Illinoia liriodendri

Distinguished from other aphids by exclusive association with Liriodendron tulipifera as host plant. Molecular identification (DNA barcoding) may be required for definitive separation from congeneric species, particularly in invaded ranges where it co-occurs with native aphids.

Urban forests, parks, and ornamental plantings of tuliptree (Liriodendron tulipifera). Found in both pit-planted and ground-planted trees. Native range occupies temperate deciduous forests of eastern North America; invasive populations established in urban environments across southern Europe.

Native to eastern North America, from Ontario and British Columbia (Canada) south to Louisiana and North Carolina (USA), with populations in California. Invasive in Europe: confirmed in France, Germany, Italy, Slovenia, UK (England and Wales), Spain, Croatia, Hungary, Slovakia, and Serbia. Also recorded in Japan and Korea.

Monoecic-holocyclic annual cycle with highest infestation levels recorded in May and June in European populations. Population dynamics vary among localities.

Phloem sap feeder specializing on Liriodendron tulipifera (tuliptree/tulip poplar). Honeydew production increases with infestation severity.

• Liriodendron tulipifera - primary hostExclusive host; tuliptree or tulip poplar, family Magnoliaceae
• Magnolia grandiflora - secondary hostSouthern magnolia; recorded as occasional host in distribution records

Monoecic-holocyclic annual cycle: completes entire life cycle on single host species (Liriodendron tulipifera) with both sexual and asexual generations. Overwintering as eggs. Peak populations occur in late spring (May-June in Europe).

Forms dense colonies on leaves and shoots. Produces copious honeydew that drips from infested trees, creating aesthetic problems and supporting growth of sooty molds. High-density aggregations on young trees can cause significant impact.

Herbivore and honeydew producer. Serves as prey for diverse natural enemy complex including Coccinellidae (lady beetles, comprising >95% of predators with positive numerical response to aphid density) and parasitoid wasps (Aphidiinae and Aphelinidae). In invaded ranges, native European parasitoids such as Areopraon silvestre (Braconidae) have rapidly colonized the aphid, contributing to biological control.

Primary pest of ornamental tuliptrees in urban landscapes. Heavy infestations impact young trees and produce nuisance honeydew. Considered the most important insect pest of Liriodendron tulipifera in urban settings. Subject to management through biological control using natural enemies and potentially chemical interventions.

• Other Illinoia speciesCongeneric aphids may require molecular identification for separation; host specificity to Liriodendron is key diagnostic feature
• Macrosiphum spp.Similar large aphids in tribe Macrosiphini; distinguished by host plant association and morphological details

• aphid
• pest
• invasive species
• urban forestry
• tuliptree
• honeydew producer
• biological control
• North American native
• European invasion

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Green Tree Ant Sister Act: Oecophylla smaragdina — Bug of the Week
• Archive — Bug of the Week
• Illinoia liriodendri . [Distribution map].
• Tuliptree Aphid Scientific Name: Illinoia liriodendri (Monell) (Insecta: Hempitera: Aphididae)
• Phenology, population trends and natural enemy complex of Illinoia liriodendri in Spain
• Genetic identification of new alien pest species Illinoia liriodendri and its parasitoid Areopraon silvestre in Croatia
• Genetic identification of new alien pest species Illinoia liriodendri and its parasitoid Areopraon silvestre in Croatia
• Survey of the parasitoids of the tuliptree aphid,Illinoia liriodendri (Hom: Aphididae), in northern California