• P. De Ley and A. Coomans. Terrestrial nematodes of the Galapagos Archipelago V: Description of Aquatides coboi sp. n., with a key to the genus (Dorylaimida: Nygolaimidae), 1-8.
• B. Weischer and M.T.M. Almeida. Ecology of longidorid nematodes, 9-21.
• E.A. Tzortzakakis, A.G. De R. Channer, S.R. Gowen and D.E. Goumas. Preliminary studies on the effect of the host plant on the susceptibility of Meloidogyne nematodes to spore attachment by the obligate parasite Pasteuria penetrans, 23-26.
• T.V. Volkova and A.S. Eroshenko. Pararotylenchus graminis sp. n. (Tylenchida: Pararotylenchidae) from native meadows in the Primorsky region, Russian Far East, 27-29.
• T.V. Volkova. Geocenamus khashanicus sp. n. (Tylenchida: Merliniinae) from the Russian Far East, 31-33.
• O.A. Kulinich and N.V. Kolossova. The potential of the pinewood nematode Bursaphelenchus xylophilus to become established in countries of the former USSR, 35-48.
• M. Liskova, D.J.F. Brown and C.E. Taylor. The occurrence and distribution of Longidoridae and Trichodoridae in the Slovak Republic, 49-60.
• T. Bongers, R.G.N. de Goede, G.W. Korthals and G.W. Yeates. Proposed changes of c-p classification for nematodes, 61-62.
• V.G. Gagarin. Morphology and taxonomy of the genus Fictor Paramonov, 1952 (Rhabditida: Diplogasteridae), 63-64.
• S.V. Zinovieva, O.L. Ozeretskovskaya, L.I. Iliinskaya, N.I. Vasyukova and Z.V. Udalova. Biogenic elicitor (arachidonic acid) induced resistance in tomato to Meloidogyne incognita, 65-67.
• Book Reviews, 68-69.

De Ley, P. and Coomans, A.

Terrestrial nematodes of the Galapagos Archipelago V: Description of Aquatides coboi sp. n., with a key to the genus (Dorylaimida:Nygolaimidae)

Summary:
Aquatides coboi sp. n. was found on Isla Fernandina and Isla Santa Cruz of the Galapagos Archipelago. This new species is smaller than any known species of the genus (L = 0.7-1.0 mm) and appears to be autotokous (no males found, no sperm seen in fifty-two females). It has a lip region with sucker-shaped anterior surface and small liplets, a mural tooth measuring 11 - 15 µm, and very short uteri (5-16 µm). SEM photographs are shown. Two females from Isla Santa Cruz of the known species A. thornei are also described. A lattice key to Aquatides is presented.

Key words: new species, Aquatides, A. coboi sp. n., nematoda, key, taxonomy, Galapagos.

Weischer, B. and Almeida, M.T.M.

Ecology of longidorid nematodes

Summary:
This review demonstrates how the main aspects of a nematode's biology are influenced by major ecological factors. Global distribution of longidorids is determined by natural geological events (e.g. continental drift) and by man-made dissemination with plant material. The present regional distribution is due to quaternary glaciation, post-glacial spread, climate and soil properties. Local occurrence is essentially governed by microclimate, soil and vegetation. Depth distribution depends mainly on soil texture, soil moisture and host roots. Soil texture is particularly important for migration because large nematodes such as longidorids are unable to force a passage through the soil as roots do. Main factors influencing population development are the reproductive capacity of a species, the climate, host plants and antagonists. Some longidorids have developed strategies for survival in plant-free soil and under adverse conditions.

Key words: Longidorus, Xiphinema, Paralongidorus, distribution, ecology, survival, host interactions.

Tzortzakakis, E.A., Channer, A.G.De R., Gowen, S.R. and Goumas, D .E.

Preliminary studies on the effect of the host plant on the susceptibility of Meloidogyne nematodes to spore attachment by the obligate parasite Pasteuria penetrans

Summary:
Variability in the number of spores of the bacterial parasite Pasteuria penetrans which attached to second stage juveniles of a mixed Meloidogyne javanica / M. incognita population after development on different host plants was recorded. These differences may result from the prevalence of different selected sub-populations with variable susceptibility to the bacterium due to competitive differences in growth and reproductive efficiency between species, races and biotypes. Therefore, the long term effect of the parasite on field populations of Meloidogyne is likely to be less consistent under crop rotations than under monoculture.

Key words: bacterial parasite, Meloidogyne javanica, M. incognita, root knot nematodes, spore adhesion.

Volkova, T.V. and Eroshenko, A.S.

Pararotylenchus graminis sp. n. (Tylenchida: Pararotylenchidae) from native meadows in the Primorsky region, Russian Far East

Summary:
Pararotylenchus graminis sp. n. is described from the rhizosphere of wild grasses growing in the south of the Primorsky region, Russian Far East. It differs from P. pini by having a shorter body and stylet and a longer tail and from P. flexuosus by having a shorter body and stylet and by the presence of males.

Key words: Pararotylenchus graminis sp. n., spiral nematode, Pararotylenchidae, taxonomy, Primorsky region, Russia

Volkova, T.V.

Geocenamus khashanicus sp. n. (Tylenchida:Merliniinae) from the Russian Far East

Summary:
A new species Geocenamus khashanicus sp. n. is described from the rhizosphere of Carex cryptocarpa and Geranium soboliferum from the south of the Primorje Territory. It is distinguished from G. patternus by the presence of a smooth terminus, absence of cuticular longitudinal lines and longer spicules and gubernaculum.

Key words: Geocenamus khashanicus sp. n., Merliniinae, taxonomy, stunt nematodes, Russian Far East.

Kulinich, O.A. and Kolossova, N.V.

The potential of the pinewood nematode Bursaphelenchus xylophilus to become estabished in countries of the former USSR

Summary:
The potential for establishment of the pinewood nematode Bursaphelenchus xylophilus in countries of the former USSR and their possible threat to conifers in these areas are discussed. Bursaphelenchus mucronatus is wide-spread, however B. xylophilus has not been found in the former USSR territories. Conditions exist which are suitable for the colonization by B. xylophilus, and the resultant occurrence of pine wilt disease, in both the European and Asian parts of the former USSR: vectors (Monochamus), susceptible plants, and favorable climatic factors. Based on an analysis of the potential distribution of B. xylophilus it may be concluded that a threat exists to conifer forests in several areas and territories of the former USSR. This threat is mainly from B. xylophilus, which has the potential to develop as a major factor to the detriment of Russian forestry due to both disease establishment and problems presented with international export of timber product.

Key words: Bursaphelenchus xylophilus, B. mucronatus, pinewood nematode, Monochamus, vector, former USSR, distribution, coniferous forest, climate.

Liskova, M. , Brown, D.J.F. and Taylor, C.E.

The occurrence and distribution of Longidoridae and Trichodoridae in the Slovak Republic

Summary:
The occurrence and geographical distribution in Slovakia of members of the Longidoridae was comprehensively examined during 1992 and 1993 and the occurrence of Trichodoridae in potato crops was also recorded. Nine Longidorus, one Paralongidorus and seven Xiphinema species were identified from soil samples collected in vineyards, orchards, hedgerows and forests. Additionally, from samples collected in potato fields, one Paratrichodorus and two Trichodorus species were identified. Longidorus leptocephalus and P. maximus occurred throughout the country whereas the other Longidorus species were restricted to discrete areas. Xiphinema taylori was widely distributed throughout Slovakia, X. vuittenezi was widespread in the warmer southern areas, and the other Xiphinema species had more localised distributions usually associated with particular soil or climatic characteristics or plant hosts. Longidorid nematodes were frequently recovered as populations comprised of two or more species. Trichodorus similis was present in the west, and T. primitivus and Paratrichodorus pachydermus in the east of the country, but trichodorids were not found in samples from the principal potato growing area. Southern Slovakia, which has relatively warm soil temperatures, appears to be the northern limit of the distribution of several species considered to indigenous to the Mediterranean region, viz. X. italiae, X. pachtaicum and X. similis.

Key words: Longidorus, Xiphinema, Paralongidorus, distribution, Slovakia