Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 35 , Issue 4
Showing 1-15 articles out of 15 articles from the selected issue
  • Takashi MATSUMOTO, C.S. LEE, W.S. TENG
    1969 Volume 35 Issue 4 Pages 251-259
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Transmission studies were made by using 29 different species of leafhoppers collected from the sugarcane field where the white leaf disease was very prevalent for the past several years. The resultant data so far revealed the Epitettix hiroglyphicus Matsumura could transmit the disease, but the remainders were incapable of transmitting the disease except for a single case in which 2 plants out of the 58 tested by use of Cicadulina bipunctella were infected. Although further transmission trials must be made, it is inferred that this may be accidental. Therefore, at present E. hiroglyphicus is considered to be the principal vector of our white leaf disease. The incubation period in the vector was about 4-5 weeks so far as the present experiment is concerned, and the same in the host plant was 2.5-3 months when tested during the period from spring to early summer, whereas it was longer, mostly 3-4 months, if the experiment was made in autumn or early winter. Young seedlings appear to be more susceptible than the older, first showing a pale greenish or yellowish stripe(s) on upper young unfolding leaves, then pale yellowish or whitish discoloration on newly unfolding or rolled spindle leaves starting from the base, finally the typical white leaf symptom on the uppermost spindle. These symptoms are occasionally masked, particularly when temperature is relatively low.
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  • Minoru TAMURA
    1969 Volume 35 Issue 4 Pages 260-264
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Leaf juice of Japanese black pine (Pinus thunbergii Parl.) inhibited turnip mosaic virus (TuMV) infection when radish and Chenopodium amaranticolor were inoculated with the virus 24 hours after spraying the juice on the plant. Some inhibition was observed even when the juice was sprayed 7 days before virus inoculation. The inhibitory effect of the juice was about equal in younger leaves and in older leaves of the pine.
    The inhibitory effect was observed also with juice extracted from cone and bark of young twig of Japanese black pine. While some inhibitory effect was observed when the juice was sprayed on C. amaranticolor one hour after virus inoculation, there was no inhibitory effect when radish plants were sprayed with the juice 24 hours before inoculating the virus by Myzus persicae. The inhibition became slighter when the test plants were heavily sprinkled with water 2 hours after juice spraying.
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  • M.S. PAVGI, A.N. MUKHOPADHYAY
    1969 Volume 35 Issue 4 Pages 265-270
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Protomyces macrosporus Unger inciting the stem gall disease of coriander (Coriandrum sativum L.) is perpetuated through the resting chlamydospores released in the soil after the monsoon rains from the crop debris and/or the fruit galls in uncleaned seed lot planted in the season. The pathogen also survives in the soil through the heat-resistant desiccated endo- and blastospores and possibly through the chlamydospores hibernating in an intensively cultivated field.
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  • M.S. PAVGI, A.N. MUKHOPADHYAY
    1969 Volume 35 Issue 4 Pages 271-274
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The fruits of coriander (Coriandrum sativum L.) collected from stem gall infected plants indicate comparable viability and germinability of seeds on testing with triphenyl tetrazolium chloride (TTC) and germination, respectively. Systemic invasion by the pathogen considerably reduces germinability of the seed from these plants. The seedlings raised in the latter test, however, show infection on the stem due to incipient carriage of the pathogen through the integuments, thus adding to the primary inoculum potential of the disease.
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  • A.M. DAS, D.N. SRIVASTAVA
    1969 Volume 35 Issue 4 Pages 275-281
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Wheat root extract medium with dextrose supported production of fairly high concentration of the toxic principle by Helminthosporium sativum, the incitant of foot rot disease of wheat. When glucose was deleted from the medium, the fungus failed to grow. Synthetic media containing nitrate or asparagine as nitrogen sources with and without thiamine or biotin did not support toxin production. Autoclaving of the culture filtrate preadjusted to different pH levels resulted in greater loss of the toxin activity at the acid than at the alkaline range and least at the neutral level. Root tips of wheat seedlings exposed to lower dilutions of the culture filtrate were killed by the toxic principle.
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  • Tetsuo TAMADA, Tadanori GOTO, Ichimi CHIBA, Takashi SUWA
    1969 Volume 35 Issue 4 Pages 282-285
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A new virus disease, soybean dwarf, was first noticed on the Tsurunoko variety of soybean in southern areas of Hokkaido in about 1952. Since then it has been widely observed throughout Hokkaido, causing a considerable loss in soybean yields. Soybean plants infected with the virus show dwarfing (stunting), and downward curling, rugosity, and/or interveinal yellowing of the leaves.
    The virus was transmitted by grafting and by the aphid Aulacorthum solani (Kaltenbach), but not by juice inoculation or through seeds. Three species of aphids, Aphis glycines Matsumura, Aphis craccivora Koch and Myzus persicae (Sulzer), and two species of leafhoppers, Scleroracus flavopictus Ishihara, and Psammotettix striatus (Linné) failed to transmit the virus. The virus was retained in the vector A. solani for 20 days after leaving the source plants.
    It was found that red clovers and white clovers in the neighborhood of affected soybean fields were symptomless carriers of the virus.
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  • Syoyo NISHIMURA, Shinji HAYASHI, Ihiko CHIONISHIO, Junichiro OKUDA, Ic ...
    1969 Volume 35 Issue 4 Pages 286-293
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Black scurf of Chinese yam, a disease of hitherto unknown etiology, occurred in the sand dune field of Tottori. In the early stages of the disease, black necrotic spots appear on the surface of tubers. As the disease progresses, the spots expand into black scurf-like lesions, and exhibit various degrees of blackening, corking and rifting. It is also characteristic of the disease that no symptom is recognizable on the above ground part.
    Numerous bacteria and fungi isolated from the lesions of diseased tubers did not cause the disease in greenhouse and laboratory tests. Phytotoxic substances were detected in soils where black scurf is just prevalent but not from soils free from the disease. The results of the bioassay of soil toxins revealed a close correlation between the time or the depth of maximum toxicity of soil extracts and the time or the soil depth of the occurrence of the disease in the field. A number of carbonyl compounds which were toxic to radish seedlings were isolated from the water extracts of sick soil, and were identified as acetaldehyde, furfuraldehyde and iso-valeraldehyde.
    Black scurf was particularly severe in the field treated previously with nematicides. Increased amount of soil toxins was also proved in these nematicide-treated fields.
    Heavy applications of organic manures such as chicken manure, and abnormal rise of soil temperature in the growing season of tubers, one of predestined impediments in agriculturally utilizing sand dune, could be considered as the occasional cause of black scurf. Thus, an explanation of the etiology of the disease on the basis of volatile aldehydes formed during the anaerobic decomposition of manures and humus in the soil was suggested.
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  • Yasuo KOMURO, Mitsuro IWAKI
    1969 Volume 35 Issue 4 Pages 294-298
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Tomato plants healthy in appearance were collected from five fields, in which mosaic disease had been prevalent during recent years. Leaves and roots were tested for the presence of TMV. Tests for samples of 50 plants collected from three fields, where mosaic disease did not occur, showed that 24 plants (48%) contained TMV in roots but not in leaves, while 16 plants (32%) contained TMV both in the roots and leaves. Ten plants (20%) did not show presence of TMV in either leaves or roots. No plants were found in which TMV could be detected in the leaves only. In the other two fields, 10-15% of the plants showed symptoms of mosaic disease in the fields. The samples of 40 apparently healthy plants were collected from these fields. In these samples of leaves and roots, 13 tomato plants (33%) contained TMV in roots but not in leaves, 18 plants (45%) contained TMV both in the roots and leaves, and 2 plants (5%) in leaves but not in the roots. Seven plants (17%) did not show presence of TMV in leaves and roots.
    These results show that many tomato plants apparently healthy in appearance and having no detectable virus in their foliage, collected from fields which have been continuously cultivated with tomatoes, are infected with TMV in their roots. From the 60 plants which contained TMV in the above experiments, tomato strain was found in 59 plants (98%), ordinary strain was found in 6 plants (10%), 5 plants being doubly infected with both tomato and ordinary strains.
    Roots of 25 common weeds of Youngia japonica, Sonchus oleraceous, Capsella bursapastoris, Stellaria media and Cerastium caespitosum, healthy in appearance, were collected from the same tomato fields and the roots were tested for the presense of TMV. In every case, presense of TMV could not be detected by the method used.
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  • Keizo KATSUYA, Shigehisa KIYOSAWA
    1969 Volume 35 Issue 4 Pages 299-307
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In order to know whether or not a simple method in which a formula Ra/Sa×Sv/Rv can be employed for calculation of the mutation frequency for virulence in blast fungus strains, the mixture inoculation effect between original (avirulent) and its mutant (virulent) strains was compared among several fungus strains.
    The existence of the mixture inoculation effect including the concentration effect was found in all four fungus strains tested. This leads to the conclusion that the mutation frequency obtained by such a method is slightly over estimated as compared with the actual rate of mutant spores in the spore suspension. Therefore, the mutation frequency calculated by the formula, Ra/Sa×Sv/Rv' must be corrected on the basis of the mixture inoculation effect.
    Significant differences among strains were observed in the infectivity on susceptible varieties and in the mutation frequencies from Av-k (avirulent) to Av-k+ (virulent), but not in the mixture inoculation effect. The differences in the infectivity between each original and its virulent mutant were not observed on Av-k allele in the strains used.
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  • Chun-Yiang HONG
    1969 Volume 35 Issue 4 Pages 308-314
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The present paper deals with the result of experiments on the rhizosphere microflora of cucumber seedlings and the effect of rhizosphere fungi on the damping-off of cucumber seedlings inoculated with Fusarium oxysporum f. cucumerinum.
    Fusarium sp., Botrytis sp., Trichoderma sp., Penicillium sp., Aspergillus sp. and unidentified Basidiomycetes etc. were isolated from rhizosphere of cucumber seedlings. Fusarium spp. were most frequently isolated from the rhizosphere of cucumber seedlings.
    Fusarium oxysporum f. cucumerinum (F 22), when inoculated in sterilized soil, attacked cucumber seedlings and caused typical damping-off. Occurrences of pre-emergence and post-emergence damping-off of seedlings, however, were somewhat influenced by the presence of rhizosphere fungi in soil, and the occurrence of the both type damping-off was extensively delayed by the concomitant inoculation of F 22 with rhizosphere fungi. The extent of delay was remarkable when several fungi were inoculated concomitantly with F22. The retarded growth of seedlings due to the infection of F22 was also negated by additional presence of rhizosphere fungi.
    These results suggested that occurrence pattern of pre-emergence and post-emergence damping-off in the field might be extensively influenced by the rhizosphere fungi.
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  • Chun-Yiang HONG
    1969 Volume 35 Issue 4 Pages 315-318
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The present paper deals with the result of experiments on the effect of rhizosphere bacteria and actinomycetes on the damping-off of cucumber seedlings inoculated with Fusarium oxysporum f. cucumerinum.
    Fusarium oxysporum f. cucumerinum, (F 22), showed a strong pathogenicity to cucumber seedlings and caused typical damping-off, when inoculated in sterilized soil. Occurrence of post-emergence damping-off of the seedlings, however, was extensively delayed by concomitant inoculation of F 22 with rhizosphere bacteria and actinomycetes. The extent of delay was remarkable when Gram-negative bacteria were inoculated concomitantly with F 22. Occurrence of pre-emergence damping-off of seedlings was also delayed by the concomitant inoculation of F 22 with rhizosphere bacteria and actinomycetes, isolate A-C.
    These results suggested that occurrence pattern of pre-emergence damping-off and post-emergence damping-off in the field might be extensively influenced by the rhizosphere bacteria and actinomycetes.
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  • Hazime YOSHII
    1969 Volume 35 Issue 4 Pages 319-321
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Inhibitory effects on the local lesion formation of some proteinaceous inhibitors of plant viral infection such as trypsin, pancreatin, pancreatic ribonuclease (NBC, 5X cryst.) and Chenopodium sap were studied using suitable virus-host combinations as shown in Fig. 1 and 2, cucumber mosaic virus (CMV), tobacco mosaic virus (TMV), TMV-RNA, and daikon mosaic virus (DMV) being used as the test inocula.
    Both Chenopodium sap and pancreatic ribonuclease (0.5mg/ml) showed remarkable inhibition of lesion formation in all virus-host combinations when applied within 30 to 60 minutes after inoculation. This was also the case when they were applied to Nicotiana glutionsa one day before inoculation with TMV, suggesting that the inhibition is probably attributed to their injurious effects on cytoplasm of the host cell. Both trypsin and pancreatin were also inhibitory to the lesion formation in all virus-host combinations when applied within 30 to 60 minutes after inoculation, whereas they showed little effect when applied to N. glutinosa one day before inoculation with TMV. The results led us to an interpretation that the effect of trypsion and pancreatin is attributable to interference in the formation of virus-receptor complex at the susceptible site.
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  • K.G. SINGH
    1969 Volume 35 Issue 4 Pages 322-324
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Transmission studies on penyakit merah, a virus disease of rice in Malaysia borne by the leafhopper Nephotettix impicticeps Ishihara, indicated that the virus is non-(or semi-) persistent in the vector. Acquisition, infection, and retention periods in the vector, varietal differences in resistance, showed that penyakit merah is very closely related, or possibly identical, with tungro, confirming the earlier view of Ou et al.
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  • Natsuki NISHIHARA
    1969 Volume 35 Issue 4 Pages 325-327
    Published: September 30, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • 1969 Volume 35 Issue 4 Pages 328
    Published: 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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