The Forestry Commission leads on research into pests and diseases that may affect Sitka spruce, on behalf of DEFRA.

Sitka spruce is the most prevalent and commercially valuable species in British forests. The Forestry Commission has carried out research on a number of insect pests since the 1930s. These include the green spruce aphid (Elatobium abietinum), the European spruce sawfly (Gilpinia hercyniae) and the large pine weevil (Hylobius abietis). A management support system for the pine weevil has been developed through research, which is now being used to avoid significant financial losses in young trees.

In the 1980s an outbreak of the great spruce bark beetle (Dendroctonus micans) posed a major threat to Britain's spruce forests. Research discovered a natural predator beetle which is now routinely used as part of normal forest management to control this beetle when new outbreaks are found.

There have been relatively few diseases affecting Sitka spruce but research has been undertaken into a number of important pathogens, such as conifer butt rot (Heterobasidium annosum), honey fungus (Armillaria mellea), group dying of conifers (Rhizina undulata) and more recently the susceptibility of the species to Phytophthora ramorum and Dothistroma needle blight.

Native and non-native pests of other tree species have occasionally switched hosts, or have the potential to switch hosts, and cause damage to Sitka spruce (e.g. winter

moth (Operophtera brumata) and pine-tree lappet moth (Dendrolimus pini). There are a number of other potential pests and diseases in Europe and North America that could cause serious damage to Sitka spruce if they were introduced into the UK, such as spruce budworm (Chorsitoneura spp.), the eight toothed spruce bark beetle (Ips typographus) and Sitka spruce weevil (Pissodes strobii). Research continues to be carried out by the Forestry Commission on pests and diseases present in the UK and our scientists maintain contacts with their counterparts abroad to keep abreast of other possible threats.