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Volume 15, Part 1 (2007)



Sirca, S., Geric Stare, B., Mavric Plesko, I., Virscek Marn, M. and Urek, G.

First record of Longidorus juvenilis and L. leptocephalus (Nematoda: Dorylaimida) in Slovenia and their morphometrical and ribosomal DNA sequence analysis

Summary:
Longidorus juvenilis and L. leptocephalus are reported from Slovenia for the first time. All developmental stages of these species were recovered from the rhizosphere of Vitis vinifera L. growing in the north-eastern part of Slovenia. Nematodes were identified using morphological characters of females and juveniles. All these stages are described. A bivulval female of L. juvenilis is also described. In addition, sequences of the D2-D3 expansion region of 28S rRNA gene were analysed. Obtained sequences were compared with sequences of the same and closely related species downloaded from the NCBI database. Cluster analysis of sequences confirmed and supported species identifications. The sequences of L. juvenilis and L. leptocephalus found in Slovenia and sequences of the same species from databank clustered in two separate clades, respectively. Both clades were supported in bootstrap analyses.

Key words: Vitis, rhizosphere, identification, Longidoridae, morphology, 28S rDNA.



Fatemy, S., Parvizi, R. and Greco, N.

Response of sugar beet to population of Heterodera schachtii in microplots in Iran

Summary:
Two experiments were conducted in microplots in Iran, in 2002 and 2003, to relate a range of population densities of the sugar beet cyst nematode, Heterodera schachtii, to yield of sugar beet and reproduction of the nematode. Microplots consisted of clay pots and contained 12 kg soil infested with 0, 0.25, 0.50, 1, 2, 4, 8, 16, 32, 64 or 128 eggs of H. schachtii g(-1) and each inoculum level was replicated eight times. At harvest, weights of sugar beet tap roots were fitted to the Seinhorst's model. Tolerance limits of sugar beet to H. schachtii were 0.62 egg g(-1) soil in 2002 and 1.16 eggs g(-1) soil in 2003 with all average of 0.8 egg g(-1) soil for both years. Average yield losses of 20, 50, and 80% occurred at population densities of tile nematode at sowing of 5, 14, and 40 eggs g(-1) soil, respectively. The reproduction rate of the nematode decreased with the increase of nematode population at sowing and maximum rates of 79.6 and 86.0-fold occurred at the lowest initial population density of 0.25 egg g(-1) soil in 2002 and 2003, respectively. The largest nematode density (84.6 eggs g(-1) soil) occurred at the highest inoculum density. The equilibrium density of the nematode was less than 64 eggs g(-1) soil and all average population decline of 55.5% was observed in the microplots left fallow.

Key words: Beta vulgaris , sugar beet cyst nematode, reproduction rate, tolerance limit, yield loss.



Seijas, I., Hernandez, M.A., Abolafia, J., and Pena-Santiago, R.

Tylencholaimus gallaicus sp. n. (Dorylaimida, Tylencholaimidae) from Galizia, NW Iberian Peninsula

Summary:
A new dorylaimid species, Tylencholaimus gallaicus sp. n., is described and illustrated, including LM and SEM pictures, from NW Iberian Peninsula. It is characterized by its very small body (L = 0.30-0.46), lip region rather rounded and lacking perioral disc, odontostyle 5-6 Ám long or shorter than lip region width, anterior region of the pharynx weakly muscular and extending abruptly, pharyngeal expansion occupying one-third to two-fifths of total neck length, female genital system monodelphic-prodelphic, vulva posterior (V=60-67), tail conical and slightly ventrad curved (20-28 Ám, c=12-19, c=1.6-2.4), spicules 18 mu m long and four ventromedian supplements. The new species is very close to T. minutus Vinciguerra, 1986, but it can be separated from this in having rounded shape of lip region (vs typical cap-like) lacking perioral differentiation (vs inner region of lips distinctly separated from the rest, with disc-like appearance under LM), more anterior vulva (vs V=67-73), longer tail (vs c=19-27), and four ventromedian supplements (vs two).

Key words:  Iberian Peninsula; morphology; new species; taxonomy; Tylencholaimus nematode.



Ansari, M.A., Waeyenberge, L. and Moens, M.

Natural occurrence of Steinernema carpocapsae, Weiser, 1955 (Rhabditida: Steinernematidae) in Belgian turf and its virulence to Spodoptera exigua (Lepodoptera: Noctuidae)

Summary:
During a routine survey for the white grub, Hoplia philanthus Fuessly (Coleoptera, Scarabaeidae), in turf fields, we isolated entomopathogenic nematodes from one out of 40 soil samples. The morphology and morphometrics identified the isolate as Steinernema carpocapsae. The ITS-rDNA sequence confirmed the identification. This is the first report of S. carpocapsae from Belgium. In laboratory assays the isolate demonstrated a virulence to Spodoptera exigua Hubner (Lepidoptera: Noctuidae) comparable to two commercial strains and two other strains kept in laboratories. All tested isolates including the Belgian strain caused high mortality to S. exigua larvae.

Key words: biological control; entomopathogenic nematode; ITS regions; natural occurrence; soil survey; virulence


Trdan, S., Znidarcic, D. and Vidrih, M.

Control of Frankliniella occidentalis on glasshouse-grown cucumbers: an efficacy comparison of foliar application of Steinernema feltiae and spraying with abamectin

Summary:
In a glasshouse experiment, the effectiveness of the entomopathogenic nematode Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) was compared with abamectin for the control of western flower thrips,Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) on slicer cucumbers. In a period from mid June to the end of August, cucumbers were grown in four different growth substrates: expanded perlite, expanded vermiculite, light expanded clay aggregate and peat. A suspension of entomopathogenic nematodes (2500 infective juveniles ml(-1)) was applied to cucumber leaves nine times in one growing season, whilst insecticide at recommended dose (22.5 g a.i. ha(-1)) was used three times. A significant effect of the extent of pest damage to the leaves (assessed by a six grade scale) was determined only for treatment type (nematodes, insecticide and untreated control), but not for the type of growth substrate or the damage evaluation date (16 July, 3 August, and 23 August). The leaves of cucumbers treated with nematodes and insecticide were significantly less damaged than untreated plants, with damage never exceeding 10% of the leaf surface. Nevertheless, type of growth substrate showed a significant effect on the number of fruits as well as on the mean mass of fruits. Light expanded clay aggregate was seen to be the least appropriate growth substrate, whilst the other three substrates can all be recommended for cucumber growing. The mean mass of fruits was also significantly influenced by type of suppression, with the mean mass of fruits in treated plants being significantly higher (from 7 up to 51%) than in untreated plants. The mean number of fruits per plant did not differ significantly between different types of pest suppression. Spraying nine times with nematodes and three times with abamectin gave similar efficacy against western flower thrips on glasshouse-grown slicer cucumbers.

Key words: biological control; cucumbers; entomopathogenic nematodes; greenhouse; insecticide; Rhabditida; Steinernematidae; Thysanoptera; Thripidae; western flower thrips

 


Choi, H., Kim, J., Shin, S.C, and Park, II.K.

Nematicidal activity of monoterpenoids against the pine wood nematode (Bursaphelenchus xylophilus)

Summary:
he nematicidal activity of twenty-six naturally occurring monoterpenoids was evaluated with a 96-microwell plate bioassay against the pine wood nematode, Bursaphelenchus xylophilus. Responses varied with test compounds and dose. Good nematicidal activity against male, female and juvenile nematodes of B. xylophilus was achieved with carvacrol, thymol, geraniol, nerol, (-)-menthol, beta-citronellol, (+/-)-citronellal and citral (mix. of cis and trans). Phenol, alcohol and aldehyde compounds were generally more toxic to B. xylophilus. Carvacrol and thymol showed the most potent nematicidal activity among test compounds. LC50 values of thymol and carvacrol against juvenile nematodes were 0.096 and 0.099 mg ml(-1), respectively. Citral and citronellol showed similar toxicity to juvenile nematodes. Citronellal was more toxic to juvenile nematodes (LC50 = 0.253 mg ml(-1)) than geraniol (LC50 = 0.417 mg ml(-1)). LC50 values of nerol and menthol against juvenile nematodes were 0.979 and 1.021 mg ml(-1), respectively. LC50 values of the other test compounds and trunk-injection nematicide, levamisole hydrochloride, were > 1.0 mg ml(-1) within 4 hours after treatment.

Key words:  Bursaphelenchus xylophilus; carvacrol; rnonoterpenoids; nematicidal activity; pine wood nematode; thymol

 


Jana, T., Chatterjee, A. and Manna, B.

Iotonchus cuticaudatus sp. n., a new mononchid species from West Bengal, India with an unusual case of bivulvarity

Summary:
A new species in the genus Iotonchus Cobb, 1916 from the district South 24-Parganas, West Bengal, India is described and illustrated herein. Fourteen female and seven male specimens of this species were collected. Body large (female: 2.8-3.0 mm; male: 2.3-3.1 mm), J-shaped after fixation, buccal cavity large but narrow (female: 56.6-66.6 x 33.3-36.6 Ám; male: 50-56.6 x 26.4-30.0 Ám), a small dorsal tooth at the base of the buccal cavity, females amphidelphic, ovary reflexed, sphincter at oviduct-uterus junction, advulval papillae present in female; long tail, caudal pore present, caudal glands conspicuous and spinneret terminal, cuticle at the tail terminus swollen. One female specimen was found possessing two vulva.

Key words:  bivulvarity; Iotonchus; Mononchida; new species; taxonomy

 


Tanha Maafi, Z., Sturhan, D., Kheiri, A. and Geraert, E.

Species of the Heterodera avenae group (Nematoda : Heteroderidae) from Iran

Summary:
Five species of cyst-forming nematodes belonging to the Heterodera avenae group were identified from cereal fields and grasslands in Iran. Morphological and morphometric characters of H. avenae, H. filipjevi and a still unidentified species from the H. avenae complex and of H. latipons and H. hordecalis from the H. latipons complex are presented and their relationship with similar species is discussed. Heterodera filipjevi and H. latipons are the dominant species in cereal fields; H. avenae was found in wheat fields in only one region in the west of the country. Heterodera hordecalis was recovered from a few wheat fields and around grasses in western Iran, and Heterodera sp. from grasslands at several sites in northern and western regions of the country.

Key words:  cyst nematodes; Heterodera avenae; Heterodera filipjevi; Heterodera hordecalis; Heterodera latipons; Iran; morphology

 



Spiridonov, S.E. and Zograf, J.K.

SEM study of egg-shell formation in the nematodes of the genus Binema (Chitwoodiellidae, Thelastomatoidea, Oxyurida)

Summary:
Formation of the egg-shell of the oxyurid nematode Binema sp. was studied using SEM. The surface of the fully formed ellipsoid egg-shell of Binema sp. bears filaments on both polar areas. During the early stages of the egg-shell formation, the equatorial surface of the shell is covered with tightly connected projections of 0.6-1.0 Ám height. The polar filaments are only 0.5 Ám thick at the earliest stage observed. Fully formed egg-shells are smoother than the earlier stages, being covered with 0.13-0.17 Ám diameter pits scattered throughout the surface. The middle cylindrical part of the polar filaments is 0.7-0.9 Ám in diameter. The distal parts of the Filaments are flattened into very thin (less than 0.05 Ám) lamellae. Lamellac of filaments originating from the same pole of the egg-shell are tied together. Binema sp. females lay eggs in pairs, with egg filaments of two adjoining eggs interwoven by their lamellar parts.

Key words:  Binema; egg-shell; mole-cricket nematodes; morphology; SEM



Sasanelli, N., Anton, A., D'Addabbo, T and Takacs, T.

Nematicidal properties of leaf extracts of Ruta graveolens inoculated with arbuscular mycorrhizal fungi

Summary:
The effect of arbuscular mycorrhizal fungi (AMF) oil the nematicidal activity of rue (Ruta graveolens) against the root-knot nematodes, Meloidogyne incognita and M. javanica, was studied in two in vitro experiments. In the first experiment, egg masses of M. incognita and M. javanica were immersed for 3 weeks in aqueous leaf extracts of rue plants non-inoculated or previously inoculated with Glomus mosseae or mixed AMF strains (Sclerocystis sinuosa, Glomus claroideum-1, G. claroideum-2 and G. claroideum-3). Thereafter, the hatching test continued in distilled water for a further 5 weeks. In the second experiment, egg masses of both Meloidogyne species were exposed to the different rue extracts for 4, 8 and 16 h and then incubated in distilled water for 8 weeks. Distilled water and 5 mu g ml(-1) aqueous solution of tile nematicide fenamiphos were used as controls. In the first experiment the emergence of juveniles from eggs of both Meloidogyne species was suppressed by R. graveolens extracts after the first week, with no significant differences among the treatments. Hatching in extracts of R. graveolens was significantly lower than that in water control or fenamiphos solution. Frequencies of AMF infection oil the root of rue were 93 and 97% for G. mosseae and mixed AMF, respectively. In tile second experiment a 4 h immersion of M. incognita egg masses in the extract from R. graveolens + mixed AMF reduced egg hatch compared with distilled water. Other extracts significantly suppressed final hatch of both Meloidogyne species only after 16 h of exposure. Both AMF populations significantly increased the growth of R. graveolens but the nematicidal activity of rue leaf extracts was not affected by inoculation of plants with AMF.

Key words:  Glomus spp.; Meloidogyne spp.; nematicidal properties; Ruta graveolens; Sclerocystis sinuosa