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The fungitoxicity of iprodione to a sensitive strain of Botrytis cinerea was antagonised by a variety of cytochrome P-450 mixed function oxidase inhibitors. Piperonyl butoxide, metyrapone and N-(2-ethylhexyl)-8,9,10-trinorborn-5-ene-2,3-dicarboximide (MGK-264) at non-fungitoxic concentrations were strongly antagonistic, whereas sesamex, nuarimol, fenarimol, etaconazole and 6-nitro or 6-methoxy 1,2,3-benzothiadiazole were moderately antagonistic. Phenobarbital and 2-diethylaminoethyl 2,2-diphenylvalerate (SKF 525-A) were slightly antagonistic. The results suggest that fungitoxicity of iprodione may be dependent on an activation catalysed by a cytochrome P-450 mixed function oxidase. 相似文献
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Fungal development and plant responses were examined in detached leaves and mid-bulb scales of Allum cepa. Following inoculation with suspensions of 105 conidia/ml distilled water Botrytis squamosa consistently produced spreading lesions in leaves and bulb scales. B. allii produced spreading lesions at most sites in bulbs but was very inconsistent in its infection of leaves; lesions were often confined to inoculation sites. Limited lesions were usually produced by B. cinerea but R. fabae failed to produce symptoms at most sites. Extensive colonization by B. allii and B. tauamosa required rapid penetration and totally necrotrophic fungal growth. During development of a spreading lesion, plant cell walls became very swollen around intramural hyphae and wall swelling appeared to precede epidermal cell death. Resistance to colonization was due to poor germination, failure to produce distinct infection hyphae (associated with accumulation of deposits of granular reaction material [RM] in underlying live cells) or restriction of infection ryphae amongst small groups of dead cells (limited lesion formation). Only B. fabae germinated poorly, and germ-tubes produced often failed to attempt penetration but grew over the leaf or bulb scale surface. Reducing numbers of conidia increased the frequency of sites associated with RM accumulation; granular deposits being particularly common at sites inoculated with low numbers of B. allii conidia. Electron microscopy revealed that RM granules were osmiophilic aggregates formed between the plasma membrane and epidermal cell wall. In the absence of RM, growth of avirulent species was restricted within the swollen walls of dead epidermal cells. Results ae compared with those from studies on tulip and broad bean leaves. 相似文献
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Increasing numbers of conidia were blown from sporulating cultures of Botrytis fabae and B. cinerea as windspeed increased up to 10 m/s. Partial drying of cultures increased the number of spores blown away at low and intermediate windspeeds. Release of spores at a constant windspeed was sustained over a prolonged period. Different patterns of release from colonies of the two species when windspeed was gradually increased, or at a constant windspeed. may be related to differences in spore size affecting the drying rate. Many conidia of both species were released as clumps. A higher proportion of B. cinerea than B. fabae conidia were clumped, partly because the mean number of spores per clump was greater. Individual conidia fell more slowly in still air than did clumps. The humidity in a bean crop was more favourable to development of Botrytis lesions than that above the crop. Low windspeeds measured within crops may restrict dispersal of conidia and may result in uneven distribution of chocolate spot lesions. 相似文献
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Barry K. Cooke Athanasios C. Pappas Victor W. L. Jordan Nigel M. Western 《Pest management science》1979,10(6):467-472
Benomyl, prochloraz or procymidone, applied as an overall plant spray at the openflower stage, effectively suppressed Botrytis cinerea fruit rot, whereas no control was achieved by foliar application only. Fruit rot was prevented using procymidone applied to the soil 12 days before inoculation of the flowers, whereas benomyl or prochloraz gave little or no control, respectively when applied in the same manner. Bioassays, using Penicillium expansum on leaf and flower extracts of strawberry plants growing in soil treated with procymidone, showed the presence of an inhibitory compound with the same RF value on thin-layer chromatography as that of procymidone. Analysis by gas chromatography and identification by gas chromatography—mass spectrometry established that the fungicide procymidone was translocated from the root system of strawberry plants to the leaves and flowers. 相似文献
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Degradation of stilbene-type phytoalexins in relation to the pathogenicity of Botrytis cinerea to grapevines 总被引:3,自引:0,他引:3
The ability of eight isolates of Botrytis cinerea to degrade the stilbene phytoalexins, resveratrol and pterostilbene, was compared with their pathogenicity to grapevines. All strains which degraded resveratrol and pterostilbene were highly or moderately pathogenic to in vitro cultures of grapevines ( Vitis rupestris ) after inoculation with agar disks containing mycelium, while those which were unable to degrade phytoalexins were non-pathogenic. In all cases, the hydroxystilbene-degrading activity was related to the presence of laccase activity in the culture filtrates, as shown by using syringaldazine as substrate. The role of laccase-mediated degradation of phytoalexins in relation to pathogenicity of B. cinerea to grapevines in discussed. 相似文献
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Establishment of chickpea seedlings from seed inoculated with Botrytis cinerea was increased under controlled environmental conditions by treatment of seed with Gliocladium roseum or Trichoderma virens . An isolate of G. roseum (GrH) from Horsham in the chickpea-growing region of western Victoria outperformed T. virens in three soil types, including one to which T. virens was indigenous. There was no effect of soil moisture on seedling establishment from seed treated with GrH, but recovery of G. roseum from seed in continuously wet soil was lower than from wet/dry soil. A factorial assay with three isolates of G. roseum and the soils from which they were isolated showed no interaction between isolate and soil type and no difference between isolates for establishment or recovery. In a field trial at Horsham sown in winter (July), seed treatment with GrH increased establishment from 26.0% (control) to 37.5%. Biocontrol by GrH was ineffective in a winter-sown field trial at Bundoora, but all three isolates increased establishment from 47.5% (control) to up to 87.5% in a trial at the same location sown in spring (October). The commercial implications of these observations are discussed. 相似文献
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When applied to the roots of potato plants growing in different soils iprodione became systemic in the plants. Although iprodione was adsorbed on the soils tested, sufficient fungicide was present in potato stems to prevent infection by Phoma exigua var. foveata on all plants except those grown in peat soils. The amount of fungicide present in the aerial parts of the plant was related to the soil/water distribution coefficients. Application of iprodione to the sprouts of seed potato tubers prior to planting decreased the incidence and severity of infection by Rhizoctonia solani (stem canker) and Polyscytalum pustulans on stem bases. 相似文献
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M. Ikram Khan Virginia Marroni Sandi Keenan Ian A. W. Scott Suvi L. H. Viljanen-Rollinson Simon Bulman 《European journal of plant pathology / European Foundation for Plant Pathology》2013,136(3):495-507
Botrytis spp. associated with neck rot disease were isolated from New Zealand onions. The fungi were identified using molecular sequences of the ribosomal internal transcribed spacer (ITS) and intergenic spacer (IGS) regions, and the glyceraldehyde-3-phosphate dehydrogenase (G3PDH) gene. Analyses of the sequences showed that the majority of the isolates gathered in 2005–07 were B. aclada. A new high resolution melting analysis (HRMA) assay was developed that allowed fast and simple discrimination between B. aclada and other Botrytis spp. causing onion neck rot in New Zealand. To further verify these results, Botrytis isolates from New Zealand onions, stored in the International Collection of Microorganisms from Plants (ICMP), were also examined. Only a single isolate from the ICMP collection was B. aclada while two isolates were B. byssoidea, one B. squamosa and another closely related to Botryotinia porri. Identification of the remaining Botrytis isolates was more difficult; while IGS and ITS sequences indicated a close relationship to B. allii or B. byssoidea, a previously unreported intron insertion was observed at the 3′ end of the ribosomal small subunit gene in these isolates. No evidence of heterogeneity was observed in the G3PDH gene sequences, as might have been expected of the allodiploid B. allii, but the G3PDH sequence ruled out B. byssoidea as the identity of these isolates. 相似文献
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Botrytis allii colonies incubated at low temperatures have been reported to produce larger conidia that germinate faster and give rise to longer germ-tubes than those grown at room temperature. The present study compared the effect of conidia produced at 20°C and at 0 and –2°C on their pathogenicity to artificially inoculated white onion bulbs, and the effect of conidial concentration (5×103 and 5×104 conidia/mL) on disease incidence, lesion area, incubation and latent period during storage at 20, 5 and 0°C. At all storage temperatures and periods tested conidia produced at −2°C caused a higher disease incidence and larger areas of rot than those produced at higher temperatures. When the conidial production temperature was raised to 20°C, the duration of incubation on the bulbs inoculated with 5×104 conidia/mL was more than doubled during storage at 0°C, tripled at 5°C, and took 50% longer at 20°C. The incubation period was not significantly affected by conidial concentration at 20°C, and only slightly at 5 and 0°C, but at low temperatures the latent period was longer because of the delay induced in sporulation. These data are consistent with the packers' opinion that cross-infection of spring onions by long-term refrigerated onions in grading lines caused earlier and heavier rotting. 相似文献
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J. G. HARRISON 《Plant pathology》1988,37(2):168-201
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Disease index, dry weight loss and leakage of K+ ions in the tissues of two onion cultivars demonstrated that the red cultivar Tropeana had a greater susceptibility to neck rot caused by Botrytis allii than the white cultivar Rovato. The comparison between the cultivars showed that the less susceptible one was characterized by lower polygalacturonase activity (with fewer isoenzyine forms), more rapid accumulation of phenolic compounds in the early stages and faster activation of peroxidase. Polyphenoloxidase was not found in either the healthy or the diseased tissues of the two cultivars. The significance of these findings is discussed in relation to possible host defence mechanisms. 相似文献
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Botrytis aclada and Botrytis allii, associated with onion gray-mold neck rot and isolated in Hokkaido, were tested for sensitivity to benzimidazole. Of the B. aclada strains, 59% were highly resistant and the remaining 41% were sensitive; all strains of B. allii were sensitive. Resistant strains were widespread in Hokkaido. We analyzed the sequences of the β-tubulin gene of resistant strains and detected the replacement of glutamic acid (GAG) by lysine (AAG) at codon 198. This is the first report of benzimidazole resistance in B. aclada. This study revealed a difference in fungicide sensitivity between the two Botrytis species.
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The mechanisms of action against Botrytis cinerea of the dicarboximide fungicides vinclozolin ( I ), procyrnidone ( II ), iprodione ( III ) and the less closely related compound prochloraza ( IV ) have been compared. They all inhibited mycelial growth much more than spore germination. None of the compounds affected respiration, membrane permeability or RNA production but III inhibited DNA synthesis and IV inhibited protein synthesis. Although chitin biosynthesis was inhibited by all the fungicides it was barely affected at the ED50 concentrations (the concentration required to reduce the growth or germination of the test species by 50%) and is thus unlikely to be the primary target. The fungicides altered fungal lipid composition. I and II inhibited triglyceride production but III had no effect on it; III and IV reduced sterol biosynthesis. No common primary mode of action was found. 相似文献
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Temperature optima for growth of Aspergillus niger and A. flavus on agar lay between 30°C and 35°C; the optimum for A. fumigatus was 40°C. A. flavus grew less rapidly in culture than the other two species. These fungi were recovered when a single sample of onion seeds, produced in Sudan, was plated out onto agar and incubated over a range of temperatures from 15°C to 45°C. In line with the growth optima of the fungus, the recovery of A. niger was greatest between 25°C and 35°C; recovery of A. flavus was greatest between 30°C and 35°C and recovery of A. fumigatus greatest between 40°C and 45°C. Hot-water treatment for durations of up to 60 min at 50°C failed to reduce the incidence of recovery of seedborne A. niger and A. flavus from seeds incubated at 30°C on agar; A. fumigatus was not recovered from seeds treated in this way. However, when seeds were hot-water treated at 60°C and incubated on agar at 30°C, A. niger was virtually eliminated by a treatment duration of 15 min or more; the incidence of recovery of A. fumigatus was significantly increased compared with the 50°C treatment and there was no change in the incidence of A. flavus. Hot-water treatment at 60°C for more than 30 min significantly reduced seed germination. 相似文献