R. T. V. Fox

University of Reading, Reading, England, United Kingdom

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Publications (19)14.45 Total impact

  • R. T. A. COOK, R. T. V. FOX
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    ABSTRACT: The powdery mildew Erysiphe pisi var. pisi, complete with its teleomorph, has been observed on faba beans (Vicia faba cultivars) for the first time in Britain. It appeared in a glasshouse on Syrian lines of fodder bean and English cultivars of broad bean. It also infected tare (Vicia sativa) and sweet pea (Lathyrus odoratus), but not edible pea (Pisum sativum), ornamental lupin (Lupinus polyphyllus), French bean (Phaseolus vulgaris) or sainfoin (Onobrychis viciaefolia). Inoculations in a glasshouse showed that another strain of E. pisi var. pisi found on outdoor everlasting pea (Lathyrus latifolius) was also capable of affecting faba bean, and was distinguished by its ability to infect edible pea. A third strain found on outdoor ornamental lupin infected only lupin. E. pisi var. pisi was shown to be morphologically and pathogenically distinct from the Erysiphe sp. newly affecting tomatoes in Britain.
    Plant Pathology 04/2007; 41(4):506 - 512. · 2.73 Impact Factor
  • F. Dusunceli, R. T. V. Fox
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    ABSTRACT: The accuracy of assays based on galactosidase and the enzyme-linked immunosorbent assay specific to Thanatephorus cucumeris were compared with techniques based on soil dilution plating and baiting in sterilized field soil. Although soil dilution plating is reasonably quantitative, it requires substantial time, material and labour. Plant baits gave inconsistent results in the estimation of T. cucumeris populations in the soil. Enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies is suitable for detecting the presence of a range of anastomosis groups (AGs) of 71 cucumeris in soil samples, but more quantitative applications seem to be limited to a very narrow range of concentrations of the fungus (0–10 μg/g). Monoclonal antibody ELISA could be used if the soil samples are routinely further diluted, provided the range of concentrations is uniformly low. An assay of β-galactosidase permits estimation of a more adequate range of concentrations (0–500 μg/g) and may be used in defined experiments using uninoculated soil samples.
    Soil Use and Management 01/2007; 8(1):21 - 25. · 1.97 Impact Factor
  • R.T.V. Fox
    Mycologist 05/2006; 20(2):77.
  • R.T.V. Fox
    Mycologist 02/2006; 20(1):36–37.
  • F. Raziq, R. T. V. Fox
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    ABSTRACT: Several isolates of Trichoderma harzianum, T. viride and T. hamatum, an isolate each of Dactylium dendroides, Chaetomium olivaceum and some other fungi found to be antagonistic in vitro against several isolates of the root rot pathogen, Armillaria mellea, were evaluated for their ability to suppress root rot of potted strawberry plants in the glasshouse. Some of these antagonists were selected for integration with two systemic fungicides, fosetyl-Al and fenpropidin, in the glasshouse. A significant interaction was found between the antagonists, fungicides and their sequence of application. T. harzianum isolates Th2 and Th23 showed sensitivity to direct application of fenpropidin but not to fosetyl-Al. The antagonists were generally more effective when applied with a time interval of 40 days after fenpropidin or before fosetyl-Al. Integration of Th2 and fenpropidin was the most effective treatment and resulted in the survival of 75% of strawberry plants up to the end of the experiment lasting 566 days when the fungicide was applied first; no plant survived that long when the sequence of application was reversed. High concentrations of fenpropidin, but not of fosetyl-Al, were phytotoxic to the strawberry plants. Fosetyl-Al was also significantly (p < 0.05) more effective than fenpropidin in enhancing the survival of the strawberry plants.
    Biological Agriculture & Horticulture - BIOL AGRIC HORTIC. 01/2006; 23(3):225-234.
  • F. Raziq, R. T. V. Fox
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    ABSTRACT: Several isolates of Trichoderma harzianum, T. viride and T. hamatum, and an isolate each of Dactylium dendroides and Chaetomium olivaceum, found antagonistic in vitro and under glasshouse conditions against several isolates of the root rot pathogen, Armillaria mellea, were evaluated for their ability to suppress root rot of young apple trees under field conditions. Some of these antagonists were selected for integration with two systemic fungicides, fosetyl-Al and fenpropidin. The antagonists were applied on mushroom compost with dead mycelia of Agaricus bisporus either before or after a 2000 mg 1 dose of the fungicides, with a time interval of 40 days. Some isolates of the Trichoderma spp. and D. dendroides reduced the extent of infection as compared with that on control plants inoculated only with A. mellea. A significant interaction was found between the antagonists, fungicides and their sequence of application. D. dendroides was significantly (p < 0.05) more effective in reducing the rot when applied 40 days before fosetyl- Al. Conversely, T. harzianum isolate Th23 showed greater efficacy when introduced 40 days after fenpropidin. T. hamatum isolate Tham 1, however, exhibited a greater effect when applied before fenpropidin. Changing sequence of application of the other antagonists with either of the two fungicides had no significant effect on the extent of the root rot. Trees treated with Trichoderma viride isolate Tv3 and fenpropidin had a greater increase in number of branches > 30 cm, but Chaetomium olivaceum caused a greater increase with fosetyl-Al than with fenpropidin. Similarly, increase in branches > 30 cm was significantly greater on trees treated with fosetyl-Al only, compared with those treated with fenpropidin only. Whereas dose rates of fosetyl-Al did not cause significant differences, a dose rate of 8000 mg 1 of fenpropidin resulted in significantly fewer branches < 30 cm, compared with the lower dose rates of 2000 and 4000 mg 1.
    Biological Agriculture & Horticulture - BIOL AGRIC HORTIC. 01/2006; 23(3):235-249.
  • F. Raziq, R.T.V. Fox
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    ABSTRACT: In a pot experiment with strawberry plants (cv. Cambridge Favourite), two isolates (Th1 and Th2) of Trichoderma harzianum were tested individually and in combination for their efficacy against the root rot pathogen Armillaria mellea. Similarly, an effective isolate of Dactylium dendroides, the ‘Shi-itake Pathogen’ (SP), was combined with isolates of T. harzianum, T. viride, T. hamatum and Chaetomium olivaceum for the same purpose. Isolate Th2 performed better alone than in combination with isolate Thl, protecting 75% of the plants from death during the experiment lasting 413 days. None of the plants treated with Thl alone or Thl and Th2 together survived until the end of the experiment. The presence of SP had a significant (p < 0.05) effect on the survival of the plants. The median survival time in the presence of SP was 299.5 days compared with 206.0 days in its absence. At the end of the experiment, which lasted 534 days, 41.7% of the plants treated with SP survived compared with only 16.7% when not treated with the antagonist. The plants also had significantly more living leaves and higher health scores when SP was used. The combination-antagonists did not differ significantly from controls in suppressing the disease and thus enhancing the survival of the plants. The interaction of SP with the combination-antagonists was significant. It improved the efficacy of the other antagonists tested except T. hamatum isolate Thaml and C. olivaceum isolate Co. All the plants treated with T. harzianum isolates Th2 and Th23 or T. viride isolate Tv3 alone died by the end of the experiment, while 50% of them survived when treated with a combination of any of the antagonists and SP. T. hamatum isolate Thaml protected 75% of the plants alone and only 50% in combination with SP.
    Biological Agriculture and Horticulture. 01/2005; 23:45-57.
  • F. Raziq, R. T. V. Fox
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    ABSTRACT: The antagonistic activities of six selected fungal isolates against Armillaria mellea were studied on two different concentrations of three media, on fungicides-amended malt extract agar (MEA) medium, and in glasshouse pots filled with John Innes No.2 compost and natural field soil. Trichoderma hamatum isolate Thaml was found the most effective in reducing Armillaria growths on both the low and high concentrations of malt extract, potato dextrose and V-8 juice in MEA, potato dextrose agar (PDA) and V-8 juice agar (VJA), respectively, followed by T. harzianum isolate Th2 and T. viride isolate Tv3. Neither dose rate (200 or 2000 mg l) of fenpropidin allowed any growth of Armillaria on MEA, while that of the antagonists was also completely inhibited or greatly restricted. However, both dose rates of fosetyl-Al allowed the growth of Armillaria and almost all the antagonists. Data on colony diameters of Armillaria showed Thaml as the most effective antagonist along with Th2, Th23 and Tv3. Thaml was also found the most effective in protecting hazel billets from colonization by Armillaria, followed by Th2 and Th23. Compared with 7.1 colonized billets in the inoculated controls, only 1.3, 2.6 and 2.7 billets (out of ten) were colonized, respectively, when protected with these antagonists. The results indicate that the Trichoderma isolates are able to maintain their antagonistic effects on A. mellea under a variety of nutritional, chemical and edaphic regimes. More investigations are needed to develop a system of control for the disease with these potential antagonists.
    Biological Agriculture & Horticulture - BIOL AGRIC HORTIC. 01/2004; 22(1):41-56.
  • F. Raziq, R. T. V. Fox
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    ABSTRACT: Several in vitro and in vivo experiments were conducted to develop an effective technique for culturing potential fungal antagonists (isolates of Trichoderma harzianum, Dactylium dendroides, Chaetomium olivaceum and one unidentified fungus) selected for activity against Armillaria mellea. The antagonists were inoculated onto (l) live spawn of the oyster mushroom (Pleurotus ostreatus), (2) extra-moistened or sucrose-enriched mushroom composts containing living or autoclaved mycelia of P. ostreatus or Agaricus bisporus (button mushroom), (3) pasteurized compost with or without A. bisporus mycelium, wheat bran, wheat germ and (4) spent mushroom composts with living mycelia of A. bisporus, P. ostreatus or Lentinus edodes (the Shiitake mushroom). In one experiment, a representative antagonist (isolate Th2 of T. harzianum) was grown together with the A. bisporus mycelium, while in another one, the antagonist was first grown on wheat germ or wheat bran and then on mushroom compost with living mycelium of A. bisporus. Some of the carrier substrates were then added to the roots of potted strawberry plants in the glasshouse to evaluate their effectiveness against the disease. The antagonists failed to grow on the spawn of P. ostreatus even after reinoculations and prolonged incubation. Providing extra moisture or sucrose enrichment also did not improve the growth of Th2 on mushroom composts in the presence of living mycelia of A. bisporus or P. ostreatus. The antagonist, however, grew rapidly and extensively on mushroom compost with autoclaved mycelia, and also on wheat germ and wheat bran. Colonization of the substrates by the antagonist was positively correlated with its effectiveness in the glasshouse studies. Whereas only 33.3% of the inoculated control plants survived in one experiment monitored for 560 days, 100% survival was achieved when Th2 was applied on wheat germ or wheat bran. Growth of the antagonist alone on pasteurized or sterilized compost (without A. bisporus mycelia) and simultaneous growth of the antagonist and mushroom on pasteurized compost did not improve survival over the inoculated controls, but growth over mushroom compost with the living mycelium resulted in 50% survival rate. C. olivaceum isolate Co was the most effective, resulting in overall survival rate of 83.3% compared with only 8.3% for the inoculated and 100% for the uninoculated (healthy) controls. This antagonist gave the highest survival rate of 100% on spent mushroom compost with L. edodes. T. harzianum isolate Th23, with 75% survival rate, was the most effective on spent mushroom compost with P. ostreatus, while D. dendroides isolate SP resulted in equal survival rates of 50% on all the three mushroom composts.
    Biological Agriculture & Horticulture - BIOL AGRIC HORTIC. 01/2004; 22(3):271-287.
  • F. Raziq, R. T. V. Fox
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    ABSTRACT: In a glasshouse experiment using potted strawberry plants (cv. Cambridge Favourite) as hosts, the effect of selected fungal antagonists grown on 25 or 50 g of mushroom compost containing autoclaved mycelia of Agaricus bisporus, or wheat bran was evaluated against Armillaria mellea. Another glasshouse experiment tested the effect of application time of the antagonists in relation to inoculations with the pathogen. A significant interaction was found between the antagonists, substrates and dose rates. All the plants treated with Chaetomium olivaceum isolate Co on 50 g wheat bran survived until the end of the experiment which lasted 482 days, while none of them survived when this antagonist was added to the roots of the plants on 25 g wheat bran or 25 or 50 g mushroom compost. Dactylium dendroides isolate SP had a similar effect, although with a lower host survival rate of 33.3%. Trichoderma hamatum isolate Tham1 and T. harzianum isolate Th23 protected 33.3% of the plants when added on 50 g and none when added on 25 g of either substrate, while 66.7% of the plants treated with T. harzianum isolate Th2 on 25 g, or T. viride isolate Tv3 on 50 g wheat bran, survived. Application of the antagonists on mushroom compost initially resulted in development of more leaves and healthier plants, but this effect was not sustained. Eventually, plants treated with the antagonists on wheat bran had significantly more leaves and higher health scores. The plants treated with isolate Th2 and inoculated with Armillaria at the same time had a survival rate of 66.7% for the duration of the experiment (475 days), while none of them survived that long when the antagonist and pathogen were applied with an interval of 85 days in either sequence. C. olivaceum isolate Co showed a protective effect only, as 66.7% of the plants survived when they were treated with the antagonist 85 days before inoculation with the pathogen, while none of them survived when the antagonist and pathogen were applied together or the infection preceded protection.
    Biological Agriculture & Horticulture - BIOL AGRIC HORTIC. 01/2004; 22(2):157-172.
  • P. K. Mishra, R. T. V. Fox, A. Culham
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    ABSTRACT: Inter-simple sequence repeat (ISSR) analysis and aggressiveness assays were used to investigate genetic variability within a global collection of Fusarium culmorum isolates. A set of four ISSR primers were tested, of which three primers amplified a total of 37 bands out of which 30 (81%) were polymorphic. The intraspecific diversity was high, ranging from four to 28 different ISSR genotypes for F. culmorum depending on the primer. The combined analysis of ISSR data revealed 59 different genotypes clustered into seven distinct clades amongst 75 isolates of F. culmorum examined. All the isolates were assayed to test their aggressiveness on a winter wheat cv. ‘Armada’. A significant quantitative variation for aggressiveness was found among the isolates. The ISSR and aggressiveness variation existed on a macro- as well as micro-geographical scale. The data suggested a long-range dispersal of F. culmorum and indicated that this fungus may have been introduced into Canada from Europe. In addition to the high level of intraspecific diversity observed in F. culmorum, the index of multilocus association calculated using ISSR data indicated that reproduction in F. culmorum cannot be exclusively clonal and recombination is likely to occur.
    Annals of Applied Biology 01/2003; 143(3):291-301. · 2.15 Impact Factor
  • F. Raziq, R.T.V. Fox
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    ABSTRACT: Seventeen fungal isolates were tested in vitro as potential antagonists of two isolates of the root rot pathogen, Armillaria mellea. Some of the isolates were also added on mushroom composts with living mycelia to the roots of Armillaria-inoculated potted strawberry plants in the glasshouse to find out if they had the same degree of efficacy against the disease. Dactylium dendroides isolate SP was the most effective in reducing mycelial growth of A. mellea isolate 1 (Am1), followed by Trichoderma harzianum isolate Th2 and T. viride isolate Tv4. Th2, Th22, Tv3 and SP grew extensively over Am1 colonies, disintegrating the rhizomorphs. Isolate Thaml of T. hamatum was the most effective in reducing mycelial growth of A. mellea isolate 2 (Am2), followed by Tv3. Thl2, Th22, Tvl, Tv3 and SP inhibited the initiation and growth of rhizomorphs of Am2. Regeneration tests showed that both Am1 and Am2 attacked by Trichoderma isolates and SP were no longer viable. Th23 and SP were almost as effective in vivo as in vitro. But isolate Co of Chaetomium olivaceum, which was ineffective in vitro, was found effective in vivo. Conversely, Th2, which exhibited good antagonistic activity in vitro, performed poorly in vivo. These results show that the in vitro and in vivo efficacies of potential antagonists may not necessarily be closely correlated. Hence, there is a danger that potentially effective isolates may be discarded if decisions are made only on the basis of preliminary screening tests carried out under laboratory conditions.
    Biological Agriculture and Horticulture. 01/2003; 21:263-276.
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    ABSTRACT: Common agricultural weeds and crops that grow in the high hills of Nepal were examined after artificial inoculation and under natural conditions in the UK and Nepal to determine whether such plant species could act as hosts to biovar 2 of Ralstonia solanacearum. Bacterial populations in the roots were determined 1 and 2 months after inoculation, and at various intervals after harvesting infected potato crops under natural conditions. Inoculated roots of the summer weeds Drymaria cordata and Polygonum capitata and the winter weeds Cerastium glomeratum and Stellaria media yielded 102−107 colony-forming units per g root. High populations of the bacterium were recovered from these plants even after partial surface sterilization, indicating that systemic infection had occurred. Ralstonia solanacearum populations were recovered from root extracts of 75% of naturally growing D. cordata plants when sampled 3 months after harvest of a potato crop with bacterial wilt. Similarly, root extracts of 25% of P. capitata plants carried the bacterium. No potential winter weed hosts were infected under natural conditions when sampled 5 and 6 months after harvest of infected potato, indicating that winter conditions in the high hills of Nepal are not conducive to infection. Among crops, mustard (Brassica juncea cv. Fine White) developed typical wilt symptoms after artificial inoculation in warm glasshouse conditions (20–28°C). Mustard and barley are winter crops in Nepal. However, neither mustard (Brassica juncea var. Lumle Tori) nor barley (Hordeum vulgare cv. Bonus) was infected when planted into heavily infested plots under natural conditions. The results indicated that the role of nonsolanaceous summer weeds in the persistence of biovar 2 of R. solanacearum in the environment may have been previously underestimated.
    Plant Pathology 12/2001; 49(4):403 - 413. · 2.73 Impact Factor
  • R. T. V. Fox
    01/2001: pages 240;
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    ABSTRACT: An isolate of Trichoderma virens Miller, Giddens & Foster, carboxin and a combination of both were evaluated for the control of gladiolus corm rot and wilt caused by Fusarium oxysporum f.sp. gladioli in glasshouse and field experiments. All treatments significantly reduced disease incidence in both glasshouse and field conditions. T. virens gave control at least as good as carboxin in all experiments. Control was significantly improved in two field experiments by combining the biological and chemical treatments.
    Annals of Applied Biology 11/2000; 137(3):361 - 364. · 2.15 Impact Factor
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    ABSTRACT: The sensitivity and specificity of various methods were compared for routine detection of Ralstonia solanacearum in a sandy loam soil. Populations fewer than 102 CFU per g soil were detected by dilution plating on a modified semiselective medium (SMSA). In comparison, a tomato bioassay was shown consistently to detect populations at or greater than 7·5 × 105 CFU per g soil. An indirect enzyme-linked immunosorbent assay (ELISA) was as sensitive as the tomato bioassay, but detected as few as 104 CFU per g soil when the suspension was first incubated in SMSA broth prior to testing. Detection using a nested polymerase chain reaction (PCR) was equally as sensitive as that using culture on SMSA agar, but only when the infested soil sample was first enriched overnight in SMSA broth prior to the nested PCR. Longer incubation periods in SMSA broth also increased the sensitivity of pathogen detection using a conventional PCR method, permitting detection of as few as 102 CFU per g soil after 60 h enrichment in SMSA broth. When evaluated using naturally infected field soils in Nepal, isolation of R. solanacearum on SMSA was reliable only when pathogen populations were higher than those of saprophytic soilborne bacteria. As few as 5 × 102 CFU of R. solanacearum per g were recovered from naturally infested soil, whereas the sensitivity of indirect ELISA was 106 CFU g−1.
    Plant Pathology 07/2000; 49(4):414 - 422. · 2.73 Impact Factor
  • P. K. Mishra, R. T. V. Fox, A. Culham
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    ABSTRACT: Variation within the internal transcribed spacers (ITS1 and ITS2) and 5.8S ribosomal DNA region of 60 Fusarium culmorum isolates (section Discolor), representing different hosts and diverse geographical origins was examined by polymerase chain reaction (PCR), coupled with sequencing. Phylogenetic relationships of these F. culmorum isolates were estimated in relation to Fusarium spp. from this and other sections of the form-genus, using sequences available from Genbank. The amplified ITS region was approximately 570 bp long in 56 isolates and approximately 585 bp in four other isolates. The inferred phylogeny distinguished clearly four isolates supplied as F. culmorum. These isolates differed in both morphology and sequence from the remaining F. culmorum material. Sequence analysis revealed that the remaining 56 isolates were divided into three ITS types, within which the divergence was extremely low. ITS sequence comparison among the Fusarium isolates showed two major clades, one comprising sections Discolor, Sporotrichiella and Gibbosum and the other comprising Elegans, Liseola, Martiella and Roseum. These results demonstrate the use of the ITS region to resolve the identification and taxonomic problems of Fusarium spp. especially at sectional level but demonstrate the need to develop some other molecular markers for identification at the level of species or race.
    Bulletin OEPP/EPPO Bulletin 01/2000; 30(3-4):493-498.
  • 01/1994: pages 119-133;
  • R.T.V. Fox, K. Hahne
    Proceedings of the Seventh International Conference on Root and Butt Rots.;