EPPO Global Database

EPPO Reporting Service no. 01 - 2005 Num. article: 2005/004

More details about the eradication of Thrips palmi in United Kingdom

In United Kingdom, Thrips palmi (Thysanoptera: Thripidae – EPPO A1 list) was first found in Southern England at 1 production site of chrysanthemum cut flowers in April 2000 (EPPO RS 2001/007). T. palmi had been detected during a routine survey in 2 glasshouses (2.1 and 2.6 ha). Although investigations were done, the pathway of introduction remained unknown. This outbreak was then successfully eradicated but this imposed significant costs on both the grower and the NPPO. An evaluation was made of eradication costs, as well as of the potential economic impact of T. palmi on horticulture in England, if eradication had not been achieved. Eradication measures led to the use of additional pesticides, soil sterilization with methyl bromide, imidacloprid-treated compost, plastic sheeting to cover growing media. These activities also implied additional labour costs, as well as some technical studies to improve spraying technologies and equipment. The situation was closely monitored with yellow sticky traps and many official inspections were done at the infested production site and in its vicinity (all neighbouring glasshouses within 5 km of the outbreak were checked). Bait plants were used to confirm eradication. From April 2000 to July 2001, the estimated eradication cost of this single outbreak was approximately 56,000 GBP (81,600 EUR) for the grower and 122,850 GBP (178,600 EUR) for the government (so a total of 260,200 EUR).
If eradication had not been achieved, T. palmi may have spread from the infested site to other glasshouses and gradually established throughout the country. Economic impact would include yield and quality losses, additional research and extension, plant health certification costs and, with some uncertainty, loss of exports. The economic impact of such an introduction has been estimated over a period of 10 years, with various rates of spread, and was estimated between 16.9 and 19.6 million GBP (24.5 to 28.5 million EUR). A cost/benefit analysis was also attempted to compare the cost of eradication with the cost of ‘living with T. palmi’. The ‘benefit:cost’ ratio ranged from approximately 10:1 if there is no loss of exports, and from approximately 100:1 if significant export losses resulted from the establishment of T. palmi.


MacLeod A, Head J, Gaunt A (2004) An assessment of the potential economic impact of Thrips palmi on horticulture in England and the significance of a successful eradication campaign.
Crop Protection, 23(7), 601-610.