Canadian Forest Service Publications
Beech leaf-mining weevil. 2016. J.D. Sweeney and R.C. Johns. Natural Resources Canada, Canadian Forest Service - Atlantic Forestry Centre Impact Note 61.
Issued by: Atlantic Forestry Centre
Catalog ID: 37778
Series: Impact Note (AFC - Fredericton)
Availability: PDF (download)
Plain Language Summary
The beech leaf-mining weevil (Orchestes fagi) is a common pest of beech foliage in Europe. In 2012, it was positively identified as the insect responsible for foliage damage on American beech (Fagus grandifolia) trees in the greater Halifax area of Nova Scotia. Damage to beech foliage is caused by both the larvae and the adults. The larvae feed inside the leaf, creating tunnels and blotch mines, whereas feeding by adults creates holes resulting in a very distinctive damage profile. Early results indicate that American beech trees are dying after many successive years of defoliation by the weevil. In Europe, the adults feed on a variety of alternate hosts, including cherry (Prunus spp.) and apple (Malus spp.). Feeding on alternate hosts has not yet been observed in Nova Scotia, which is important to fruit growers concerned that that their crops could be threatened by the species. Weevils overwinter under scales and in the bark of trees. Movement of logs and firewood from infested areas may contain overwintering weevils capable of infesting new areas. Protection of urban trees is being tested with stem injections of TreeAzin, a systemic insecticide that kills larvae and reduces damage to foliage, but treatment in the natural forest is not a viable option. Natural enemies, such as wasp parasitoids, help control weevil populations in Europe, but natural controls have not yet been observed in Nova Scotia.
Also available under the title:
Charançon du hêtre (French)