The occurrence of the invasive Orange Spiny Whitefly (Aleurocanthus spiniferus) has expanded rapidly in Italy, prompting responses from both native and unintentionally introduced natural enemies. Through field monitoring, morpho-molecular identification, and phenological analysis, a multi-species parasitoid complex acting on this pest was revealed. In addition to the predominant activity of Eretmocerus iulii, this study reports the first European detection of Encarsia smithi, genetically confirmed as belonging to haplogroup I, a lineage previously associated with A. spiniferus in Asia. Occasional parasitization by Cales noacki was also observed. Seasonal patterns suggest a possible ecological complementarity between Er. iulii and E. smithi, which may contribute to the suppression of A. spiniferus populations. Although climatic variables showed weak correlations with infestation or parasitism rates, a slight positive relationship was observed between rainfall and whitefly abundance. The increasing biocenotic complexity, reflected by the diversity and interactions among parasitoid species, indicates an emerging ecological balance. These findings underscore the potential role of unintentional biological control in supporting agroecosystem resilience.

The woolly whitefly, Aleurothrixus floccosus, is likely a Neotropical origin species that has spread globally. Introduced to France in 1969, it became a pest in southern European citrus groves, first reported in Italy in 1974. Integrated management using biological control agents is crucial due to the low efficacy of chemical controls. Nymphs produce waxy filaments and honeydew, limiting insecticide contact. Natural enemies, especially from Neotropics, have been documented. The parasitoids Amitus spiniferus and Cales noacki were released in France in 1970 and later observed in Liguria, Italy. In the Campania region, C. noacki was first found on Aleurotuba jelineki in 1984 and this finding preceded the first report of A. floccosus in the same area. Subsequently, C. noacki was also introduced in other regions where it showed better adaptation throughout the Italian territory, reaching high parasitization levels on the woolly whitefly nymphs. After many years since the last field investigations, surveys in 2024–2025 in organic citrus groves in central and southern Italy identified additional parasitoids. Besides C. noacki and A. spiniferus, Eretmocerus paulistus and Signiphora xanthographa were found for the first time in Italy. Both species were originally described from the Neotropical ecozone. The aphelinid finding represents its first documented establishment in Italy, while the signiphorid one represents a new record for the European fauna. E. paulistus is a primary parasitoid, while S. xanthographa is a hyperparasitoid that can limit the effectiveness of other parasitoids. The interaction of these parasitoids resulted in high parasitism rates for A. floccosus nymphs. Preserving the current complexity of parasitoids in integrated pest management (IPM) programs could effectively control the woolly whitefly in central and southern Italy.