Taxonomic information	Current valid scientific name: Takahashia japonica Synonyms: Pulvinaria japonica, Takahashia wuchangensis Name used in the EU legislation: – Order: Hemiptera Family: Coccidae Common name: Asiatic string cottony scale, string cottony scale Name used in the Dossier: Takahashia japonica
Group	Insects
EPPO code	TAKAJA
Regulated status	Takahashia japonica is neither regulated in the EU, nor anywhere in the world. T. japonica meets the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest (EFSA PLH Panel, 2023a).
Pest status in the UK	Takahashia japonica is present in the UK (Tuffen et al., 2019). The pest was recorded from West Berkshire in 2018 on Magnolia in a private garden (Malumphy et al., 2019; Tuffen et al., 2019). According to the Dossier Section 5.0 T. japonica is present in the UK: not widely distributed and not under official control.
Pest status in the EU	Takahashia japonica is present in Croatia and Italy (Limonta and Pellizzari, 2018; Landeka et al., 2021). In Italy, the pest was first reported in 2017 from the Northern provinces of Milano and Varese. High infestations of T. japonica indicated that the pest was most probably introduced some years before its detection (Limonta and Pellizzari, 2018). In Croatia, the pest was observed for the first time in 2019 from the city of Pula (Landeka et al., 2021) and eradication measures were applied by cutting down the infested branches and by applying insecticides (EPPO, online). There is no information whether the eradication was successful or not.
Host status on Acer	Acer pseudoplatanus (Limonta and Pellizzari, 2018), A. buergerianum (Wang et al., 2016), A. negundo and A. pseudosieboldianum (Suh, 2020) are reported to be hosts for T. japonica. There is no information on whether Acer platanoides may be hosts for T. japonica.
PRA information	Available Pest Risk Assessments: – Scientific opinion on pest categorisation of Takahashia japonica (EFSA PLH Panel, 2023a); – Scientific opinion on the commodity risk assessment of Malus domestica plants from United Kingdom (EFSA PLH Panel, 2023b); – UK Risk Register Details for Takahashia japonica (DEFRA, online).
Other relevant information for the assessment
Biology	Takahashia japonica is a soft‐scale insect native to Asia (Limonta et al., 2022), where it is reported from China, India, Japan, South Korea and Taiwan. The species has been introduced in Europe (Croatia, Italy and the UK) (Limonta et al., 2022; García Morales et al., online). Takahashia japonica is a parthenogenetic species. The scale has three development stages: egg, nymph (two instars) and adult. In Italy, it has one generation annually. Females start laying eggs from late April till early May. The female settles on the twig and in several days creates an ovisac. The ovisac is white string‐like loop that can be up to 7 cm long. Fecundity is very high. It was counted that there are around 1,200 eggs in a 1‐cm length of the ovisac. Eggs start to hatch into first‐instar nymphs (crawlers) in early June. The crawlers are small, about 740 μm long and 325 μm wide. The crawlers are the main natural dispersal stage, and they migrate from twigs to underside of leaves. During this migration, the crawlers can be easily carried by the wind, insects or birds to other host plants. Long‐distance dispersal is with infested traded plants. In late August and in September, the population consists of second‐instar nymphs, which are about 1.3 mm long.
	In September and October, the second instar nymphs migrate back from leaves to twigs, to overwinter. Overwintering second‐instar nymphs are brown and covered by transparent wax plates. After overwintering, the nymphs resume activity from March onwards and reach the length of about 1.5 mm and the width of 0.5 mm. The moult to the adult female occurs at the same overwintering site. The first moults occur in early April, and the whole population reaches the adult stage over about 10 days. The adult female's body size increases quickly from about 1.5 to 6–7 mm long and 5 mm wide. In this growing phase, the pre‐ovigerous females feed and produce honeydew droplets (Limonta et al., 2022). Several natural enemies of T. japonica are recorded in the literature. The scale was found to have been parasitised in Italy and the UK (Tuffen et al., 2019; Limonta et al., 2022). Possible pathways of entry for T. japonica are plants for planting (except seeds bulbs and tubers) (DEFRA, online).
Symptoms	Main type of symptoms	Heavy infestations of T. japonica on twigs cause dieback and necrosis of buds. It is mainly harmful to young trees (Limonta et al., 2022). The production of honeydew by females is limited (Limonta et al., 2022). From late April onwards (when the females start oviposition), the long white ovisacs hanging from the twigs and branches can be seen. Moreover, the ovisacs persist on the plants long after the eggs have hatched and are still present in winter (Limonta et al., 2022).
	Presence of asymptomatic plants	Low initial infestations in the absence of ovisacs may be overlooked.
	Confusion with other pests	Takahashia japonica can be hardly confused with other scales, due to the characteristic ovisacs hanging from the twigs and branches (Malumphy et al., 2019).
Host plant range	Takahashia japonica is highly polyphagous species with total of 35 known host species in 17 families (Limonta et al., 2022). The hosts are Acer negundo, A. buergerianum, A. pseudoplatanus, A. pseudosieboldianum, Albizia julibrissin, Alnus japonica, Carpinus betulus, Celtis australis, C. sinensis, Citrus sp., Cornus officinalis, Cydonia oblonga, Diospyros kaki, Juglans regia, Lespedeza sp., Lespedeza bicolor, Liquidambar styraciflua, Loropetalum chinense, Magnolia kobus, M. obovate, Malus pumila, Morus sp., M. alba, M. nigra, Parthenocissus tricuspidata, Prunus cerasifera, P. glandulosa, P. salicina, P. tomentosa, Pyrus serotina, Rhododendron schlippenbachii, Robinia pseudoacacia, Salix chaenomeloides, S. glandulosa, Styphnolobium japonicum, Ulmus davidiana and Zelkova serrata (Wang et al., 2016; Limonta and Pellizzari, 2018; Suh, 2020; Limonta et al., 2022; García Morales et al., online).
Reported evidence of impact	There are no reports of economic or ecological damage induced by T. japonica in Asia (Malumphy et al., 2019). According to Limonta et al. (2022) in Italy, its impact on urban trees has mostly involved some honeydew production and the unsightly appearance of infested trees – long white ovisacs hanging from the branches. Takahashia japonica can potentially reduce esthetical value of plants (Malumphy et al., 2019). No data about damage on Acer species is available.
Evidence that the commodity is a pathway	According to DEFRA (online), T. japonica can travel with plants for planting. Therefore, the commodity is a pathway for T. japonica.
Surveillance information	According to the Dossier Section 5.0, T. japonica is not under official surveillance in the UK, as does not meet criteria of quarantine pest for Great Britain.