Mississippi-river-delta
Guides
Nipponaclerda biwakoensis
Roseau Cane Mealybug, Phragmites Scale Insect
Nipponaclerda biwakoensis is a scale insect in the family Aclerdidae, native to East Asia (Japan, China, Korea) and first described from Japan in 1907. It is a specialist herbivore on Phragmites australis (common reed), feeding on phloem sap. The species was detected as an invasive pest in Louisiana's Mississippi River Delta in 2016, where it has caused extensive dieback of roseau cane—the dominant coastal wetland plant critical for shoreline stabilization. In its invasive range, densities can exceed 150 individuals per meter of stem and damage over 80% of reeds in affected areas. The species has since spread to Texas, Mississippi, and Alabama. In its native range, population dynamics are influenced by five species of hymenopteran parasitoids and predation by wintering birds.