Viburnum leaf beetle

First egg hatch Active

Pyrrhalta viburni

33 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

Order
Coleoptera
Type
defoliator
Host Plants
33
GDD₃₂ First egg hatch
1,085
Indicator: Deutzia first bloom
Peak Activity
May-June: Larval feeding and skeletonization. Late June-July: Pupation in soi...
Damage Severity
lethal
Now: Larval Hatching & FeedingHigh Risk

Larvae hatch at approximately 210 GDD50 (deutzia first bloom) and immediately begin skeletonizing leaf undersides. Three instars over 4-5 weeks. Peak larval feeding and damage in May-June.

Next: Pupation

Viburnum leaf beetle First egg hatch typically begins around 1085 GDD₃₂. As of May 19, 2026, all seven Puget Sound stations have passed this threshold (2045.5–2249.7 GDD₃₂), so First egg hatch is likely underway across the lowlands.

Regional Season Tracker

GDD₃₂ accumulation across 7 Puget Sound stations · as of May 19, 2026
Station GDD₃₂ Current Stage Next To Go
Issaquah / East King 2,250 First egg hatch — —
Kent / Auburn 2,222 First egg hatch — —
Seattle / UW 2,189 First egg hatch — —
Olympia / Tumwater 2,151 First egg hatch — —
Bellingham / Whatcom 2,124 First egg hatch — —
Tacoma / Puyallup 2,117 First egg hatch — —
Sequim / Rain Shadow 2,046 First egg hatch — —
Regional estimate

Source: UMD IPMnet catalog (210 GDD50 for egg hatch/larval emergence). Cornell confirms mid-May hatch timing. About GDD₃₂ →

Monitoring & Action

How to Monitor

In winter (December-March), inspect undersides of terminal Viburnum twigs for egg-laying scars (dark pit marks in rows, capped with frass). Prune infested twigs before egg hatch in May. In spring, inspect leaf undersides for small greenish-yellow larvae with black tubercles. In summer, watch for adult beetles and shot-hole leaf damage.

When to Act

Any confirmed VLB population warrants management on susceptible species. Even moderate larval populations can cause complete defoliation, and 2-3 consecutive years of heavy defoliation kills plants. On resistant species, monitoring only.

What Damage Looks Like

Both larvae and adults feed on Viburnum leaves but at different times. Larvae (spring) skeletonize leaf undersides between veins, creating a lace-like pattern. Mature larvae chew small irregular holes through the leaf. Adults (summer) produce larger oblong feeding holes. Severe infestations leave only midribs and major veins, causing complete defoliation. Repeated defoliation over 2-3 years causes branch dieback and plant death. Even resistant species can be killed under sustained heavy pressure.

Cultural Controls

  • Winter pruning of egg-scarred terminal twigs (December-March) is the most effective single control measure. Look for distinctive rows of dark pit marks covered with frass on twig undersides.
  • Plant resistant species: V. plicatum var. tomentosum, V. carlesii, V. burkwoodii, V. davidii, V. rhytidophyllum. Avoid highly susceptible species (V. dentatum, V. opulus) in areas with known VLB populations.
  • Hand-pick adults and larvae during active feeding.
  • Apply sticky barrier or V-shaped tape collar around trunk base to intercept larvae crawling down to pupate in soil.

Host Plants (33)

Viburnum × bodnantense Bodnant Viburnum, Dawn Viburnum Viburnum awabuki Sweet Viburnum Viburnum bracteatum Bracted Viburnum, Limerock Arrowwood Viburnum Viburnum burkwoodii Burkwood Viburnum Viburnum carlesii Koreanspice Viburnum Viburnum cassinoides Witherod Viburnum, Northern Wild Raisin Viburnum cinnamomifolium Cinnamon Viburnum Viburnum davidii David's Viburnum Viburnum dentatum Arrowwood Viburnum Viburnum dilatatum Linden, Viburnum, Linden, Arrowwood Viburnum edule Mooseberry Highbush Cranberry, Moosewood Viburnum, Squashberry Viburnum ellipticum Oregon Viburnum, Western Wayfaring Tree Viburnum farreri Fragrant Viburnum Viburnum juddii Judd Viburnum Viburnum lantana Wayfaringtree Viburnum Viburnum lantanoides Hobblebush Viburnum lentago Nannyberry Sheepberry Viburnum nudum Possumhaw Smooth Witherod Northern Wild Raisin Viburnum opulus var. americanum American Cranberrybush Viburnum Viburnum opulus var. opulus European Cranberrybush Viburnum, Guelder-rose Viburnum opulus var. sargentii Sargent Viburnum Viburnum plicatum Doublefile Viburnum, Japanese Snowball, Japanese Snowball Viburnum, Snowball Viburnum Viburnum plicatum var. plicatum Japanese Snowball Viburnum Viburnum plicatum var. tomentosum Doublefile Viburnum Viburnum pragense Prague Viburnum Viburnum prunifolium Blackhaw Viburnum Viburnum rafinesquianum Downy Arrowwood Viburnum, Rafinesque Viburnum Viburnum rhytidophyllum Leatherleaf Viburnum Viburnum rufidulum Rusty Blackhaw Viburnum, Southern Blackhaw Viburnum setigerum Tea Viburnum Viburnum suspensum Sandankwa Viburnum, Sandanqua Viburnum Viburnum tinus Laurustinus Viburnum trilobum American Cranberrybush Viburnum

First WA specimens found in Whatcom County (early 2000s, shortly after 2001 BC detection). By 2015, gardeners were removing viburnums killed by VLB. Invasive from Europe, continuing to spread through Washington. Native V. edule and V. ellipticum are at risk from this invasive pest. WSU Extension FS202E provides detailed WA-specific management guidance.

— Chris Welch, ISA Certified Arborist

Sources & References

Primary: Cornell University Viburnum Leaf Beetle Research

Data Maturity
Structured Multiple sources. Expert review underway.