Viburnum leaf beetle
Pyrrhalta viburni
32 host plants
Last updated
Viburnum leaf beetle larvae skeletonize leaves in May and June, leaving only the upper leaf surface intact and creating a lacy appearance. Later, adults chew irregular holes in summer foliage (July to September). You will see small black egg-filled pits in viburnum twigs in fall. This invasive beetle has been documented in northern regions of the Pacific Northwest.
Prune and destroy infested twigs in late fall when eggs are visible as black caps on branches. Severe infestations warrant removal of entire branches or even plants if spread to new areas. For new infestations, contact your county extension office. Parasitoid wasps and predatory beetles provide natural control over time. Do not use broad-spectrum pesticides.
Quick Reference
Viburnum leaf beetle First egg hatch typically begins around 1085 GDD₃₂. As of April 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂. 5 of 7 stations have reached the threshold.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,181 | First egg hatch | — | — |
| Seattle / UW | 1,171 | First egg hatch | — | — |
| Kent / Auburn | 1,111 | First egg hatch | — | — |
| Olympia / Tumwater | 1,106 | First egg hatch | — | — |
| Bellingham / Whatcom | 1,101 | First egg hatch | — | — |
| Tacoma / Puyallup | 1,075 | Pre-season | First egg hatch | 10 |
| Sequim / Rain Shadow | 1,070 | Pre-season | First egg hatch | 15 |
Source: UMD IPMnet catalog. Sources: UMD: extension.umd.edu; Cornell: blogs.cornell.edu. About GDD₃₂ →
Cultural Controls
- Prune out egg infested twigs during winter months.
- Hand-pick and kill emerging larvae.
- Apply sticky barrier on the trunk to trap and kill mature larvae as they migrate down the bush.