6 research outputs found
Identification of race 1 of Fusarium oxysporum f. sp. lactucae on lettuce by inter-retrotransposon sequence-characterized amplified region technique
No full textFusarium wilt of lettuce, caused worldwide by Fusarium oxysporum f. sp. lactucae, is an emerging seed-transmitted disease on Lactuca sativa. In order to develop a molecular diagnostic tool for identifying race 1 (VCG0300) of the pathogen on vegetable samples, an effective technique is presented. Inter-retrotransposon amplified polymorphism polymerase chain reaction (PCR), a technique based on the amplification of genomic regions between long terminal repeats, was applied. It was shown to be useful for grouping F. oxysporum f. sp. lactucae race 1 isolates. Interretrotransposon sequence-characterized amplified regions (IR-SCAR) was used to develop a specific set of PCR primers to be utilized for differentiating F. oxysporum f. sp. lactucae isolates from other F. oxysporum isolates. The specific primers were able to uniquely amplify fungal genomic DNA from race 1 isolates obtained in Italy, Portugal, the United States, Japan, and Taiwan. The primers also were specific to pathogen DNA obtained from artificially infected lettuce seed and naturally and artificially infected plants
Vegetative compatibility groups of Fusarium oxysporum f. sp. lactucae from lettuce
No full textFusarium oxysporum f. sp. lactucae, the causal agent of Fusarium wilt of lettuce, has been reported in three continents in the last 10 years. Forty-seven isolates obtained from infected plants and seed in Italy, the United States, Japan, and Taiwan were evaluated for pathogenicity and vegetative compatibility. Chlorate-resistant, nitrate-nonutilizing mutants were used to determine genetic relatedness among isolates from different locations. Using the vegetative compatibility group (VCG) approach, all Italian and American isolates, type 2 Taiwanese isolates, and a Japanese race 1 were assigned to the major VCG 0300. Taiwanese isolates type 1 were assigned to VCG 0301. The hypothesis that propagules of Fusarium oxysporum f. sp. lactucae that caused epidemics on lettuce in 2001-02 in Italian fields might have spread via import and use of contaminated seeds is discussed
Multitrophic interaction of Diabrotica virgifera virgifera larvae and fungal communities in the rhizosphere and endorhiza of maize
No full textPopulationsdynamik / Epidemiologie / Prognose (Poster)
No full text130 - Zeuner, T.; Kleinhenz, B.; Röhrig, M. iGreen Pflanzenschutzplaner131 - Bouma, E.GEWIS: ein Entscheidungshilfesystem für die gezielte Ausbringung von Pflanzenschutzmitteln132 - Moltmann, E.; Gauer, A.; Röhrig, M. Erstellung eines neuen Programms zur Verbesserung der Feuerbrandprognose (Erwinia amylovora)133 - Hausladen, H.; Räder, T. 10 Jahre PhytophthoraModell Weihenstephan – Gezielte Bekämpfung der Kraut- und Knollenfäule134 - Eichhorn, J.; Ziegler, J.; Laun, N.; Keil, B.; Racca, P.; Kleinhenz, B.; Aldenhoff, L. Stemphylium-Prognose mit TomCast135 - Dinnesen, S.; Hummel, H.E.; Grozea, I.; Goßmann, M.; Büttner, C. Spektrum der Fusarium spp. und der Mykotoxinbelastung im westrumänischen Körnermaisanbaugebiet unter Berücksichtigung der Populationsdichten verschiedener Schadinsekten und der Fruchtfolge136 - Dematheis, F.; Kurtz, B.; Vidal, S.; Smalla, K. Multitrophische Interaktionen des Fraßverhaltens von Diabrotica Larven und pilzlichen Gemeinschaften in der Rhizosphäre und Endorhiza von Mais137 - Heibertshausen, D.S.; Racca, P.; Zeuner, T.; Kleinhenz, B.; Hau, B. Risikoanalysen ausgewählter Schaderreger an Mais und Raps auf Basis regionaler Klimaprojektionen für Niedersachsen138 - Richerzhagen, D.; Heibertshausen, D.; Racca, P.; Zeuner, T.; Kleinhenz, B.; Hau, B. Einsatz regionaler Klimaprojektionen zur Untersuchung des Auftretens von Blattkrankheiten an Zuckerrüben139 - Mahlein, A.-K.; Mewes, T.; Steiner, U.; Dehne, H.-W.; Oerke, E.-C. Spektrale Vegetationsindizes zur Abbildung des Befallsverlaufs und der Befallsstärke von Blattkrankheiten der Zuckerrübe140 - Mewes, T.; Menz, G. Spektrale Anforderungen an Fernerkundungsdaten für die Detektierbarkeit von Pflanzenstress141 - Racca, P.; Tschöpe, B. SIMCOL1+3: Erarbeitung eines Entscheidungshilfesystems zur Optimierung der Bekämpfungsstrategie für die Anthraknose der Blauen Lupine142 - Tschöpe, B.; Racca, P. Die Ontogenese der Lupine: Modellierung und Validierung143 - Hau, B.; Kraul, J. Raum-zeitliche Dynamik des Echten Gurkenmehltaus im Gewächshaus144 - Schuster, A.-K.; Bandte, M.; Von Bargen, S.; Büttner, C. Birken-assoziierte Insekten als potentielle Vektoren des Cherry leaf roll virus145 - Andrae, M.; Feilhaber, I.; Döring, V.; Jäckel, B. Veränderung des Spektrums und der Populationsdichte von Schadorganismen im Stadtgrün von Berli
Bio-control of root rot disease in vanilla
No full textA thesis submitted in partial fulfilment of the
requirements of the University of Wolverhampton
for the degree of Doctor of PhilosophyFusarium oxysporum Schl. var. vanillae (Tucker) Gondon is known to cause root rot in Vanilla planifolia Andrews in most regions where it is grown, including the major plantations in Xishuangbanna, Yunnan Province of China. This is of serious economic concern to the Province since the vanilla flavouring extractable from the beans of the plant is a valuable food product and an important export commodity. There are no fungicides registered for the control of Fusarium root rot and the only available chemical control methods are ineffective and cause serious contamination of the soil. Breeding for resistance is difficult when no dominant gene is known or where little information is available on fungal pathogenicity. Biocontrol is the main alternative for disease control in this crop, an attractive approach because of increasing concerns for environmental protection. The investigation considers two biocontrol strategies: first the introduction of virulent, antagonistic, non-pathogenic strains, closely-related to the pathogen, to overcome pathogenic populations in infected soils; second the use of essential oils with antimicrobial properties when applied to infected soils. Pathogenicity tests have been done on 81 out of 87 F. oxysporum isolates collected in Yunnan Province. Among these, 32 isolates were non-pathogenic and 49 were pathogenic. The pathogenicity results showed the complexity of F. oxysporum in Yunnan. Seventeen isolates were recovered from the Daluo plantation, of which 14 were pathogenic isolates and 3 non-pathogenic isolates; 26 from the Menglun plantation, in which 12 were pathogenic and 14 were non-pathogenic; 18 isolates from the Manjingdai plantation, in which 12 isolates were pathogenic, whilst the other 6 were non-pathogenic and 20 were obtained from the plantation in Hekou i County, of which 11 were pathogenic isolates and 9 were non-pathogenic. Genetic diversity within this population of F. oxysporum has been investigated with respect to vegetative compatibility and to determine the relationship between VCGs and virulence. The VCG results showed that the 87 strains of Fusarium oxysporum f.sp vanillae isolated from Yunnan Province were complex. They could be distributed into 12 different VCGs and that a direct relationship between VCGs group and virulence could not be drawn. Two non-pathogenic strains, ML-5-2 and HK-5b-4-1, have been screened from 87 strains as candidate biocontrol agents by pathogenicity and VCG, which are self-incompatible and closely related to the pathogens. These two strains were effective in vanilla root rot control in controlled environments, but their effects in field experiments were less conclusive. Seven essential oils, which have long been regarded as having inhibitory effects on pathogens in nature, have also been investigated as biocontrol agents. Three oils, cinnamon oil, thyme oil and clove oil, were effective in inhibiting the growth of pathogen in vitro. These oils may develop into useful components of different management strategies with non-pathogenic strains. For the future, consideration will need to be given to the mechanism(s) of the interaction of the antagonistic components with the soil microbe population and host plant and also to appropriate formulation, to take account of soil type, crop status, cultural practices, environmental and economic factors. Biocontrol methods have considerable potential but must be acceptable to farmers as part of an overall crop management programme
