Meloidogyne partityla on Pecan Isozyme Phenotypes and Other Host

Meloidogyne sp. from five pecan (Carya illinoensis) orchards in Texas were distinctive in host range and iszoyme profiles from common species of Meloidogyne but were morphologically congruent with Meloidogyne partityla Kleynhans, a species previously known only in South Africa. In addition to pecan, species of walnut (Juglans hindsii and J. regia) and hickory (C. ovata) also were hosts. No reproduction was observed on 15 other plant species from nine families, including several common hosts of other Meloidogyne spp. Three esterase phenotypes and two malate dehydrogenase phenotypes of M. partityla were identified by polyacrylamide gel electrophoresis. Each of these isozyme phenotypes was distinct from those of the more common species M. arenaria, M. hapla, M. incognita, and M. javanica.     

Morphological Comparison of Meloidogyne Female Head Structures,Perineal Patterns,and Stylets

The external morphology of female heads of three populations of each of two cytological races of Meloidogyne hapla (race A-meiotic, race B-mitotic) and single populations of M. arenaria, M. incognita, and M. javanica was compared by light (LM) and scanning electron microscopy (SEM). Perineal patterns of all nine populations were observed with a LM and then examined with a SEM. In addition, female stylets of each population were excised, viewed with a SEM, and compared with observations made with a LM. Head morphology of the females, including shape of medial and lateral lips, expression of sensilla, and head annulation, was distinct for each species, each race of M. hapla, and each population of M. hapla race A. The morphology of a given perineal pattern appeared similar with the SEM and the LM. The SEM emphasized surface details, whereas the LM revealed subcuticular structure as well. Stylet morphology was unique for each species but similar in all populations of M. hapla. There were differences between species in the shape of the cone, shaft, and knobs and in the distance of the dorsal esophageal gland orifice from the stylet knob base. Several of the morphological characters first detected in the SEM were seen subsequently with the LM and are helpful in species identification.     

Noctuidonema dibolia n. sp. (Aphelenchida: Acugutturidae), an Ectoparasite of the moth Mocis latipes (Lepidoptera: Noctuidae)

Noctuidonema dibolia n. sp., an ectoparasite of adults of the noctuid moth Mocis latipes (Guenée) is described. The differentiating characters are a club-shaped body with a subterminal vulva in the female, spicules with a reduced matrix and sheath and closely apposed dorsal and ventral arms in the male, very long stylet and conus, moderately prominent stylet knobs, a bluntly rounded head, and a large renette cell in both sexes. Lateral fields, rectum, anus, bursa, and gubernaculum are absent. Noctuidonema dibolia differs from the other species of the subfamily Noctuidonematinae in the size and robustness of the body, the length of the stylet and conus, the length of the tail, and the shape of the spicules.     

Ultrastructure of Male Sexual Apparatus of Scutellonema brachyurum

Electron micrographs of serial sections show that the male sexual apparatus of Scutellonema brachyurum includes two morphologically identical spicules. Each is composed of a swollen tubular head, crescentic shaft, and leaf-like blade with membranous velum expanded from the central trunk. The spicules are concave and grooved on the ventral side and convex on the dorsal side near the trunk. The trunk is continuous with the shaft and head. Nerve tissue occupies the core of the spicule and includes a dendritic process which gains access to the exterior via a small pore on the lateral side of the spicule tip. Three protractor and two retractor muscles are associated with each spicule. A sensory accessory piece connects with the tip of the gubernaculum and protrudes from the lower side of the opening of the spicular pouch; it protracts and retracts with the muscularized gubernaculum. The gubernaculum varies from bow-shaped in the distal part to boat-shaped in the mid region. A sac exits beneath the accessory piece as a buffer for its movement. A cuticular guiding bar originating from the dorsal wall of the spicular pouch has a tongue. The ventral surface of the tongue is sclerotized to separate the two spicules. It is mobile by muscles of the protractor gubernaculi, retractor gubernaculi, and seductor gubernaculi.     

Panagrellus ceylonensis n. sp. (Nematoda: Cephalobidae)

Panagrellus ceylonensis n. sp. is described from rubber latex in Ceylon. Its long, slender spicules are curved ventrally with a dorsal deflection at two-thirds of their length. The manubrium is thick and hooked, and the shaft is not widened at the shoulder. The terminal bifurcations are wide, with the dorsal one considerably longer and thicker than the ventral. The main ventral element is continuous with the terminal sheath with the ventral bifurcation arising within it.     

Strelkovimermis spiculatus n. sp. (Mermithidae: Nematoda) Parasitizing Aedes albifasciatus Mac. (Culicidae: Diptera) in Argentina

Strelkovimermis spiculatus n. sp. (Mermithidae: Nematoda), a parasite of the mosquito Aedes albifasciatus Mac. in Argentina, is described. Diagnostic characters of this species include a ventrally shifted mouth opening and spicules fused at the tips. The mermithid has been reared on Culex pipiens L. larvae in the laboratory.     

Meloidogyne californiensis n. sp. (Nemata: Meloidogyninae), Parasitic On Bulrush,Scirpus robustus Pursh

Meloidogyne californiensis n. sp. is described and illustrated from bulrush Scirpus robustus in California. LM and SEM studies revealed that this species differs from other known species in the genus Meloidogyne especially by the prominent posterior cuticular protuberances in the female, the distinct shape of the perineal pattern which is marked by one prominent stria in the perineum, indistinct lateral lines, many broken discontinuous striae on both sides of the arch, and the excretory pore being located posterior to stylet base. Second-stage juveniles 448-628 μm long, stylet length 11-13 μm, styler delicate, with small knobs sloping posteriorly, cephalic region with 2 or 3 annuli, and inflated rectum. Males vary greatly in size (712-1,952 μm), stylet length 18-28 μm (mean 22 μm), cephalic region slightly set off the body with two or three annuli, spear heavy with massive rounded knobs, lateral field marked by four areolated incisures as seen by SEM.     

Morphological Comparison of Head Shape and Stylet Morphology of Second-stage Juveniles of Meloidogyne Species

Head shape and stylet morphology of second-stage juveniles of one population each of M. incognita, M. javanica, M. arenaria, and M. hapla were compared by light microscopy. Excised stylets of each species were also compared by scanning electron microscopy (SEM). Differences in head morphology were observed only between M. hapla and the other three species. In SEM, differences in stylet size, shape, and relative distance of the dorsal esophageal gland orifice to the base of the stylet were evident. Differences in stylet morphology between M. incognita and M. javanica could not he detected by light microscopy, but M. arenaria and M. hapla could be distinguished from each other and from the other two species. Head shape and styler morphology of second-stage juveniles are considered useful taxonomic characters.     

Two New Species of Aphelenchoididae (Nemata) from Declining Red Pines in Maryland

Aphelenchoides resinosi n. sp. and Ektaphelenchus joyceae n. sp. are described and illustrated from red pines of the Allegheny plateau of Maryland, USA. The new species were found in trees infested with Bursaphelenchus xylophilus. Primary diagnostic characters of A. resinosi females are constriction of the head, basal stylet knobs, tong postuterine sac, two incisures in the lateral field, and conical tail four to five anal body widths long with a simple terminal mucro. Diagnostic characters of the males are two pairs of subventral caudal papillae and spicule shape: Primary diagnostic characters of E. joyceae females are a slight constriction of the head, six similar lips, conical tail, and short postuterine sac. Diagnostic characters of the males are spicule size and shape, a single row of spermatocytes, and one pair of caudal papillae. Within-tree distributions of A. resinosi and E. joyceae are presented. A total of 70% of both red-needled and chlorotic-needled trees in the study were positive for A. resinosi and E. joyceae. Branch hierarchy was related to the percentage of samples positive for A. resinosi.     

Host Range and Ecology of Isolates of Pasteuria spp. from the Southeastern United States

Isolates of Pasteuria penetrans were evaluated for ecological characteristics that are important in determining their potential as biological control agents. Isolate P-20 survived without loss of its ability to attach to its host nematode in dry, moist, and wet soil and in soil wetted and dried repeatedly for 6 weeks. Some spores moved 6.4 cm (the maximum distance tested) downward in soil within 3 days with percolating water. The isolates varied greatly in their attachment to different nematode species and genera. Of five isolates tested in spore-infested soil, three (P-104, P-122, B-3) attached to two or more nematode species, whereas B-8 attached only to Meloidogyne hapla and B-I did not attach to any of the nematodes tested. In water suspensions, spores of isolate P-20 attached readily to M. arenaria but only a few spores attached to other Meloidogyne spp. Isolate P-104 attached to all Meloidogyne spp. tested but not to Pratylenchus scribneri. Isolate B-4 attached to all species of Meloidogyne and Pratylenchus tested, but the rate of attachment was relatively low. Isolate P-Z00 attached in high numbers to M. arenaria when spores were extracted from females of this nematode; when extracted from M. javanica females, fewer spores attached to M. arenaria than to M. javanica or M. incognita.     

Description of Sclerorhabditis miniata n. sp. and First Description of Male of Diploscapter coronatus Cobb, 1913 (Nematoda: Rhabditidae)

A population of Sclerorhabditis miniata n. sp. is described and illustrated from Poonch district of Jammu and Kashmir State, India. The new species is characterized by small body size, with an annulated cuticle, offset labial region, crown shaped, strongly sclerotized lips, thin lateral lips, membranous, stegostom without glottoid apparatus, cheilostom rod shaped, sclerotized, spicules free, strong and thick, gubernaculum simple, bent proximally, bursa open, peloderan with seven pairs of bursal papillae in 1+1/1+1+2+1 pattern. The males of Diploscapter coronatus are described for the first time. They are usually smaller than the females and have labial region similar to females. Spicules separate, with a small dorsal velum, gubernaculum simple, almost straight, bursa open, pseudopeloderan with seven pairs of bursal papillae in 1+1/1+2+1+1 pattern.     

Morphology and Description of Bursaphelenchus platzeri n. sp. (Nematoda: Parasitaphelenchidae), an Associate of Nitidulid Beetles

Bursaphelenchus platzeri n. sp., an associate of nitidulid beetles in southern California, is described and illustrated. Adult males and females of B. platzeri n. sp. were examined by scanning electron microscopy for ultrastructural comparisons with other members of the genus. Bursaphelenchus cocophilus (red ring nematode) appears to be the closest related taxon to B. platzeri n. sp. based upon shared morphological features of the fused spicules, female tail shape, phoresy with non-scolytid beetles, and molecular analysis of the near full-length small subunit (SSU) rDNA. Unfortunately, sequence data from the D2D3 expansion segments of the large subunit (LSU) rDNA and partial mitochondrial DNA COI did not help resolve the relationship of nearest relative. In addition to significant molecular sequence differences in SSU, LSU, and COI, B. platzeri n. sp., which is an obligate fungal feeder, can be differentiated from B. cocophilus because it is an obligate parasite of palms. Bursaphelenchus platzeri n. sp. can be differentiated from all other species of Bursaphelenchus by the length and shape of the female tail and spicule morphology. The spicules are fused along the ventral midline and possess unfused cucullae; the fused unit appears to function as a conduit for sperm. Population growth of B. platzeri n. sp. was measured in a time-course experiment at 25°C in the laboratory on cultures of the fungus Monilinia fructicola grown on 5% glycerol-supplemented potato dextrose agar (GPDA). Nematode population densities rapidly increased from 25 to approximately 200,000/culture within 14 d and then plateaued for up to 28 d.     

Comparisons of Isozyme Phenotypes in Five Meloidogyne spp. with Isoelectric Focusing

Meloidogyne incognita race 1, M. javanica, M. arenaria race 1, M. hapla, and an undescribed Meloidogyne sp. were analyzed by comparing isozyme phenotypes of esterase, malate dehydrogenase, phosphoglucomutase, isocitrate dehydrogenase, and α-glycerophosphate dehydrogenase. Isozyme phenotypes were obtained from single mature females by isoelectric focusing electrophoresis. Of these five isozymes, only esterase and phosphoglucomutase could be used to separate all five Meloidogyne spp.; however, the single esterase electromorphs were similar for M. incognita and M. hapla. Yet when both nematodes were run on the same gel, differences in their esterase phenotypes were detectable. Isozyme phenotypes from the other three isozymes revealed a great deal of similarity among M. incognita, M. javanica, M. arenaria, and the undescribed Meloidogyne sp.     

Paraiotonchium muscadomesticae n. sp. (Tylenchida: lotonchiidae) a Parasite of the House Fly (Musca domestica) in Brazil and a Key to Species of the Genus Paraiotonchium

Paraiotonchium muscadomesticae n. sp., a parasite of the house fly, Musca domestica L., is described and illustrated from material collected in Brazil. The life cycle of P. muscadomesticae is similar to that of P. autumnale (Nickle), consisting of alternating gamogenetic and parthenogenetic generations. Paraiotonchium muscadomesticae n. sp. can be distinguished from P. nicholasi Slobodyanyuk, P. autumnale (Nickle) Slobodyanyuk, and P. crassirostris (Yatham &Rao) Siddiqi by the shorter body length of young heterosexual females, 652 g.m (530-709) for P. muscadomesticae compared to 750 μm or more (801-1,050) for the others. Paraiotonchium muscadomesticae is close to P. nicholosi but differs from it by V ratio and spicule length (V = 80-84; spicule = 16-21 p.m in P. muscadomesticae compared to V = 73-78; spicule = 25-35 μm in P. nicholasi). Paraiotonchium muscadomesticae and P. nicholasi differ from all species of this genus by the absence of a bursa on males of these two species.     

External Morphology of the Spicules of some Trichodoridae

External morphology of spicules in several species of Trichodoridae was studied by scanning electron and light microscopy. The bristles on the spicules observed in the light microscope in several species were revealed as small scales forming a sheath which covers most of the spicule body. Some species have smooth spicules, whereas other species exhibited complicated structures formed by projections. In all of the species studied, either a ventro-terminal or terminal opening of the spicules was observed.     

Redescription of Three Ektaphelenchus Species (Nematoda: Aphelenchina)

Three Ektaphelenchus species with unusual spicules are redescribed. Ektaphelenchus obtusus and E. riograndensis are redescribed from newly discovered material in the collection of the USDA Forest Service RMRS. Lectotype slides are designated for both species. Ektaphelenchus obtusus is characterized by a set-off head, lips of unequal size, double rows of oocytes and spermatocytes, and a hooked spicule terminus. Ektaphelenchus riograndensis is distinguished by a rounded head with six equal lips, and spicules with a large, rounded apex, and recurved terminus. A bursa and gubernaculum are absent in both species. Ektaphelenchus scolyti is redescribed from type material deposited in the collection of Rothamsted Experimental Station. It is characterized by a well set-off head, double rows of oocytes and spermatocytes, and spicules with a hooked terminus. A bursa and gubernaculum are absent.     

Ochoterenella esslingeri n. sp. (Nematoda: Onchocercidae: Waltonellinae) from Bokermannohyla luctuosa (Anura: Hylidae) in Minas Gerais,Brazil, with notes on Paraochoterenella Purnomo & Bangs, 1999

The waltonelline Ochoterenella esslingeri n. sp., a filarial parasite of the anuran Bokermannohyla luctuosa in Minas Gerais, Brazil is described. Several characters distinguish this new species from the 15 species presently included in the genus: the cuticular ornamentation of the female that is restricted to the posterior region of the body, the irregular arrangement of the small, rounded bosses, the postoesophageal vulva, the short glandular oesophagus, the size and shape of the microfilariae, the long left spicule and high spicular ratio. Irregularly arranged, tiny, rounded bosses are common in the monotypic genus Paraochoterenella from an Indonesian ranid, which is not well defined but likely valid. In the Neotropical Realm, the type hosts of the species of Ochoterenella are Hylidae (O. esslingeri n. sp.), Leptodactylidae (two species) and the remaining 13 species were described from the giant toad Rhinella marina (Bufonidae).     

Trichodorus elefjohnsoni n. sp. (Nemata: Trichodoridae) from Undisturbed Appalachian Forest

A new species of Trichodoridae, Trichodorus elefjohnsoni, is described from undisturbed regions of Great Smoky Mountains National Park, United States. It resembles T. orientalis De Waele &Hashim, 1984, T. persicus De Waele &Sturhan, 1987, and T. taylori De Waele, Mancini, Roca, '' Lamberti, 1982 in arrangement of ventromedian cervical papillae and posterior preanal supplements, but differs by combinations of the following characteristics: body length 516-731 μm; spicule length 33-50 μm, spicules densely striated, constricted medially; vaginal sclerotizations ovate; one pair of lateral body pores near vulva.