NOTES ON SOME PLANT-PARASITIC NEMATODES FROM SOUTH AMERICA BY ESTHER VAN DEN BERG1) and JUAN HEYNS2) 1)National Collection of Nematodes, Biosystematics Division, Plant Protection Research Institute, P/Bag X134, Pretoria, 0001 South Africa; 2)Department of Zoology, Rand Afrikaans University, P.O. Box 524, Auckland Park, 2006 South Africa Plant-parasitic nematodes were studied from several localities in Chile, Brazil and French Guiana. Measurements, new information on the morphology and illustrations consisting of draw- ings and SEM photos are given for Criconema annuliferum, Criconema orellanai and Hoplolaimus diadematus. Tylenchorhynchus queirozi and Xiphinema krugi are also recorded. Keywords: Brazil, Chile, Criconema, French Guiana, Hoplolaimus, Nematoda,
Hirschmanniella caribbeana sp. n. is described and figured from mangrove
vegetation from Guadeloupe. Females are characterised by the tail terminus
having two lateral peg-like projections with a smaller, irregular
intermediate projection, a low, rounded lip region with five to six annuli,
a 17-20 μm long stylet, areolated lateral fields, intestine not overlapping
the rectum and phasmids situated at midtail. Males numerous, similar to
females except for sexual characters. Juvenile tail ends in a single, thin,
pointed mucro. Notes, morphometrics, descriptions and figures are given for
Pratylenchus flakkensis, P. jordanensis, P. teres and P. loosi all new
records for this region. Hirschmanniella caribbeana sp. n. provenant de
mangrove de Guadeloupe est décrit et illustré. Les femelles sont
caractérisées par l’extrémité de la queue munie de deux projections
latérales digitées encadrant une autre projection plus petite et
irrégulière, une région céphalique basse, arrondie, comportant cinq à six
anneaux, un stylet long de 17-20 μm, des champs latéraux aréolés, l’intestin
ne recouvrant pas le rectum et les phasmides situées au milieu de la queue.
Les mâles, nombreux, sont semblables aux femelles à l’exception des
caractères sexuels. L’extrémité de la queue des juvéniles porte un mucron
simple, pointu et fin. Des notes, des mensurations, des descriptions et
illustrations sont données pour Pratylenchus flakkensis, P. jordanensis, P.
teres et P. loosi, toutes espèces signalées pour la première fois dans cette
Criconema zantene n. sp., found in the rhizosphere of a Podocarpus sp. tree,
is described and illustrated. Females are characterised by having 46-56 body
annuli covered with tile-like scales, stylet 101-122 μm long, one lip
annulus with a greater diameter than first body annulus, distinct submedian
lobes, tooth-like lobes on posterior body annuli with a double row of lobes
on first annulus directly posterior to vulva, a sigmoid vagina and an
overhanging anterior vulval lip. Second, third and fourth stage juveniles
with varying numbers of longitudinal rows of filamented scales on cuticle.
Criconema princeps (Andrássy, 1962) Raski & Luc, 1985, Mesocriconema
dherdei (De Grisse, 1967) Loof & De Grisse, 1989 and Paratylenchus
straeleni (De Coninck, 1931) Oostenbrink, 1960 are reported from South
Africa for the first time. These species are briefly discussed, illustrated
and morphometrics given. Additional data is given for C. pauciannulatum Van
den Berg, 1992.
NEW RECORDS AND DESCRIPTIONS OF PLANT NEMATODES FROM RAIN FOREST SOIL IN FRENCH GUIANA, WITH A FIRST DESCRIPTION OF MALES OF MESOCRICONEMA SURINAMENSE (DE GRISSE & MAAS, 1970) LOOF & DE GRISSE, 1989 (TYLENCHIDA: NEMATA) BY ESTHER VAN DEN BERG1), P. QUÉNÉHERVÉ2) and L. TIEDT3) 1)Biosystematics Division, Plant Protection Research Institute, Private Bag X134, Pretoria 0001, South Africa; 2)Nematology Unit, ORSTOM-INRA, Centre ORSTOM, BP 8006, 97259 Fort de France, Martinique; 3)Electron Microscope Unit, Potchefstroom University for Christian Higher Education, Potchefstroom 2520, South Africa Redescriptions are given for Mesocriconema surinamense (De Grisse & Maas, 1970) Loof & De Grisse, 1989, associated
Pin nematodes of the genus Paratylenchus are widely distributed
across the world and associated with many plant species. Morphological
identification of Paratylenchus species is a difficult task
because it relies on many characters with a wide range of intraspecific
variation. In this study we provide morphological and molecular characterisation
of several pin nematodes: Paratylenchus aquaticus, P.
dianthus, P. hamatus, P. nanus
and P. straeleni, collected in different states of the USA and
South Africa. Paratylenchus aquaticus is reported from South
Africa and Hawaii and P. nanus is found from South Africa for
the first time. Morphological descriptions, morphometrics, light and scanning
electron microscopic photos and drawings are given for these species. Molecular
characterisation of nematodes using the D2-D3 of 28S rRNA and ITS rRNA gene
sequence revealed that samples morphologically identified as P.
aquaticus, P. hamatus and P.
nanus indeed represent species complexes containing several
species. Sequences of the rRNA genes are also provided for several unidentified
Paratylenchus. Phylogenetic relationships within the genus
Paratylenchus are given as inferred from the analyses of
the D2-D3 of 28S rRNA and ITS rRNA gene sequences. We present here the most
complete phylogenetic analysis of the genus.
The association between the burrowing nematode Radopholus similis and giant
swamp taro is studied in detail for the first time in corms collected from
swampy taro patches in Yap, one of the states of the Federated States of
Micronesia. The R. similis population from Yap displays similar variation in
morphometrics and morphology as reported in the literature. The rot caused
by the nematodes is wet with a loose mass of brown dead tissues and a deep
brown necrotic centre housing nematodes inside. Usually, the infected
tissues spread a disgusting odour typical of this disease. The dead tissues
progress into shallow to deep cavities that advance towards the edible,
central portion of the corm giving a perforated appearance on the outside of
the otherwise smooth corm. The disease becomes more severe as the age of the
plant increases. Nematode-infected plants seldom show any above-ground
symptoms. The market quality of the corm is greatly reduced by the nematode
damage. The widespread occurrence of the disease and the type of damage R.
similis causes to the corms pose a serious threat to giant swamp taro
production, food security and the continuation of traditional customs on
those islands where R. similis occurs.
The genus Scutellonema contains more than 40 species of spiral nematodes with enlarged phasmids called scutella. In this study, we provide morphological and molecular characterisation of S. clavicaudatum sp. n., S. brachyurus, S. bradys, S. cavenessi, S. transvaalense, S. truncatum and Scutellonema sp. A. from North and Central America, and Africa. The new species, S. clavicaudatum sp. n., was found on sugarcane in South Africa and is characterised by a lack of lip annuli as in S. africanum, S. siamense and S. truncatum. The lip region, in both males and females, is conical and marked by six large rectangular blocks separated or fused with the submedian and lateral lip sectors, which surround a round and distinct labial disc. Females of this new species also have large vaginal glands, a functional spermatheca, the lateral field posterior to the scutellum ending in a bluntly pointed shape and a clavate tail. Morphological descriptions, measurements, light and scanning electron microscopic photos and drawings are also given for S. bradys, S. cavenessi, S. transvaalense and S. truncatum. The study of spiral nematode samples from Florida, USA, confirmed the presence of a morphologically and genetically atypical populations of S. bradys. The morphology of the S. bradys population from Bermuda grass in pasture land from central Florida fits that of type specimens of this species, but differs in having a truncate tail terminus rather than round and also a prominent spermatheca filled with flagellate spermatozoa. Other Florida Scutellonema samples analysed in this study belonged to S. cavenessi, a species native to West Africa. This is the first report of S. cavenessi in Florida, where it parasitises the ornamental plant Sansevieria trifasciata. Our study showed a high level of intraspecific variation for Scutellonema rRNA and mtDNA genes, which can reach 5.6% for the D2-D3 of 28S rRNA, 12.9% for the ITS rRNA genes and 14.4% for the COI gene. Phylogenetic relationships within Scutellonema are given as inferred from the analyses of the D2-D3 of 28S rRNA, ITS rRNA and the COI mtDNA gene sequences.
During recent collections in South Africa, two species of Criconemoides were found. Criconemoides brevistylus is described and illustrated from a golf course in KwaZulu-Natal Province. It is compared with several closely related species, and three previously described species (C. helicus, C. onostris and C. paronostris) are regarded as junior synonyms of C. brevistylus. Criconemoides obtusicaudatus is described and illustrated from a maize field in Limpopo Province. The male of the species is described for the first time. Molecular characterisation of C. brevistylus and C. obtusicaudatus using the D2-D3 expansions segments of 28S rRNA and ITS rRNA gene sequences are provided. Phylogenetic relationships of these species with other Criconemoides are discussed.
Two Hemicycliophora species, H. lutosa and H. typica, found in samples from fallow soil and sugarcane soil in South Africa, were studied morphologically and, for the first time, molecularly. Diagnostic PCR-IT-rRNA-RFLP profiles generated by five restriction enzymes are provided. Study of phylogenetic relationships using D2-D3 expansion segment of 28S rRNA gene sequences revealed that H. lutosa was related to H. poranga. Hemicycliophora lutosa and H. poranga are compared morphologically. SEM photographs are given for H. typica and for H. lutosa for the first time. The male of H. typica represents a first report for South Africa.
Caloosia longicaudata is described from Maui, the Hawaiian Islands, for the
first time and both sexes are characterised morphologically using light and
scanning electron microscopy. Molecular characterisation of C. longicaudata
using the D2-D3 domain of 28S rRNA, partial 18S rRNA and ITS rRNA gene
sequences is also provided. The phylogenetic relationships of this species
with other representatives of the suborder Criconematina are presented and
discussed. A diagnostic PCR-ITS-RFLP profile for C. longicaudata is given
together with an identification table for eight species of Caloosia.
Caloosia langola n. comb. is transferred to the genus and C. shorai is
synonymised with H. psidii.