Species Heterarthrus nemoratus - Late Birch Leaf Edgeminer

Birch Leaf Edge Miner(1)

Heterarthrus nemoratus (Fallén 1808)

4.5 mm(1)

Larva is 10mm(2)

native to Europe & w. Siberia, adventive in NA: Canada (widely distributed), AK & ne. US(4)(1)(5)

host: Betula (Birch)(3)

Parthenogenic; the only birch leafmining sawfly to pupate in the leaf

Overwinters as larvar(2)

Females deposit their eggs in slits cut in the edges of mature leaves at all levels in the trees. The larvae feed in tissues between the upper and lower surfaces of the leaf, producing large, blister-like or blotch mines free of frass. Each full-grown larva constructs a cocoon or hibernaculum within its mine. The leaf then falls to the ground and the larva remains there throughout the winter.(2)

One generation per year.(2)

Introduced from Europe early in the 20th century(4); at one time a severe pest of wild birch, now a minor aesthetic pest(1)

In the 1920s and 1930s several parasites were imported. Two became established: Kratochviliana laricinellae and Phanomeris phyllotomae