Yeasts as antagonists against fireblight     

A. Seibold  A. Fried  S. Kunz  E. Moltmann  E. Lange  W. Jelkmann 《EPPO Bulletin》2004,34(3):389-390

Yeasts are potential antagonists of microorganisms in the phyllosphere. Due to their osmotolerance, they should also be able to colonize apple flowers. In field experiments, we applied yeast agents against fireblight at two different sites in the southern part of Germany. They showed efficiencies 0–20% below Plantomycin (streptomycin). Co-culture experiments in liquid basal media with synthetic nectar resulted in suppression of Erwinia amylovora by yeast. This effect could not be confirmed with population studies of yeasts and E. amylovora in flower clusters. Field and laboratory experiments indicated that yeasts have antagonistic properties against fireblight but further research is needed to investigate this potential.  相似文献   

A modified fluorometric method to quantify the concentration effect (pI₅₀) of photosystem II-inhibiting herbicides     

Masaki Hiraki  Wim J. Vredenberg  Jack J.S. van Rensen  Ko Wakabayashi 《Pesticide biochemistry and physiology》2004,80(3):183-191

Chlorophyll fluorescence induction curves of isolated thylakoids were measured in the absence and in the presence of various concentrations of photosystem II-inhibiting herbicides. A mathematical program was applied to simulate the curves. Based on these simulated curves a new method is developed to determine the concentration effect (pI₅₀) of the herbicides. The results of the new method correspond well with reported values in the literature. The method is very convenient and time-saving.  相似文献   

Differences in the growth stages of Erysiphe pisi on cultivars of field pea (Pisum sativum L.)     

Su  H.  Hwang  S. F.  Chang  K. F.  Conner  R. L.  Howard  R. J.  Turbull  G. D.  Blade  S. F. 《植物病害和植物保护杂志》2004,111(1):64-70

Journal of Plant Diseases and Protection - The infection process of Erysiphe pisi on field pea cvs. ‘Highlight’ and ‘Tara’ carrying resistance gene erl, line...  相似文献   

Repression of deoxynivalenol accumulation and expression of Tri genes in Fusarium culmorum by fungicides in vitro   总被引：1，自引：0，他引：1  

L. Covarelli  A. S. Turner  P. Nicholson † 《Plant pathology》2004,53(1):22-28

A defined medium was developed in which to monitor deoxynivalenol (DON) accumulation, fungal growth and expression of genes involved in trichothecene biosynthesis (designated Tri genes). In liquid culture, DON accumulated shortly after maximum expression of Tri6 and coincident with expression of Tri5. This was generally 96 h after inoculation. The effects of sublethal concentrations of the fungicides azoxystrobin, trifloxystrobin, kresoxim-methyl and tebuconazole on biosynthesis of the trichothecene DON by Fusarium culmorum were studied using this medium. The strobilurin fungicides trifloxystrobin and azoxystrobin significantly reduced the accumulation of DON in culture medium at a range of concentrations. Kresoxim-methyl, also a strobilurin, and tebuconazole, a triazole, did not significantly reduce the accumulation of DON, although levels were lower than those in nonamended cultures. Trifloxystrobin significantly reduced the accumulation of DON when added to cultures before initiation of trichothecene biosynthesis. RT-PCR assays of the expression of Tri6 and Tri5 genes indicated that trifloxystrobin acted by inhibiting the initiation of trichothecene biosynthesis.  相似文献   

First report of walnut canker caused by Fusarium incarnatum in Argentina     

S. Seta  M. Gonzalez  G. Lori 《Plant pathology》2004,53(2):248-248

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Wind-mediated spread of Rice yellow mottle virus (RYMV) in irrigated rice crops     

S. Sarra  P. Oevering  S. Guindo  D. Peters † 《Plant pathology》2004,53(2):148-153

A study was carried out to demonstrate that Rice yellow mottle virus (RYMV), a virus known to be transmitted by beetles, can spread between rice plants by direct leaf contact caused by wind. Almost all healthy plants surrounding an infected plant became infected when exposed to a fan blowing for 15 min at a distance of 50 cm. Spread of RYMV by plant contact, mediated by wind, was also demonstrated in field experiments, the extent of spread depending on plant density. Infection was almost 10 times higher in plots with a density of 33 plants m⁻² than in plots with 16 plants m⁻². Less spread was observed in plots protected by 1·5 m high windscreens. It is suggested that wind-mediated spread of RYMV may result from abrasive contact between leaves of plants.  相似文献   

Rust of Queensland arrowroot (Canna edulis) caused by Puccinia thaliae: a new record for India     

M. L. Jeeva  V. Hegde  T. Makeshkumar  S. Sriram  R. R. Nair  S. Edison  N. Mathur 《Plant pathology》2004,53(2):261-261

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Canker on umbra tree caused by Fusarium sambucinum     

M. R. Carranza  G. A. Lori  S. Larran 《Plant pathology》2004,53(4):532-532

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First report of gummy stem blight caused by Didymella bryoniae on muskmelon (Cucumis melo) in India     

J. Sudisha  T. Vasanth Kumar  S. R. Niranjana  H. Shekar Shetty 《Plant pathology》2004,53(4):533-533

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First report of Mungbean yellow mosaic India virus on mungbean in Pakistan     

M. Hussain  J. Qazi  S. Mansoor  S. Iram  M. Bashir  Y. Zafar 《Plant pathology》2004,53(4):518-518

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