Definition of willow borer
1 : any of several small bronzy longicorn beetles of the genus Agrilus that bore in the sapwood of the willow tree and often kill it: such as a : a beetle (A. politus) b : a beetle (A. anxius) that infests also poplars and birches
2 : poplar borer
3 : a European weevil (Cryptorhynchus lapathi) introduced and destructive to willows in the eastern U.S.
Start your free trial today and get unlimited access to America's largest dictionary, with:
- More than 250,000 words that aren't in our free dictionary
- Expanded definitions, etymologies, and usage notes
- Advanced search features
- Ad free!
Seen and Heard
What made you want to look up willow borer? Please tell us where you read or heard it (including the quote, if possible).