Pest or disease?

Latin name:
Aproceros leucopoda

Host trees:
English elm, wych elm, field elm

Present in the UK?
Yes in England, in the South East and East Midlands

Tree Alert required?

Elm zigzag sawfly is an introduced pest from eastern Asia.

This pest poses a serious threat to our elm trees, they are already in rapid decline due to introduced Dutch elm disease. Additional losses of elm would further threaten our elm dependent species such as the white-letter hairstreak butterfly.

This pest, like many of our other priority pests, causes damage to the tree during it's larval stage. The larvae look like small green caterpillars and feed on elm leaves in a distinctive pattern, producing a zigzag between the leaf veins. However, it is important to note that as the larvae mature these patterns become less noticeable and eventually, they stop feeding in this manner. Other signs include dieback and loss of leaves. For more information on elm zigzag sawfly please see the resources below.