A study was undertaken to determine the effect of decomposition period on the efficacy of mustard (Brassica campestris) and cotton (Gossypium hirsutum) seed oil cakes added to soil as organic amendments for control of root-knot nematode (Meloidogyne incognita) on eggplant (Solanum melongena) in pot experiments. The oil cakes were applied at the rate of 0, 0.50, 0.75 and 1.00%(w/w) and allowed to decompose for 10, 20 and 30 days before planting twenty-one-day old seedlings of the crop. Soil amended with either of the oil seed cakes had a lower root gall index and greater shoot height, shoot weight and root weight than the control treatment. At the highest rate, maximum reduction in root galling was achieved but at this rate plants suffered from phytotoxicity that caused a slight reduction in plant growth compared to the lower rates. Effectiveness of the oil cakes to control root-knot nematode and enhance plant growth increased with increasing decomposition period. Even at the highest rate no phytotoxicity appeared when the oil cakes were allowed to decompose for 30 days before planting. Jpn. J. Nematol. 22: 1-10 (1992).

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A new root-knot nematode, Meloidogyne ichinohei n. sp., detected from Iris laevigata (rabbit-ear iris) cultivated in a paddy field in Hisayama, Fukuoka, Kyushu is described and illustrated. This new species has unique combination of characters and can be differentiated from all other known Meloidogyne spp. including morphologically similar species such as M. acronea and M. megriensis having posteriorprotuberances in females. The female has prominent posterior-protuberance, laterally located neck, perineal pattern made up by extraordinarily faint and broken striae, stylet 12.3μm long and excretory pore located about four times the stylet length behind the stylet knob. The second-stage juvenile has a hemizonid located just in front of the excretory pore, undilated rectum, body length of 470μm, a-value of 31.3, tail length of 54.2μm, stylet length of 11.3μm and distance of 5.2μm from the dorsal gland orifice to the base of stylet. The shape of the hyaline tail of the secondstage juvenile is usually triangular, but variant forms with protruded tail tips sometimes appear. The males are very rare. The only known host plant of this species is I. laevigata. Egg masses are produced within usually terminal galls. Jpn. J. Nematol. 22: 11-20 (1992).

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Aphelenchoides involutus n. sp. is described from Macroptilium atropurpureum (purple bean or siratro) in Ishigaki Is., Okinawa, Japan. This new species resembles A. africanus DASSONVILLE & HEYNS, 1984 and A. jacobi HUSAIN & KHAN, 1967 in the long and slender tail with pointed terminus, but differs from them in the presence of basal thickenings of stylet, longer tail, smaller c-value, more anterior located vulva, and absence of male adults. By SEM observation, face view of A. involutus has basically the same pattern of those of some other species of this genus reported. Jpn. J. Nematol. 22: 21-25 (1992).

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Eight species of the genus Helicotylenchus found from crop fields in Thailand are measured, described and illustrated as follows: H. abunaamai, H. certus, H. crenacauda, H. dihystera, H. egyptiensis, H. indicus, and 2 unidentified species. Variability of the characters observed in the Thai specimens are remarked. This is the first record for H. certus in Thailand. Jpn. J. Nematol. 22: 26-36 (1992).

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The seasonal occurrence of nematodes in the mud sediment of the Ariake Sea, Saga, was investigated from April 1991 to March 1992 at two localities, Rokkaku river estuary and Higashiyoka coast, the protected and unprotected areas of the mudskipper, Beleophthalmusp ectinirostris, respectively. In both localities, most of nematodes were isolated from the surface soil layer by centrifugal flotation technique. Totally 43 species were isolated from the coastal soil and 41 from the estuarine soil. Of all the species isolated, 34 were common to the two localities. The dominant species was Desmodora cazca in the coast and Spilophorella sp. in the estuary. The overall species diversity of nematode was higher in the former locality than in the latter one, where the nematode population precipitously declined in winter season. The similarity value between the nematode fauna in the two localities was high during May to July, while relatively low August to March. The relation between nematode fauna and mudskipper's habitat was briefly discussed.

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Occurrence and distribution of the potato cyst nematode, Globodera rostochiensis, were investigated in 5 major potato-producing areas in Sri Lanka in 1991. Distribution of the nematode was restricted to the potato fields in and around Nuwara Eliya district, where the nematode had been detected in 1989. This nematode was presumably introduced accidentally by imported seed potatoes around 1984. Crop rotation, especially cabbage after the potato, appeared to be effective in reducing the nematode population. Jpn. J. Nematol. 22: 43-48 (1992).

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A root-knot nematode population originating from soil around Zoysia matrella and reproduced on Panicum crus-galli in Kyushu, Japan is identified as M. marylandi. This population has small and round perineal pattern consisted of coarse and broken striae, stylet length of 13.9 μm and excretory pore located at about the level of stylet knob in female, hemizonid located posterior to excretory pore, dilated rectum, body length of 392 μm, tail length of 64 μm, c-value of 6.2, hyaline tail length of 12.3 μm, stylet length of 12.9 μm and distance from dorsal gland orifice to the base of stylet of 2.5 μm in second-stage juvenile. These are fairly coincided with that of M. marylandi. This is the first record of the species from Japan. Jpn. J. Nematol. 22: 49-52 (1992).

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[in Japanese]

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