Classical Biological Control of Diaphorina citri in Cyprus: High Parasitism, Population Suppression, and the First Record of the Hyperparasitoid,

ABSTRACT

Asian citrus psyllid, Diaphorina citri , was first detected in Cyprus in 2023. This finding initiated an eradication campaign and a classical biological control program based on the introduced ectoparasitoid Tamarixia radiata . Recent integrative taxonomic work revealed the presence of a second primary parasitoid species, Tamarixia citricola , associated with D. citri nymphs in Cypriot citrus orchards. Here, we provide a post‐release monitoring update on this biological control program based on field surveys conducted in late October 2025 at citrus sites selected because of previous records of D. citri or recent reports of psyllid activity from the Cypriot Plant Health Services. Overall, adult D. citri abundance was very low; adults were absent from nearly all orchards and were detected at clearly higher levels in only one site, where 60% of tap‐sampled flush shoots were positive for adult presence. Nymphs showed a similar pattern, with only sparse, low‐density colonies detected across the surveyed orchards. Importantly, the site with the highest D. citri density also showed the highest nymph parasitism (96.2%), consistent with strong parasitoid‐associated suppression. Of the primary parasitoids that emerged, 96.9% were T. radiata , whereas 3.1% were T. citricola . For the first time in Cyprus, we also recorded the hyperparasitoid Marietta leopardina , which reached 26.7% hyperparasitism and showed a marked association with primary parasitoids developing in third‐instar nymphs. These results support the important role of T. radiata in the current classical biological control program in Cyprus and underscore the need for continued monitoring to understand better emerging trophic interactions that may influence long‐term outcomes.