Monitoring of Root-Knot Nematodes (Meloidogyne spp.) in Croatia (2022–2024): Occurrence, Distribution and Species Identification

Root-knot nematodes (RKNs) of the genus Meloidogyne spp., are among the most economically important groups of plant-parasitic nematodes worldwide, causing significant economic losses through yield reduction across a wide range of crops. In Croatia, although the presence of Meloidogyne spp. has been documented for decades, data at the species level was limited. As accurate identification is crucial for implementation of effective management strategies, we attempted to fill this gap. This study presents the results of a national survey of RKNs affecting potato crops as well as an early warning programme targeting vegetable crops, conducted across Croatia between 2022 and 2024. Nematodes were identified using morphological analyses (female perineal patterns and second-stage juveniles) and molecular methods (PCR with group-specific and species-specific primers, as well as DNA sequencing). Meloidogyne spp. were detected in 61 out of 210 samples, corresponding to an infestation rate of 29%. Four species were identified: M. incognita, M. hapla, M. arenaria, and M. javanica. Notably, M. incognita and M. javanica are reported here for the first time in Croatia. These results provide updated insights into the distribution and identity of RKNs in Croatia, thereby establishing a foundation for the implementation of sustainable management strategies.