Invasion of Nipponaclerda biwakoensis (Hemiptera: Aclerdidae) and associated Phragmites australis dieback in southern Louisiana, U.S.A

Authors: KNIGHT, IAN - Louisiana State University; WILSON, BLAKE - Louisiana State University; GILL, MADELINE - Louisiana State University; AVELES, LESLIE - Louisiana State University; CRONIN, JAMES - Louisiana State University; NYMAN, JOHN - Louisiana State University; Schneider, Scott; SCOTT, A. - Louisiana State University; DIAZ, RODRIGO - Louisiana State University

Submitted to: Biological Invasions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2018
Publication Date: 5/15/2018
Citation: Knight, I.A., Wilson, B.E., Gill, M., Aveles, L., Cronin, J.T., Nyman, J.A., Schneider, S.A., Scott, A., Diaz, R. 2018. Invasion of Nipponaclerda biwakoensis (Hemiptera: Aclerdidae) and associated Phragmites australis dieback in southern Louisiana, U.S.A. Biological Invasions. 20(10):2739-2744. https://doi.org/10.1007/s10530-018-1749-5.
DOI: https://doi.org/10.1007/s10530-018-1749-5

Interpretive Summary: Many scale insects are recognized as highly invasive pests, responsible for billions of dollars of annual agricultural losses resulting from direct damage to plants and associated management costs. A newly invasive species of scale insect from Asia is causing high levels of die-off in reed grasses along the Louisiana coast. The loss of these reeds can be incredibly damaging, with the potential to impact erosion, water quality, natural ecosystems, and even the oil industry - since these grasses reduce wave action in an area of the gulf where underwater drilling occurs. This article is the first report of the establishment of this species in the United States, with a discussion of ongoing research efforts to understand and mitigate the impact of this new invasive species.

Technical Abstract: Common reed, Phragmites australis (Cav.) Trin. Ex Steud., is the dominant emergent vegetation in the lower Mississippi River Delta (MRD), Louisiana, USA and is comprised primarily of introduced lineages of different phylogeographic origins. Dense stands of P. australis are important for protecting marsh soils from wave action and storm surges. In the Fall of 2016, while investigating symptoms of die-back of Phragmites stands in the lower marsh, a non-native scale was found infesting affected stands in high densities. Identified as Nipponaclerda biwakoensis (Kuwana) (Hemiptera: Aclerdidae), the scale was well established across the lower MRD. This report represents the first recorded population of Nipponaclerda biwakoensis in North America. Intriguingly, there are noticeable differences in die-back and in scale densities among different lineages of Phragmites in the MRD, with stands of the well-known European invasive lineage appearing healthier and having lower scale densities than other Phragmites lineages. Given its apparent relationship with the die-back syndrome, the scale may have serious implications for the health and stability of Phragmites marsh communities across coastal Louisiana. Efforts are currently underway to investigate the role of the scale and other abiotic stressors in the die-backs and potential management solutions.