. Interestingly, carbosulfan was found to induce DNA damage in red blood cells (comet assay) and proved to be mutagenic as revealed by the Ames test. Results indicate that blood AChE and ALA-D of rainbow trout may be a sensitive biomarker for assessment of carbosulfan contaminated water bodies. Furthermore, because the Ames test and comet assay were proven successful to detect the genotoxicity of carbosulfan, we proposed that nonlethal techniques such as blood collection from caudal vein of fish should be used to determine potential toxic effects of other pesticides to surrounding environment.     

Effects of carbaryl and azinphos methyl on juvenile rainbow trout (Oncorhynchus mykiss) detoxifying enzymes

In this study, the effects of sublethal exposures to the anticholinesterase insecticides azinphos methyl (AzMe) and carbaryl on the detoxifying responses of juvenile rainbow trout Oncorhynchus mykiss were investigated. Juvenile specimen were exposed to sublethal concentrations of AzMe (2.5 and 5 μg/L) and carbaryl (1 and 3 mg/L) for 24, 48 and 96 h. Carboxylesterase (CbE), catalase (CAT) and glutathione S-transferase (GST) activities as well as reduced glutathione (GSH) and cytochrome P450-1A (CYP1A) levels were monitored in liver and/or kidney. In all exposed groups liver CbE was significantly inhibited. Liver and kidney GSH level was reduced after sublethal exposure to both compounds. Carbaryl induced CAT activity during the first 48 h of exposure, followed by a significant decrease, whereas AzMe continuously decreased CAT activity. GST activity and CYP1A were transiently induced at 24 h by carbaryl exposure (3 mg/L) but sublethal exposure to AzMe did not affect GST activity or CYP1A. Our results show that the O. mykiss detoxifying system are a target for carbaryl and AzMe action, probably affecting redox balance. Although the responses showed similar trends in both organs, they were more important in liver than in kidney. The early inhibitory effect in CAT activity and GSH content produced by AzMe may be associated with a high degree of oxidative stress. Early induction of CYP1A, GST and CAT by carbaryl followed by enzyme inhibition suggests a milder or delayed oxidative stress, revealing differences between both pesticides metabolization. CbE inhibition is a good biomarker for AzMe and carbaryl exposure.     

异硫氰酸甲酯对小麦网腥黑穗病菌杀灭效果研究

在20℃和60%温湿度条件下,分别测定了氧硫化碳、异硫氰酸甲酯(Methyl isothiocyanate,MITC)等7种新型熏蒸剂对小麦网腥黑穗病菌(Tilletia caries(DC.)Tul.,TCT)的熏蒸效果。结果表明,除MITC外,其他6种熏蒸剂均不能完全杀灭TCT病菌;MITC熏蒸120h可有效杀灭TCT病菌,其LD90、LD95、LD99、LD99.9963分别为15.438、17.046、20.530、32.414g/m3。但是,由于小麦对MITC的高吸附性导致熏蒸剂空间浓度过低,使得有载物熏蒸试验中投药50、100g/m3MITC均未能有效杀灭小麦中的TCT病菌。残留检测结果表明,散气16d后小麦中MITC残留量分别降至0.29、1.07mg/kg,残留较高。结论:MITC对TCT有很好的杀灭效果,但由于小麦对MITC的吸附性很强,需进一步研究熏蒸方式,方可实际应用。