Zelkova
Guides
Aproceros leucopoda
elm zigzag sawfly
Aproceros leucopoda, commonly known as the elm zigzag sawfly, is a small sawfly native to eastern Asia (China and Japan) that has become an invasive pest in Europe since 2003 and North America since 2020. The species derives its common name from the distinctive zigzag-shaped feeding pattern created by young larvae on elm leaves. Populations are entirely female and reproduce through thelytokous parthenogenesis, enabling rapid establishment from single individuals. The species can cause severe defoliation of elm trees and has recently been documented feeding on Japanese zelkova.
Eriosomatini
Eriosomatini is a tribe of gall-forming aphids in the subfamily Eriosomatinae, comprising approximately 140 species across 16 genera. All members induce galls on host plants in the family Ulmaceae, primarily on Ulmus (elms) and Zelkova species. The tribe exhibits complex life cycles with alternation between primary and secondary hosts, though some species have reduced or lost host alternation. Molecular studies have demonstrated that DNA sequencing can reliably associate morphologically distinct life stages to species, addressing a major identification challenge in the group.
Trachys
Leaf-mining Jewel Beetles
Trachys is a genus of leaf-mining jewel beetles (Buprestidae: Trachyinae) characterized by their flattened, compact, wedge-shaped adult morphology—an adaptation distinct from the elongate cylindrical form typical of most buprestids. The genus contains approximately 20 species in Japan and is widely distributed from Africa through Asia to Europe. Larvae mine within leaves rather than boring through wood, a habit that has driven their distinctive body plan. Some species are significant forest and agricultural pests, including the introduced Trachys minutus established in Massachusetts and T. yanoi, a serious pest of Zelkova serrata in East Asia.