Fresh second-stage larvae of three amphimictic and three parthenogenetic populations of Rotylenchulus reniformis were examined for the developmental rate in distilled water having different pH and temperatures. Rate of larval development assessed by “21 developmental phases” at 27 to 28°C showed a sigmoid curve on time and probit transformation of the rate appeared to be statistically reasonable for comparison. Declines of time-developmental rate regression lines were significantly different between the amphimictic (MIZ) and parthenogenetic (AKN) populations. Most larvae of all populations tested died in pH 2.9 solution in the early developmental phases and some live specimens of the amphimictics (MIZ and HAW) showed little development. Significantly suppressed development in all populations was observed at pH 4.3. No infulence of pH was proved in the range of pH 5.3 to 8.2 for all populations. Remarkable inhibition of development in the parthenogenetics was contrast to the development in the amphimictics receiving a slight suppression at 34°C. The amphimictics developed fastest at 29°C but the parthenogenetics developed as rapid as at 25°C. Development of the parthenogenetics progressed more than that of the amphimictics at 20°C.

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Meloidogyne camelliae Golden, 1979, which had been said to be a native of Japan, was found on cultivars of Camellia japonica and C. sasanqua in Sagamihara, Kanagawa, in September, 1979 and on Cleyera japonica later. The state of M. camelliae on these plants was investigated in February, 1980. Both Camellia sasanqua and Cleyera japonica, new hosts, seemed to be favorable for M. camelliae as is Camellia japonica. The distinction of M. camelliae from other species of Meloidogyne was possible with its outstanding perineal pattern. It seemed possible to distinguish M. camelliae from 5 species of Meloidogyne (M. arenaria, M. hapla, M. incognita, M. javanica, and M. mali), already known in Japan, with the measurements of 2nd-stage larvae. The measurements of M. camelliae were as follows: body length (455-504μm), tail length (40.8-44.9μm), c-value (11.0-11.8), position of excretory pore (18.6-19.4%). When aged hosts were heavily infected with M. camelliae, swellings of rootlets were recognized, and a couple of females were found embedded in the root-tissue. Wine-colored cyst-like females of M. camelliae, parasitized by a fungus, were found on both Camellia japonica and C. sasanqua. Considering the derivation of the investigated plants, M. camelliae may be distributed throughout, at least, Kanto district including Kanagawa and Saitama prefectures.

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In Mt. Aso region, Kumamoto Prefecture, four Nothocriconema species were collected and identified with N. longulum (Gunhold), N.jaejuense Choi & Geraert, and two new species, N. palliatum and N. bellatulum. N. palliatum n. sp. was detected from rhyzosphere of Clethra barbinervis, Aralia elata, Helwingia japonica, Cornus controversa, Elaeagnus pungens, and Acer Sieboldianum. This new species is closely related to N. loofihaving a thin cuticular sheath around tail-top annules, but differs from it by smaller body size, shorter stylet and smaller number of body annules. N. bellatulum n. sp. from Weigela japonica resembles N.longulum and N. demani, but differs from them by smaller body size and shorter stylet. Male- and female adults and larval stages of those four species were described and illustrated.

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The following seven species of five genera of Crioconematidae were collected from mulberry fields in Japan; Crossonema multisquamatum, Variasquamata gracile, V. querci, Nothocriconema mutabile, Neolobocriconema serratum, Macroposthonia sphaerocephala and M. xenoplax. Their morphology and parasitism were studied. V. gracile was most commonly found and V. querci was less common. The other five species were rare. N. mutabile, V. gracile and V. querci were regarded to be parasitic to mulberry, while the parasitism of the other species was obscure.

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Head morphology of second-stage larvae of M. incognita, M. javanica, M. hapla, M. arenaria, M. mali and M. camelliae was compared by scanning electron microscopy. The external features, including shape and proportion of labial disc and lips, expression of labial and cephalic sensilla, and markings on head region, were distinctly different among each species. M. incognita was characterized by surface manifestation of cephalic sensilla and two to three incomplete head annulations. The labial disc and medial lips were dumbbell-shaped. M.javanica was differentiated from other species by bowtie-shaped labial disc and medial lips, and triangular-shaped lateral lips. M. hapla was characterized by the absence of surface manifestations of cephalic sensilla and the smaller labial disc and medial and lateral lips than those of other species. M. arenaria was similar to M. incognitabut the head region was annulated. M. mali had labial disc of rectangular-shaped and larger lateral lips than those of other species. M. camelliae was characterized by the absence of lateral lips.

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Males of six Meloidogyne species, M. incognita, M. javanica, M. hapla, M. arenaria, M. maliand M. camelliae were examined with a scanning electron microscope for characters which might be usuful in the identification of this genus. It became clear that shape of labial disc and medial lips, the absence or presence of head annules and lateral lips, and expression of amphidial aperture were distinctly different in these six species. The labial disc and medial lips of males were elongated oval in M. incognita, dumbbell-shaped with squarish medial lips in M.javanica, and of rectanglular form in M. hapla and M. camelliae. M.camelliae was similar to M.hapla but had larger amphidial apertures. The junction of the labial disc and medial lips indented markedly in M. arenaria. In M. arenaria, the head region usually possessed two to four incomplete annulations. The labial disc was oval in M. mali.

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