Taxonomic information	Current valid scientific name: Scirtothrips dorsalis Synonyms: Anaphothrips andreae, Anaphothrips dorsalis, Anaphothrips fragariae, Heliothrips minutissimus, Neophysopus fragariae, Scirtothrips andreae, Scirtothrips dorsalis padmae, Scirtothrips fragariae, Scirtothrips minutissimus, Scirtothrips padmae Name used in the EU legislation: Scirtothrips dorsalis Hood [SCITDO] Order: Thysanoptera Family: Thripidae Common name: Assam thrips, chilli thrips, flower thrips, strawberry thrips, yellow tea thrips, castor thrips Name used in the Dossier: Scirtothrips dorsalis
Group	Insects
EPPO code	SCITDO
Regulated status	The pest is listed in Annex II of Commission Implementing Regulation (EU) 2019/2072 as Scirtothrips dorsalis Hood [SCITDO]. Scirtothrips dorsalis is included in the EPPO A2 list (EPPO, online_a). The species is a quarantine pest in Israel, Mexico, Morocco and Tunisia. It is on A1 list of Brazil, Chile, Egypt, Kazakhstan, Russia, Türkiye, Ukraine, the UK and EAEU (Eurasian Economic Union – Armenia, Belarus, Kazakhstan, Kyrgyzstan and Russia). It is on A2 list of Bahrain (EPPO, online_b).
Pest status in the UK	Scirtothrips dorsalis was found for the first time in the UK in December 2007 in a greenhouse (Palm House) at Royal Botanic Garden Kew in South England (Scott‐Brown et al., 2018). Since 2008 the discovered population has been under official control by the plant health authorities with the objective of achieving complete eradication (Collins, 2010). Eradication measures were applied and since 2019 the pest was no longer found (EPPO, online_c). According to the Dossier Section 5.0, S. dorsalis is present: not widely distributed and under official control. This is a regulated quarantine pest for GB. It has been found in one tropical glasshouse at Kew (Botanic Gardens, Richmond, London), and at no other location. It has been subject to control measures for many years, and there have been no recent records – last official records are from 2012. It is possible that this pest has been eradicated, but the UK is unable to officially confirm this at this time. Therefore, the Panel cannot exclude that the pest is still present in the UK.
Pest status in the EU	Scirtothrips dorsalis is present with restricted distribution in Spain and transient in the Netherlands (EPPO, online_c). According to EUROPHYT Oubreaks database (online), there were three outbreaks, which are under eradication: in the Netherlands (2019) on plants for planting of Podocarpus; in Spain (2016) on plants of citrus and pomegranate; in Spain (2019) in mango greenhouses. Scirtothrips dorsalis is continuously intercepted in the EU points‐of‐entry on different commodities: plants for planting; cut flowers and branches with foliage; fruits and vegetables (EUROPHYT/TRACES‐NT, online).
Host status on Acer	Acer palmatum is reported host of S. dorsalis (Ohkubo, 1995; CABI, online). Scirtothrips dorsalis is a pest of other Acer species such as A. buergerianum and A. sieboldianum (Ohkubo, 1995; CABI, online). There is no information on whether S. dorsalis can also attack A. pseudoplatanus.
PRA information	Available pest risk assessments: – CSL pest risk analysis for Scirtothrips dorsalis (MacLeod and Collins, 2006); – Pest Risk Assessment Scirtothrips dorsalis (Vierbergen and van der Gaag, 2009); – Scientific Opinion on the pest categorisation of Scirtothrips dorsalis (EFSA PLH Panel, 2014); – Scientific opinion on the commodity risk assessment of Jasminum polyanthum plants from Israel (EFSA PLH Panel, 2020); – Scientific Opinion on the commodity risk assessment of Ficus carica plants from Israel (EFSA PLH Panel, 2021a); – Scientific Opinion on the commodity risk assessment of Persea americana from Israel (EFSA PLH Panel, 2021b); – Scientific Opinion on the commodity risk assessment of Jasminum polyanthum unrooted cuttings from Uganda (EFSA PLH Panel, 2022a); – Scientific Opinion on the commodity risk assessment of Ligustrum delavayanum topiary plants grafted on Ligustrum japonicum from the UK (EFSA PLH Panel, 2022b); – UK risk register details for Scirtothrips dorsalis (DEFRA, online).
Other relevant information for the assessment
Biology	Scirtothrips dorsalis is a thrips present in Africa (Cote d'Ivoire, Kenya, Uganda), Asia (Bangladesh, Brunei Darussalam, China, India, Indonesia, Iran, Israel, Japan, Malaysia, Myanmar, North Korea, Pakistan, Philippines, South Korea, Sri Lanka, Taiwan, Thailand, Vietnam), Europe (the Netherlands, Spain, Türkiye, the UK), North America (Caribbean, Florida, Georgia, Hawaii, Mexico, Texas), Oceania (Australia, Papua New Guinea, Solomon Islands) and South America (Brazil, Colombia, French Guiana, Suriname, Venezuela) (CABI, online; EPPO, online_c). In the literature, its origin is contradictory, it is reported as either native to Asia, Australasia or South Africa. For more details, refer to Mound and Palmer (1981), Seal et al. (2006), Hoddle et al. (2008), Kumar et al. (2013) and CABI (online). According to Dickey et al. (2015), S. dorsalis is a species complex that includes at least nine cryptic species and two morphologically distinguishable species (S. oligochaetus and S. aff. dorsalis). Scirtothrips dorsalis develops through five life stages: egg, larva (two instars), prepupa, pupa and adult (Dev, 1964; Kumar et al., 2013). They can be found on all the aboveground plant parts (Kumar et al., 2014), and they damage young leaves, buds, tender stems and fruits by sucking tender tissues with their stylets (Kumar et al., 2013). Temperature thresholds for development are 9.7°C and 32°C, with 265 degree‐days required for development from egg to adult (Tatara, 1994). The adult can live up to 13–15 days (Kumar et al., 2013, citing others). Scirtothrips dorsalis can have annually up to 8 generations in Japan (Tatara, 1994). In the US, it was estimated by a degree‐day model that in some of the southern states the thrip can potentially have up to 18 generations per year (Nietschke et al., 2008). Scirtothrips dorsalis can reproduce both sexually and by haplodiploid parthenogenesis, with females developing from fertilised and males from unfertilised eggs (Dev, 1964). Female can lay between 60 and 200 eggs (Seal and Klassen, 2012), which are inserted into soft plant tissues of buds and young leaves near the mid rib or into the veins. But sometimes they are also laid into older leaves (Dev, 1964). The eggs hatch in 6–8 days (Seal and Klassen, 2012). Eggs are glassy white about 0.25 mm long and 0.1 mm wide. First and second‐instar larvae are white, yellow to light orange and their length size ranges between 0.29–0.32 and 0.48–0.59 mm, respectively (Dev, 1964). Prepupa is yellowish and pupa dark yellow (CABI, online) with 0.59–0.63 mm in length (Dev, 1964). Adults are pale yellow to greyish white in colour (Seal and Klassen, 2012). Female is approximately 1.05 mm long and 0.19 mm wide. Males are smaller 0.71 mm long and 0.14 mm wide
	(Dev, 1964). Larvae and adults tend to gather near the mid‐vein or near the damaged part of leaf tissue. Pupae are found in the leaf litter, on the axils of the leaves, in curled leaves or under the calyx of flowers and fruits (MacLeod and Collins, 2006; Kumar et al., 2013). Prepupa and pupa stages never feed (Tatara, 1994). Adults fly actively for short distances – tens of metres (Masui, 2007a) and passively on wind currents, which enables long‐distance spread (EFSA PLH Panel, 2014). They overwinter as adults (Okada and Kudo, 1982) in bark, litter, soil and protected in plant parts (Shibao, 1991; Holtz, 2006). The thrips cannot survive if the temperature remains below – 4°C for 5 or more days (Nietschke et al., 2008). Scirtothrips dorsalis is a vector of plant viruses including capsicum chlorosis virus (CaCV), chilli leaf curl virus (CLC), melon yellow spot virus (MYSV), peanut chlorotic fan virus (PCFV), peanut necrosis virus (PBNV), peanut yellow spot virus (PYSV), tobacco streak virus (TSV) and watermelon silver mottle virus (WsMoV) (Satyanarayana et al., 1996; Rao et al., 2003; Seal et al., 2010; Kumar et al., 2013). However, these viruses are not reported to infect Acer species. Possible pathways of entry for S. dorsalis are plants for planting, cut flowers, fruits, vegetables, soil and growing media (EFSA PLH Panel, 2014). Scirtothrips dorsalis causes economic loses to chilli (Capsicum annuum) in India with yield loss estimated between 61% and 74% (Kumar et al., 2013, citing others), mango in Malaysia (Aliakbarpour et al., 2010), vegetables in China and the US (Reitz et al., 2011), tea, grapevine and citrus in Japan (Tatara, 1994, citing others; Masui, 2007b). No information is available about damage on Acer species.
Symptoms	Main type of symptoms	According to Dev (1964) and Kumar et al. (2013; 2014), main symptoms caused by S. dorsalis are: – ‘sandy paper lines’ on the epidermis of the leaves; – leaf crinkling and upwards leaf curling; – leaf size reduction; – discoloration of buds, flowers and young fruits; – silvering of the leaf surface; – linear thickenings of the leaf lamina; – brown frass markings on the leaves and fruits; – corky tissues on fruits; – grey to black markings on fruits; – fruit distortion; – early senescence of leaves; – defoliation. When the population is high, thrips may feed on the upper surfaces of leaves and cause defoliation and yield loss (Kumar et al., 2013). There is no information on the symptoms caused to Acer plants.
	Presence of asymptomatic plants	Plant damage might not be obvious in early infestation or during dormancy (due to absence of leaves). The presence of S. dorsalis on the plants could hardly be observed.
	Confusion with other pests	Plants infested by S. dorsalis appear similar to plants damaged by the feeding of broad mites (Kumar et al., 2013). Due to small size and morphological similarities within the genus, the identification of S. dorsalis, using traditional taxonomic keys, is difficult. The most precise identification of the pest is combination of molecular and morphological methods (Kumar et al., 2013).
Host plant range	Scirtothrips dorsalis is a polyphagous pest with more than 100 reported hosts (Kumar et al., 2013). The pest can infest many more plant species, but they are not considered true hosts, since the pest cannot reproduce on all of them (EFSA PLH Panel, 2014). Some of the many hosts of Scirtothrips dorsalis are (alphabetically): Abelmoschus esculentus, Acacia auriculiformis, Acacia brownii, Acer palmatum, A. buergerianum, A. sieboldianum, Actinidia deliciosa, Allium cepa, Allium sativum, Anacardium occidentale, Arachis hypogaea, Asparagus officinalis, Beta vulgaris, Camellia sinensis, Capsicum annuum, Capsicum frutescens, Citrus spp., Citrus aurantiifolia, Citrus sinensis, Cucumis melo, Cucumis sativus, Cucurbita pepo, Dahlia pinnata, Dimocarpus longan, Diospyros kaki, Fagopyrum esculentum, Ficus spp., Ficus carica, Fragaria spp., Fragaria ananassa, Fragaria chiloensis, Glycine max, Gossypium spp., Gossypium hirsutum, Hedera helix, Helianthus annuus, Hevea brasiliensis, Hydrangea spp., Ipomoea batatas, Lablab purpureus, Ligustrum japonicum, Litchi chinensis, Mangifera indica, Melilotus indica, Mimosa spp., Morus spp., Nelumbo spp., Nelumbo lutea, Nelumbo nucifera, Nephelium lappaceum, Nicotiana tabacum, Passiflora edulis, Persea americana, Phaseolus vulgaris, Populus deltoides, Portulaca oleracea, Prunus spp., Prunus persica, Punica granatum, Pyrus spp., Ricinus communis, Rosa spp., Rubus spp., Saraca spp., Solanum spp., Solanum lycopersicum, Solanum melongena, Solanum nigrum, Syzygium samarangense, Tamarindus indica, Viburnum spp., Vigna radiata, Vitis spp., Vitis vinifera, Zea mays subsp. mays and Ziziphus mauritiana (Ohkubo, 1995; Hodges et al., 2005; Kumar et al., 2014; CABI, online). For a full host list refer to Ohkubo (1995), Hodges et al. (2005), Kumar et al. (2014), CABI (online).
Reported evidence of impact	Scirtothrips dorsalis is an EU quarantine pest.
Evidence that the commodity is a pathway	Scirtothrips dorsalis is continuously intercepted in the EU on different commodities including plants for planting (EUROPHYT/TRACES‐NT, online) and according to EFSA PLH Panel (2014), S. dorsalis can travel with plants for planting. Therefore, plants for planting are possible pathways of entry for S. dorsalis.
Surveillance information	Scirtothrips dorsalis has been found in one tropical glasshouse at Kew (Botanic Gardens, Richmond, London), and at no other location. This pest has been subject to control measures for many years, and there have been no recent records. FERA diagnostics records show that sticky trap surveys at Kew were carried out in November 2007; January 2008; September 2022; October 2022 and November 2022 – all proved negative for the presence of this pest. It is possible that this pest has been eradicated, but the UK is unable to officially confirm this at this time (Dossier Section 3.0).