Adult female pupillarial; in life, concealed inside sclerotized exuviae of second instar, which is dark brown to black, slightly convex, sometimes covered with a thin film of wax; single dark exuviae terminal, sometimes lost FOFOL.jpg . Scale cover of male shorter than that of female, fairly flat, elongate oval with terminal mid-brown exuviae FOFOL.jpg .
Slide-mounted adult female pupillarial, body elongate and membranous; antennal bases not enlarged; without any membranous process between antennal bases FOFOO.jpg . Pygidium with at least a few 2-barred ducts; median lobes not zygotic, projecting from margin of pygidium; feeding on bamboos FOFOP.jpg . Second instar pygidium FOFO2I.jpg .
Formosaspis formosana has been recorded from hosts belonging to the plant family Gramineae, especially the genus Bambusa (Borchsenius, 1966).
Affected plant stages: vegetative growing, flowering and fruiting stages
Affected plant parts: on stem underneath leaf sheaths
Biology and ecology
The biology of F. formosana has not been studied. Crawlers are the primary dispersal stage and move to new areas of the plant or are dispersed by wind or animal contact. Mortality due to abiotic factors is high in this stage. Dispersal of sessile adults and eggs occurs through human transport of infested plant material.
No mention of the economic impact of F. formosana has been found in the literature, possibly because any such papers are in Chinese.
Detection and inspection methods
Peel back the leaf sheaths of bamboos and examine the exposed stem for dark brown to black, slightly convex scale covers, sometimes covered with a thin film of wax, with a single dark terminal exuviae.
The natural enemies of F. formosana have not been studied.
See Formosaspis formosana distribution.
Microscopic examination of slide-mounted adult females is required for authoritative identification to species.
Formosaspis stegana Ferris FOSTS.jpg could be misidentified as F. formosana, but differs in having two pairs of pygidial lobes more or less developed, about 10 stigmatic pores associated with each anterior spiracle FOSTP.jpg, and the second instar has the long axis of each marginal macroduct orifice perpendicular to the margin FOST2I.jpg. In contrast, F. formosana has only one pair of pygidial lobes FOFOP.jpg, only 1 or 2 stigmatic pores associated with each anterior spiracle, and the second instar has the long axis of each marginal macroduct orifice lying parallel with the adjacent margin FOFO2I.jpg. Formosaspis stegana is known from China (Yunnan) on stems of species of Arundinaria and Bambusa sp. (Danzig and Pellizzari, 1998; Tao, 1999; Ferris, 1952). FOSTL.jpg
Formosaspis takahashii Lindinger (Protodiaspis nigra Takahashi is a synonym) FOTAS.jpg could easily be misidentified as F. formosana, but differs in having more dorsal (about 4) and ventral (about 12) ducts on the pygidium FOTAP.jpg. In contrast, F. formosana has about 2 dorsal and few if any ventral ducts on the pygidium FOFOP.jpg. Formosaspis takahashii is known from Taiwan and China (Anhui, Yunnan, Zhejiang) on leaves of species of Arundinaria, Bambusa and Phyllostachys (Tao, 1999; Takagi, 1970; Ferris, 1952). FOTA2I.jpg
Formosaspis formosana is originated in China or Taiwan, and has not been recorded outside these countries.
Hong Kong: present, no further details (Tao, 1999; Takagi, 1970)
Taiwan: present, no further details (Tao, 1999; Takagi, 1970)