Fecundity of the fungivorous nematode, Aphelenchus avenae, cultured on Botrytis cinerea and Fusarium oxysporum at 25°C was compared.
A. avenae laid an average of 230 eggs on B. cinerea and 89 on F. oxysporum with oviposition periods of 25.8 and 22.3 days, respectively. Peak oviposition generally occurred within 4-6 days with B. cinerea and 10-12 days with F. oxysporum after maturation. The average life span of females was 32.3 days with B. cinerea and 29.6 days with F. oxysporum. Larval mortality was 15 and 20 percent with B. cinerea and F. oxysporum, respectively. Survivorship of females on both fungi declined in a similar manner. Intrinsic rate of natural increase (r_m) of A. avenae was estimated to be 0.79 and 0.50 with B. cinerea and F. oxysporum, respectively. Jpn. J. Nematol. 21: 1-5 (1991).

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Mungbean plants infested with the root-knot nematode, Meloidogyne javanica, became severely damaged and were even frequently killed. These plants under the heavy infestation of M. javanica displayed a marked reduction of yield. Antagonistic plants such as marigolds reduced the nematode population as effectively as non-host plants such as guinea grass or maize when introduced into the mungbean based-cropping system, though the latter plant was found to be more suitable as rotation crops. Mungbean varieties highly resistant to M. javanica have not been found hitherto, but one strain, UT 8104-B-3 seemed to be moderately resistant to the nematode, since a smaller number of root-knots were observed on its roots. Jpn. J. Nematol. 21: 6-10 (1991).

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The growth and propagation of Steinernema carpocapsae, S. feltiae and S. glaseri on nutrient agar were comparatively investigated at 25°C to clarify a dependency of these nematodes on their symbiotic bacteria, Xenorhabdus spp. The infective juveniles (J3) of S. glaseri promptly exsheathed, molted and propagated themselves to over 10, 000 per 5.5 cm petri dish in 6 days after inoculation with ca. 500 J3. Compared to S. glaseri, S. feltiae molted and developed slowly and the highest population was ca. 1, 000 nematodes 10 days after inoculation. The exsheathment, molting, and development were the slowest in S. carpocapsae; some J3 developed to adults but most of them did not produce progenies due to a poor gonad development. However, their ovaries started to develop and produced progenies when they were transferred onto dog food agar after 4 days' preculture on nutrient agar. Jpn. J. Nematol. 21: 11-17 (1991).

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Two new species of Pratylenchus from forest soil in Japan are described and illustrated. P. yamagutii n. sp. from Mt. Eniwa, Hokkaido is characterized by two head annuli, rounded spermatheca, and presence of males. This new species is similar to P. coffeae, P. alleni and P. neglectus, but differs from the first species in the shorter body, smaller b-value and dumbbell shaped submedian face segment; from the second in the longer stylet, rounded to oval spermatheca and slender tail; and from the third in the presence of males, more tail annuli and anterior location of phasmids in tail. P. okinawaensis n. sp. from Kunigami, Okinawa has two head annuli, crenate tail terminus and oblong spermatheca. This new species resembles P. flakkensis in the shape of the tail terminus, but can be separated from the latter by the oblong spermatheca and larger V-value. Jpn. J. Nematol. 21: 18-25 (1991).

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Six Japanese populations ascribed to Pratylenchus neglectus were compared in morphology and with statistics. Variability in outlines of lip region, spear knobs and tail terminus were observed: tail terminal outline is stable within a population and slight difference is recognized between some populations. Five morphometrics were selected to discriminate the 3 groups within the P. neglectus complex by the stepwise linear discriminant function analysis. The use of these selected characters were verified by the canonical discriminant function analysis and principal component analysis. The groups were identified as P. neglectus and 2 new Pratylenchus species, then characterized by the selected characters. P. gotohi n. sp., a possible sibling species of the P. neglectus, is described. The new species is distinguished from P. neglectus by the thicker spear knobs, posterior excretory pore, shorter postvulval uterine branch, lower m-value, larger number of tail annules (20 vs. 17 in mean values). Jpn. J. Nematol. 21: 26-42 (1991).

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