Zafar A. Handoo

Morphological and molecular characterisation of Pratylenchus arlingtoni n. sp., P. convallariae and P. fallax (Nematoda: Pratylenchidae)

Pratylenchus arlingtoni n. sp. from the rhizosphere of grasses Poa pratensis and Festuca arundinacea at Arlington National Cemetery, VA, USA is characterised by six to eight lines in the lateral field, and pyriform to slightly overlapping pharyngeal glands. Morphological comparisons are made with lesion nematodes having similar morphometrics, six lateral lines, or crenate tail tips. Molecular sequences of the LS 28S rDNA were generated for the new species as well as P.fallax and P.convallariae. The new species differs by only 1% from identical sequences found in P.fallax and P.convallariae.

Taxonomy, Morphology and Phylogenetics of Coffee-Associated Root-Lesion Nematodes, Pratylenchus spp

This review includes a synthesis of information on eight species of root-lesion nematodes (Pratylenchus spp.) that parasitize coffee or inhabit its rhizosphere. It includes a table of important morphological characters, a diagnostic key, photographs of anterior ends and tails of specimens from the USDA nematode collection, and a phylogenetic tree based on ribosomal DNA with drawings of scanning electron microscopic face-patterns. Information sources are evaluated and future research needs are outlined.

Evaluation of Some Vulval Appendages in Nematode Taxonomy

Abstract A survey of the nature and phylogenetic distribution of nematode vulval appendages revealed 3 major classes based on composition, position, and orientation that included membranes, flaps, and epiptygmata. Minor classes included cuticular inflations, protruding vulvar appendages of extruded gonadal tissues, vulval ridges, and peri-vulval pits. Vulval membranes were found in Mermithida, Triplonchida, Chromadorida, Rhabditidae, Panagrolaimidae, Tylenchida, and Trichostrongylidae. Vulval flaps were found in Desmodoroidea, Mermithida, Oxyuroidea, Tylenchida, Rhabditida, and Trichostrongyloidea. Epiptygmata were present within Aphelenchida, Tylenchida, Rhabditida, including the diverged Steinernematidae, and Enoplida. Within the Rhabditida, vulval ridges occurred in Cervidellus, peri-vulval pits in Strongyloides, cuticular inflations in Trichostrongylidae, and vulval cuticular sacs in Myolaimus and Deleyia. Vulval membranes have been confused with persistent copulatory sacs deposited by males, and some putative appendages may be artifactual. Vulval appendages occurred almost exclusively in commensal or parasitic nematode taxa. Appendages were discussed based on their relative taxonomic reliability, ecological associations, and distribution in the context of recent 18S ribosomal DNA molecular phylogenetic trees for the nematodes. Characters were found to be distributed across subsets of terminal and phylogenetically distant taxa, demonstrating considerable homoplasy. Accurate definitions, terminology, and documentation of the taxonomic distribution of vulval appendages are important in evaluations of hypotheses for either parallelism and developmental constraint or convergence and adaptation.

Supplemental description of Paraphelenchus acontioides (Tylenchida: Aphelenchidae, Paraphelenchinae), with ribosomal DNA trees and a morphometric compendium of female Paraphelenchus

Summary – Nematodes were isolated from surface-sterilised stems of cheatgrass, Bromus tectorum (Poaceae), in Colorado, grown on Fusarium (Hypocreaceae) fungus culture, and identified as Paraphelenchus acontioides. Morphometrics and micrographic morphology of this species are given to supplement the original description and expand the comparative species diagnosis. A tabular morphometric compendium of the females of the 23 species of Paraphelenchus is provided as the last diagnostic compilation was in 1984. Variations in the oviduct within the genus are reviewed to evaluate the taxonomic assignment of P. deckeri , a morphologically transitional species between Aphelenchus and Paraphelenchus. Sequences were generated for both 18S and 28S ribosomal DNA, representing the first identified species within Paraphelenchus so characterised. These sequences were incorporated into phylogenetic trees with related species of Aphelenchidae and Tylenchidae. Aphelenchus avenae isolates formed a well supported monophyletic sister group to Paraphelenchus. The ecology of Paraphelenchus, cheat grass and Fusarium is also discussed.

Morphological and molecular studies on Heterodera sacchari, H. goldeni and H. leuceilyma (Nematoda: Heteroderidae)

Heterodera sacchari, H. leuceilyma and H. goldeni are closely related members of the H. sacchari species complex, which is mainly characterised and distinguished from all other described Heterodera species by the presence of finger-like projections of the strongly developed underbridge in the vulval cone of the cysts. Males are rare in all three species and are described here in H. goldeni for the first time. Reproduction appears to be parthenogenetic. There are only minor morphological distinctions between the three species, particularly after our present studies have emended their original descriptions from various populations. Heterodera sacchari and H. goldeni showed differences in the ITS-rRNA gene sequences. Heterodera sacchari was described and reliably identified from many tropical African countries, H. leuceilyma is known only from Florida, USA, and H. goldeni has been identified in Egypt, Israel and Iran. All three species have grasses and other Poaceae as hosts, H. sacchari commonly attacking rice and sugarcane, and H. goldeni reproducing successfully on sugarcane ratoon seedlings. Morphological data emending the descriptions of H. sacchari, H. goldeni and H. leuceilyma from various populations are presented and discussed along with their host and distribution. Molecular characterisation of H. sacchari and H. goldeni is provided. An analysis of phylogenetic relationships within species of the sacchari-group using ITS-rRNA gene sequences is also presented.

First Report of the Soybean Cyst Nematode, Heterodera glycines, in New York

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is the most damaging pathogen of soybean (Glycine max (L.) Merr.), causing more than

First Report of the New Root-Lesion Nematode Pratylenchus sp. on Soybean in North Dakota

1 billion in yield losses annually in the United States (Allen et al. 2017). The SCN distribution map updated in 2014 showed that SCN were detected in all major soybean-producing states in the U.S. except West Virginia and New York (Tylka and Marett 2014). Soybean shows great economic promise in NY and its production area in the region has been expanding rapidly. In coordination with a statewide soybean disease survey, soil samples have been collected from seventeen counties throughout NY since 2013 to search for the presence of SCN. A post-harvest soil sample collected in the fall of 2016 from a soybean field in Cayuga County, NY, was processed using the sugar centrifugal-flotation method to extract nematodes and a few brown and lemon-shaped cysts, similar to those of SCN, were isolated. The lemon-shaped cysts were light to dark brown and had a zigzag patter...

List of Type Specimens Deposited Since 1998 in the United States Department of Agriculture Nematode Collection, Beltsville, Maryland

Root-lesion nematodes (RLN; Pratylenchus spp.) are important nematode pests on soybean (Glycine max (L.) Merr.). In May 2015 and 2016, sixtwo soil samples were collected from a soybean field in Walcott, Richland County, ND. Nematodes were extracted from soil using a sugar centrifugal flotation method., revealing these two All the samples contained RLN from 125 to 2, 000and 350 root-lesion nematodes per kg soil, respectively. In 2016, four soil samples were collected from the same field and all the samples had root-lesion nematodes ranging from 300 to 2,000. One soil sample with 350 RLN lesion nematodes per kg soil was planted withto soybean cultivar Barnes in four replicates each in a pot (6.4-cm × 25.4-cm) with 500 g soil(n = 4). After 15 weeks of growth at 22°C in a greenhouse room at 22°C, the root-lesion nematode RLN population was found to have increased greatly. The final population density in soil was 1,518 ± 541 lesion nematodesRLN per kg soil. Soybean roots were rinsed with water and brown lesion...

A key and diagnostic compendium to the species of the genus pratylenchus filipjev, 1936 (lesion nematodes).

The United States Department of Agriculture Nematode Collection (USDANC) is one of the largest and most valuable in existence and includes millions of specimens housed in over 39,800 permanent slides and 9,300 vials. This collection preserves type specimens of nematodes to serve as a reference for identifications and future taxonomic revisions. Also, the collection provides useful information on nematode hosts, occurrence, and distribution. The present list includes type specimens added to the USDANC since 1998. Since that time, the collection has expanded, with 474 type species mounted and preserved on 2,564 glass slides and 180 vials. We encourage nematologists throughout the world to deposit type specimens in the USDANC for use by future generations.