Trioza adventicia

Tuthill, 1952

syzygium leaf psyllid, lillypilly psyllid, eugenia psyllid

Trioza adventicia is a sap-sucking hemipteran in the Triozidae that creates pit galls on leaves of Syzygium paniculatum. Native to eastern subcoastal Australia, this has been introduced to California, southern Australia, and New Zealand where it affects ornamental plantings. For decades it was misidentified as Trioza eugeniae in scientific literature, horticultural resources, and programs until a 2019 taxonomic revision using morphological and evidence clarified the distinction. The biological control program in the United States unknowingly targeted the correct species despite the nomenclatural confusion.

Trioza adventicia by no rights reserved, uploaded by Jesse Rorabaugh. Used under a CC0 license.

Trioza adventicia (2 inner apical spines on the metatibia) by S.E. Thorpe. Used under a Public domain license.

Pronunciation

How to pronounce Trioza adventicia: //ˈtraɪ.oʊ.zə ædˈvɛn.tɪ.siə//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from the similar Trioza eugeniae by wing shape and venation: T. adventicia has larger, more ovate fore wings with dark infuscation around R and R1, while T. eugeniae has smaller, more elongate fore wings lacking this infuscation. T. eugeniae has vein Rs relatively longer, meeting the closer to the wing apex, and possesses long, fine divergent setae on certain veins that T. adventicia lacks. Male paramere shape differs between . Metatibial spur count is unreliable for separation. confirms species distinction.

Images

Appearance

have larger, slightly more ovate fore wings compared to the similar T. eugeniae, with dark infuscation around R and R1. Vein Rs is relatively shorter, meeting the further from the wing apex. The wings lack long, fine divergent setae on certain veins. Male parameres are somewhat broadly pyriform with slightly more sclerotized apices. The metatibial spur configuration (typically two inner and one outer) is inconsistent and unreliable for separation. Nymphs develop within pit galls in leaves.

Habitat

Eastern subcoastal Australia in native range; introduced occur in urban and ornamental settings in southern Australia, New Zealand, and California where plants are cultivated.

Distribution

Native to eastern subcoastal Australia; introduced to southern Australia, New Zealand, and the United States (California).

Diet

Feeds on phloem sap of Syzygium paniculatum.

Host Associations

Syzygium paniculatum - plantCreates pit galls in leaves; nymphal development occurs within galls

Life Cycle

Nymphs form pit galls in leaves of the plant. Specific details of , nymphal instars, and not documented in available sources.

Behavior

Nymphs induce pit gall formation in leaves, which stunts plant growth. Subject to nearly 30 years of taxonomic misidentification under the name T. eugeniae.

Ecological Role

Herbivore that induces gall formation on plants; serves as target for programs using imported agents.

Human Relevance

Significant pest of ornamental Syzygium paniculatum (lillypilly, brush cherry) in horticulture and landscaping. Target of programs in the United States, which successfully imported appropriate agents despite the being misidentified as T. eugeniae at the time.

Similar Taxa

Trioza eugeniaeHistorically confused with T. adventicia for decades; distinguished by smaller, more elongate fore wings lacking dark infuscation around R and R1, longer vein Rs meeting closer to apex, presence of long fine divergent setae on certain veins, and narrowly pyriform male parameres with weakly sclerotized apices. T. eugeniae has restricted distribution in southern subcoastal New South Wales, Australia.

Misconceptions

Widely misidentified as Trioza eugeniae Froggatt, 1901 in ornamental plant industry, literature, and horticultural resources for approximately 30 years. This misidentification persisted in academic literature and practical applications despite the biological control program unknowingly targeting the correct .

More Details

Taxonomic History

A 2019 study using morphological evidence and confirmed T. adventicia and T. eugeniae as distinct , determined that the widespread introduced species on Syzygium paniculatum was T. adventicia, and designated a lectotype for T. eugeniae. The true T. eugeniae is only known from a small region of southeastern Australia.

Biological Control

Despite the taxonomic confusion, the program in the United States that operated under the name T. eugeniae was actually targeting T. adventicia, and successfully imported appropriate agents for this .