First report of Thrips setosus in the Netherlands: addition to the EPPO Alert List
The NPPO of the Netherlands recently informed the EPPO Secretariat of the first record of Thrips setosus (Thysanoptera: Thripidae) on its territory. This is also the first time that this species is found in the EPPO region. In September 2014, a grower located in the municipality of Kudelstaart reported thrips damage on plants for planting of Hydrangea. A sample of 10 adult thrips was collected and the identity of the pest was confirmed on 2014-10-03. Many adults and typical thrips feeding damage (silvery spots with dark punctures) were observed on the leaves of the Hydrangea plants inside and outside the greenhouse, as well as on weeds growing in their immediate vicinity (notably on Heracleum sphondylium, Lamium purpureum and Urtica dioica). Feeding damage could also be seen on the sepals of Hydrangea flowers. The origin of this incursion is unknown but could be linked to imports of cuttings from Japan. It is estimated that the pest has been present since June 2014 at least, but might have been introduced earlier. T. setosus is known to occur in Japan and the Republic of Korea. It can cause direct damage to plants by feeding on their foliage and is also a known vector of Tomato spotted wilt virus (Tospovirus, TSWV – EPPO A2 List). A preliminary pest risk analysis has been completed. Phytosanitary measures are pending, depending on the outcome of further tracing investigations and surveys which are currently being carried out on the premises of other growers.
The pest status of Thrips setosus in the Netherlands is officially declared as: Transient, incidental finding on Hydrangea plants for planting, measures are pending further tracing investigations and a specific survey.
Thrips setosus (Thysanoptera: Thripidae)
Why: The presence of Thrips setosus has recently been reported by the Netherlands in one production site of Hydrangea plants for planting. T. setosus is a polyphagous species which can transmit Tomato spotted wilt virus (Tospovirus, TSWV – EPPO A2 List). Because this is the first time that this potentially damaging thrips species is reported in the EPPO region, the EPPO Secretariat has decided to add it to the EPPO Alert List.
Where: until recently, T. setosus was only known to occur in parts of the Asia.
EPPO region: Netherlands (transient). In the Netherlands, the pest was first found in autumn 2014 in one production site of Hydrangea plants for planting grown indoors and outdoors. Official measures are being considered.
Asia: Japan (widespread), Korea (Republic of).
On which plants: T. setosus is a highly polyphagous species. In Japan, it has been found on many plant species including crops [e.g. Capsicum annuum (sweet pepper), Cucumis sativus (cucumber), Cucurbita moschata (pumpkin), Dioscorea japonica (Japanese mountain yam), Momordica charantia (bitter gourd), Nicotiana tabacum (tobacco), Pisum sativum (pea), Sesamum (sesame), Solanum lycopersicum (tomato), Solanum melongena (aubergine), Solanum tuberosum (potato), Vicia sativa subsp. angustifolia (narrow leaf vetch)], ornamental plants [e.g. Abelia spathulata, Brassica olearacea var. acephala (ornamental cabbage), Chrysanthemum morifolium, Dahlia, Hippeastrum, Iris, Liriope platyphylla, Oenothera, Ophiopogon jaburan, Tagetes], weeds and wild plants [Ailanthus altissima, Cirsium japonicum, Lamium amplexicaule, Polygonum, Pueraria lobata]. In the Republic of Korea, it was reported on rice (Oryza sativa). In Japan, it is considered to be a pest of tobacco (Nicotiana tabacum) and tomato (Solanum lycopersicum). In the Netherlands, T. setosus was found on Hydrangea plants, as well as on several weeds (e.g. Heracleum sphondylium, Lamium purpureum, Urtica dioica) growing in their vicinity.
Damage: T. setosus feeds on leaves but not on pollen. Damage is typical of leaf-feeding thrips (silvery spots with dark punctures on the foliage). In the Netherlands, feeding damage was also observed on the sepals of Hydrangea flowers. T. setosus has been shown to be a vector of TSWV, a virus which has a very large host range, including economically important vegetable and ornamental crops.
Dissemination: the potential of T. setosus for natural spread is relatively limited. Over long distances, the international trade of plants for planting is probably the main pathway.
Pathway: Plants for planting, cut flowers and foliage, fruit and vegetables, soil and growing media.
Possible risks: Information is generally lacking on the biology, distribution and economic impact of T. setosus. In the available literature, there is no indication that T. setosus is causing severe direct or indirect damage in its area of origin. However, studies carried out in Japan have shown that T. setosus has a fast development, high fecundity and high potential for population increase. These studies also concluded that the broad host plant range, high population growth rate, and virus transmission ability would have the potential to make T. setosus an important pest, in particular in glasshouse crops. As is the case for other thrips species, due to its small size and high rates of reproduction, T. setosus is likely to be difficult to detect and control. Finally, considering the impacts of earlier introductions of thrips species such as Frankliniella occidentalis, as direct plant feeders and virus vectors, it seems desirable to prevent any further spread of T. setosus in the EPPO region.
EPPO RS 2014/181
Panel review date - Entry date 2014-10
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