Japanese Journal of Nematology
Online ISSN : 2186-2672
Print ISSN : 0388-2357
ISSN-L : 0388-2357
Volume 6
Displaying 1-21 of 21 articles from this issue
  • Kei SHIMIZU
    1976 Volume 6 Pages 1-6
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    When paddy rice was grown under upland condition in pots which had been inoculated with 0, 400, or 4, 000 larvae of the upland rice cyst nematode, distinct differences in grain weight were observed; the grain weights per pot were 71.2gm, 67.2gm, and 59.5gm, respectively. It was also found that the reduction in rice yield was related to the time of invasion of the roots by the nematode; higher rates of the yield reduction were observed when the roots were invaded by the nematodes before tillering stage. In a field experiment, negative correlation between the yield and the final population of cysts in soil were found more clearly in early seeding culture than in later ones. Actual influences of the nematodes on the plant growth were considered more severe at later stages of the plant growth.
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  • Haruo INAGAKI, Kazuo KEGASAWA
    1976 Volume 6 Pages 7-9
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    Those encysted larvae and eggs of potato cyst nematode which passed through the digestive tracts of hen were not viable at all. On the other hand, those reisolated from dung of swine within 48 hr after feeding remained viable. This difference was partially explained by the difference in their body temperatures. Namely, it was shown in the temperature treatment experiments that the body temperature of hen (41.9°C) was lethal to the encysted larvae and eggs of this nematode if they were exposed at this temperature for 24 hr, but that of swine (38.8°C-39.0°C) was not lethal to them if the exposure was ceased within 48 hr. Jap. J. Nematol. 6: 7-9 (1976)
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  • Masaaki TSUTSUMI
    1976 Volume 6 Pages 10-13
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    Several kinds of experiments were carried out to study the influence of the conditions, under which the potato root-diffusate was collected, on the hatching of potato cyst nematode, Heterodera rostoehiensis Woll.
    The root-diffusate was collected by saturating the soil with 2l of tap water in 1/5, 000a pot in a greenhouse at about 25°C, where 2 potato plants were grown and by draining the solution from the pot after certain period of time. This solution was filtered and stored at 5°C until use.
    The root-diffusate collected within 66 days after transplanting the potato seedlings of about 5 cm in height gave the hatching rates higher than 60%, especially that collected in a period from 20 to 40 days after transplanting gave higher hatching rates over than 90%. So, this period is considered to be an optimum time to collect the root-diffusate.
    In the terms of stimulating effect on the nematode hatching, there was no appreciable difference in the duration of time from the initiation of saturating the soil to draining the solution from the pots. Namely, the solutions collected from just after the initiation of saturating the soil till 48 hrs after it gave almost the same rates of hatching, higher than 70%.
    A solution was collected at any time from the soil from which the roots of potato plants were removed at the time of flowering. The hatching rate was higher than 60 % in the solution collected one month after the removal of the roots and a weak but obvious effect on the hatching was found to remain till 100 days after it.
    The root-diffusates collected from five potato varieties differing in the maturation period were examined. Those solutions collected before 49 days after transplanting the seedlings showed a high effect on the hatching in the cases of all of the varieties and no difference was noted among the varieties so far.
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  • Yoji MOMOTA, Yasuomi OHSHIMA
    1976 Volume 6 Pages 14-23
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    Three Heterodera species, H. elachista, H. avenae, and H. glycines, and one Globodera species, G. rostochiensis (2nd stage larvae) were examined with a scanning electron microscope (SEM) to see if any additional information for the separation of species could be obtained. The oral discs of 2nd stage larvae presented dumbbellshape in H. elachista, elongated oval in H. avenae, a modification of dumbbell-shape in H. glycines, and oval with submedian lips in G. rostochiensis. The oral discs of males presented dumbbell-shape in H. elachista, elongated oval in H. avenae, and oval with lips in H. glycines. In mature females and cysts, H. elachista and H. glycines had the highly domed cone top with wide vulva, but with different numbers of perineal ridges, and H. avenae was distinguished from the former two species by the low domed cone top with narrow vulva. Thus, these species could be easily separated with SEM. The face views of these females were slightly dissimilar having varied rectangular oral discs with more or less concave side, but they could not be clearly separated. The two minute pores opening near the tip of each spicule located outside in H. elachista and H. glycines, but inside the spicule in H. avenae. Only in male of H. glycines the six inner labial papillary openings were observed about the oral aperture. Therefore, the morphological characters which are important in the identification and taxonomy of Heterodera species newly included the location of two minute pores on each spicule tip, the absence or presence of papillary opening, and the lip pattern of male. In view of these observations, it was recognized that the introduction of SEM technology made possible the rapid and accurate identification of cyst nematodes.
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  • Zen-ichi SANO
    1976 Volume 6 Pages 24-26
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    Susceptibilities to ethylene dibromide were compared among the second-stage larvae of the root-knot nematodes, Meloidogyne incognita, M. hapla and M. javanica by the modified Moje method. Garden pea was used as a host, and the nematodes were reproduced under the same conditions. As a result of tests, LC-50s of each species varied from 53 ppm to 60 ppm. The larvae of the three Meloidogyne species tested were considered to be approximately equal in their susceptibility to the nematicide.
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  • Eizo KONDO, Nobuyoshi ISHIBASHI
    1976 Volume 6 Pages 27-34
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    The structural changes of the 2nd stage larvae of Heterodera glycines, which were exposed to temperatures at-20°C and 40-60°C, were investigated under light and electron microscopes. Normally the cuticle was 0.64 μm in thickness and composed of 4 layers. The thickness of cuticle changed slightly by thermal treatments and the ratio of cuticle to body diameter decreased significantly by the treatment at-20°C for 1 hr. Spacial arrangements of myofilaments were disordered in the nematodes treated at 60°C, while they were stable at 45°C for 5 min and at-20°C for 60 min. Lipid droplets became irregular in shape at 60°C. Mitochondria and glycogen were disordered by all thermal treatments. Jap. J. Nematol. 6:27-34(1976)
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  • Nobuyoshi ISHIBASHI, Eizo KONDO
    1976 Volume 6 Pages 35-38
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    The 2nd stage larvae (L2) of Meloidogyne incognita and M. hapla, which had been subcultured by inoculating a single larva from a single egg mass, were inoculated at various levels (1-160 L2s) on tomato seedlings growing in small glass tubes with and without fertilizers. The reproduction rates of both species were maximum in the inoculum levels ranging from 10 to 20 L2s as well as the ratios of egg masses harbouring in roots. The number of eggs in an egg mass was slightly larger in the multiple L2s than in a single L2 inoculum. With increasing the inoculum level the brown egg masses and males increased in parallel, especially in the hosts receiving less nutrients. Since brown egg masses were also obtained from a single L2 inoculation to the plants without fertilizers, males would not participate in the occurrence of brown egg masses which are more bearable to adverse conditions than white ones. Jap. J. Nematol. 6:35-38 (1976)
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  • Kazuya HIRANO
    1976 Volume 6 Pages 39-46
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    Control effect against the damping off in cucumber seedlings grown in the soil infested with M. incognita was significantly high in the treatments with the volatile chemicals, chloropicrin, NCS, D-D, DBCP; the organic insecticide, Methomyl (Lannate); and the selective fungicides, DAPA (Dexon) or Hymexazol (Tachigaren). However the treatments with other selective fungicides, Benomyl (Benlate) or PCNB resulted in accelerative incidence of the damping off in seedlings. Among several isolates taken from the disease materials, five isolates of Pythium spp. including P. aphanidermatum (Isolate-A, Isolate-B), P. debar yanum, P. spinosum and P. sp. were the dominant group compared with other fungi, Fusarium spp. or Rhizoctonia solani. Incidence of the damping off in seedlings inoculated with each fungal isolate and the nematode increased rapidly in plots of the inoculation containing Pythium spp. and M. incognita. In some inoculation studies on P. aphanidermatum and M. incognita, the influence of root-knot nematode on the damping off development varied with the fungal inoculation level and the growing stage of seedlings. Particularly, at the seeding stage when seedlings have high susceptibility to the fungus, the disease severely occurred in seedlings inoculated with the fungus and the nematode simultaneously, but at a later stage, 7 or 14 days after seeding, the heavier disease development appeared in seedlings inoculated with the root-knot nematode 7 or 14 days before the fungus inoculation than in those inoculated with both pathogens simultaneously. It was observed that infection of P. aphanidermatum zoospores in cucumber roots on agar plate was more rapid among the roots invaded by the root-knot nematode.
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  • Yasushi MITSUI, Takeshi YOSHIDA, Koichi OKAMOTO, Ryosuke ISHII
    1976 Volume 6 Pages 47-55
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    The experiments were conducted from 1966 to 1968 in peanut fields of volcanic ash soil at Yachimata, Chiba Prefecture, where the peanut had been cultivated successively for more than 3 years. Various amendments-manures of peanut plant, rice straw, or sawdust, iron sludge, and lime-added to soil had no effect upon the populations of trapping fungi and of Meloidogyne hapla in fields at 3 sections, Sumino, Ozeki, and Sasabiki, where the amendment treatments were made for 1, 2, or 3 years, respectively. Positive correlations with high coefficient were observed between population densities of the nematode trapping fungi and of the root-knot indices at Ozeki in June and October, 1967, and June, 1968, and at Sumino in October, 1967. Similar results were obtained in June 14 fields at different localities which excluded low land field, field of low soil pH value, and deeply plowed field. However, negative correlations with high coefficient were observed, on the contrary, at these fields in October. Thus, the significant role of the trapping fungi in relation to the checking of the nematode infestations was observed in many instances in these fields, when the relationships between the population densities of the fungi and that of the nematodes were analyzed in consideration of seasonal changes in these organisms. No correlations were observed between densities of the nematode trapping fungi or the root-knot indices and conditions of field soils such as the solid phase, the liquid phase, or pH.
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  • Tomoya KIYOHARA
    1976 Volume 6 Pages 56-59
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    The extended subculture of B. lignicolus on the fungal mat of B. cinerea resulted in the decrease of pathogenicity to pine trees as well as the propagation rate. The population of B. lignicolus collected in 1969, which had been highly pathogenic inasmuch as they brought about the entire death of pine trees inoculated, exhibited the degradation of the pathogenicity after being subcultured on the fungi for 5 years. The population also showed a lower rate of propagation when compared with that of the injurious fresh population.
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  • Hirotada TAMURA
    1976 Volume 6 Pages 60-66
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    The investigation was conducted to obtain some basic data to examine an accuracy of the boring method by the distributional pattern of Bursaphelenchus lignicolus in the pine tree (Pinus densiflora S. et Z.) died from the infection of the nematode.The distributional pattern of the nematodes in the disks cut transversely from the 19-20 years old pine trees at one meter interval above the ground in October of the year was determined by the index of dispersion, 16, which was calculated from the number of nematodes per dry weight g of each divided block (2×2×2 cm) of the disks. The Iδ values were between 1.32 and 3.24 and indicated a contagious pattern. In the disks of the dead pine trees cut at four meters above the ground in May of the next year, the population density of nematodes was higher in the marginal part than in the central part and in the disks cut at the same height from the logs laid down above the ground for seven months after falling in October of the year, it was higher in the central part than in the marginal part. In the disks cut at two heights from the 83 years old pine trees which died in October of the year, the population density was much higher in the sapwood than in the heartwood.
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  • V. Mechanism of the symptoms development
    Yuzuru UEBAYASHI, Takashi AMANO, Isamu NAKANISHI
    1976 Volume 6 Pages 67-72
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    The occurrence of two types of Kokutenmai seemed to be closely related to the development of endosperm. When the rice white tip nematodes injured the kernel during the early milk ripe stage, the abnormal rice of longitudinal type (longitudinally cracked and blackened kernels) may be developed, and that of horizontal type (transversely crack wedged kernels) may also be developed from the late milk ripe stage to the early yellow ripe stage. The symptoms of these abnormal rices appeared mostly on the ventral side of the kernel. It was considered the reason was that the nematodes likely lived in space between the hull and the ventral side of developing endosperm, and also that the epidermis of the ventral side of kernels were more easily cracked because the number of aleuron cell layers on this side were less by two to four layers than that of the dorsal side. When inoculating some fungi and bacteria separated from Kokutenmai, the symptoms were hardly found. However, when the ears of the rice plant infected with the nematode were immersed in the solution of Streptomycin at the concentration of 1, 000 ppm at the heading time, the abnormal rices were decreased by half. It was suggested that these rices might be caused by infection of bacteria following the injury by the nematodes.
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  • Tsutomu NISHIZAWA
    1976 Volume 6 Pages 73-79
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    Recently with the increased infestation of white tip nematodes in paddy rice in this country, occurrence of diseased rice kernels with black wedge-shaped spots, a new type of damage in rice production, has widely been observed. These kernels bear a striking resemblance to “black eye-spot of rice grains” which were caused by a bacterial disease as reported in 1941 by Miyake and Tsunoda. The white tip nematodes were, however, found to be the primary cause of the black wedged rice, as a result of some observations made in paddy fields of commercial growers and of a field experiment done by inoculating the nematodes. In addition to the primary role of the nematodes, necessity of the secondary action by saprophytic microorganisms, such as Enterobacter agglomerans, for black discoloration process was ascertained by duplicated inoculation experiments of these organisms. Diseased kernels showing similar symptom were recognized among the nematode-infected rice grains produced in Thailand, and it was suggested that “L type” pecky rice occurring in Louisiana, Texas, and Arkansas (Douglas, 1950) is possibly identical to this disease primarily caused by the nematodes.
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  • Yoshiaki KOBAYASHI
    1976 Volume 6 Pages 80-83
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    In December of 1975, occurrence of A. besseyi was observed on strawberries (cultivar Flokowase) growing in some greenhouses in Oigawa-cho, Shizuoka-ken, Japan. The strawberries infected by the nematodes showed dwarfing symptom that was very similar to summer dwarf. The symptom became less distinct from winter to spring, but many nematodes were isolated from buds of strawberries in late spring. The fact showed that the nematode could easily do overwintering under these conditions. While A. besseyi has been known as a parasite of strawberries in the southern U. S. A., the nematodes have been widely distributed in Japan as a parasite of rice plant but not of strawberries. So, concerning the occurrence of the nematodes on strawberries, a study has to be made to see if there is any correlation between the population of the nematodes on rice plants and that on strawberries.
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  • Kazutoshi NAKASONO, Naoki KATSURA
    1976 Volume 6 Pages 84-88
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    The second stage larvae of Rotylenchulus reniformis molt and develop into immature females or mature males without feeding. This paper describes an inhibitory effect of visible light on the molting and development of the nematodes incubated in 0.6ml of deionized water contained in a small Syracuse watch glass. Only bluelight among all visible lights emanated from colored fluorescent lamps showed theinhibitory effect on the molting and development, and finally caused the death.The irradiation energy stronger than 8, 000 erg cm-2sec-1was effective. Irradiationtest with monochromatic lights produced through interference-filters revealed thatthe shorter wavelength of blue light the more effective against the larvalmolting, and the upper limit of the wavelength, which was effective, was postulated to bebetween 433 nm and 463 nm.
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  • II. Observations on the embryonic development of eggs and life-cycle of the nematode in a mulberry field
    Hideyuki YAGITA
    1976 Volume 6 Pages 89-95
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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    Eggs of Longidorus martini showed somewhat curved sausage-like shape with hemispherically rounded ends. Their dimensions were as follows: length=180.4±9.2μ, wide=43.4±2.2μ, and length/wide=4.2. From these characters, the eggs were easily distinguished from those of Xiphinema spp. co-inhabiting in mulberry field. As a results of observations on the embryonic development of the eggs at 20-25°C, stages of morula, gastrula, and vermiform were observed at 1-3, 3-8, and 7-10 days, respectively, after the beginning of the cleavage. Moulting of the larvae in the eggs was not observed and hatching of the larvae occurred between 16-23 days after the cleavage. When young females, which were collected from soils of mulberry field in winter, were inoculated to mulberry seedlings at 20-24°C, many females with fully grown gonads and ovipositing ones appeared within 2-3 weeks and 3-4 weeks, respectively. Fig, tomato, and egg plant were newly added as the hosts of the nematodes, but no host plants were found among weeds growing naturally in mulberry fields. Oviposition of this nematode in a mulberry field began in May, increased rapidly reaching the peak in June, and declined markedly or ceased in July-August. A secondary small peak of oviposition occurred again in September-October. After the peak of oviposition larvae at the three larval stage and adult females appeared at the maximum rate at intervals of approximately one month. The nematode survived for about seventeen months at room temperature (0-28°C), and more than thirty months at 0-9°C, in soils without host plants.
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  • Haruo INAGAKI, Maria M. De SCURRAH
    1976 Volume 6 Pages 96-97
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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  • [in Japanese], [in Japanese]
    1976 Volume 6 Pages 98
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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  • [in Japanese]
    1976 Volume 6 Pages 99
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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  • [in Japanese], [in Japanese], [in Japanese]
    1976 Volume 6 Pages 99a
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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  • 1976 Volume 6 Pages 100-103
    Published: October 15, 1976
    Released on J-STAGE: August 11, 2011
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