Recent outbreaks of the spruce bark beetle Ips typographus in the UK: Discovery, management, and implications

Abstract

The eight-toothed spruce bark-beetle Ips typographus is the most damaging insect pest of Norway spruce in Europe, and it poses a serious risk to spruce in other countries where it is not currently present but might be introduced. The beetle is not native to the UK and before 2018 it had not been found established anywhere within the country. In November 2018, however, several adult Ips typographus were found in a billet trap set up as part of annual surveys that the UK carries out to monitor for this and other quarantine bark beetle pests. The finding of adult beetles in the billet trap, a few miles south of Ashford in Kent, led to the discovery of a breeding population in an adjacent woodland. Delimiting surveys to 1 km and further surveys to 50 km showed that the infestation was confined to a single stand of Norway spruce. The stand was felled in January and February 2019, and the material destroyed, and beetles emerging on the site were trapped out using pheromone traps, billet piles and trap trees. These prompt actions eradicated the breeding population, but small numbers of adult Ips typographus continued to be caught on the outbreak site in 2020 and 2021. These captures, and numerous adult Ips typographus caught in pheromone traps set up across the region in response to the outbreak, indicate that incursions of adult Ips typographus are occurring on a regular basis, most likely from source populations in northern France and Belgium. The arrival of adult Ips typographus over a wide area and the potential for further outbreaks represents a continuing threat to spruce woodlands in south-east England, and has important implications for surveillance and monitoring and the management of spruce in this part of the UK.

Keywords

• Bark beetles
• Eradication
• Ips typographus
• Monitoring
• Norway spruce
• Pheromone trapping