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1.
Melon plants grown in a liquid nutrient solution were separately treated either with benomyl, 2-aminobenzimidazole (2-AB), or benzimidazole (BZ), and after 60 days each compound had decomposed into significant concentrations of metabolites, those from 2-AB and BZ corresponding to the metabolites from benomyl. This supported the following postulated metabolic pathway for benomyl in melon plants: benomyl → carbendazim → 2-AB→BZ Involvement of the other identified metabolites of benomyl (2-aminobenzonitrile, o-phenylenediamine, aniline, and the conjugates of carbendazim and 2-AB) cannot be proposed unequivocally. In the extracts from plants treated with 2-AB or BZ, new and unidentified metabolites have also been observed using gas-liquid chromatography (g.l.c.).  相似文献   

2.
The persistence and distribution in leaves and fruits of benomyl, carbendazim and methylthiophanate were investigated, following fungicide spray treatments in pear orchards. Chemical analysis and bioassays showed that basal leaves sprayed more than once with benomyl, contained 50 ppm of methyl benzimidazole carbamate (MBC) 4 days after the last spray. Seven months later. 8 ppm MBC was detected in the basal leaves, just before normal abscission. In apical leaves, the fungicide levels were lower than in the basal ones. Analyses of basal leaves showed that the residue level of MBC, 5 and 7 months after the last treatment with benomyl. carbendazim or methylthiophanate, was very similar in all treatments. Bound MBC was not detected in the leaves and only low concentrations of 2-amino benzimidazole (2-AB) were detected. There was no translocation of these fungicides from treated leaves to new young leaves. Chemical analysis of pear fruits from an orchard sprayed with benomyl revealed that 3 weeks after the last spray treatment, the residue level of MBC was 0.4 ppm. About 85% of the fungicide was found in the peel, and only 15% in the pulp. The more infected fruits consistently contained a lower concentration of MBC than the less infected fruits.  相似文献   

3.
The content and homologue composition of alkylresorcinols were investigated in rye seedlings (Secale cereale L.) treated with benzimidazole fungicides and grown for 5 days under various thermal and light conditions. The fresh and dry biomasses of green and etiolated plants were greatly increased by benomyl and carbendazim at 29 °C. At 22 and 15 °C benomyl had an inhibitory action on growth of rye, whereas the effects caused in the presence of carbendazim were slightly dependent on external stimuli. On the other hand, benomyl enhanced resorcinol biosynthesis in green seedlings grown at all temperatures, while carbendazim only at 29 °C. In plants kept in the darkness, both fungicides increased content of alkylresorcinols at 29 °C and decreased its at 22 and 15 °C. The qualitative pattern of resorcinolic homologues was also significantly modified in the presence of benomyl and carbendazim and depended on other physical stimuli.  相似文献   

4.
The effects of benomyl [methyl 1 (butylcarbamoyl)-benzimidazol-2-ylcarbamate] and carbendazim (methyl benzimidazol-2-ylcarbamate) on mitosis in hyphae of Botrytis cinerea and root tips of onion (Allium cepa) were studied. The effect of the fungicides on root tips was compared with the effect produced by griseofulvin.Benomyl or carbendazim had a rapid effect on dividing hyphal nuclei. The effects of the fungicides were apparent after 5 min, and the normal stages of division were not seen clearly in any of the treated material. Chromosomes became visible at prophase-metaphase, but they did not separate completely. At the end of division, the chromatin became stretched into long threads, daughter nuclei did not separate completely, and chromatin was often present as irregular shaped masses.Benomyl and carbendazim induced abnormalities in cell division in about 3% of onion root tip cells. After treatment for 6 h, formation of the cell plate was inhibited and cells were seen with two nuclei; other aberrations produced were lagging chromosomes and anaphase bridges. After 3 days chromosomes sometimes occurred as amorphous clumps, and nuclei were found with more than two nucleoli. Griseofulvin produced similar effects in onion root tip cells, but the chromosome bridges persisted through to telophase.The results show that benomyl and carbendazim can interfere with mitosis in cells in green plants as well as in hyphae of fungi.  相似文献   

5.
An in vivo technique was developed to observe colonisation of mushroom compost by Trichoderma spp. Isolates of T. harzianum (Th2), T. harzianum (Th1), T. koningii (Tk) and T. viride (Tv) were artificially introduced into compost using a mini-bag system. Wheat grains, colonised by Trichoderma spp, were placed centrally on a layer of compost at the bottom of 1-litre polythene bags which were then filled with 350 g of spawned or un-spawned compost, and partially sealed. After 14 and 21 days incubation at 27 degrees C, the bags were assessed for recovery of Trichoderma from middle and top zones using a needle stab re-isolation technique and a visual colonisation scoring system. Visible green mould contamination, similar to that observed in practice, developed within 21 days. The visual colonisation scoring was reliably related to the re-isolation success. In this evaluation, Trichoderma spp showed considerable differences in their relative abilities to colonise spawned and un-spawned compost, with Th2 isolates being consistently superior to the other isolates of Th1, Tk and Tv in colonising spawned compost. This technique was employed to evaluate the effects of fungicides on the colonisation of mushroom compost by three Trichoderma spp: Th2, Th1 and Tk, using 1-litre and 5-litre mini-bag systems. Aqueous suspensions of benomyl, carbendazim, thiabendazole, prochloraz and prochloraz+carbendazim incorporated into the compost at 50 mg litre(-1), or applied to spawn at 50 mg kg(-1), reduced the colonisation by Trichoderma spp. Prochloraz and prochloraz+carbendazim were superior to benomyl, carbendazim or thiabendazole in reducing compost colonisation by Th2, Th1 and Tk, with Th2 being the most persistent type, capable of colonising treated compost in the presence of all five fungicides. The prochloraz+carbendazim mixture, not normally used in mushroom production, was equal to or better than prochloraz alone. The incidence of green mould colonisation by Th2 was as extensive in the 5-litre compost bags as in the 1-litre bags, but colonisation by Th1 and Tk was more apparent in the 5-litre bags. The in vivo mini-bag evaluations using wheat grain Trichoderma inoculum and needle stab re-isolation procedures proved an efficient method for studying colonisation and screening for effectiveness of fungicides applied to mushroom compost or spawn.  相似文献   

6.
The toxicities of five systemic fungicides [benomyl, carbendazim, methyl 4-(2- aminophenyl)-3-thioallophanate (NF48), thiabendazole and thiophanate-methyl] and of two non-systemic fungicides (guazatine and phenylmercury acetate) against Fusarium culmorum were compared on agar plates; their performance as seed treatments was measured by inoculating the shoot bases of wheat seedlings with F. culmorum in pot experiments. The two most effective compounds, benomyl and thiabendazole, and the less effective thiophanate-methyl, were evaluated in further seed treatment experiments in which leaf sheaths and roots of slightly older plants were infected. The three fungicides protected the first leaf sheath for more than 5 weeks, but thiophanate-methyl was least effective. Against root disease, they were effective when infection was mild, but only thiabendazole significantly controlled severe infection. Bioautography confirmed that fungicide levels in shoots were greater after benomyl and thiabendazole, than after carbendazim and thiophanate-methyl treatments, and that concentrations of fungicide after benomyl, carbendazim and thiophanate-methyl treatments generally declined between 5-13 weeks after treatment. Thiabendazole produced a second fungitoxic component detectable in plants after 34 days.  相似文献   

7.
Forty-nine greenhouses of vegetable crops were surveyed in southeast Spain at the beginning of the disease season in December 1992 to estimate frequencies of resistance to benzimidazoles, dicarboximides and N -phenylcarbamates (NPC) in B. cinerea . Out of 261 isolates collected, 28% were sensitive to both benzimidazoles and dicarboximides, 15% were benzimidazole-resistant and dicarboximide-sensitive, 8% were benzimidazole-sensitive and dicarboximide-resistant and 46% were benzimidazole- and dicarboximide-resistant. Resistance to benzimidazole, dicarboximide and N -phenylcarbamate was determined by measuring the ability of each isolate to grow in the presence of carbendazim, procymidone and diethofencarb fungicides respectively. Carbendazim- or procymidone- resistant isolates were found in all surveyed greenhouses. Three isolates were found with resistance to carbendazim, procymidone and diethofencarb collected in two adjacent greenhouses that were sprayed with the carbendazim and diethofencarb mixture. All other isolates were sensitive to the mixture because they were either sensitive to carbendazim and resistant to diethofencarb or vice versa. Fitness of 31 isolates of B. cinerea was determined in vivo by measuring their sporulation and lesion growth rate on leaf disks. No fitness costs were associated with resistance to iprodione (dicarboximide) and benomyl (benzimidazole). Isolates with EC50 values higher than 101 mg/L for benomyl and 1.6 mg/L for iprodione were considered to be field resistant (they caused visible lesions on cucumber leaf disks treated with each fungicide).  相似文献   

8.
A laboratory-assembled high pressure liquid chromatograph with variable wavelength ultraviolet detector is described. The chromatography of the systemic fungicides benomyl, thiabendazole, thiophanate, related fungicides and benzimidazoles (13 compounds in all) is described using reverse phase and adsorption systems. Temperature affects reverse phase systems but not adsorption systems. Use of a variable wavelength detector increases sensitivity and selectivity. High pressure liquid chromatography (h.p.l.c.) has been applied to measurements of the solubility of benomyl and carbendazim in water and the degradation of benomyl in solution. Use of h.p.l.c. to measure benzimidazole residues awaits the development of methods of avoiding interference by substances extracted from crops and soils.  相似文献   

9.
Benzimidazoles were used successfully against gummy stem blight of cucurbits for only one growing season (1980). It was soon noticed in experiments in vivo that they were not effective against some isolates of the pathogen. In a survey during the 1981 crop season, 76 out of 102 isolates collected from 20 plastic greenhouses all over the main cucurbit-growing areas of Crete were resistant to benomyl. The average benomyl concentrations that reduced mycelial growth rates of seven resistant and seven sensitive isolates by 50% were 716 ± 49 and 1.2 ± 0.34μg/ml respectively. The average growth rate of resistant isolates was lower than that of sensitive isolates but there were no differences in spore production and spore germination. The pathogenicity of resistant isolates on young cucumber plants was lower than that of sensitive isolates. The application of benomyl, carbendazim, cypendazole and thiophanate methyl to young cucumber plants at the rate of 300μg a.i./ml 1 day before inoculation with 500 000 spores/ml of the resistant isolates did not affect the infection rate of the disease after 4 days. Sensitive isolates caused no onslight symptoms on similarly treated plants.  相似文献   

10.
Mycelial isolates (115) of Pseudocercosporella herpotrichoides were obtained from five field sites in England. Carbendazim-resistant isolates were detected by their mycelial growth on agar containing 1 μg/ml carbendazim. Resistant isolates were found at two of the five sites examined and one of these had never been treated with benzimidazole fungicides. Amongst the carbendazim- resistant isolates there was a predominance of isolates with pale mycelium, an irregular colony margin and a relatively slow growth rate; however, this association was not absolute. Large differences in the effects of carbendazim on mycelial growth of sensitive and resistant isolates were demonstrated; growth of sensitive isolates was completely inhibited at 0.5 μg /ml carbendazim whilst five of the six resistant isolates examined grew on agar containing 1000 μg/ml fungicide. The carbendazim-resistant isolates were cross-resistant to benomyl, thiophanate-methyl and to a Icsser degree thiabendazole, but not to prochloraz. Conidia of carbendazim-resistant isolates were as resistant. Carbendazim-resistant isolates were just as pathogenic to wheat as sensitive isolates. The implications of these results and other reports of benzimidazole resistance in P. herpotrichoides are discussed in relation to disease control.  相似文献   

11.
Gas-chromatographic analyses of extracts of soil samples from plots, treated with a 50% atrazine wettable powder at dose rates of 2 and 4 kg a.i. ha?1, showed the presence of a new atrazine degradation product. This product was isolated, concentrated and purified by column chromatography and high-performance liquid chromatography. The chromatographic properties of this material were identical with those of a product isolated from a 0.02% methanolic solution of 2-amino-4-chloro-6-isopropyl-amino-1,3,5-triazine that had been stored under laboratory conditions. A combined gas-liquid chromatographic/mass spectrometric assay identified the new product in soil as 2-isopropylamino-4-methoxy-6-methylamino-1,3,5-triazine.  相似文献   

12.
Seeds of perennial ryegrass Lolium perenne treated with four fungicides, benomyl, captan, iprodione and metalaxyl, used singly and in all combinations were sown in soil in pots. The soil was maintained at a low moisture content to predispose the seedlings to pre-emergence infection by soil-borne fungi. Thirteen of the fifteen fungicide treatments significantly increased seedling emergence and all but one contained benomyl and/or captan. In another pot experiment, a combination of benomyl and captan was tested against four similar treatments, carbendazim+captan, thiabendazole+captan, thiabendazole+metalaxyl and thiabendazole+thiram and also drazoxolon. Only benomyl+captan and drazoxolon did not increase seedling emergence significantly. A natural infection of the seedlings by powdery mildew Erysiphe graminis was reduced significantly by all treatments except thiabendazole+thiram and drazoxolon. Only car-bendazim+captan significantly increased the dry weight of seedlings per pot 98 days after sowing. Benomyl+captan seed treatment significantly increased seedling emergence in 9 of 16 soils collected from widespread sites. One perennial ryegrass cultivar, Parcour, was used in the above experiments and in a comparison with 12 other diploid cultivars its response to benomyl seed treatment was about mid-range.  相似文献   

13.
The performance of carbendazim and its chemical precursors benomyl, thiophanatemethyl and methyl 4-(2-aminophenyl)-3-thioallophanate ( I ) ( “NF48” ) as systemic fungicidal seed treatments on barley was investigated. In field trials all treatments significantly decreased smut (Ustilago nuda) at 3.2 g kg-1 of seed; the order of effectiveness was I > benomyl > thiophanate-methyl > carbendazim. Control of barley mildew (Erysiphe graminis) followed a similar pattern but results were less clear-cut. Measurements of uptake and translocation from seeds, treated with radiolabelled fungicide and planted in pots of Woburn soil in a controlled environment room, showed that seedlings accumulated much more I than the other compounds over 28 days. This substantial early uptake into leaves could explain why I was particularly effective against smut in the field trials. Comparisons of amounts taken up. with solubility in water, octanol/water partition coefficient, extent of adsorption on soil and pKa values suggested that the effects of these properties on availability in the soil solution may be more important than their influence on penetration into the root in determining relative uptake and disease control in the case of localised applications such as seed treatments.  相似文献   

14.
The fungicide benomyl, previously reported to be an anti-cholinesterase and toxic to earthworms, has now been shown to have little or no effect on cholinesterase. However, it breaks down to form two products: butyl isocyanate. which is an irreversible inhibitor of the enzyme of comparable potency to organophosphates; and methyl benzimidazol-2-ylcarbamate (MBC, carbendazim), which does not inhibit at all. The reported inhibitory power of benomyl is therefore likely to be due to formation of small quantities of the former. It is also concluded that toxicity of benomyl and MBC to earthworms cannot be due to inactivation of cholinesterase.  相似文献   

15.
C. SAYDAM 《EPPO Bulletin》1981,11(2):59-62
While a number of common wheat diseases are well controlled in Turkey, Septoria leaf blotch (due to Septoria tritici ) has been gaining in importance in Turkey since 1967, when the Mexican wheat varieties were first imported. Surveys in six locations in the Aegean Region in April-May 1975–1977 showed that S. tritici was common throughout the region. In 1978, trials with four fungicides (mancozeb, benomyl, carbendazim in two formulations) in eight combinations showed that threefold treatment with benomyl was most effective. However, a better economic return was obtained with two applications of Derosan. The first application can usefully be combined with normal weed control.  相似文献   

16.
Plots of a sugar beet field in Belgium were treated pre-emergence with 1.3, 1.95 or 2.6 kg a.i. ha-1 chloridazon. Some of these plots had been amended 1 month before sowing with 50 1 ha-1 cow manure. Soil samples were taken al regular intervals and analysed by gas-liquid chromatography and gas-liquid chromatography combined with mass spectrometry. During the first month following chloridazon application, soil dissipation followed apparent first-order kinetics with soil half-lives being independent of the dose, and were 37 days in the non-manured plots and 96 days in the manured plots. After the first month, rates of chloridazon soil dissipation increased, giving the same residual chloridazon soil concentration of c. 0.25 mg a.i, kg-1 in all plots 1.8 months after application. Residual levels remained at this concentration up to the third month after application, and then disappeared, leaving no delectable soil residues at harvest. Chloridazon soil dissipation thus occurred according to unusual kinetics.  相似文献   

17.
Mixtures of the plant growth regulators (PGRs) gibberellins A4 and A7 (GA 4/7) and ethephon (2-chloroethylphosphonic acid), applied as soak treatments at 20° C for 24 h, were toxic to pycnidiospores of Septoria apiicola on agar, apparently as a result of low pH of their solutions. Ultraviolet spectroscopy showed that the aqueous solubility of the fungicides benomyl and carbendazim increased significantly when buffered at low pH or mixed with aqueous solutions of GA 4/7 and ethephon. This resulted in greater quantities of 14C-labelled fungicides entering celery seeds imbibed in PGR/fungicide mixtures in comparison with fungicides alone.
A 24-h seed soak at 20° C in a mixture of aqueous benomyl, GA 4/7 and ethephon eliminated S. apiicola in infected celery seeds. A thiram soak was also effective but PGR mixtures alone did not completely eliminate the pathogen.  相似文献   

18.
Earthworms, Eisenia fetida, were treated by surface exposure to the fungicide benomyl at various stages of posterior segmental regeneration. Teratogenic effects of benomyl were observed when worms were treated 7–11 days after amputation (i.e. during the normal period of segmental replication), but not during days 1–5, 13–17, or 19–23. Teratogenic effects included a reduction in the number of regenerated segments, an increased frequency of segmental groove anomalies, and a variety of monstrosities. The effects of benomyl treatment on the number of regenerated segments and frequency of anomalies were dose-dependent within a narrow concentration range (approximately 0.2–5.0 mg litre?1); at higher concentrations (e.g. 25 mg litre?1) teratogenic effects were less frequent because the onset of segmental delineation was delayed until well after exposure. Non-invasive electrophysiological recordings from treated worms indicated that functional integrity of giant nerve fibre conduction pathways was established in all anomalously regenerated tail segments, except in a two-tailed monstrosity. The evidence supports the hypothesis that these teratogenic effects derive from an antimitotic mode of action of benomyl on segmental regeneration.  相似文献   

19.
Dichlofluanid controlled cane spot ( Elsinoë veneta ) of raspberry cv. Mailing Jewel when applied before harvest in a four-spray programme, but carbendazim, vinclozolin and iprodione were ineffective. Lesions predominated in the fruit-bearing region of canes in a zone 46-120 cm above soil level. Bait plants exposed for periods of 2 weeks in two infected plantations in north-east Scotland developed lesions, after incubation for 4-6 weeks, only on internodes which were the youngest at the time of exposure. Infection occurred in all periods from mid-April to late July. The infection of bait plants was related to the distribution of lesions on canes in the spray trial.
An isolate of E. veneta obtained from a plantation sprayed with carbendazim and vinclozolin was resistant when tested in vitro to carbendazim, benomyl and thiophanate-methyl. This isolate and another MBC-sensitive strain were both relatively insensitive to the dicarboximide fungicides iprodione and vinclozolin.  相似文献   

20.
Tomato powdery mildew   总被引：2，自引：5，他引：2  
A powdery mildew ( Erysiphe sp.) occurred on greenhouse-grown tomato crops in southern England in 1987. White pustules appeared on the upper surfaces of leaves of affected crops and only rarely on the under surfaces. In greenhouse experiments, stems were very severely affected. In host range studies 19 tomato cultivars and six breeders' lines were susceptible as well as Nicotiana tabacum. N. xanthi. Solanium melongena, S. pseudocapsicum, S. tuberosum, Datura stramonium and Petunia hybrida. Conidia germinated readily at 15, 20 and 25 C and were viable for 2 days in the laboratory and at least 6 days in the greenhouse. The disease was well controlled by a range of fungicides including benomyl, bupirimate, carbendazim, chlorothalonil, fenarimol and pyrazophos. All of these except pyrazophos are approved for use on tomatoes in the UK. The pathogen was very sensitive to low concentrations of benomyl and fenarimol but less so to bupirimate.  相似文献   

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