Eradication of an invasive alien pest, Thrips palmi

Thrips palmi Karny, the melon thrips, is a polyphagous pest that has spread widely in tropical and subtropical regions. It is absent from Europe, although outbreaks have occurred in the Netherlands (1988–98), the UK (2000–01) and most recently Portugal (2004). An outbreak of T. palmi occurred in Sussex in 2000. It was already well established when the UK Plant Health Service first notified. High populations were discovered in two glasshouse sites on the same nursery, growing all-year-round chrysanthemums. An intensive, largely chemically based eradication programme was carried out, with applications of aerosol ‘space’ treatments, systemic and foliar insecticides. Other measures included the use of sticky yellow sheets, methyl bromide fumigation of flowerbeds and plastic mulches. Together, these controls resulted in the collapse of the outbreak, within 7 months. Eradication was subsequently declared after freedom from the pest had occurred over two complete cropping cycles.