Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 50 , Issue 5
Showing 1-17 articles out of 17 articles from the selected issue
  • Toshinobu TAKAHASHI, Noriyuki DOKE
    1984 Volume 50 Issue 5 Pages 565-573
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Unwashed bacterial cells of Xanthomonas campestris pv. citri were found to adhere preferentially to a wounded portion of citrus leaf tissues rather than intact leaf surfaces. Washed bacterial cells of X. campestris pv. citri and unwahhed bacterial cells of a colony mutant lacking the ability to produce extracellular polysaccharides (EPS) hardly adhered even to wounded tissues of citrus leaves.
    The adhesion of unwashed bacterial cells was inhibited when the wounded leaf tissues were pretreated either with D-glucosamine, pronase or low pH citrate buffer. The adhesion of unwashed bacterial cells was also observed to the disks of various nonhost tissues to an extent, but it was not influenced by the pretreatment with D-glucosamine solution at all.
    These results suggested that X. campestris pv. citri adhered to host tissues through the EPS-agglutinin interaction and that the process might involved in the initial step for establishing the host-parasite relationship in citrus canker.
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  • Kenji KITAZAWA, Ichiro FUJISAWA, Shun-ichi IMABAYASHI
    1984 Volume 50 Issue 5 Pages 574-581
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In 1982-83, it was observed that three species of aphids, Myzus persicae, Aphis gossypii, Brevicoryne brassicae, and the greenhouse whitefly, Trialeurodes vaporariorum, were affected by white fungal mycelia which had covered insect body in a greenhouse of the Hokkaido National Agricultural Experiment Station. Further study has revealed that this fungus is to be referred to Verticillium lecanii (Zimm.) Viégas which has never been reported in Japan. Within the isolates of V. lecanii from these insect species, three different types were recognized; white mycelial type which grows faster with linear colony margin, yellow mycelial type growing comparatively slow with undulate or dendroid colony margin, and another white mycelial type moderately fast growing with undulate or dendroid colony margin. The fungus is pathogenic only to insects while not to plants; high affection rates of insects were shown by the inoculation with the fungus which had been isolated from the same insect species, at least seven days after inoculation. A series of insect controlling test in a greenhouse showed that isolates from different insect species can similarly affect Aphis gossypii and the greenhouse whitefly within two or three weeks after inoculation. From these results, it is very likely that this fungus can be effectively utilized to control aphids and the greenhouse whitefly in Japan.
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  • Tetsu TSURUSHIMA, Shigeyuki MAYAMA, Toshikazu TANI, Tamio UENO, Hirosh ...
    1984 Volume 50 Issue 5 Pages 582-589
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Two self-inhibitors were found in germination fluids of uredospores of Puccinia coronata var. avenae. Major one identified in the previous paper as methyl cis-3, 4-dimethoxycinnamate (MDC) was released in the germination fluid as soon as the uredospores were floated on water and mostly liberated from uredospores within 40min, before protrusion of germ tubes. On the other hand, a minor inhibitor (unidentified) became detectable in the germination fluid when germ tubes had mostly germinated, and increased thereafter. MDC strongly inhibited the germination, but exhibited little effect on the germ tube growth and differentiation of infection structures at the concentration giving complete inhibition of germination. MDC decreased its activity in the presence of sodium pelargonate. Characteristic behaviors of germination and infection structure formation of P. coronata var. avenae were different in various respects from those of rust fungi producing MDC, but rather resembled those of Puccinia graminis var. tritici which produced another self-inhibitor, methyl cis-ferulate. It is proposed that the hypothesis that rust species producing the same self-inhibitors are closely related to each other in the characteristics of germination and differentiation should be reexamined.
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  • Yoshio HISADA, Toshiro KATO, Chikara NODA
    1984 Volume 50 Issue 5 Pages 590-599
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Botrytis cinerea resistant to procymidone was isolated from the vegetables grown in greenhouses. All of them showed low level of resistance (ED50 values were approximately 10 times), and no isolate with high level of resistance was found. Although the resistant isolates were indistinguishable from the sensitive strain in growth rate of hypha, ability to sporulate and spore germination on a nutrient agar, some of them did not grow after incubation at a high temperature of 32C. When the resistant strain was inoculated to tomato fruits together with the sensitive strain, the resistant strain rapidly decreased in a population and often disappeared during successive inoculations to other fresh fruits. In cases that procymidone was treated preventively or curatively against the resistant strain on the leaves of cucumber, the controlling efficacy was inferior to that against the sensitive strain. On the other hand, when the resistant and sensitive strains were mixedly inoculated to the plants, curative application of procymidone was more effective in controlling the disease than when the resistant strain was singly inoculated. The fungicide sensitivity of B. cinerea isolates from 7 greenhouses in Kochi Prefecture, where the resistant strain was extremely dominant in a population in March of 1982, was examined in December of 1982. The resistant strain was still dominant in 1 greenhouse, but no resistant B. cinerea was detected in 5 greenhouses and only a few in 1 greenhouse. These results suggest that the population of procymidone-resistant B. cinerea would be unstable in the concomitant presence of the sensitive strain.
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  • Nitaro MAEKAWA, Mikihiro YAMAMOTO, Syoyo NISHIMURA, Keisuke KOHMOTO, M ...
    1984 Volume 50 Issue 5 Pages 600-609
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The causal pathogen of Alternaria black spot of strawberry was identified as a distinct pathotype of Alternaria alternata (Fries) Keissler. Only one strawberry cultivar Morioka-16 was susceptible to the pathogen. Several cultivars of Japanese pear including Nijisseiki which were susceptible to A. alternata Japanese pear pathotype were also diseased by this pathogen. This fungus produced at least three species of host-specific toxins (named AF-toxin I, II and III, respectively). AF-toxin I and II were considered the major toxins. AF-toxin I induced necrosis and potassium leakage on the susceptible cvs. Morioka-16 and Nijisseiki. AF-toxin II induced only potassium leakage from cv. Morioka-16 but did not induce necrosis. AF-toxin II as well as AF-toxin I caused necrosis and potassium leakege from the cv. Nijisseiki.
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  • Mikihiro YAMAMOTO, Syoyo NISHIMURA, Keisuke KOHMOTO, Hiroshi OTANI
    1984 Volume 50 Issue 5 Pages 610-619
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The role of AF-toxins in the interaction of A. alternata strawberry pathotype and its hosts, strawberry cv. Morioka-16 and Japanese pear cv. Nijisseiki, was investigated at the early stage of infection. Time course study of the production of AF-toxins from germinating spores elucidated that all three AF-toxins (I, II and III) were detectable early after inoculation and increased in quantity with incubation time. The leaves inoculated with pathogen were allowed to leak electrolytes by AF-toxin produced during the germination of spores. The electrolyte leakage was shown to have two peaks at different stages of the infection behaviors of the spores; the first was detected before the establishment of infection and the second was detected after the establishment of infection. The first peak suggests that the AF-toxins from germinating spores prior to fungal invasion could change the physiological potential related to the membrane system of the host cells to be desirable to the pathogen. The effect of AF-toxins on the establishment of infection by pathogenic spore was investigated by treating the leaves both the high molecular weight fraction “inducer” in germination fluids of spores and AF-toxins. The treatment with “inducer” rendered the susceptible leaves relatively resistant to the pathogen, while, the treatment with AF-toxins rendered the leaves susceptible even to non-pathogenic A. alternata. Concomitant treatment with the “inducer” and AF-toxins resulted in the suppression of the induction of host resistance. These data suggest that pathogenic spores of A. alternata strawberry pathotype produce AF-toxins during their germination, and thereby may suppress the resistance response through the disturbance of membrane integrity of the host cells, and consequently succeed in establishing infection.
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  • Meisaku KOIZUMI, Shigematu KUHARA
    1984 Volume 50 Issue 5 Pages 620-627
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Several isolates of yeasts and bacteria were collected from citrus leaves naturally affected with pseudo greasy spot (PGS), a disease of unknown etiology in Japan. Based on inoculations by injection and spraying, two groups of the yeasts different from each other in colony type were pathogenic. One comprising three isolates (No.3, 4, and 6) was highly virulent and identified as Sporobolomyces sp. because of asymmetric ballistospore formation, no mycelial form, multilateral budding and salmon-pink colony. Another group (No.10 and Ta-7415) was identified as Aureobasidium sp. because of the characteristic true mycelium. Based on pathogenic activity, fungicidal sensitivity and ecological property, the Sporobolomyces sp. is probably main pathogens of the disease.
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  • Etsuji HAMAYA, Tojiro TSUSHIDA, Tadahiro NAGATA, Chikao NISHINO, Nobuy ...
    1984 Volume 50 Issue 5 Pages 628-636
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Characteristic antifungal components were found in camellia (Camellia japonica), wabisuke group and C. granthamiana plants. The active substances were easily extracted from leaves and petals of the plants to ten volumes of water by homogenization or autoclaving for 5 minuites at 120C. On the potato-sucrose liquid medium mixed with the same volume of the extract, normal conidial germination or growth of hyphae of many fungi were inhibited. Namely almost no conidium germinated in Pyricularia oryzae and Cochliobolus miyabeanus, germ tubes or conidia themselves swelled resembling balloons and no normal hypha grew in Pestalotia longiseta, Gloeosporium theae-sinensis, Diaporthe citri, Botrytis cinerea, etc., and growth of hyphae was worse in Alternaria kikuchiana and Alternaria mali. Two triterpenoid saponins were isolated as the antifungal compounds from aqueous extract of camellia leaf and given designations camellidin I and camellidin II. Their molecular formulas were C55H86O25 (MW=1146) and C53H84O24 (MW=1104) respectively, the activity was stronger in the former. It was presumed that these saponins were concerned in the resistance of camellia and the closely related plants against the fungal infection.
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  • Yoshiaki CHIKUO, Toshiya SUGIMOTO, Katsuichi KANZAWA, Hirokatsu UCHINO
    1984 Volume 50 Issue 5 Pages 637-640
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Kenji KITAZAWA, Norio SATO
    1984 Volume 50 Issue 5 Pages 641-642
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A potato wilt disease new to Japan was found. Diseased plants became yellow, defoliated and dead rapidly. Verticillium nigrescens Pethybridge was isolated from the plants. Inoculation tests on various plants in a greenhouse proved that the fungus caused disease only on potato, and not on eggplant, tomato, bell pepper, cucumber, melon, adzuki bean and soybean.
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  • Kenji KITAZAWA, Kisaku YANAGITA
    1984 Volume 50 Issue 5 Pages 643-645
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Wilt of adzuki bean [Phaseolus angularis (Willd.) Wight] caused by Fusarium oxysporum Schl. occurred in Hokkaido. This disease had been reported, but the details of a causal agent is still obscure. Pathogenicity of our isolates was found specific to adzuki bean, and designation of forma specialis is under way.
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  • Ryutaro SAKAI, Hideaki KAWAMURA, Yosuke MINO, Reza EMAMI-SARAVI, Akio ...
    1984 Volume 50 Issue 5 Pages 646-648
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Takken MATUO, Yoichi MIYAZAWA
    1984 Volume 50 Issue 5 Pages 649-652
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Ryutaro SAKAI, Minoru AKIMA, Yosuke MINO, Reza EMAMI-SARAVI
    1984 Volume 50 Issue 5 Pages 653-655
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Hiroyuki IEKI, Akira YAMAGUCHI
    1984 Volume 50 Issue 5 Pages 656-658
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Nobuyuki YOSHIKAWA, Satoshi T. OHKI, Hirofumi KOBATAKE, Takeshi OSAKI, ...
    1984 Volume 50 Issue 5 Pages 659-663
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Hiroshi YAEGASHI, Masao YAMADA
    1984 Volume 50 Issue 5 Pages 664-667
    Published: December 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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