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Alternatives to hazardous insecticides are urgently needed for an environmentally friendly and effective management of insect pests. One such option is the use of entomopathogenic nematodes (EPN). To increase the availability of EPN with potential for biocontrol, we surveyed agricultural soils in the Republic of Rwanda and collected two Steinernema isolates. Initial molecular characterization showed that they represent a new species, for which we propose the name S. africanum n. sp. To describe this new species, we reconstructed phylogenetic relationships, calculated sequence similarity scores, characterized the nematodes at the morphological level, conducted crossing experiments, and isolated and characterized their symbiotic bacteria. At the molecular level, S. africanum n. sp. is closely related to S. litorale and S. weiseri. At the morphological level, S. africanum n. sp. differs from closely related species by the position of the nerve ring and also because the stoma and pharynx region is longer. The first-generation males have ventrally curved spicules with lanceolate manubrium and fusiform gubernaculum and the second-generation males have rounded manubrium and anteriorly hook-like gubernaculum. Steinernema africanum n. sp. does not mate or produce fertile progeny with any of the closely related species.

The diversity and seasonal fluctuations of plant-parasitic nematodes (tylenchids) were investigated in five alfalfa fields in five counties of the Kerman Province of Iran during four consecutive seasons in 2013. Hundred soil samples were obtained per county, with 25 sub-samples per field being composited to five to represent five replicates per field per county per season. In total, 500 samples were analyzed during the study. Nematodes were extracted from soil samples using the modified tray method. In total, 11 plant-parasitic nematode genera and 12 species were recorded. According to prominence values, Ditylenchus (e.g. D. acutus, D. myceliophagus, D. terricolus and D. sarvarae), followed by Helicotylenchus pseudorobustsus, Pratylenchus neglectus and Meloidogyne javanica were the most prominent species. The season and the localities significantly affect the population densities of nematodes. Values for both the Shannon (H’) and Evenness (E) indices were the highest in Bam and the lowest in Jiroft counties. A significant, negative correlation existed between soil pH and mean population densities of Scutylenchus rugosus, while significant and positive correlations existed between soil electrical conductivity and Helicotylenchus pseudorobustus, Aphelenchoides sp., Amplimerlinius globigerus and Pratylenchus neglectus. In conclusion, diversity of plant-parasitic nematodes in Bam county was higher than other localities.

Hirschmanniella anchoryzae from Iran and Pratylenchus hippeastri from South Africa were recovered during a survey of plant-parasitic nematodes belonging to the family Pratylenchidae. Both species were studied using morphological and molecular techniques. Hirschmanniella anchoryzae is identified based on the flattened head, short stylet (19–22 µm), excretory pore position (anterior to pharyngo-intestinal junction), spicule length (27–30 µm), and existence of an axial mucro at the tail end. Phylogenetic analysis using 28S rDNA showed monophyly of Hirschmanniella which Iranian H. anchoryzae placed close to H. halophila (EU620464; EU620465). This result was supported by the principal component analysis of Hirschmanniella species. SEM observation of the South African population of P. hippeastri showed the presence of two annuli in the lip region. Morphometric characters resembled those of specimens earlier reported from South Africa. Hierarchal cluster using morphometrical criteria showed that the Floridian (USA) and South African populations form a group. However, the principal component analysis showed variation within this species. The molecular study of P. hippeastri populations using 18S, ITS, 28S rDNA, and COI of mtDNA showed that all P. hippeastri cluster in one group and confirmed the identification of the species using both morphological and molecular techniques. In addition, the results indicated that South African populations group close to the USA populations. Illustrations of both species including light and scanning electron microscopy observations for P. hippeastri are provided.

Summary: During a survey of soil nematodes in 2022, a free-living bacterivorous nematode, described here as Mesorhabditis sudafricana n. sp., was discovered in association with kikuyu grass in Limpopo Province, South Africa. The new species was distinguished by a relatively long body (716-815 μ m in females and 605-689 μ m in males), long spicules (61-66 μ m), and gubernaculum (22-24 μ m) and a short tail (15-20 μ m in females and 18-21 μ m in males). The vulva is positioned posteriad (93-95% of body length), and the distance from vulva to anus is long (1.5-1.9 times tail length). Additionally, the new species bears seven lateral field incisures and a peloderan bursa with the genital papillae in arrangement 2/3+ph+1+3, being two precloacal and eight postcloacal. The 28S rDNA BlastN showed 94% similarity with an unidentified Mesorhabditis (deposited as Bursilla (EF990722). By contrast, the ITS rDNA BlastN showed 82% similarity with Mesorhabditis paucipapillata (MT710243). The phylogenetic analysis of 28S and ITS rDNA placed the new species separately from the other Mesorhabditis. Description, measurements, illustrations and SEM micrographs for M. sudafricana n. sp. are provided. [ABSTRACT FROM AUTHOR]

During a survey of soil nematodes in Iran, a population of a species belonging to the order Mononchida was recovered. The new species, Paramylonchulus iranicus sp. n. is characterized by body length (1292–1535 μm in females and 1476–1670 μm in males), c (20.2–29.0 in females and 19.9–27.4 in males), buccal cavity length (23.0–26.0 μm), post vulval uterine sac length (135–162 μm), spicule length (46.0–50.0 μm), gubernaculum length (8.0–11.0 μm), and tail length (49.0–70.0 μm in females and 55.0–73.0 μm in males). Canonical discriminant analysis clearly separated P. iranicus sp. n. from the closely related species Paramylonchulus based on the important morphometric characters of females and males. A molecular study of the 18S rDNA region of P. iranicus sp. n. places this population in a well-supported clade with other species of the genus. [ABSTRACT FROM AUTHOR]