Aleurocanthus spiniferus, an alien invasive threat to Europe. AssociatEd bacterial community and natural enemies

Aleurocanthus spiniferus also known as orange spiny whitefly (OSW), is a pest native to tropical Asia that in the last century has spread throughout Asia, reaching Africa, Australia, and Pacific islands. In 2008 the first European OSW population was recorded in Apulia region (South East Italy) and allowed EPPO to add the species as a quarantine threat to Europe now in the A2 list. In the following years OSW spread and invaded new territories of Italy, Croatia and Montenegro. Although OSW polyphagy is already well-known, new associations with autochthonous and allochthonous plants have been reported showing its host-shifting ability. To counteract an upcoming pan-Mediterranean invasion updated bio-ethological information of the pest and the role of possible natural enemies are essential to implement a correct IPM strategy. Field samplings have been aimed at the identification of natural enemies and the evaluation of their efficacy. Furthermore, through insect small-RNA sequencing and by Denaturing Gradient Gel Electrophoresis (DGGE) technique coupled with 16S-rRNA gene sequencing, the primary symbiotic bacteria of OSW have been identified. Sampling on natural enemies highlighted the presence of predatory species belonging to the Coccinellidae family. Besides to the almost ineffective populations of Oenopia conglobata and Clithostetus arcuatus, new findings detected scattered Delphastus sp. populations along the western coast of Italy. Both adult and larvae of this ladybird species preyed OSW developmental stages. The evaluation of the role of Delphastus sp. as biocontrol agent is underway. The first study on OSW microbiota allowed to find symbiotic bacteria commonly associated with the genus Aleurocanthus: Portiera sp., Serratia sp., Wolbachia sp., Rickettsia sp. and, although sporadically, other species. Further studies will target the functional role of these symbionts to develop an effective IPM tailored for Countries at risk.