Several bacteria were isolated from Meloidogyne incognita egg masses, and Heterodera zeae cysts. Screening the isolates for nematoxic effects resulted in five species with antagonisms to plant parasitic nematodes. The isolates were Bacillus sp., Corynebacterium sp., Serratia sp., Arthrobacterium sp., and Streptomyces sp. They were frequently associated with both egg masses and cysts. Liquid cultures of the five isolates at concentration as low as 0.1% inhibited hatching of M. incognita eggs. The culture filtrates at a concentration of 0.6% were highly toxic to juveniles of Meloidogyne incognita, Rotylenchulus reniformis, and Tylenchulus semipenetrans. At lower concentrations, however, this toxic effect varied with the different nematode species. Jpn. J. Nematol. 24 (2) 55-59 (1994).

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Nictation, infectivity, and sex ratio of Steinernema carpocapsae infective juveniles (IJs) were tested after storage for 0, 2, 4, 6, and 8 weeks at 8°C after emergence from cadavers of Galleria mellonella. The rate of IJs nictating in the presence of host feces rose with increasing storage time; 13.2, 17.7, 33.1, 38.8, and 58.2% for each respective interval, whereas 3.2, 8.4, 14.8, 10.5, and 13.2% nictated in the absence of host feces for each respective interval. The infectivity also increased with storage time; 32.6, 45.1, 33.2, 44.3, and 58.3% for nictating IJs collected from bark compost and 11.4, 29.1, 21.0, 23.1, and 51.6% for non-nictating IJs= (IJs kept in water for 24 hr at 25°C after various storage time), for each respective storage interval. The sex ratio (% male) of penetrating IJs were 55.4 and 37.2% for nictaiting IJs and non-nictating IJs throughout storage. When host insects were placed on top of the bark compost column (5cm deep) with nictating IJs inoculated on the bottom, the sex ratio for infective nematodes was ca. 70% on average despite reduced penetration efficiency. We suggest that this nematode increases the probability of survival by delaying the infection period and that male IJs are more active than females in the infective process under stressful conditions. Jpn. J. Nematol. 24 (2) 60-68 (1994).

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Agronomic practices aimed at minimizing the use of chemical fertilizers and pesticides will contribute to sustainable agriculture by enhancing soil and environmental quality. As a part of the studies involving application of organic sources of nutrients, the effects of soil application of dried cattle feces (DCF) on population of the soybean cyst nematode (Heterodera glycines) were examined using a non-nodulating soybean genotype, T201, as a host plant. DCF application @ 20 g kg^-1 soil increased the number of female adults on the soybean roots but no association was found between their number and the growth of soybean plants during the first 3 weeks after seedling emergence. DCF application increased evidently hatching rate and the number of the second stage juveniles in the soil even in the absence of the host plant. From the results obtained, possibility of the control of the soybean cyst nematode by the application of organic amendments are discussed. Jpn. J. Nematol. 24 (2) 69-74 (1994).

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