Ambermarked birch leafminer
Profenusa thomsoni (Konow) (Hymenoptera: Tenthridinidae)
Orientation to pest
The ambermarked birch leafminer, Profenusa thomsoni (Konow), is a European sawfly that feeds inside the leaves of several species of birch (Betula). It invaded North America at the beginning of the 20th century but was first reported in Canada in 1959. It is found both in the northeastern USA (New England through the Great Lakes region) and in eastern Canada from the Maritimes to Manitoba, where it is not considered a pest because of its low densities. It also occurs in western Canada and Alaska, where it reached high densities in Alberta (1990s) and Alaska (2000-2008), especially in urban areas before being brought under biological control with an introduced parasitoid and two native species. This sawfly overwinters as prepupae in earthen cells in the soil. Pupation occurs in the spring, and adults emerge in early summer. Eggs are inserted singly into tissue of mature leaves, and larvae create leafmines where they feed. The blotch-shaped mines of this species increase in size and several mines may merge as larvae grow. In Alaska there is one generation per year, however, in Massachusetts, there are two.
Hosts commonly attacked
The principal birch species used as hosts by ambermarked birch leafminer are gray (Betula populifolia Marshal) and paper (Betula papyrifera Marshal) birch, but yellow birch (Betula alleghaniensis Britt.) is also reported as a host. Several introduced European birches are also attacked in landscape plantings.
Distribution
This sawfly occurs from the northeastern USA (New England to the Great Lake States), eastern Canada from the Maritimes to Manitoba, in western Canada (Alberta, Northwest Territories), and Alaska. Small urban populations are found in additional locations (e.g., Bozeman, Montana) and many of these may be unrecognized, being taken for mines of Fenusa pumila Leach.
Images of ambermarked birch leafminer
| Figure 1. Adult of ambermarked birch leafminer, Profenusa thomsoni | Figure 2. Eggs of ambermarked birch leafminer | Figure 3. Mine of nearly mature larva of ambermarked birch leafminer |
| Figure 4. Older instar of ambermarked birch leafminer, with mine opened to reveal larva | Figure 5. Close up of branch with mines of ambermarked birch leafminer | Figure 6. Birch trees (brown) in Alaska heavily mined by ambermarked birch leafminer |
| Figure 7. Important parasitoids of ambermarked birch leafminer in Alaska: Aptesis segnis (Provancher) (left), Lathrolestes soperi (center), and Lathrolestes thomsoni (right) | ||
Important biological control agents related to this pest species
Three ichneumonids (Lathrolestes soperi Reshchikov, Lathrolestes thompsoni Reshchikov, and Aptesis segnis (Provancher) are important biological control agents of this leafminer. The two Lathrolestes species attack the host larva in the mine. Lathrolestes soperi is known from Anchorage, Alaska and is of unknown origin. This species is particularly common in forested habitats. Lathrolestes thompsoni is a species that was observed to provide control of this leafminer in Edmonton, Alberta and was moved to Anchorage, Alaska, where it was established to provide biological control. Aptesis segnis is a facultative hyperparasitoid that attacks the host (or parasitoid) in the host's pupal cells in the soil.
Web links for information on ambermarked birch leafminer
Articles
- Digweed, S.C., R. L. McQueen, J. R. Spence, and D. W. Langor. 2003. Biological control of the ambermarked birch leafminer, Profenusa thomsoni (Hymenoptera: Tenthredinidae), in Alberta. Information Report NOR-X-389. Natural Resources Canada, Canadian Forest Service, Northern Forestry Centre, Edmonton, Alberta. 8 pp.
- Digweed, S.C. and D. W. Langor, D.W. 2004. Distributions of leafmining sawflies (Hymenoptera: Tenthredinidae) on birch and alder in northwestern Canada. The Canadian Entomologist 136: 727-731.
- Digweed, S. C., C. J. K. MacQuarrie, D. W. Langor, D. J. M. Williams, J. R. Spence, K. Nystrom, and L. Morneau,. 2009. Current status of invasive alien birch-leafmining sawflies (Hymenoptera: Tenthredinidae) in Canada, with keys to species. The Canadian Entomologist 141: 201-235.
- Reshchikov, A. V., A. Soper and R. G. Van Driesche. 2010. Revision of the Nearctic species of Lathrolestes (Hymenoptera: Ichneumonidae), with special reference to species attacking Betula leaf mining Tenthredinidae (Hymenoptera). Zootaxa 2614: 1-17.
