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Part 3. Mode of Reaction in Citrus Fruit and Leaf against Infection of D. citri
Yutaka ARIMOTO, Yasuo HOMMA, Tomomasa MISATO
1982 Volume 48 Issue 5 Pages
559-569
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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The epidermal cell of fruit and leaf of satsuma mandarin (
Citrus unshiu), which was penetrated by the hypha of
Diaporthe citri (Faw.) Wolf, granulated and turned brown in color within 1 and 2 days after inoculation. Further granulation and browning of cells occurred around the initially browned epidermal cell. A group of necrotic cells consisted of 3 to 5 cell layers was then formed in a semi-spherical shape around the initially damaged epidermal cell. Subsequently, each cell in one or two layers adjacent to the necrotic cells became a pair of cells through a cell division. The cell division was repeated to make up a callus consisting of 10 to 12 cell layers around the necrotic cells. Thereafter, periderm was formed between the necrotic cells and the callus. Thus the melanose spot was finally formed by the three parts of a group of necrotic cells, a callus and a periderm, and invaded tissue was demarcated histologically. This phenomenon means self-protecting reaction responsed to the stimulation of citrus epidermal cell with penetration of
D. citri, and melanose spot was formed as a mechanical barricade tissue by the self-protecting reaction. Star melanose and scar developed also in a similar fashion to that of melanose spot, consisting of a group of necrotic cells, a callus and a periderm. It seems that the self-protecting reaction started by response to the local damages resulting in dead cells of citrus by penetration of pathogens, permeation of drugs and mechanical injurys.
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V. Application for Control of Fusarium Wilt of Strawberry
Takashi KODAMA, Toshio FUKUI
1982 Volume 48 Issue 5 Pages
570-577
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Soil disinfestation by solar heating in closed plastic house was examined for applicability in control of
Fusarium wilt of strawberry. During midsummer, experimental plastic house was entirely sealed and the soil surface was mulched with plastic film. To keep the soil in high moisture level, the soil was temporarily irrigated with sufficient volume of water before mulching. When soluble starch (25, 50g/kg dry soil) was ploughed into naturally infested soil before being submerged, solar heating treatment was more effective. The lethal exposure limit to the causal fungus was assumed to be 8-14 days at 40C. Soil temperature at 20cm deep in closed plastic house reached to 40C, effective lethal temperature, within 3 days in more insolated summer, but within 5 days in less insolated summer. To keep the temperature at 40C throughout day and night, 12-17 days were necessary in more insolated summer, but 20 or more days were necessary in less insolated summer. It was considered that rapid increase of soil temperature at 20cm deep in closed plastic house varied coincidentally with air temperature in the open field, especially with averaged maximum atmospheric temperature for 3 consecutive days. The following equation was obtained: Y=2, 37X-33.27, r=0.889
**, where Y=soil temperature (C) at the depth of 20cm in the plastic house; X=averaged maximum atmospheric temperature of 3 consecutive days in the open field. However, it might be necessary to adjust this epuation according to size of the house or some other factors affecting the temperature in the tested plastic house. In naturally infested strawberry field, the temporarily submerged soil was mulched with plastic film in closed plastic house during July and August in several years. Population density of
Fusarium oxysporum in the soil at 10-20cm deep decreased rapidly, and even 9 months after the treatment only a few of the fungus was recovered. Field experiments which were carried out in naturally infested strawberry field for 2 years demonstrated that solar heating treatment should be applicable to control Fusarium wilt of strawberry, and it brought an increase in yield and growth of the plant.
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Sakae ARASE, Hiromichi NITTA, Setsumi ITOI
1982 Volume 48 Issue 5 Pages
578-584
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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When ragi leaves (
Eleusine coracana (L.) Gaertn.) were treated for 10 or 15sec at 55C in water before inoculation,
Pyricularia oryzae and
P. grisea exhibited the pathogenicity. The induced-susceptibility was manifested by the presence of sporulating lesions on leaves treated at the higher heat dosage and by the increased size of necrotic lesions. Phenomena associated with heat-induced susceptibility, lesion formation and sporulation on lesions, disappeared within 24 to 48hr after heat treatment.
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Tadaoki INABA, Tadashi MORINAKA
1982 Volume 48 Issue 5 Pages
585-591
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Effect of light and darkness on oospore formation of downy mildew fungus,
Peronospora manshurica, of soybean,
Glycine max, was investigated. Oospores were more abundantly formed in lesions floated on water at a light intensity of 20, 000lux than those in darkness. The ratio of total number of oogonia and oospores under light to that in darkness was 2.9-4.0. The total number of oogonia and oospores increased from the 3rd day of incubation and reached a maximum the 4th day of incubation in darkness. Under light, the total number of oogonia and oospores rapidly increased from the 2nd to 7th day of incubation. The oogonium was differentiated on the 3rd day of incubation and the oospore was formed on the 5th day of incubation in darkness. In contrast, under light, the oogonium was differentiated on the 2nd day of incubation, one day earlier than in darkness, and the oospore was formed on the 3rd day of incubation, 2 days earlier than in darkness. The number of oospores increased with the increase of incubation days in the light and photoperiod. Oospore formation was reduced by the treatment of lesions with 3-(3, 4-Dichlorophenyl)-1, 1-dimethylurea (DCMU) at concentrations of 10
-6-10
-4M under light. DCMU, however, did not affect the oospore formation at concentrations of ranging between 10
-7-10
-4M in darkness. This phenomenon supports the idea that oospore formation in lesions was decreased by means of the inhibition of photosynthesis of downy mildew lesions. It was concluded from these results that the oospore formation of soybean downy mildew fungus closely depends on the photosynthesis of host soybean leaves.
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Ichiro FUJISAWA, Tsuneo TSUCHIZAKI, Norio IIZUKA
1982 Volume 48 Issue 5 Pages
592-599
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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In 1978-1980, three viruses were isolated from field-grown spinach plants in Hokkaido. These viruses were identified as bean yellow mosaic virus (BYMV), tobacco mosaic virus (TMV) and beet necrotic yellow vein virus (BNYVV) by the experiments based on host range, physical properties, vector relationships, particle morphology and serology. BYMV isolated from spinach showing vein necrosis had flexuous filaments of about 750nm in length, and was transmitted by aphids in a non-persistent manner. Infectivity of crude sap from the infected plants was lost by heating at 55-60C for 10 minutes, by diluting at 10
-3-5×10
-3, and by aging at 20C for 2-4 days. Antiserum against this virus positively reacted with P strain of BYMV (BYMV-P) in immunodiffusion test, and a spur developed between the precipitin lines to the virus and BYMV-P. The virus infected many leguminous and non-leguminous plant species and caused top necrosis on broad bean and pea. The results indicated that the virus was N strain of BYMV. A virus showing mosaic symptoms on spinach, having straight rods of 300nm in length, and infected many species of
Cruciferae was isolated. Infectivity in crude sap from infected plants was lost by heating at 90-95C for 10 minutes and diluting at 10
-4-5×10
-4. Antiserum against the virus reacted clearly with a crucifer strain of TMV, TMV-C. From these results, this virus was identified as a crucifer strain of TMV. Another virus was isolated from spinach showing mosaic and yellows symptoms. This virus was rod-shaped particles of 100-390nm in length, and was transmitted by infested soil but not by aphids. In crude sap from infected plants, the infectivity was lost by heating at 65-70C for 10 minutes, by diluting at 10
-3-5×10
-3, and aging for 2-4 days at 20C. As the virus reacted with antiserum against BNYVV, it was identified as BNYVV.
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Mitsuro HYAKUMACHI, Tadao UI
1982 Volume 48 Issue 5 Pages
600-606
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Disease incidence in damping-off of sugarbeet seedlings induced by
Rhizoctonia solani AG2-2 declined rapidly after two successive triweekly plantings. However, there was not a great decrease in saprophytic activity by the flax baits until five to seven successive plantings. In a certain combination of soil and isolate, i.e., in Kiyokawa soil inoculated with sclerotia of isolate Rh-65, abnormally slow growth isolates in the early stage (less than half of the hyphal growth of healthy isolates during 5 days on potato dextrose agar) appeared after three to five successive plantings and then gradually accounted for almost the whole number of isolates.
When sclerotia were inoculated into the soil repeatedly with sugarbeet replants, disease incidence in the second successive crop of sugarbeet was extremely low (20%) compared with that of the first crop (60%), and disease incidence of the third crop was almost negligible. Such disease suppressiveness could have been induced only by adding living sclerotia to the soil independently of the presence of the host plant, but not induced by dead sclerotia or by successive replantings.
There was a greater increase in the number of soil microorgaisms in the soil of 11th, but not 2nd successive crop of sugarbeet, than in the soil of non-inoculated and non-planted soil (control). The disease decline was not closely related with the total number of soil microorganisms.
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Hajime KATO, Tomio YAMAGUCHI
1982 Volume 48 Issue 5 Pages
607-612
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Two mating groups of rice-strain were determined by crossing isolates of rice-strain with standard isolates of ragi-strain belonging to two mating types. Of 718 monoconidial isolates of rice-strain from Senegal, Guinea, Mali, Côte d'Ivoire, Haute Volta, Cameroon, Egypt, Uganda, Madagascar, Italy, India, Thailand, Malaysia, Indonesia, Philippines, People's Republic of China, Japan, Colombia, Surinam and Brazil, 172 isolates were disclosed to be
A type, 18 isolates
a type, and 528 isolates unknown type. Morphology of perithecium, ascus, and ascospore formed by mating among rice-strains was similar to both those of
Magnaporthe grisea (Hebert) Barr and those by crossing between rice-strain and ragi-strain.
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Takashi YAMAMOTO, Masayoshi ISHII, Toshihiro KATSUBE
1982 Volume 48 Issue 5 Pages
613-619
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Twenty isolates of WMV collected from different locations of western Japan were examined by leaf-dip serology and immunodiffusion test. The antiserum used in this study was prepared to an isolate 8 (E) which induced typical mosaic, veinbanding, leaf distortion and dwarf symptoms on cucurbits. Thirteen isolates reacted positively with the antiserum while seven isolates from Kagawa prefecture were negative. The serologically positive isolates were further classified into two groups on the basis of reactions on broadbean and garden pea; 4 isolates infected these species systemically while 9 isolates did not induce systemic infection. The isolates that did not react with the antiserum infected broadbean and garden pea systemically inducing mosaic symptoms. The two types of WMV were detected in field-infected cucurbit plants collected from Kagawa prefecture. These results indicate that there are at least two serologically distinct types of WMV in Kagawa prefeccture.
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Satoshi WAKIMOTO, Ikuyo UTATSU, Norifusa MATSUO, Nagao HAYASHI
1982 Volume 48 Issue 5 Pages
620-627
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Washed cells of the virulent isolates and avirulent or weakly-virulent mutants of
Pseudomonas solanacearum suspended in pure water at a concentration of 10
2-3 cells/ml rapidly multiplied up to a level of 10
6 cells/ml during four days of incubation at 22C. The mode of multiplication was investigated with two virulent isolates, Ku7501-1 and KT-2, and avirulent mutant Ku7501-1-Av. All isolates multiplied to converge to the concentration of 10
6-7 cells/ml when initial concentration was low (less than 10
4 cells/ml) or moderate (10
4-6 cells/ml), while neither multiplication nor reduction occurred when initial concentration was high (higher than 10
6 cells/ml). The final concentration of the bacteria was maintained for long period. Bacterial multiplication in pure water was further confirmed by serial subculture experiment with the isolate Ku7501-1. When bacterial suspension was added to sterile pure water at a concentration of 10
2-3 cells/ml and subcultured serially 5 times, the bacteria multiplied up to 10
6-7 cells/ml during each incubation period of 3 days, suggesting that the cells propagated 10
15 times in total. No difference was observed in the size of bacterial cells before and after multiplication with the electron microscope.
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Mitsuro HYAKUMACHI, Tadao UI
1982 Volume 48 Issue 5 Pages
628-633
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Survival of sugarbeet root rot fungus (
Rhizoctonia solani AG2 Type 2) in the field and the role of the overwintered plant debris and sclerotia as inoculum have been studied. After overwintering, as the disease index increased, sclerotial number, viable sclerotial number (sclerotial number×sclerotial germination %), and the appearance of
R. solani from plant debris (%) in the soil around the diseased sugarbeet were increased, and there were high correlations among them. Appearance of
R. solani from overwintered plant debris (%) was extremely low (0∼4.2%). Although, sclerotial germination decreased rapidly from autumn to the next spring, there were many viable sclerotia in the soil around the sugarbeet with high disease index. Hyphal density emerging from plant debris was low (0.3%), and there was no correlation between the appearance of
R. solani from plant debris (%) and the damping-off of seedlings of sugarbeet (%). On the other hand, hyphal density emerging from sclerotia was high (34.2%), and there was a high correlation between number of viable sclerotia and damping-off of seedlings of sugarbeet (%). Viable sclerotia, not plant debris, were thought to be the main inoculum.
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Nobuyuki OSHIMA, Yasunobu TACHIBANA, Masamichi NISHIGUCHI
1982 Volume 48 Issue 5 Pages
634-641
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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A strain of TMV, LFD-St (=
Lycopersicon fruit deforming streak strain) was isolated from an immature fruit of a streak-diseased tomato plant which showed convex irregular green rings, 1∼2cm in diameter, on the surface. In tomato this strain caused dark brown necrotic streaks along the veins on the undersides of the leaves and then these streaks developed on the petioles and the stem. The leaves showed interveinal necrotic spots and sometimes mosaic symptoms. Samsun tobacco produced necrotic local lesions on the LFD-St-inoculated leaves generally, but sometimes necrotic oak leaf patterns which surrounded the midrib and the larger veins of the inoculated leaves, instead of distinct local lesions. LFD-St caused also necrotic lesions on the inoculated leaves of many other tobacco cultivars,
Nicotiana species, petunia, and
Chenopodium amaranticolor. No local and systemic symptoms were produced on LFD-St-inoculated
Phaseolus vulgaris. In tomato plants the infection of LFD-St was cross-protected by the preinoculation of L
11A, an attenuated tomato strain of TMV. Samsun tobacco which produced necrotic local lesions by the inoculation of LFD-St showed often mild mosaic on the upper leaves from about 20 days to one month after inoculation. From such upper leaves a strain of TMV, LFD-1, was isolated. Other two strains of TMV, LFD-2 and LFD-3, were also isolated from Bright Yellow and Samsun tobacco, respectively, which had been inoculated originally with local lesion isolates of LFD-St. LFD-1 caused only local lesions on Bright Yellow tobacco, and LFD-2 local lesions followed by systemic necrotic and chlorotic lesions. LFD-3 caused severe mosaic on Samsun tobacco, local lesions and systemic mosaic symptoms on Bright Yellow tobacco, and necrotic local lesions on
Phaseolus vulgaris. These three strains caused mosaic symptoms but no necrosis on tomato plant. LFD-St was inactivated by dilution between 10
-5 and 10
-6, and in ten min. at 90C. The dilution end points of LFD-1, -2, and -3 were between 10
-8 and 10
-9. The virus particles of these four strains were 300nm long and rod-shaped like the OM strain of TMV.
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Hiroshi KAMIUNTEN, Satoshi WAKIMOTO
1982 Volume 48 Issue 5 Pages
642-647
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Effect of infection with filamentous phage Xf on the growth, ultrastructure and virulence of
Xanthomonas campestris pv.
oryzae N5850 was investigated. The growth of Xf-infected bacteria was considerably retarded at 30C as compared with that of uninfected bacteria. The Xf-infected bacteria, however, rapidly multiplied from 36hr after infection to almost the same level of concentration as reached by uninfected cells after 72hr of incubation. The infected bacteria could grow even at 35C to some extent, while uninfected bacteria could not. Electron microscopic observation of the ultrathin sectioned Xf-infected bacteria grown at 30, 33.8 and 35C revealed that a number of vesicles exist on the cell surface. Some remarkable changes in the intracellular structures, viz., lack of uniformity in distribution of both ribosomes and fibrils in nucleoid area were observed in the Xf-infected bacteria. Xf-infection caused the bacteria to produce a greater amount of extracellular polysaccharide and to increase virulence.
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Chitta Ranjan MOHANTY, Srijib GANGOPADHYAY
1982 Volume 48 Issue 5 Pages
648-658
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Blast resistance in parental rice varieties Zenith, Tetep, Tadukan, Ratna, Karuna and Co. 13 and F
2 seedling derived from them were tested during
kharif (October, 1981) and
rabi (February-March, 1982) seasons applying high and low doses of nitrogen against C
1, virulent and C
3, less virulent isolates of
Pyricularia oryzae. Zenith, Tetep and Tadukan were found resistant and Ratna, Karuna and Co. 13 were found susceptible to either isolates. Genetic constituent for blast resistance in Zenith and Tetep to C
1 and C
3 isolates was found to be digenic and monogenic, respectively. But in Tadukan two and three genes operate against both the isolates respectively for resistance. Resistant×resistant crosses produced some susceptible plants in F
2 generation during both the seasons due to application of low and high doses of nitrogen to C
1 isolate only. Susceptible×susceptible crosses could not produce a single resistant plant against C
1 and C
3 isolates. Variation in nitrogen doses and seasons did not affect the genetic status of the plants. Only we observed some shifting of ratios, i.e., from 13:3 to 9:7, 57:7 to 54:10, and so on due to high dose of nitrogn.
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I. Genetic relatedness within anastomosis group 1
Shiro KUNINAGA, Ryozo YOKOSAWA
1982 Volume 48 Issue 5 Pages
659-667
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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DNA base sequence homology among AG-1 isolates of
Rhizoctonia solani was investigated on the basis of DNA-DNA reassociation kinetics, and the genetic relationship among pathological types was examined. High values of DNA homology (range from 98.0 to 100.3%) were observed among isolates of the sasakii type (IA). There was also high homology among isolates of the web-blight type (IB) (range from 95.7 to 99.4%). While, comparatively low values of DNA homology were observed between isolates of both types (range from 49.9 to 55.9%). These results indicated that each pathological type in AG-1 is genetically homogenous, but both types are genetically divergent from each other.
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II. Genetic relatedness within anastomosis group 2
Shiro KUNINAGA, Ryozo YOKOSAWA
1982 Volume 48 Issue 5 Pages
668-673
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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DNA base sequence homology among AG-2 group isolates of
Rhizoctonia solani was investigated on the basis of DNA-DNA reassociation kinetics, and the genetic relationship among pathological types was examined. DNA homology value among isolates within each single type was 100.3% with the winter crops type (II), 98.1% with the rush type (IIIB) and 100.1% with the root rot type (IV). Comparatively high values of DNA homology ranging from 68.6 to 71.5% were observed between rush type isolates and root rot type isolates, both belonging to AG-2-2. DNA homology values of winter crops type isolates of AG-2-1 with rush type isolates of AG-2-2 was 37.6 to 40.1%, and 43.5 to 49.4% with root rot type isolates of AG-2-2. These results suggested that each pathological type in AG-2 is genetically homogenous, and that between the rush type and the root rot type of AG-2-2 there is a small but significant partial heterogeneity. AG-2-1 and AG-2-2 may form genetically distinct groups.
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Takio ICHITANI, Hisakazu GOTO
1982 Volume 48 Issue 5 Pages
674-676
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Greyish Leaf Blight of Quercus myrsinaefolia Caused by Coniothyrium fuckelii
Shigeru KANEKO
1982 Volume 48 Issue 5 Pages
677-680
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Nobuo MURATA
1982 Volume 48 Issue 5 Pages
681-684
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Masahiko IRI, Tomio SHIMURA, Hideo TOGAWA, Katsuyasu UENO
1982 Volume 48 Issue 5 Pages
685-687
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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In order to eliminate the grapevine leaf roll virus (GLRV) from grape cultivar, Zenkoji (socalled Ryugan), some experiments on the heat treatment and meristem tip culture were conducted and new plants were successfully obtained. These plants were indexed for GLRV by the observation of symptoms appeared on them and also indicator cultivar, Pinot noir, plants green-grafted with candidate plants. The results indicated that the elimination ratio in meristem tip culture (80.4%) was higher than that in heat treatment (27.3%).
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Hiroshi HAGIWARA, Shoshiro TAKEUCHI
1982 Volume 48 Issue 5 Pages
688-690
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Radish residue infested with radish-yellows fusarium was piled up for 20 days to examine for inactivating effect on the pathogen. No
Fusarium oxysporum was detected in the tissue samples collected from the lower parts of the pile without plastic-film cover, from the parts where temperature rose up more than 50C, and from almost all parts of the pile covered with plastic-film even though temperature ranged from 15 to 35C. These results suggest that
F. oxysporum is well inactivated under the conditions of anaerobic fermentation.
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Tokiya SHIMIZU, Takio ICHITANI
1982 Volume 48 Issue 5 Pages
691-694
Published: December 25, 1982
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Mikio KUSUNOKI, Takio ICHITANI
1982 Volume 48 Issue 5 Pages
695-698
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Takashi KODAMA, Toshio FUKUI
1982 Volume 48 Issue 5 Pages
699-701
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Solar heating of out-door field soil with plastic-film mulching produced significant raise of soil temperature. Maximum temperature in the mulched soil were 45.2-47.0C and 37.9-39.9C at the depth of 5 and 20cm, respectively.
Fusarium oxysporum was not detected at all from the mulched soil at the depth of 5cm, and approximately 60% decrease of
F. oxysporum population was noted from that at the depth of 10 to 15cm. Disease incidence in the mulched field was significantly reduced, especially in lightly infested soil and in more insolated summer. Effect of combined treatment of plastic-film mulching with application of calcium cyanamide on the disease incidence was almost similar to that of mulching only.
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Toshiro SHIDA, Ichijuro FURUKI, Yutaka ARIMOTO, Yasuo HOMMA, Keisuke T ...
1982 Volume 48 Issue 5 Pages
702-704
Published: December 25, 1982
Released on J-STAGE: February 19, 2009
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Since 1973, a new disease of maskmelon caused by
Rhizopus sp. occured in Shizuoka prefecture. The fungus of
Rhizopus disease attacks on fruits of maskmelon were arrived at a market.
Rhizopus sp. isolates obtained with high frequency from affected fruits. The symptoms appeared on the peduncle of muskmelon fruits at the begining of the disease development. The symptom on peduncle are covered with black mycelia. Soon after, the disease fruits softened and rotted circularly at the peduncle. The fungus was similar to
Rhizopus stolonifer because of the agreements in their morphological and pathogenical properties to the description by Inui and Zycha. From these results, the causal fungus was identified as
Rhizopus stolonifer (Eherenberg Ex Fr.) Lind (syn.
Rhizopus nigricans Ehr.).
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