Tamás Lakatos

Between July and September 2021, researchers collected 100 specimens of the Spanish slug, Arion vulgaris, and dissected their cadavers to examine them for parasitic nematodes. Molecular techniques were used to identify the nematodes, which confirmed the presence of Oscheius myriophilus, marking the first recorded instance of this nematode in a gastropod host. To test the virulence of Slovenian strains of O. myriophilus and Phasmarhabditis papillosa and their effects on the feeding behavior of the Spanish slug, grey field slug (Deroceras reticulatum), and vineyard snail (Cernuella virgata), laboratory bioassays were conducted using nematodes grown in vivo. Nematodes were applied at various doses ranging from 10 to 500 nematodes/gastropod. The results showed that O. myriophilus and P. papillosa caused significant mortality (82.5% ± 2.5% at 15 °C) of the Spanish slug while being less effective against the vineyard snail and grey field slug. Nematodes were more virulent at a lower temperature (15 °C) than at the higher temperature (20 °C) tested in the experiment. Additionally, both nematode species significantly reduced gastropod herbivory. The potential use of O. myriophilus and P. papillosa as biological control agents against gastropods is discussed.

Gram-negative, motile, rod-shaped bacterial strains (designated 4F2 T and Kf) were isolated from decaying tissues of various deciduous tree species. Phylogenetic analyses based on their 16S rRNA gene sequences showed that the novel isolates belong to the genus Brenneria and showed highest (98.3 %) sequence similarity to Brenneria goodwinii . Isolate 4F2 T formed a separate branch on the phylogenetic tree based on concatenated sequences of four housekeeping genes or whole genome sequences, clearly separate from Brenneria goodwinii , suggesting that novel isolates should belong to a novel species. Orthologous average nucleotide identity scores and in silico DNA–DNA hybridization values between isolate 4F2 T and type strains of other species in the genus Brenneria were less than 85 and 30 %, respectively, significantly lower than the species boundary cut-off values (95 and 70 %). A negative reaction for β-galactosidase, the ability to use dextrin and maltose as carbon sources, and an inability to use lactose are the main phenotypic characteristics that can be used to differentiate the novel isolates from B. goodwinii . Based on phenotypic and genotypic characteristics, isolates 4F2 T and Kf belong to a novel species of the genus Brenneria , for which the name Brenneria bubanii sp. nov. is proposed. The type strain is 4F2 T (=NCAIM B 02661 T =LMG 32183 T ).