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Volume 5, Part 1 (1997)

Tzortzakakis, E.A.

Observations on the variability in reproduction of some populations of root-knot nematodes (Meloidogyne spp.) on resistant tomatoes in Crete, Greece.

Summary:
Experiments under controlled conditions with a few naturally occurring populations and single egg mass lines of root-knot nematodes (Meloidogyne spp.) from Crete demonstrated the nematodes ability to produce low numbers of egg masses on several resistant tomato cultivars. Except for one naturally virulent population of M. javanica, reproduction on resistant cultivars was significantly lower than on a susceptible cultivar. A quantitative nature of the Mi resistance gene was revealed by the differential reproduction of a partially virulent line of M. javanica on heterozygous and homozygous resistant tomatoes. Virulent clones were not produced from a few single egg mass lines of Meloidogyne spp. on a resistant cultivar during a two generation period. Only one line produced two egg masses for two generations but the evidence is probably insufficient to prove a genetic inheritance of virulence. At high soil temperature (>28 C) resistance was probably decreased and a non-virulent population reproduced on a resistant cultivar. The requirements for further research and practical recommendations for successful implementation of resistant tomatoes in management strategies are discussed.

Key words: Lycopersicon esculentum, Mi gene, Meloidogyne javanica, M. incognita, plant resistance, root-knot nematodes,
virulence

Liebanas, G. & Peña-Santiago, R.

Nematodes of the order Dorylaimida from Andalucia Oriental, Spain. The genus Nygolaimus Cobb, 1913. II. Description of two new species

Summary:
Two new species of the genus Nygolaimus Cobb, 1913 are described from material collected in different natural areas from southeastern Spain. Nygolaimus baeticus sp. n. is characterized by its slender (a=47.6-64.1), long (L=2.3-3.2 mm in females and L=1.8-2.5 mm in males) body, lip region set-off by constriction, mural tooth deltoid and 11-13.5 µm long at the dorsal side or about four-fifths of the lip region width, V=53.3-59.7%, tail rounded, conoid (31-42 µm, c=71.4-96.5 and c'=0.8-1.1 in females; 27-44 µm, c=54.5-81.3 and c'=0.9-1.4 in males), spicules 37-42 µm long and one or no ventromedian supplement. Nygolaimus similis sp. n. can be distinguished by its relatively slender (a=40-57.7), long (L=2.4-3.2 mm in females and L=1.6-1.8 mm in males) body, lip region 18-21 µm and set-off by a deep constriction, mural tooth deltoid and 14.5-17 um long at the dorsal side or about three-fourths of the lip region diameter, V=48.5-55.3%, tail rounded, conoid (34-49 µm, c=52.9-81.9, c'=1.0-1.3 in females; 34-36 µm, c=44.1-52.5, c'=1.1-1.2 in males) with an indentation in the cuticle of the tail in the subterminal dorsal position, spicules 38-39 um and no ventromedian supplement. Both species are illustrated and tables of morphometrics are given.

Key words: Nygolaimus baeticus sp. n., Nygolaimus similis sp. n., Spain

Jimenez Guirado, D. and Escuer, M.

Mononchid nematodes from Spain. A description of Anatonchus acutus Altherr, 1974.

Summary:
Females and juveniles of Anatonchus acutus Altherr, 1974 are described and illustrated for the first time from specimens collected in Spain. Male specimens are also described from the same populations. The species is redefined and characterized by its medium size, lip region offset by a strong depression, buccal cavity 23-32 x 28-42 µm, teeth located in the anterior half of the stoma with the apex of the dorsal tooth at 46-63% of the buccal cavity length measured from the base, V=67-73%, female genital system pseudomonodelphic or didelphic with the posterior branch reduced, ejaculatory glands in tandem, spicules 52-68 µm, lateral guiding pieces bifurcate with straight arms, 9-13 ventromedian supplements, tail conical, elongate with acute terminus and caudal glands or spinneret absent. It is similar to A. amiciae Coomans & Lima, 1965 and A. monohystera Altherr, 1977 in the characteristics of the female genital system but it differs in tail shape and absence of caudal glands and spinneret.

Key words: Anatonchus acutus, Mononchida, Spain, taxonomy

Osipova, E.V., Rudenko, M.I., Balakhnina, V.P. and Pukhalskiy, V.A.

The selection of homozygous lines of barley resistant to Heterodera filipjevi based on the nematode resistant Turkish k-6808 cultivar

Summary:
New lines of barley with genetic resistance against Heterodera filipjevi were produced from crossing the high yielding but nematode susceptible cultivar Donetsky 4 with the low yielding but highly nematode resistant Turkish k-6808 cultivar. The Turkish cultivar of barley was used here for the first time as a source of resistance against the nematode. The yield characteristics of the new barley lines were comparable with that of Zazersky 85, the most widely grown cultivar in the former Soviet Union.

Key words: Heterodera filipjevi, barley, resistance, homozygous line.

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

Two new species of Criconemella (Tylenchida: Criconematidae) from meadows in the Primorsky region, Russian Far East

Summary:
Two new species Criconemella ripariensis sp. n. and C. sigillaria sp. n. are described from specimens collected from the rhizosphere of Carex appendiculata and C. lasiocarpa growing in meadows in the Khassan district of the Primorsky region, Russia. Criconemella ripariensis sp. n. is characterized by the presence of 125-150 cuticular annules, stylet 64-73 µm long, conical tail curved on the dorsal side and deformed annules on the tail terminus. C. sigillaria sp. n. is characterized by the presence of 115-127 cuticular annules with anastomoses, stylet 46-51 µm long and conical tail with dorsally curved terminus with numerous finger-like appendages. Macroposthonia digiticauda Eroshenko & Volkova, 1988 is transferred to Criconemella digiticauda (Eroshenko & Volkova, 1988) comb. n.

Key words: Criconemella ripariensis sp. n., C. sigillaria sp. n., taxonomy, Russian Far East.

Artyukhovsky, A.K., Kozodoi, E.M., Reid, A.P. and Spiridonov, S.E.

Redescription of Steinernema arenarium (Artyukhovsky, 1967) topotypes from Central Russia and a proposal for S. anomalae (Kozodoi, 1984) as a junior synonym.

Summary:
A redescription of Steinernema arenarium (Artyukhovsky, 1967) Poinar 1990 is presented based on topotypes collected from the type locality in the Voronezh, Central Russia. The synonymization of S. anomalae (Kozodoi, 1984) Curran, 1989, originally described from nematodes collected in the Ryazan region, Central Russia, with S. arenarium is proposed based on morphometrics, protein electrophoresis and DNA analysis.

Key words: entomopathogenic nematodes, Steinernema arenarium, S. anomalae, synonymization, Central Russia, redescription.

Liebanas, G. and Peña-Santiago, R.

Nematodes of the order Dorylaimida from Andalucia Oriental, Spain. The genus Nygolaimus Cobb, 1913. III. Description of N. diversus sp. n.

Summary:
Nygolaimus diversus sp. n. is described from natural biotopes in southeastern Spain. It is characterized by its medium body length (L=1.3-2.0 mm), asymmetrical lip region 12.5-15.0 µm wide offset by a weak constriction, deltoid mural tooth with its dorsal side 10.5-12.0 µm long or two-thirds to four-fifths of the lip region width, V=53-59%, rounded conoid tail (25-32 µm, c=43-63 and c'=1.1-1.4), makes unknown and females not containing sperm. Illustrations and a table of morphometrics are provided.

Key words: Nygolaimus diversus sp. n., Spain, taxonomy.

De Ley, P. and Coyne, D.L.

Actinca irmae sp. n., a new species of Actinolaimidae (Nematoda: Dorylaimida) from Ivory Coast.

Summary:
Actinca irmae sp. n. was found in three soil samples from rice fields in Gagnoa, Ivory Coast. It is characterized by having a peg-like cuticular ornamentations anteriorly in the neck region and in having males with a total of 20-26 pseudosupplements, including two subventral rows of 5-7 pseudosupplements lying anterior to the first fascicle. The structure of the cheilostom is also distinctive, having a post-onchial part that is strongly constricted just anterior to the guiding ring and is 11-13 um long, distinctly sclerotized and expanded over most of its length. The new species is further characterized by a relatively well-developed vestibular ring, a slightly expanded lip region that is wider than high, a slender 27-31 um long odontostyle and 14 cuticular ridges. As A. irmae sp. n. combines features of the genera or subgenera Actinca and Stomachoglossa it is proposed that the latter be considered a junior synonym of the former.

Key words: Actinca irmae sp. n., Ivory Coast, taxonomy, morphology, SEM.

Miduturi, J.S., Waeyenberge, L. & Moens, M.

Natural distribution of entomopathogenic nematodes (Heterorhabditidae and Steinernematidae) in Belgian soils.

Summary:
In eight provinces of Belgium, 248 soil samples were collected in 72 ecologically diverse habitats to isolate indigenous entomopathogenic nematodes (epns). Using the Galleria larva bait technique, 21 soil samples were found positive for epns. The morphometric study of infective juveniles (IJs) classified 20 populations as Steinernema spp., and one population as Heterorhabditis sp. Further biochemical characterization differentiated eight Steinernema feltiae A1 type, eight S. affinis, four Steinernema sp. B3 and one Heterorhabditis megidis (northwest European type). The entomopathogenic nematodes were recovered from 38.1%, 28.5%, 23.8% and 9.6% of the samples taken in woodland, roadside verges, cultivated land and grassland respectively. Steinernema feltiae A1 type was isolated in all the habitats except in roadside verges, whereas, S. affinis was not found in cultivated land. Steinernema sp. B3 was isolated from cultivated fields and roadside verges; H. megidis from grassland. Steinernema feltiae was prevalent in sand to loamy sand soils with a wide range of organic matter content. Steinernema affinis was recovered in sand and sandy clay loam soils. Heterorhabditis sp. and Steinernema sp. B3 were isolated in sandy loam and loam soils with organic matter content of 5.6% and 7.5% respectively. All isolates were found in soils with a pH range of 3.6-7.8. However, most of the S.feltiae populations were isolated in acidic soils.

Key words: entomopathogenic nematodes, morphometrics, habitat, soil type, RFLPs

Miduturi, J.S., Moermans, R. and Moens, M.

Distribution of entomopathogenic nematodes in a grassland

Summary:
The distribution of Steinernema feltiae and Heterorhabditis megidis (NWE type) in a grassland habitat was studied during autumn 1994. Larvae of the wax moth, Galleria mellonella, were used as bait. Results indicated an aggregated distribution for both species. Sand fraction and organic matter content did not always influence the distribution of the nematodes. Largest numbers of S. feltiae were detected in samples with a sand fraction content higher than 90%. The area in which H. megidis was detected, was somewhat limited and had a sand fraction greater than 94%. Numbers of S. feltiae were negatively influenced by higher organic matter content.

Key words: aggregation, granulometry, organic matter