Monitoring of the invasive species Rhagolethis completa Cresson and the harmfulness of flies that damages walnut fruits

Goal. The study aimed primarily at monitoring the walnut fly Rhagoletis complete Cresson and other fly species damaging the walnut tree Juglans regia L. Methods. Monitoring of the walnut fly R. completa was conducted using EC Firuț traps with food attractants and yellow Card Cue traps, placed 2.5 meters above the ground. The traps were installed at the end of May and the beginning of June, both in industrial walnut orchards and isolated walnut stands in urban areas. Results. Harvesting of damaged fruits began in mid-August, and the analysis involved removing the endocarp and examining the kernel to count the ontogenetic stages of pest species. During, the spring-summer period, no walnut flies were found in the traps, but a few specimens of Rhagolethis cerasi were observed. By the end of summer, two species of flies were identified. The first species, Polyodaspis ruficornis, the second species, Odinia meijerei. They can be taxonomically differentiated by pupae and adults. Conclusions. Monitoring with food pheromones did not indicate the presence of R. completa in the central region of Moldova, but characteristic damage of this species was observed. Fruit analysis showed that the damage was caused by the cereal fly P. ruficornis. Maximally, up to 97 pupae and larvae were found in a single fruit. In the stations, an average number of 0.01 to 18.4 per 50 analyzed fruits was recorded, which constituted 68% of affected fruits. Additionally, parasitism of the pupae by more than two species of parasites and from the Pteromalidae, Eulophidae families was observed. The results underscore the importance of ongoing monitoring and research of local pests, as well as their significant impact on walnut production in Moldova. The study highlights the need for effective pest management measures to protect walnut crops and maintain sustainable production.