Details on the taxonomy and biology of Rhizoecus hibisci
The root mealybug Rhizoecus hibisci (Homoptera: Pseudococcidae – EPPO A1 quarantine pest) is frequently intercepted by the Netherlands on bonsais from China. In general, root mealybugs cause slow plant growth. Serious damage was only noticed once on imported Serissa foetida in a glasshouse in the Netherlands in 1992. Usually, damage is rather limited, despite the presence of high numbers of R. hibisci. In general, little information is available on the biology and morphology of pre-adult stages of this pest. These aspects were studied in the laboratory in the Netherlands. It was observed that at 21°C, one generation lasted 61 days on Serissa and much longer on Nerium (approximately 90 days). Numbers of eggs in ovisacs varied from 11 to 84 on different hosts. On average, eggs hatch after 9 days. 3 nymphal stages were observed followed by pupa and adult stages. Although males were never seen in intercepted bonsais, they could be observed in the laboratory on Serissa. A list of host plants gathered from the literature and observations is given: Crinum asiaticum (Amaryllidaceae), Nerium oleander (Apocynaceae), Dieffenbachia (Araceae), Cryptanthus (Bromeliaceae), Dichorisandra thyrsiflora (Commelinaceae), Carex (Cyperaceae), Pelargonium (Geraniaceae), Hakonechloa macra (Poaceae), Cuphea hyssopifolia (Lythraceae), Hibiscus rosa-sinensis (Malvaceae), Calathea makoyama (Marantaceae), Ficus benjamina (Moraceae), Areca, Kentia, Phoenix canariensis, P. roebelenii, Rhapis excelsa, Sabal (Arecaceae), Sageretia thea (Rhamnaceae), Serissa foetida (Rubiaceae), Celtis, Zelkova serrata (Ulmaceae). Finally, detailed descriptions of nymphal instars are also presented.
Sources
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Jansen, M.G.M. (2001) Instar identification and some notes about the life cycle of Rhizoecus hibisci Kawai ; Takagi (Coccoidea: Pseudococcidae).
Bollettino di Zoologia Agraria e di Bachicoltura, Serie II, 33(3), 53-56.
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