Roseslug
Endelomyia aethiops
14 host plants
Last updated
Yellow-green sawfly larvae with orange heads feed on the undersides of rose leaves, grazing away tissue and leaving only the leaf epidermis; this window-pane damage dries and becomes white or pale brown. Roselugs reach about 3/4 inch length and often feed in groups, creating a distinctive ragged and skeletonized appearance.
Inspect leaf undersides in late spring for damage and larvae. Hand-pick roselugs or spray leaf undersides to dislodge them. Apply horticultural oil or soap targeting new growth. Roses recover well from damage and often require no chemical intervention.
Quick Reference
Roseslug Emergence (est.) typically begins around 1035 GDD₃₂. As of April 3, 2026, all seven Puget Sound stations have passed this threshold (1070–1180.6 GDD₃₂), so Emergence (est.) is likely underway across the lowlands.
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 | Emergence (est.) | — | — |
| Seattle / UW | 1,171 | Emergence (est.) | — | — |
| Kent / Auburn | 1,111 | Emergence (est.) | — | — |
| Olympia / Tumwater | 1,106 | Emergence (est.) | — | — |
| Bellingham / Whatcom | 1,101 | Emergence (est.) | — | — |
| Tacoma / Puyallup | 1,075 | Emergence (est.) | — | — |
| Sequim / Rain Shadow | 1,070 | Emergence (est.) | — | — |
Source: Pest GDD Catalog (UMD IPMnet), Added 2026-04-03 About GDD₃₂ →
Cultural Controls
- Hand-pick and destroy individual rose slugs.
- Wash rose slugs off foliage with a strong stream of water.