Nipponaclerda

Wetlands dominated by stands of Phragmites australis (common reed); in native range found in reed beds associated with lakes and freshwater habitats; in invasive range occupies coastal marshes and freshwater wetlands of the Mississippi River Delta

Native to East Asia including Japan, China, Korea, and Taiwan; invasive in North America with established populations in coastal Louisiana detected in 2016, subsequently spreading to Texas, Mississippi, and Alabama; capable of dispersing across open water to colonize restored patches

In native range, three discrete generations per year with adult female abundance increasing exponentially from July to December; overwintering occurs as immature stages inside host scales or as adult females on reed shoots; in invasive range, population dynamics follow similar seasonal patterns with peak densities in late growing season

Sap-sucking specialist; feeds on Phragmites australis stems; nymphs can temporarily establish on Spartina alterniflora and Schoenoplectus californicus but survival to adulthood occurs only on P. australis

• Phragmites australis - primary hostcommon reed; specialist host required for survival to adulthood; European lineages show lower scale survival than Delta lineages due to higher phenolic and silicon content
• Spartina alterniflora - transient hosttemporary nymph establishment only, no survival to adult
• Schoenoplectus californicus - transient hosttemporary nymph establishment only, no survival to adult

Crawler stage (first-instar nymph) lasts approximately 72 hours and represents the only active dispersal stage; after settling, females become sessile and remain immobile for remainder of life cycle; females are oviparous, carrying fully developed eggs after settling; three generations per year in native range; immature stages overwinter inside host scales or as adult females on reed shoots

Crawlers exhibit active short-distance crawling and passive dispersal via wind, water currents, or hitchhiking; within-plant settlement decisions influenced by plant chemistry and natural enemy pressure; vertical distribution along stems creates population structure affecting parasitoid interactions; gravid females occur more frequently at stem bases in field conditions despite laboratory preference for middle sections

Invasive populations contribute to large-scale dieback of Phragmites australis, reducing biomass production even at low densities; threatens wetland ecosystem services including shoreline stabilization, erosion control, water filtration, and wildlife habitat in the Mississippi River Delta; serves as host for multiple hymenopteran parasitoid species; in native range, population dynamics regulated by parasitism and predation by wintering birds

N. biwakoensis is a serious agricultural and environmental pest in Louisiana, damaging over 80% of reeds in some areas; threatens critical infrastructure including shipping channels and oil infrastructure protected by roseau cane stands; subject to classical biological control research focusing on importation of parasitoids from native range; common names include 'roseau cane mealybug' and 'Phragmites scale insect'

• scale insect
• invasive species
• wetland pest
• Phragmites specialist
• biological control target
• Aclerdidae
• Hemiptera

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• ECOLOGY OF THE ROSEAU CANE SCALE (NIPPONACLERDA BIWAKOENSIS, HEMIPTERA: ACLERDIDAE) IN COASTAL LOUISIANA
• Frequent successful multiparasitism by five parasitoids attacking the scale insect Nipponaclerda biwakoensis
• Plant Chemistry and Enemy Pressure Shape Within-Stem Distribution of the Invasive Scale Nipponaclerda biwakoensis
• Exploratory surveys in Taiwan of the roseau cane scale Nipponaclerda biwakoensis Kuwana (Hemiptera: Aclerdidae) and its associated parasitoids
• Differential oviposition timing by seasonality and oviposition timing of parasitoids of the invasive roseau cane scale (Nipponaclerda biwakoensis) as revealed by multiplex PCR assays
• Within‐plant vertical distributions of the scale insectNipponaclerda biwakoensisand its five parasitoids that exhibit frequent successful multiparasitism on the common reed
• Abundances of five parasitoids attacking the scale insect Nipponaclerda biwakoensis on morphologically changed reed shoots due to damage by a stem‐boring caterpillar
• Seasonal population changes of five parasitoids attacking the scale insect Nipponaclerda biwakoensis on the common reed, with special reference to predation by wintering birds
• Figure 4 from: Sparks V, Kang I, Carrere M, Broadley H, Diaz R (2025) Differential oviposition timing by seasonality and oviposition timing of parasitoids of the invasive roseau cane scale (Nipponaclerda biwakoensis) as revealed by multiplex PCR assays. Journal of Hymenoptera Research 98: 1133-1152. https://doi.org/10.3897/jhr.98.150721
• Figure 5 from: Sparks V, Kang I, Carrere M, Broadley H, Diaz R (2025) Differential oviposition timing by seasonality and oviposition timing of parasitoids of the invasive roseau cane scale (Nipponaclerda biwakoensis) as revealed by multiplex PCR assays. Journal of Hymenoptera Research 98: 1133-1152. https://doi.org/10.3897/jhr.98.150721
• Supplementary material 3 from: Sparks V, Kang I, Carrere M, Broadley H, Diaz R (2025) Differential oviposition timing by seasonality and oviposition timing of parasitoids of the invasive roseau cane scale (Nipponaclerda biwakoensis) as revealed by multiplex PCR assays. Journal of Hymenoptera Research 98: 1133-1152. https://doi.org/10.3897/jhr.98.150721
• Supplementary material 1 from: Sparks V, Kang I, Carrere M, Broadley H, Diaz R (2025) Differential oviposition timing by seasonality and oviposition timing of parasitoids of the invasive roseau cane scale (Nipponaclerda biwakoensis) as revealed by multiplex PCR assays. Journal of Hymenoptera Research 98: 1133-1152. https://doi.org/10.3897/jhr.98.150721
• Supplementary material 2 from: Sparks V, Kang I, Carrere M, Broadley H, Diaz R (2025) Differential oviposition timing by seasonality and oviposition timing of parasitoids of the invasive roseau cane scale (Nipponaclerda biwakoensis) as revealed by multiplex PCR assays. Journal of Hymenoptera Research 98: 1133-1152. https://doi.org/10.3897/jhr.98.150721
• Figure 2 from: Sparks V, Kang I, Carrere M, Broadley H, Diaz R (2025) Differential oviposition timing by seasonality and oviposition timing of parasitoids of the invasive roseau cane scale (Nipponaclerda biwakoensis) as revealed by multiplex PCR assays. Journal of Hymenoptera Research 98: 1133-1152. https://doi.org/10.3897/jhr.98.150721
• Figure 1 from: Sparks V, Kang I, Carrere M, Broadley H, Diaz R (2025) Differential oviposition timing by seasonality and oviposition timing of parasitoids of the invasive roseau cane scale (Nipponaclerda biwakoensis) as revealed by multiplex PCR assays. Journal of Hymenoptera Research 98: 1133-1152. https://doi.org/10.3897/jhr.98.150721
• A key to the flat grass scale genus Nipponaclerda (Hemiptera, Coccomorpha, Aclerdidae).