The current status of the development of commercial products for the biological control of plant-parasitic nematodes is discussed. An example is given of problems encountered by our program in patenting biocontrol agents in the United States. Two hypothetical approaches to the control of plant nematodes are considered. First, recent experimental results relating to the theory on intervention with host-finding by plant nematodes are reviewed. Second, a newer hypothesis considering the possibilities for genetic approaches to modifying molecular signals between nematodes and their parasites is described. Jpn. J. Nernatol. 24 (1): 1-13 (1994).

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The morphology and morphorhetrics of Ditylenchus angustus (BUTLER, 1913) FILIPJEV, 1936 were studied under light and scanning electron microscope (SEM). Lip region is cap-like, not distinctly offset and without distinct striations. Body annules are 0.7-1.2, μm wide. Lateral fields with four equally spaced incisures and areas between them are further divided to 6-8 sub-incisures. Vulval slit is less than half way across the body with slightly protruding lips. The measurements of the nematode are compared with those given in previous reports. Dimensions such as b₁, G₁, H, M, O, S, L', V', MB, length of tail, DGO and esophagus are first reported for D. angustus. Jpn. J. Nernatol. 24 (1): 14-19 (1994).

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The rates of nictating Steinernema carpocapsae infective juveniles (IJs) were at most 20% and 10% for nematodes harvested from insect cadaver, Galleria mellonella, and for those from chicken offal medium, respectively. Repeated employment of nictating IJs for the nictation performance did not raise the rate, but kept almosthe initial levels. Accordingly, after four performances, the number of nictating individuals became 0.16% of the initial population. The nictating IJs were more attracted to the host cue (larval plasma of Spodoptera litura) and more penetrated to the host insect than did non-nictating IJs obtained from nematode-water suspension. There were no significant differences in the migration/penetration between the nictating IJs with and without insecticides; acephate, permethrin, and oxamyl at 50 pg/ml each. The experiments confirmed that nictating behavior was a positive or precursory behavior for infection of S. carpocapsae. Jpn. J. Nematol. 24 (1): 20-29(1994)

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[in Japanese]

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[in Japanese]

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