First Report of Xiphinema rivesi (Nematoda, Longidoridae) in Washington State.

Dagger nematode, Xiphinema rivesi Dalmaso, 1969 reportedly transmits several viruses in North America and Europe (2) leading to severe yield reduction in crops. Soil samples were collected in March 2013 during a survey of cherry orchards in Chelan County, WA; these historically suffer from cherry rasp leaf disease, caused by Cherry rasp leaf virus (CRLV) (genus Cheravirus). Soil samples were transported to the WSDA nematology laboratory in Prosser, WA, where 250-cc subsamples were processed using sucrose centrifugal flotation (1). Dagger nematodes were hand-picked and stored in 0.1% sodium chloride before being sent to the USDA-ARS Nematology Laboratory in Beltsville, MD, for morphological and molecular identification. The morphological and molecular analysis of adult females identified the dagger nematode species as Xiphinema rivesi Dalmaso, 1969 (4). Morphological characters used for identification included female body, and total stylet length (odontostyle and odontophore), location of guiding ring from oral aperture, head and tail shape, various tail measurements, and vulva percentage in relation to body length. Measurements of females (n = 10) include a mean body length of 1,902 ± 162.4 (1,832 to 2,203) µm, odontostyle 83 ± 3.5 (80 to 90) µm, odontophore 54.8 ± 4.2 (50 to 65) µm, total stylet 137.8 ± 4.2 (130 to 145) µm, guiding ring from oral aperture 70 ± 5.1 (60 to 75) µm, tail 30.8 ± 2.5 (27.5 to 35.0) µm, body diameter at anus 24.7 ± 1.7 (22 to 28) µm, J (hyaline portion of tail) 6.0 ± 0.9 (5.0 to 7.5) µm, body diameter at beginning of J 8.5 ± 1.0 (7.5 to 10.5) µm, body diameter at 5 µm from tail terminus 7.5 ± 0.2 (7.0 to 8.0) µm, and V% 52.2 ± 1.8 (49.4 to 55.0) µm. Molecular diagnosis of X. rivesi was confirmed after DNA was extracted from two individual nematodes by mechanical disruption with a micro knife in 20 µl worm lysis buffer containing 500 mM KCl, 100 mM Tris-Cl (pH8.3), 15 mM MgCl2, 10 mM dithiothreitol (DTT), 4.5% Tween 20, and 0.1% gelatin. DNA extracts were stored at -80°C until needed, then thawed, 1 µl proteinase K (from 2 mg/ml stock) was added, and the tubes were incubated at 60°C for 60 min, followed by 95°C for 15 min. The 28S large ribosomal D2-D3 expansion segment was amplified with D2A (5'-ACAAGTACCGTGAGGGAAAGTT-3') and D3B (5'-TCGGAAGGAACCAGCTACTA-3'), and the internal transcribed spacer (ITS) region was amplified with primers TW81 (5'-GTTTCCGTAGGTGAACCTGC-3') and AB28 (5'-ATATGCTTAAGTTCAGCGGGT-3'), as previously described (3). To verify the identity of the sequences generated from PCR, sequenced products were subjected to a database search using BLAST. Sequences from the 28S region were >99% identical to several sequences of X. rivesi sampled from Spain (GenBank Accessions JQ990038, JQ990039, HM921357, and HM921358). Sequences from the ITS region were 97 to 98% identical to X. rivesi sequences (FR878063 to FR878066) obtained from the host Vitis vinifera from Italy. To the best of our knowledge, this is the first report of this nematode from the Washington. The quick and persistent spread of CRLV in most of the orchards visited calls for concern and there is need for urgent control measures against this vector nematode. References: (1) W. R. Jenkins. Plant Dis. Rep. 48:692, 1964. (2) S. Sirca et al. Plant Dis. 91:770, 2007. (3) Skantar et al. J. Nematol. 44:58, 2012. (4) M. R. Wojtowicz. et al. J. Nematol. 14:511, 1982.

Molecular and Morphological Characterization of the Corn Cyst Nematode, Heterodera zeae, from Greece.

The corn cyst nematode Heterodera zeae was detected in soil from an organic maize field in northern Greece. In greenhouse studies, reproduction of H. zeae was detected on maize plants (Zeae mays) using soil high in organic matter; the field was under winter fallow at the time of sampling. Maize plants were grown in a greenhouse with soil from the affected field used as inoculum. Females appeared after six weeks incubation, and abundant cysts were present after 12 weeks. Morphological and molecular diagnosis confirmed the presence of H. zeae in the field. Cysts were identified on the basis of cyst shape and characteristics of the cyst terminal cone, including nature of fenestration, presence of bullae, cyst wall pattern, and fenestral diameter. Second-stage juveniles were identified by body and stylet length, the shape of stylet knobs, shape and length of the tail and hyaline tail terminus, and by the number of lateral lines. Molecular analysis included amplification of the ribosomal internal transcribed spacer regions (ITS 1&2 rDNA) 28S large ribosomal subunit (LSU) D2-D3 expansion segment, and partial 18S small ribosomal subunit (SSU). Restriction fragment length polymorphism (RFLP) of ITS rDNA exhibited several unique enzyme patterns that may be diagnostically useful for H. zeae. These findings are in agreement with prior analysis of H. zeae populations from the U.S. and India. Phylogenetic relationships inferred from ITS rDNA are congruent with previous analyses that placed H. zeae in a clade with H. turcomanica, H. salixophila and species of the Humuli group. Phylogenetic trees based upon heat shock protein (Hsp90) coding sequence were in general agreement with a prior study using the same marker. This study represents the first record of H. zeae in Greece and the second report of this nematode in Europe.

Morphological and molecular characterization of Globodera populations from Oregon and Idaho.

An unusual population of cyst nematode was found in soils collected from a Powell Butte, OR field with a cropping history including potato, wheat, other crops, and significant weed presence. These nematodes could not be placed with certainty into any known species and exhibited some unique morphological features in some specimens. Compared with Globodera pallida, the cyst body length was slightly longer and the second-stage juvenile stylet length was slightly shorter. In some individuals, the J2 stylet knob height was greater and the tail annules were more prominent than in G. pallida, and the tail abruptly narrowed, with a slight constriction near the posterior third of the hyaline terminus. Compared with G. rostochiensis, the hyaline tail terminus had a larger number of refractive bodies, and cysts of this population had a smaller Granek's ratio and fewer cuticular ridges between the anus and vulva. In some individuals, the tail termini of second-stage juveniles were more bluntly pointed, and the stylet knobs were more anteriorly directed with greater height. Unlike G. tabacum, the cyst wall often lacked a network-like pattern and, in some individuals, the juvenile tail terminus distinctly narrowed after a constriction. Molecularly, the population was distinct from G. pallida, G. rostochiensis, and G. tabacum. Multiplex polymerase chain reaction of the internal transcribed spacer (ITS) rDNA region gave results similar to G. tabacum; however, ITS restriction fragment length polymorphism patterns were observed to have individual bands in common with G. rostochiensis and G. pallida. Phylogenetic analysis based on ITS1 and -2 rDNA sequences showed greatest similarity to populations from Argentina and Chile; together, they form a moderately supported clade, distinct from G. rostochiensis, G. tabacum, G. "mexicana," European type G. pallida, and several G. pallida populations from South America.

First Report of the Sting Nematode Belonolaimus longicaudatus on Soybean in Delaware.

In late July of 2005, several, large, irregular areas of severely chlorotic, stunted, and dead soybean plants were observed in two fields of soybean (Glycine max), 8.05 km apart, in sandy soil (94% sand, 2% silt, and 4% clay) in southwestern Sussex County, DE. The grower also had observed stunted corn the previous year in the same areas and thought the fields had a fertility problem. The morphology of adults and molecular analyses of the juveniles isolated from soil samples established the identity of the species as the sting nematode, Belonolaimus longicaudatus (1-4). The population density was 216 nematodes per 250 cm3 of soil. Morphological characters used for identification included female body, stylet and tail length, shape of head, stylet knobs, tail and tail terminus, number of lines in the lateral field, and vulva percentage in relation to body length. The male characters critical for identification were the following: body, stylet, spicule, and gubernaculum length; shape of head and stylet knobs; and number of lines in the lateral field. Measurements of females (n = 5) included body length (range = 2,035 to 2,120 µm, mean = 2,073.7, standard deviation [SD] = 37.0), stylet (117.0 to 127.5, 123.4, 4.5), V% (48.4 to 52.3, 50.6, 1.5), and tail (109 to 140, 120, 14.2). The lateral field had one incisure. Shape of head, stylet knobs, and tail were also consistent with B. longicaudatus. Males (n = 4) were characterized by the body length (range = 1,500 to 2,070 µm, mean = 1,753.3, SD = 290.2), stylet (117.0 to 127.5, 121.5, 5.4), spicules (41 to 50, 47, 5.2), and gubernaculum (17.0 to 18.5, 17.8, 0.8). Molecular diagnosis as B. longicaudatus was confirmed by sequencing two ribosomal DNA markers from three juveniles. Sequence of the internal transcribed spacer region ITS1 and 2 (GenBank Accession No. GQ896549) from this population was 99% identical to Florida isolate BlCi6 (DQ672368), and the 28S large ribosomal subunit D2-D3 expansion region (GQ896548) was 99% identical to Florida isolate BlCi4 (DQ672344). A high degree of similarity (>98%) was also shared by several other B. longicaudatus sequences (1). This detection represents a new state record in Delaware for B. longicaudatus. Since this detection in 2005, there have been no new reports of other observations of sting nematode or spread from these two fields tilled by the same farm operator in Delaware. Elsewhere, B. longicaudatus is known to occur in subtropical regions of the lower coastal plain, from Virginia to Florida and along the Gulf Coast into Texas. On the east coast, USDA Nematode Collection records document this nematode from Florida, Georgia, New Jersey, and South Carolina. Within Delaware, another sting nematode species, Belonolaimus maritimus, was detected on American beachgrass (Ammophila breviligulata) and bitter panicgrass (Panicum amarum var. amarulum) from Fenwick Island, near the Maryland border. Sting nematodes have also been reported in Burlington County, NJ. References: (1) U. Gozel et al. Nematropica 36:155, 2006. (2). H.-R. Han et al. Nematropica 36:37, 2006. (3) G. J. Rau. Proc. Helminthol. Soc. Wash. 25:95, 1958. (4) G. J. Rau. Proc. Helminthol. Soc. Wash. 30:119, 1963.

Molecular rDNA phylogeny of Telotylenchidae Siddiqi, 1960 and evaluation of tail termini.

Three stunt nematode species, Tylenchorhynchus leviterminalis, T. dubius and T. claytoni were characterized with segments of small subunit 18S and large subunit 28S rDNA sequence and placed in molecular phylogenetic context with other polyphyletic taxa of Telotylenchidae. Based upon comparably sized phylogenetic breadth of outgroups and ingroups, the 28S rDNA contained three times the number of phylogenetically informative alignment characters relative to the alignment total compared to the larger 18S dataset even though there were fewer than half the number of taxa represented. Tail shapes and hyaline termini were characterized for taxa within these subfamily trees, and variability discussed for some related species. In 18S trees, similar terminal tail thickness was found in a well-supported clade of three Tylenchorhynchus: broad-tailed T. leviterminalis branched outside relatively narrow-tailed T. claytoni and T. nudus. Terminal tail thickness within Merliniinae, Telotylenchinae and related taxa showed a mosaic distribution. Thick-tailed Trophurus, Macrotrophurus and putative Paratrophurus did not group together in the 18S tree. Extremely thickened tail termini arose at least once in Amplimerlinius and Pratylenchoides among ten species of Merliniinae plus three Pratylenchoides, and three times within twelve taxa of Telotylenchinae and Trophurinae. Conflicting generic and family nomenclature based on characters such as pharyngeal overlap are discussed in light of current molecular phylogeny. Contrary to some expectations from current taxonomy, Telotylenchus and Tylenchorhynchus cf. robustus did not cluster with three Tylenchorhynchus spp. Two putative species of Neodolichorhynchus failed to group together, and two populations of Scutylenchus quadrifer demonstrated as much or greater genetic distance between them than among three related species of Merlinius.

Morphological and molecular characterization of Pratylenchus lentis n. sp. (Nematoda: Pratylenchidae) from Sicily.

Pratylenchus lentis n. sp. parasitizing roots of lentil in Sicily, Italy, is described and illustrated. The new species is characterized by a relatively high lip region with three annuli, mean stylet length of 16 mum, with anteriorly flattened knobs, cylindrical body with a relatively anterior vulva, large and ovoid spermatheca full of sperm, plump tail with truncate, irregularly annulated terminus, and by the presence of males. Molecular ITS-RFLP and sequencing analyses of the new species showed clear differences from other most morphologically similar species, such as P. thornei and P. mediterraneus. Preliminary host range tests revealed that chickpea, pea, faba bean and durum wheat are good hosts of P. lentis n. sp., whereas common bean, alfalfa and barley are less robust hosts and tomato, bell pepper, eggplant, melon and sunflower are poor hosts for the nematode.

First Record of the Cyst Nematode Heterodera filipjevi on Wheat in Oregon.

Plant and soil samples from an irrigated winter wheat (Triticum aestivum) field near Imbler (Union County), OR were evaluated for root diseases during April 2007. The field exhibited patches with as much as 90% plant mortality. Previous crops were winter wheat (2004), chickpea (Cicer arietinum, 2005), and spring wheat (cv. Jefferson, 2006). Stubble was baled and removed, and the field was cultivated before replanting to winter wheat cv. Chukar in October. Patches of stunted seedlings (three- to five-leaf stage) appeared in March 2007. Stunted seedlings exhibited chlorotic or necrotic lower leaves, healthy younger leaves, few or no tillers, rotting of lower culms and crowns, and light brown roots with little or no branching. Signs and symptoms of fungal pathogens (Pythium spp., Gaeumannomyces graminis var. tritici, Rhizoctonia solani AG-8, and Typhula incarnata) were present on affected plants. Most small grain fields in Union County are infested with Heterodera avenae (4) but none of the roots, on either healthy or stunted plants, exhibited the bushy branching pattern typical of sites where H. avenae females penetrate and encyst. Extraction of motile nematodes (Whitehead tray method) from soil revealed high populations of Pratylenchus neglectus (6,560/kg of soil), Tylenchorhynchus spp. (2,369/kg of soil), and a species initially thought to be H. avenae (3,098 juveniles/kg of soil). Cysts were also extracted. During PCR-restriction fragment length polymorphism identification (1) of H. avenae collected in Oregon, Washington, and Idaho, four restriction enzymes applied to amplified DNA of cysts from the Imbler field consistently revealed a pattern identical to that of a H. filipjevi DNA standard and distinct from patterns of H. avenae, H. schachtii, and H. latipons. DNA standards were obtained from R. Rivoal, INRA, Rennes, France. Morphological evidence confirmed that the specimens were H. filipjevi, a member of the 'H. avenae Group' of cereal cyst nematodes (2,3). Measurements of second-stage juveniles (n = 15) included length of body (range = 530 to 570 µm, mean = 549, st. dev. = 13.0), stylet (22.5 to 24.5, 23.2, 0.6) with anchor-shaped basal knobs, tail (52.5 to 62.5, 57.4, 2.7), and hyaline tail terminal (30 to 38, 33.5, 2.6). The lateral field had four lines of which the inner two were more distinct. Shapes of the tail, tail terminus, and stylet knobs were also consistent with H. filipjevi. Cysts (n = 10) were lemon shaped and light brown. The cyst wall had a zigzag pattern. The vulval cone was bifenestrate with horseshoe-shaped semifenestra. The cysts were characterized by body length including neck (range = 718 to 940 µm, mean = 809.7, st. dev. = 61.8), body width (395 to 619, 504, 71.2), L/W ratio = (1.1 to 2.2, 1.4, 0.3), neck length (75 to 140, 103.2, 22.1) and width (50 to 95, 71.4, 10.9), fenestra length (50 to 65 µm, 56.5, 6.6) and width (27 to 40, 29.0, 3.8), heavy underbridge (60 to 80, 69, 8.5), vulval slit (7.5 to 8.5, 7.8, 0.4), and many bullae. As described for H. filipjevi, cysts hatched much more readily and at lower temperatures than populations of H. avenae. Detection of H. filipjevi in Oregon represents a new record for the occurrence of this species in the United States and for North America. The pathotype and resistance genes for incorporation into wheat, barley, and oat are being identified. References: (1) S. Bekal et al. Genome 40:479, 1997. (2) Z. A. Handoo. J. Nematol. 34:250, 2002. (3) R. Holgado et al. J. Nematol. Morphol. Syst. 7:77, 2004. (4) R. W. Smiley et al. J. Nematol. 37:297, 2005.

Morphological and Molecular Identification of Globodera pallida Associated with Potato in Idaho.

The identity of a newly discovered population of pale potato cyst nematode Globodera pallida associated with potato in eastern Idaho was established by morphological and molecular methods. Morphometrics of cysts and second-stage juveniles were generally within the expected ranges for G. pallida with some variations noted. The Idaho population and paratype material from Epworth, Lincolnshire, England, both showed variations in tail shape, with bluntly rounded to finely pointed tail termini. Compared to literature values for the paratypes, second-stage juveniles of the Idaho population had a somewhat shorter mean body length, and cysts had a slightly higher mean distance from the anus to the nearest edge of the fenestra. PCR-RFLP of the rDNA ITS region, sequence-specific multiplex PCR and DNA sequence comparisons all confirmed the identity of the Idaho population as G. pallida. The ITS rDNA sequence of the Idaho isolate was identical to those from York, England, and the Netherlands. Species-specific primers that can positively identify the tobacco cyst nematode Globodera tabacum were also developed, providing a new assay for distinguishing this species from G. pallida and the golden potato cyst nematode Globodera rostochiensis.

First Report of the Pale Cyst Nematode, Globodera pallida, in the United States.

In 2006, a cyst nematode was discovered in tare dirt at a potato (Solanum tuberosum) processing facility in eastern Idaho. The nematode was found during a routine survey conducted jointly by the Idaho State Department of Agriculture and the USDA Animal and Plant Health Inspection Service through the Cooperative Agricultural Pest Survey program. Extensive additional sampling from two suspect fields led to the identification of the same nematode in a 45-acre (18.2-ha) field located in northern Bingham County. The morphology of cysts and second-stage juveniles and molecular analyses established the identity of the species as the pale cyst nematode Globodera pallida (Stone 1973) Behrens 1975. Morphological characters used for identification included cyst shape, characteristics of cyst terminal cone including nature of fenestration, cyst wall pattern, anal-vulval distance, number of cuticular ridges between anus and vulva, and Granek's ratio (1,4). The second-stage juvenile morphologies critical for identification were the following: body and stylet length, shape of stylet knobs, shape and length of tail and hyaline tail terminus, and number of refractive bodies in the hyaline part of tail (1,4). Diagnosis as G. pallida was clearly confirmed by two molecular tests. First, PCR-RFLP (restriction fragment length polymorphism) profiles of a ribosomal DNA fragment using restriction enzymes RsaI, TaqI, and AluI (2) were consistent with a G. pallida control and not G. rostochiensis. Second, the ribosomal DNA region that extends from the 3' end of the 18S ribosomal subunit and includes all of ITS1, 5.8S, and ITS2 to the 5' end of the 28S ribosomal subunit was used to generate sequence for the most accurate species determination. Sequences obtained from three individual juveniles were compared with those from several Globodera species (3), revealing unequivocal similarity to G. pallida. This detection represents a new country record for G. pallida in the United States. Collection of additional information regarding distribution of this nematode within the region is underway. References: (1) J. G. Baldwin and M. Mundo-Ocampo. Heteroderinae, Cyst- and Non-cyst-forming Nematodes. Pages 275-362 in: Manual of Agricultural Nematology. W. R. Nickle, ed. Marcel Dekker, New York, 1991. (2) V. C. Blok et al. J. Nematol. 30:262, 1998. (3) L. A. Pylypenko et al. Eur. J. Plant Pathol. 111:39, 2005. (4) A. R. Stone. Nematologica 18:591, 1973.

Characterization of the Cystoid Nematode Meloidoderita kirjanovae (Nemata: Sphaeronematidae) from Southern Italy.

A population of the cystoid nematode Meloidoderita kirjanovae was detected parasitizing water mint (Mentha aquatica) in southern Italy. The morphological identification of this species was confirmed by molecular analysis using the internal transcribed spacer 1 (ITS1) and 5.8S gene sequences of nuclear ribosomal DNA (rDNA), which clearly separated it from the closely related species Meloidoderita polygoni. A phylogenetic analysis of M. kirjanovae with species of related genera was conducted using sequences of the D2-D3 expansion segments of the 28S nuclear ribosomal RNA gene. The resulting phylogenetic tree was congruent with trees from an extended dataset for Criconematina and Tylenchida. The basal position of the genus Meloidoderita together with Sphaeronema within the Criconematina clade in this tree may indicate their close relationships. The anatomical changes induced by M. kirjanovae population from Italy in water mint were similar to those reported for a nematode population infecting roots of M. longifolia in Israel. Nematode feeding caused the formation of a stellar syncytium that disorganized the pericycle and vascular root tissues.

Morphological and Molecular Characterization of Longidorus americanum n. sp. (Nematoda: Longidoridae), a Needle Nematode Parasitizing Pine in Georgia.

We describe and illustrate a new needle nematode, Longidorus americanum n. sp., associated with patches of severely stunted and chlorotic loblolly pine, (Pinus taeda L.) seedlings in seedbeds at the Flint River Nursery (Byromville, GA). It is characterized by having females with a body length of 5.4-9.0 mm; lip region slightly swollen, anteriorly flattened, giving the anterior end a truncate appearance; long odontostyle (124-165 microm); vulva at 44%-52% of body length; and tail conoid, bluntly rounded to almost hemispherical. Males are rare but present, and in general shorter than females. The new species is morphologically similar to L. biformis, L. paravineacola, L. saginus, and L. tarjani but differs from these species either by the body, odontostyle and total stylet length, or by head and tail shape. Sequence data from the D2-D3 region of the 28S rDNA distinguishes this new species from other Longidorus species. Phylogenetic relationships of Longidorus americanum n. sp. with other longidorids based on analysis of this DNA fragment are presented. Additional information regarding the distribution of this species within the region is required.

Morphological and Molecular Evaluation of a Meloidogyne hapla Population Damaging Coffee (Coffea arabica) in Maui, Hawaii.

An unusual population of Meloidogyne hapla, earlier thought to be an undescribed species, was found causing large galls, without adventitious roots, and substantial damage to coffee in Maui, Hawaii. Only in Brazil had similar damage to coffee been reported by this species. Unlike M. exigua from South and Central America, this population reproduced well on coffee cv. Mokka and M. incognita-susceptible tomato but poorly on tomato with the Mi resistance gene. Characterization included SEM images, esterase isozymes, and five DNA sequences: i) the D3 segment of the large subunit (LSU-D3 or 28S) rDNA, ii) internal transcribed spacer (ITS-1) rDNA, iii) intergenic spacer (IGS) rDNA, iv) the mitochondrial interval from cytochrome oxidase (CO II) to 16S mtDNA, and v) the nuclear gene Hsp90. Sequences for ITS-1, IGS, and COII were similar to other M. hapla populations, but within species ITS-1 variability was not less than among species. One LSU-D3 haplotype was similar to a previously analyzed population with two minor haplotypes. Hsp90 exhibited some variation between Maryland and Hawaiian populations distinct from other species. Females were narrow with wide vulval slits, large interphasmidial distances, and more posterior excretory pores; 20% of perineal patterns had atypical perivulval lines. Males had a low b ratio (<12 microm). Juveniles had a short distance between stylet and dorsal gland orifice. Juvenile body length was short (<355 microm) and was different between summer and winter populations.

Morphological and Molecular Characterization of a New Root-Knot Nematode, Meloidogyne thailandica n. sp. (Nematoda: Meloidogynidae), Parasitizing Ginger (Zingiber sp.).

A root-knot nematode Meloidogyne thailandica n. sp. was discovered on roots of ginger (Zingiber spp.) intercepted from Thailand in October 2002 by the U.S. Department of Agriculture Animal and Plant Health Inspection Service at the port of San Francisco. Comparison by light microscopy (LM) and scanning electron microscopy (SEM) to five other morphologically related species (M. incognita, M. arenaria, M. microcephala, M. megatyla, and M. enterolobii) revealed that the new species differs from these by one or more of the following: body, tail and hyaline tail length, shape of head, tail and tail terminus of second-stage juveniles; stylet length and shape of spicules in males; perineal pattern, stylet length and shape of knobs in females. The distinctive perineal pattern is oval to rectangular, with smooth to moderately wavy and coarse striae, and with characteristic radial structures present underneath the pattern area; the dorsal arch is high, sometimes round to rectangular, and striae in and around the anal area form a thick network-like pattern interrupted by lateral lines and large phasmids. Second-stage juveniles have a long, slender tail and long, gradually tapering hyaline tail region ending in a rounded terminus. Male spicules commonly have an acutely angled shaft with a bidentate terminus. Molecular data from the ribosomal large subunit D3 expansion segment revealed four haplotypes, two of which were unique and distinguish M. thailandica n. sp. from M. arenaria, M. incognita, and M. javanica.

Morphological, Molecular, and Differential-Host Characterization of Meloidogyne floridensis n. sp. (Nematoda: Meloidogynidae), a Root-Knot Nematode Parasitizing Peach in Florida.

A root-knot nematode, Meloidogyne floridensis n. sp., is described and illustrated from peach originally collected from Gainesville, Florida. This new species resembles M. incognita, M. christiei, M. graminicola, and M. hispanica, but with LM and SEM observations it differs from these species either by the body length, shape of head, tail and tail terminus of second-stage juveniles, body length and shape of spicules in males, and its distinctive female perineal pattern. This pattern has a high to narrowly rounded arch with coarsely broken and network-like striae in and around anal area, faint lateral lines interrupting transverse striae, a sunken vulva and anus, and large distinct phasmids. Molecular data from ribosomal IGS illustrate that M. floridensis n. sp. is different from the mitotic species M. arenaria, M. incognita, and M. javanica. Data from RAPDs confirm it and suggest that this new species lies in an intermediate phylogenetic position between the previous species and the meiotic species M. hapla, M. fallax, and M. chitwoodi. Differential host tests based on annual crops and on Prunus accessions are reported.

Effect of Entomopathogenic Nematodes on Mesocriconema xenoplax Populations in Peach and Pecan.

The effect of Steinernema riobrave and Heterorhabditis bacteriophora on population density of Mesocriconema xenoplax in peach was studied in the greenhouse. Twenty-one days after adding 112 M. xenoplax adults and juveniles/1,500 cm(3) soil to the soil surface of each pot, 50 infective juveniles/cm(2) soil surface of either S. riobrave or H. bacteriophora were applied. Another entomopathogenic nematode application of the same density was administered 3 months later. The experiment was repeated once. Mesocriconema xenoplax populations were not suppressed (P

Suitability of Southern Pines, Other Selected Crops, and Nutsedge to a Longidorus sp. Associated with Stunting of Loblolly Pine Seedlings.

An undescribed needle nematode (Longidorus sp.) has been associated with severely stunted loblolly pine seedlings at a south Georgia nursery. Containers with selected crop and weed species were infested with 100 or 200 adults and juveniles of the Longidorus individuals to evaluate host suitability. Nematode populations increased in containers with slash, loblolly, and longleaf pine seedlings. The Longidorus sp. significantly reduced the dry root weights of slash (P = 0.008) and loblolly (P = 0.047) but not longleaf (P = 0.095) pine compared with controls. Populations of Longidorus decreased on nutsedge and small grains, including wheat, rye, oat, sorghum, and millet; and, in most experiments, populations decreased to levels found in fallow containers. Populations decreased on tomato and cabbage but increased slightly on red oak. The periodic removal of fields from pine production to grow cover crops consisting of small grains or to maintain fallow fields may be an important practice for management of this Longidorus sp.

First Report of Columbia Root-Knot Nematode (Meloidogyne chitwoodi) in Potato in New Mexico.

Following a report of Columbia root-knot nematode in potatoes (Solanum tuberosum L.) imported by Mexico from the United States in spring 2000, six fields in San Juan County, NM, were surveyed in August 2000. Soil samples from two fields in which the exported potatoes had been produced contained second-stage juveniles that were tentatively identified as Columbia root-knot nematode. During the 2000 potato harvest, state inspectors detected tubers from four additional fields that exhibited symptoms of Columbia root-knot nematode, including warty exteriors and discrete small brown lesions that were apparent to a depth of 1 cm below the tuber surface. Meloidogyne chitwoodi Golden et al. (1) was confirmed from a subsample of tubers sent to the USDA Nematology Laboratory in Beltsville, MD, in October 2000. Identification was based on morphological examination of the nematodes recovered from tubers. To our knowledge, this is the first report of M. chitwoodi from New Mexico. No Columbia root-knot nematodes were recovered from soil samples collected at 26 locations throughout San Juan County in 1988 and 1989, nor had symptomatic tubers or plants been observed in this area previously. Columbia root-knot nematode most likely represents a recent introduction into northwestern New Mexico. Additional information regarding distribution of this nematode within the region is needed. References: (1) A. M. Golden et al. J. Nematol. 12:319-327, 1980.

First Report of Meloidogyne partityla on Pecan in New Mexico.

For several years, decline was observed in mature pecan (Carya illinoensis (F.A. Wangenheim) K. Koch) trees in an orchard in Dona Ana County, New Mexico despite normal fertilization and irrigation practices. Affected trees were growing in sandy soil in two widely separated irrigation terraces and exhibited chlorosis of foliage and substantial die-back of branches in the upper canopy. Examination of feeder roots revealed the presence of numerous small galls and egg masses, with root-knot nematode females often visibly protruding from root tissue. Attempts to culture the nematode on tomato (Lycopersicon esculentum Mill. 'Rutgers') were unsuccessful. Females and egg masses were collected from fresh pecan roots and sent to the USDA Nematology Laboratory in Beltsville, MD, in October 2000, where specimens were identified as Meloidogyne partityla Kleynhans (1) based on morphological examination. This is the first report of M. partityla from New Mexico, and the second report of this nematode outside South Africa. Starr et al. (2) first reported M. partityla from pecan in the United States in 1996, after recovering the nematode from five orchards in Texas. In their study, the host range of M. partityla was limited to members of the Juglandaceae, which may explain the inability of the New Mexico population to reproduce on tomato. Additional information is needed regarding distribution of this nematode within pecan-growing regions throughout North America. References: (1) K. P. N. Kleynhans. Phytophylactica 18:103, 1986. (2) J. L. Starr et al. J. Nematol. 28:565, 1996.

A key and diagnostic compendium to the species of the genus tylenchorhynchus cobb, 1913 (nematoda: belonolaimidae).

An identification key to 111 species of Tylenchorhynchus is given. Tylenchorhynchus is defined as containing only those species with four incisures in the lateral field. A compendium providing the most important diagnostic characters for use in identification of species is included as a supplement to the key. Some species in a related but unnecessary genus were placed in the genus Tylenchorhynchus, based on morphological structures and logical groupings of the species. Bitylenchus iphilus is transferred to Tylenchorhynchus. The diagnosis of Tylenchorhynchus is emended, and a list of all the valid species of the genus is given. The characters most useful for separating species are the stylet length, shape of lip region, number of lip annules, shape of tail and tail terminus, number of tail annules, and position of vulva (V%). As defined in the paper, the genus currently is composed of 111 valid species.