Thrips of the British Isles

Thrips as pests in Great Britain and Ireland

Less than 100 species of thrips have been recorded as pests around the world, and most of these are found in the Family Thripidae. Many of these are localised both in their distribution and in their effect. However, a few polyphagous species such as Frankliniella occidentalis, Scirtothrips dorsalis and Thrips palmi have been spread around the world by the trade in plants and plant products, and then caused serious economic damage in the region of their arrival. Thrips can be crop pests in one of two ways:

1. Direct feeding damage affects either crop yield or the marketability of fruit, vegetables or ornamental plants.
2. A very small number of species are plant virus vectors, able to transmit plant tospoviruses between plants which then become the major agent of economic loss (Rotenberg et al., 2015).

Much plant quarantine activity is dedicated to preventing ingress of both non-native vector and non-native tospovirus, in order to prevent them coming together.

The first non-native species to be recorded from Britain, in 1836, was Heliothrips haemorrhoidalis, a species of South American origin now widely found in heated glasshouses in temperate regions. Morison (1957) rated the species as the then most widespread and economically important species to have been introduced into Great Britain, though through most of the twentieth century the Palearctic species Thrips tabaci was the most economically important pest species, both in outdoor crops and, in particular, in commercial glasshouse production. Thrips nigropilosus was another occasional pest of ornamental flower production. Minor pests of outdoor production include Thrips atratus, T. major and T. fuscipennis (strawberry production and rose-growing; e.g., Buxton & Easterbrook, 1988). A number of introduced species are contamination pests of plants in protected botanical collections or indoor landscaping schemes (e.g., Chaetanaphothrips orchidii, Hercinothrips femoralis, Parthenothrips dracaenae) or are contaminants of specific traded plants, such as the Gladiolus Thrips, Thrips simplex. The huge increase in the international horticultural trade in recent decades has facilitated the introduction of further pest species. Two species, Frankliniella occidentalis and Echinothrips americanus, have established in Great Britain and Ireland, but remain restricted to protected environments (Baker et al., 1993: Collins, 1998). Frankliniella occidentalis, a vector of a number of tospoviruses including Chrysanthemum stem necrotic virus and Tomato spotted wilt virus, was introduced into Great Britain in the mid-1980s, and is now the dominant thrips pest of horticultural production. It is also now regarded as a major pest of polytunnel strawberry production, though it has not been found surviving independently outdoors in the British Isles. Echinothrips americanus became established in the mid-1990s and is still regularly encountered, particularly in heated houses. Elsewhere in Europe, it has been recorded as a pest of Capsicum crops. A further introduced pest, Scirtothrips dorsalis, remains present in a single glasshouse at Kew Gardens, but is subject to an eradication policy (Scott-Brown et al., 2018). Similarly, the Japanese Flower Thrips, Thrips setosus, was found for the first time in Great Britain in 2016 in a commercial glasshouse in West Sussex (EPPO Global Database, 2017a).