Volume 10, Part 2 (2002)
D.G. Karpouzas and I.O.
Biodegradation and enhanced biodegradation: a reason for
reduced biological efficacy of nematicides, 59-78
R. Peña-Santiago, B. Torres and G.
Nematodes of the order Dorylaimida from Andalucía Oriental, Spain. The genus Discolaimus
Cobb, 1913. II. Two previously known species, with comments on their taxonomy, 79-88
Crozzoli and F. Lamberti. Species of Criconema
Hofmänner & Menzel, 1914 and Ogma Southern, 1914 occurring in Venezuela, with description of Ogma araguaensis sp. n.
(Nematoda: Criconematidae), 89-98
Lamberti, S. Molinari, M. Moens and D.J.F. Brown.
The Xiphinema americanum-group. II. Morphometric relationships, 99-112
R. Neilson and B. Boag.
Marine nematode associations from an intertidal estuarine biotope, 113-121
J. Zheng, C. Pan, C. Furlanetto, R. Nielson and D.J.F. Brown.
The morphology of the odontophore of Longidorus litchii Xu
& Cheng, 1992 (Nematoda: Longidoridae), 123-126
A. Fürst von Lieven. The sister group of the Diplogastrina (Nematoda), 127-137
S.A. Subbotin, D. Sturhan, H.J. Rumpenhorst and M.
Description of the Australian cereal cyst nematode Heterodera australis
sp. n. (Tylenchida: Heteroderidae), 139-148
and Giannakou, I.O.
Biodegradation and enhanced biodegradation: a reason for reduced biological efficacy of
The phenomenon of enhanced
biodegradation of fumigant and non-fumigant nematicides is reviewed. Several
cases of reduced nematode control have been linked with rapid microbial
degradation of nematicides by a specialized fraction of the soil microflora that
has adapted to rapidly metabolize specific nematicides. The mechanisms involved
in the development of enhanced degradation are described. High soil pH and
optimal moisture and temperature conditions favour the development of enhanced
biodegradation in soils. However, the persistence of enhanced biodegradation in
the absence of further nematicide applications and the existence of
cross-enhancement amongst nematicides are the most important factors controlling
the practical significance of the phenomenon. The susceptibility shown to
enhanced biodegradation by the majority of the currently available nematicides
might intensify the problem in the future compared with the current situation.
Sufficient chemical rotation i.e., the use of active ingredients from
different chemical groups, in combination with crop rotation and use of
resistant cultivars may help to limit the establishment of enhanced
biodegradation of nematicides in soils.
Key words: enhanced biodegradation, nematicides, soil microorganisms.
Peña-Santiago, R., Torres, B.
and Liébanas, G.
Nematodes of the order Dorylaimida from Andalucía Oriental, Spain. The genus
Cobb, 1913. II. Two previously known species, with comments on their taxonomy
Two close known species of the genus Discolaimus, D. major and D. agricolus, are described and illustrated, including SEM
obervations, from material collected in southeastern Spain. The identity and
the taxonomy of both species are discussed and new criteria for their
separation are proposed. A revision of data from literature reveals that D. major is the most widely distributed Discolaimus species in the world, but
also that some of its previous records may be doubtful and/or erroneous. D. paramajor and D. perplexans are considered new junior synonyms of D. major.
Key words: description, Discolaimus, new synonyms, Spain,
Crozzoli, R. and Lamberti, F.
Species of Criconema
Hofmänner & Menzel, 1914 and Ogma Southern, 1914 occurring in Venezuela, with description of
Ogma araguaensis sp. n. (Nematoda: Criconematidae)
Five known species of Criconema Hofmänner & Menzel, 1914 and two of Ogma Southern, 1914 and Ogma araguaensis
sp. n. are described from Venezuela. Additional morphometric information is
provided on C. californicum (Diab & Jenkins, 1966) Siddiqi, 1986, C.
calvum (Raski & Golden, 1966) Raski & Luc, 1985, C. demani Micoletzky, 1925, C. mutabile (Taylor, 1936) Raski &
Luc, 1985, C. sphagni Micoletzky, 1925, O. civellae (Steiner, 1949)
Raski & Luc, 1987, and O. decalineatum (Chitwood, 1957) Andrássy, 1979. C.
californicum, C. calvum, C. sphagni and O. decalineatum constitute new records from Venezuela. O. araguaensis sp. n. resembles O. murray Southern, 1914 and Ogma crenulatum Wouts, Yeates & Loof, 1999 from which it differs in its shorter body and more anterior vulva.
Dichotomous identification keys to the species of Criconema and Ogma
occurring in Venezuela are provided.
Key words: Criconema, dichotomous key,
Lamberti, F., Molinari, S., Moens, M. and Brown, D.J.F.
The Xiphinema americanum-group. II. Morphometric relationships
cluster analysis based on morphometrics placed 117 populations, representing 39
putative species, of the Xiphinema
americanum group into four clusters. Cluster 1 consisted of three
populations identified as X. brevisicum;
Cluster 2 consisted of five sub-clusters of populations; and Clusters 3 and 4
each consisted of seven sub-clusters. When several populations ascribed to a
putative species were used, they usually clustered with a low range of
variability, thus confirming their similarity. A population that had been
identified as representing X. diffusum and
another as being X. incognitum were
placed in clusters different from that which characterized the rest of the
populations of each species, respectively. Populations identified as
X. americanum sensu stricto, X.
thornei, X. santos and X. pachydermum were placed in 2 and 3
different sub-clusters within the same major cluster. Conversely, several
populations of X. madeirense, X. duriense, X. simileand X.
pachtaicum had a low coefficient of dissimilarity (<2.8), which is
considered as being indicative of intra-specific variability. Four populations,
each identified as representing X.
pachydermum, were placed in three different sub-clusters of Cluster 4, thus
indicating wide morphometric variability for this putative species.
Key words: hierarchical cluster analysis, intra-specific variability, morphometrics, nematodes.
Neilson, R. and Boag, B.
Marine nematode associations from an intertidal estuarine biotope
Correlations between the 20 most prevalent marine
nematode species from an intertidal estuarine biotope and sedimentary
ecological factors yielded few significant relationships. Seven of the 20
nematode species were significantly correlated with distance from a pollution
source, although few nematode species were correlated with concentrations of
six different heavy metals and organic C. Sediment particle size was
significantly correlated with only three species suggesting that as a single
factor it had little impact on nematode distributions. The chi-squared test for
contingency that tests the joint occurrences between species and indicates the
statistical significance of their relationships was applied to the same 20
nematode species. Species abundance data were also analysed to determine
whether any correlations existed between species. Many species in this study
were significantly associated or correlated with each other. This contrasted
with previous studies that reported nematode species from both deep-sea and estuarine
biotopes were negatively associated.
Key words: associations, estuarine, intertidal, spatial
Zheng, J., Pan, C., Furlanetto, C., Nielson, R. and Brown, D.J.F..
The morphology of the odontophore of Longidorus litchii Xu
& Cheng, 1992 (Nematoda: Longidoridae)
The morphology of the odontophore of Longidorus
litchii Xu & Cheng, 1992, is described and depicted in photomicrographs
from specimens collected from the locality of the type habitat i.e. clay soil around roots of litchi
trees (Litchi chienesis Sonn) in Zhangzhou,
Fujian province, eastern China.The odontophore is swollen and has a tri-radiate
base containing well developed flanges.These taxonomically important
characteristics were not reported in the original description of the species.
Key words: basal flanges, China,
Litchi chienesis, Longidoridae, plant nematode.
Fürst von Lieven, A.
The sister group of the Diplogastrina (Nematoda)
This paper presents arguments for a sister group
relationship between diplogastrids and bunonematids. Five synapomorphies were
found to substantiate this hypothesis. The pattern of genital papillae in Bunonema pini is homologized with that
of diplogastrids. The question whether the stem species of diplogastrids
possessed a bursa or not is discussed.
Key words: Bunonema, bursa,
genital papillae, haustrulum, pharyngeal sleeve.
Subbotin, S.A., Sturhan, D., Rumpenhorst, H.J. and Moens, M.
Description of the Australian cereal cyst nematode
Heterodera australis sp. n. (Tylenchida: Heteroderidae)
Populations of cereal
cyst nematode sampled in Australia are described as a new species, Heterodera
australis sp. n. This species is morphologically and morphometrically similar
to H. avenae. It is distinguished from H. avenae and other species of the
avenae complex by sequence and RFLP of the ITS region of rDNA and IEF patterns.
The phylogenetic relationships among species of the H. avenae complex based on
analyses of the ITS-rDNA sequences are presented.
Key words: Australia, cereals, Heterodera avenae, IEF,