Correction: Ryss, A.Y.; Subbotin, S.A. New Records of Wood- and Bark-Inhabiting Nematodes from Woody Plants with a Description of Bursaphelenchus zvyagintsevi sp. n. (Aphelenchoididae: Parasitaphelenchinae) from Russia. Plants 2023, 12, 382.

In the original publication [...].

New Records of Wood- and Bark-Inhabiting Nematodes from Woody Plants with a Description of Bursaphelenchus zvyagintsevi sp. n. (Aphelenchoididae: Parasitaphelenchinae) from Russia.

Wood- and bark-inhabiting parasitic nematodes are of great economic importance. Nematodes can cause wilt diseases in conifers and deciduous trees. In 2014-2022, during nematology surveys conducted in different regions of Russia and Belarus, adults and dauer juveniles of nematodes were collected from wood, bark and beetle vectors. Using traditional morphological taxonomic characters integrated with molecular criteria, we identified in the studied samples the following nematode species: Aphelenchoides heidelbergi, Bursaphelenchus eremus, B. fraudulentus, B. michalskii, B. mucronatus, B. willibaldi, Deladenus posteroporus, Diplogasteroides nix and Laimaphelenchus hyrcanus, several unidentified species: Aphelenchoides sp.1 and sp.2, Cryptaphelenchus sp.1, sp.2 and sp.3, Laimaphelenchus sp.1, Micoletzkya sp.1, Parasitaphelenchus sp.1, Parasitorhabditis sp.1, three unidentified tylenchid nematodes and a new species, Bursaphelenchus zvyagintsevi sp.n. Morphological descriptions and molecular characterization are provided for B. zvyagintsevi sp. n. belonging to the Abietinus group and B. michalskii belonging to the Eggersi group. Findings of Aphelenchoides heidelbergi, Bursaphelenchus eremus, B. michalskii, Deladenus posteroporus, Diplogasteroides nix and Laimaphelenchus hyrcanus are new records for Russia. Phylogenetic positions of studied species were reconstructed using D2-D3 expansion segments of 28S rRNA gene sequence analysis. The data obtained in this study may help to detect the refugia of opportunistic plant pests and find possible native biocontrol nematode agents of insect vectors causing diseases.

Morphology, development stages, and phylogeny of the Rhabditolaimus ulmi (Nematoda: Diplogastridae), a phoront of the bark beetle Scolytus multistriatus from the elm Ulmus glabra Huds. in Northwest Russia.

The nematode Rhabditolaimus ulmi was found in galleries, adults, and larvae of Scolytus multistriatus, the vector of the Dutch elm disease, in St. Petersburg parks. This nematode co-occurred with Bursaphelenchus ulmophilus, which is another phoretic partner of S. multistriatus. Nematodes were cultured on the fungus Botryotinia fuckeliana in potato sugar agar (PA) and used for morphological analyses of adults, juveniles, eggs, and dauers. Nematode females showed a didelphic female genital tract rather than a monoprodelphic gonad as reported in the original description. Male bursa peloderan, caudal papillae include three preanal pairs and one precloacal unpaired papillae; seven postanal papilla pairs, among which one is pore-like and possibly the phasmid homolog, one subdorsal, and a pair of three closely situated posteriorly at bursa alae. The juvenile stages differ in size and structure of their sexual primordia. Sex of juveniles may be identified from the third stage. The dauer juvenile is a phoretic third juvenile stage (DJ3), which enters and remains localized in the buccal cavity of beetle adults and last-instar larvae and also under the elytra and in the ovipositor's cavity of pupae and imagoes. The first molt J1-J2 occurred inside the eggshell. Adult females laid eggs in early stages of embryonic development or containing molted J2. The propagative non-phoretic J2 inside the egg and J3 have a long and well-developed median bulb. The phoretic dauer DJ3 has a small spherical bulb like the J1 juvenile within the egg. In a sterile fungal culture, the nematodes feed on both mycelium and their unidentified ecto-symbiotic bacteria, located on nematode surface coat and multiplying in PA. Diagnosis and tabular key to the Rhabditolaimus species are given. Phylogenetic analysis of the D2-D3 of 28S rRNA gene sequences resulted in the Bayesian consensus tree with the highly supported clade of the Rhabditolaimus species.

Characterization of Juvenile Stages of Bursaphelenchus crenati Rühm, 1956 (Nematoda: Aphelenchoidoidea).

In this study juvenile stages of Bursaphelenchus crenati (Sexdentati group) were distinguished based mainly on the genital primordium structure. Dauer stage juveniles were sampled under elytra of Hylesinus crenatus in galleries in bark of the wilted Fraxinus excelsior in the Voronezh region of Russia and were multiplied in laboratory cultures on the fungus Botrytis cinerea. Individual development included five stages (J1-J4 and adults) separated by molts. The first molt J1 to J2 occurred inside the egg and the J2 was at the hatching stage. Sex of juvenile stages can be identified using the morphology and size of the genital primordia and a body size of nematodes. Sex of juveniles may be identified from the J3 stage by the presence of the cloacal primordium in male juvenile and orientation of the germinal zone of the genital primordium. A tabular key to developmental stages of B. crenati is given. The body grows during molts and within each stage. The body increases rapidly after J3 stage combined with the most active cellular differentiation and elongation of the genital primordium. The dauer juveniles collected from elytra of vector beetles were similar to the third juvenile stage of the propagative generation by genital primordium structure and body size.In this study juvenile stages of Bursaphelenchus crenati (Sexdentati group) were distinguished based mainly on the genital primordium structure. Dauer stage juveniles were sampled under elytra of Hylesinus crenatus in galleries in bark of the wilted Fraxinus excelsior in the Voronezh region of Russia and were multiplied in laboratory cultures on the fungus Botrytis cinerea. Individual development included five stages (J1-J4 and adults) separated by molts. The first molt J1 to J2 occurred inside the egg and the J2 was at the hatching stage. Sex of juvenile stages can be identified using the morphology and size of the genital primordia and a body size of nematodes. Sex of juveniles may be identified from the J3 stage by the presence of the cloacal primordium in male juvenile and orientation of the germinal zone of the genital primordium. A tabular key to developmental stages of B. crenati is given. The body grows during molts and within each stage. The body increases rapidly after J3 stage combined with the most active cellular differentiation and elongation of the genital primordium. The dauer juveniles collected from elytra of vector beetles were similar to the third juvenile stage of the propagative generation by genital primordium structure and body size.

A Simple Express Technique to Process Nematodes for Collection Slide Mounts.

The new simple technique of hot fixation and a method for processing a mass quantity of nematodes to prepare nematode collection slides for taxonomic and ecological purposes, combined with an abrupt reduction of the set of procedures caused by the "cocktail" principle (a stratification of layers with a gradient of glycerol concentrations), are described.

Redescription of Robustodorus megadorus with Molecular Characterization and Analysis of Its Phylogenetic Position within the Family Aphelenchoididae.

Based on a new record of the rare species Robustodorus megadorus from Utah, the generic diagnosis was amended to include the following characters: a labial disc surrounded by six pore-like sensilla; the absence of a cephalic disc; a lobed cephalic region devoid of annulation; a hexagonal inner cuticular structure of the pouch surrounding the stylet cone; large stylet knobs, rounded in outline and somewhat flattened on their lateral margins; a large spermatheca with an occluded lumen and lacking sperm; the excretory pore located between the median bulb and nerve ring. The stylet orifice consists of an open, ventral, elongate slit or groove. These characters distinguish the genus from the closely related genus Aphelenchoides. A lectotype and paralectotypes were designated. Results of phylogenetic analyses of the 18S and D2-D3 of 28S rRNA gene sequences revealed that R. megadorus occupies a basal position within one of the two main clades of the subfamily Aphelenchoidinae and shares close relationships with a species group of the genus Aphelenchoides that includes A. blastophthorus, A. fragariae, A. saprophilus, A. xylocopae, and A. subtenuis. Several specimens in our collection of R. megadorus were infected with Pasteuria sp. as were some of the paralectotypes.