Download Pest profile – Large larch bark beetle

Pest profile – Large larch bark beetle
Scientific name: Ips cembrae (Heer)
Taxonomic position: Coleoptera: Scolytidae
Common name: Large larch bark beetle
Hosts: Larch species including European, Russian and Japanese larch (Larix
decidua, Larix russica and Larix kaempferi). It may occasionally breed in other
conifer species including pines (Pinus spp.), spruces (Picea spp.) and firs (Abies
spp.) It attacks the stem of plants and tunnels to form characteristic Y-shaped
galleries within the bark of living trees where their larvae feed and develop,
sometimes resulting in the death of the tree.
Threats: The tree may be damaged or even killed through the boring of galleries
around the stem. Damage may also be caused through a bark and cambium killing
fungus, Ceratocystis laricicola, which may be spread by the large larch bark beetle.
Adult beetles also damage the young branches through maturation feeding. The
large larch bark beetle has been shown to attack healthy trees in the UK, although it
prefers damaged or drought stressed trees.
Distribution and spread: First reported in Britain in the 1950s. The distribution is
restricted across the UK; the large larch beetle has been found in larch plantations in
England, Eastern Scotland and part of Wales but has not yet established in Ireland.
The beetle may spread with the movement of forest products.
Climate change: The effects of climate change will be similar to those for other bark
beetles; the large larch Bark beetle may be able to have two generations in a single
year. More drought stress in some larch stands could also help this beetle become a
pest in areas that currently have regular rainfall in the summer months.
Control: Management of infected trees, removing logs and thinnings as soon as
possible to prevent the build-up of a large population. The time of harvesting larch
can be important in preventing an outbreak. Larch sites that have been felled or
treated as part of Phytophthera management should be considered as a riskstanding dead larch especially may help the large larch bark beetle to build up a
large population so that healthy trees may be attacked more easily.
Monitoring: Pheromone trapping is a viable method of monitoring the large larch
bark beetle, as well as visual survey techniques using the characteristic galleries left
by the feeding larvae to diagnose the pest.
Life Cycle:
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Males initiate boring in early summer and release a pheromone.
Females then excavate galleries, usually three in total, away from the entry
hole. Often two tunnels are created in in one direction and one tunnel in the
opposite direction, creating a characteristic Y-shaped gallery. Larvae feed and
develop off these main galleries.
Adults fly from June onwards.
The new generation feed on younger branches until mature.
Hibernation may take place under thick bark or in the forest litter.
The IMPACT project, with partners Forest Research in Wales, Swansea University
and the National University of Ireland, Maynooth is looking at improved pest control
measures. Top of the agenda for the Integrated Management of forest Pests
Addressing Climate Trends (IMPACT) team is assessing how changing climate will
influence the damage caused by pests and pathogens. The project is part funded
by the European Regional Development Fund through the Ireland – Wales
Programme (INTERREG IVA) and Forestry Commission Wales. For more
information log on to:
www.impactproject.eu