Twelve plant-parasitic nematode genera and 25 species were identified in soil and root samples collected from 17 localities in the soybean production areas of South Africa during the 1995/96 season. Predominant endoparasites found included Meloidogyne incognita, M. javanica, M. hapla, M. ethiopica, Pratylenchus zeae and P. brachyurus. Meloidogyne species occurred in 91% of all root samples, P. zeae in 87% and P. brachyurus in 33%. The occurrence of the three predominant endoparasites was not restricted to sandy soil, but they were also prevalent in soils with high clay contents. Other endoparasitic nematode species were Pratylenchus crenatus, P. teres, P. neglectus, P. thornei, Rotylenchulus parvus and Ditylenchus africanus. Nematodes found in soil included Helicotylenchus dihystera and Scutellonema brachyurus, which occurred in 78 and 71%, respectively, of all soil samples. Other nematodes found in soil samples were Helicotylenchus pseudorobustus, H. digonicus, H. microcephalus, Scutellonema truncatum, Rotylenchus unisexus, Mesocriconema sphaerocephalum, Paratrichodorus minor, Longidorus pisi, Xiphinema vanderlindei, X. elongatum and Tylenchorhynchus goffarti. Highest prominence values (PV) for Meloidogyne species were recorded on cultivars Prima, Bakgat, Tamboti, Hutcheson and Knap and the lowest on cultivars PAN812, SCS1, Nyala, Gazelle and A7119. Eight nematode genera and 19 species extracted during this study are reported for the first time in association with soybean in South Africa.

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Fertilization and hatching of D. ranarum eggs under laboratory conditions are described. The morphology of the newly hatched larvae was studied by scanning electron microscopy and the results are compared with existing knowledge.

The branchiuran ectoparasite Dolops ranarum (Stuhlmann, 1891) was described almost one hundred years ago. This descriptional though valid is incomplete. A redescription is given. New information was obtained with light and scanning electron microscopy. Morphometric values are included and a species diagnosis is presented.

The effects of the association between the root-lesion nematodes, Pratylenchus brachyurus and P. zeae, and the root-rot fungus, Fusarium moniliforme, on maize growth, root-rot severity and root-lesion nematode population were studied under greenhouse conditions. Five inoculation treatments were applied and the effects monitored over 12 weeks. The results demonstrated that the root-lesion nematodes and the fungus affected plant growth more when combined than when alone, and were most severe during the seedling stage. Root-rot severity fluctuated during the experiment and significant differences between the treatments could only be found from 4 weeks following planting. The presence of the fungus facilitated the attraction and/or penetration of the root-lesion nematodes into the roots of the maize seedlings.

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A general account is given of the morphology of the gnathosoma of Phityogamasusprimitivus (Oudms.) based on serial sections. The examination of the hypostomal region of Phityogamasus Athias, Laelaps Koch and Ornithonyssus Sambon using Scanning Electron Microscopy has revealed significant structural differences between these genera which are attributed to their different feeding habits.

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