Bruno, P.; Rahman, S.; Balakrishnan, K.; Kais, B.; Gross, J.; Rostas, M.

The planthopper Pentastiridius leporinus (Hemiptera: Cixiidae) is the primary vector of two phloem restricted prokaryotes, which can cause the disease syndrome de basses richesses (SBR) in sugar beet (Beta vulgaris L.). Heavy infestations of this insect have contributed to significant yield losses in Central Europe, but little is known about how different B. vulgaris genotypes influence vector behavior and performance. Understanding such interactions is critical for both pest management and the development of sugar beet cultivars that are less favorable to the vector. We investigated oviposition decisions, nymphal development, and belowground chemotaxis of P. leporinus using twelve B. vulgaris genotypes: eight sugar beet genotypes with contrasting SBR tolerance, two Swiss chard, and two beetroot varieties. In no choice assays, females oviposited at similar rates on all tested genotypes, indicating broad host suitability. However, in three choice tests, significant differences emerged, with several genotypes receiving more egg batches than the reference variety Vasco. Despite adult host preferences, nymphal survival, growth, and instar development did not differ among genotypes. In contrast, belowground olfactometer assays revealed that nymphs exhibited clear chemotactic responses: several genotypes attracted significantly more individuals than others. This represents the first documentation of chemotactic host location in P. leporinus nymphs. Our findings reveal a mismatch between adult oviposition preference and nymphal performance, a pattern not uncommon in other generalist herbivores. Both adult and nymphal behaviors were nevertheless influenced by genotype-specific traits, likely linked to plant chemistry. Identifying these cues could inform breeding strategies aimed at reducing vector attraction, thereby complementing pathogen-targeted approaches and supporting integrated management of SBR in sugar beet.