Tools and Resources
Not present in UK
Notifiable – see ‘Report a sighting’ below
Scientific name – Agrilus fleischeri (A.fleischeri)
Agrilus fleischeri is an important pest of aspen and poplar (Trees in the genus Populus). Willows (Salix spp) have also been recorded as hosts of this pest. It is native to East-Asia.
There have been no reported discoveries of the pest in the United Kingdom (UK), but we remain vigilant for an accidental introduction. Suspected sightings must be notified immediately to the forestry authorities: see ‘Report a sighting’ below.
A. fleischeri is native to East Asia, from Russia to China and as far west as Kazakhstan. It has not been reported outside of its native range.
In its native range, A. fleischeri has been found to infest Eurasian aspen (Populus tremula), Korean aspen (P. tremula var. davidiana), laurel-leaf poplar (P. laurifolia), Lombardy poplar (P. nigra var. italica) and to a lesser extent, willows (Salix spp).
Lombardy poplar, which is not native to A. fleischeri’s range, is more susceptible to the pest then native species. This should be considered if it were ever to become established in the UK. It could be a threat to the rare native black poplar (P. nigra var. betulifolia) as well as damaging to the more widespread Eurasian aspen (P. tremula).
A. fleischeri is a cambial-feeding (beneath the bark) pest with a preference for stressed trees, causing dieback and increased mortality.
A. fleischeri is a pest of species present in the UK, such as the Eurasian aspen (P. tremula). Since it infests a wide variety of poplars, aspens and willows in its native range, it is assumed that any tree of the genus Populus or Salix could be at risk. In addition, the pest seems to prefer certain species that are foreign to its native range, such as Lombardy poplar (P. nigra var. italica).
A. fleischeri could be damaging to the widespread willows (Salix spp.) present in the UK, though they are not its preferred host. It poses a much greater threat to the less common Eurasian aspen (P. tremula). Its preference for the Lombardy poplar (P. nigra var. italica) is worrying for the closely related subspecies Black poplar (P. nigra var.betulifolia), which is endangered in the UK.
Adult A. fleischeri are dark brown to black in colour with two pairs of white spots on their elytra (back), with one pair in the center and the other at the tip. They tend to be between 7.3 And 12.3 mm long and 1.8 to 3.4 mm wide. Adult A. fleischeri beetles are very similar in appearance to the native A. ater, making distinction between the two difficult.
Pictured above: Adult A. fleischeri with D-shaped exit hole. Photo credit: Mr. Zang Kai
Adults and signs of their feeding can be found on the leaf margins of their host species. They also leave D-shaped exit holes on the trunks of trees.
Pictured above: A. fleischeri larval feeding galleries. Photo credit: Mr. Zang Kai (Agrilus fleischeri (AGRLFL)[Photos]| EPPO Global Database)
The larvae produce characteristic serpentine galleries (above), which can be exposed when pieces of bark fall or are cut from damaged trees which have been infested for one or two years. Typical A. fleischeri galleries meander, bend sharply, and are packed with frass (the fine, brown, powdery refuse produced by the boring activity, and the excrement of the larvae).
Signs of infestation in hosts are yellow foliage, dying branches, dieback and mortality. The smooth pale bark of some aspens (ex: P. tremula var. davidiana) becomes dark brown and cracks vertically. This is not visible on other species with rougher bark such as P. nigra var. italica.
Pictured below: Infested Populus davidiana, Liaoning province (China) Photo credit: Mr. Zang Kai (Agrilus fleischeri (AGRLFL)[Photos]| EPPO Global Database)
If you believe you have observed A. fleischeri,, or signs of its presence in one of the tree species listed above, you must report it immediately.
Note that TreeAlert and TreeCheck both require clear, well lit digital photographs of the pest and/or symptoms of its presence.
Suspected sightings, especially sightings within the plant trade, can also be reported:
If possible, catch any beetles you find and place them in secure containers such as sealed glass jars so that an inspector can collect them. The beetles are not harmful to people.
A. fleischeri has a one-to-two-year life cycle. Adults emerge from late May to mid-August, leaving D-shaped exit holes on trunks which are on average 3 mm in length and 2 mm in width. Adults survive on average for 34 days, feeding on the leaves of their host plants.
Females lay on average 218 eggs within bark cracks and crevices of poplars, aspen or willows. Larvae produce serpentine galleries under the bark bore, feeding on the cambium where they feed, and later go on to feed on the xylem as well. They then create pupal chambers in the outer sapwood, where they pupate into adults.
A. fleischeri is a quarantine pest for the United Kingdom, and is on the EPPO A1 list of quarantine pests with potential to cause extensive damage if introduced.
The UK Government website has details of the regulations governing the importation of:
See the UK Government website for guidance on the regulations designed to protect the UK from accidental introductions of plant pests.
The action which would be taken in the event of a discovery of an outbreak of A. fleischeri in the UK would aim to eradicate the outbreak. It would be likely to include: