Journal of Applied Entomology (2022) 146, 596-606

Amado O. Cortez Jr, Cheng-Lung Chu, Hannah J. Broadley, Yong-Sin Lo, Yu-Chun Chen, Michael W. Gates, Laura A. Meyerson, Kim A. Hoelmer, Juli R. Gould and Shaw-Yhi Hwang (2022)
Exploratory surveys in Taiwan of the roseau cane scale Nipponaclerda biwakoensis Kuwana (Hemiptera: Aclerdidae) and its associated parasitoids
Journal of Applied Entomology 146 (5), 596-606
Abstract: Roseau cane (Phragmites australis (Cav). Trin. ex Steud.) is the dominant plant species of the Mississippi River Delta in Louisiana, USA, and protects the coastline from erosion and storm-related impacts, maintaining shipping channels and oil infrastructure. Widespread dieback and thinning of P. australis were noted in the Mississippi River Delta in the fall of 2016. Invasive populations of the roseau cane scale (Nipponaclerda biwakoensis Kuwana), which is native to Asia, were found at outbreak levels in the stands. Subsequent research implicated N. biwakoensis in the diebacks. As a safe, cost-effective and long-term approach for managing this invasive scale, classical (importation) biological control methods are being considered. As the first step to developing biological control, research evaluating the natural enemies of the N. biwakoensis in the native range is necessary. This study investigated the population dynamics of N. biwakoensis and its associated parasitoids on P. australis in Taiwan from July to November 2019 at five study sites. Scale densities across sites increased over the growing season, peaking in September at 85.77 ± 6.36 scales/stem, which is half as dense as found in Louisiana. Mean parasitism of adult female scales across sites and season was 14.00%, while parasitism on immature scales was lower (3.00%). Four parasitoid wasp species were reared from the scale—Asytymachus lasallei Noyes and Higashiura, Boucekiella depressa Hoffer, Neastymachus japonicus Tachikawa and Aprostocetus sp. Westwood. Neastymachus japonicus was the dominant species parasitizing adult female scales, while A. lasallei was the dominant wasp species parasitizing immature scales. Astymachus lasallei and B. depressa were frequently reared from the same individual host, suggesting multiparasitism or hyperparasitism. Overall, this study provides important information on the identity and role of parasitoids of N. biwakoensis in its native range, which will aid in developing a classical biological control programme for the invasive N. biwakoensis.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Hannah J. Broadley, Laura A. Meyerson, Kim A. Hoelmer, Juli R. Gould, Shaw-Yhi Hwang

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation
classical biocontrol/new introduction

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Nipponaclerda biwakoensis		Taiwan
	Nipponaclerda biwakoensis		U.S.A. (mid S)
Astymachus lasallei (parasitoid)	Nipponaclerda biwakoensis		Taiwan
Boucekiella depressa (parasitoid)	Nipponaclerda biwakoensis		Taiwan