Roseslug
Endelomyia aethiops
13 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 May 13, 2026, all seven Puget Sound stations have passed this threshold (1906.2–2098.2 GDD₃₂), so Emergence (est.) is likely underway across the lowlands.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of May 13, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,098 | Emergence (est.) | — | — |
| Kent / Auburn | 2,089 | Emergence (est.) | — | — |
| Seattle / UW | 2,063 | Emergence (est.) | — | — |
| Olympia / Tumwater | 2,025 | Emergence (est.) | — | — |
| Tacoma / Puyallup | 1,993 | Emergence (est.) | — | — |
| Bellingham / Whatcom | 1,972 | Emergence (est.) | — | — |
| Sequim / Rain Shadow | 1,906 | Emergence (est.) | — | — |
Source: Pest GDD Catalog (UMD IPMnet), Added 2026-04-03 About GDD₃₂ →
Slugs are closely related to snails but have no shell. Slug damage can be distinguished easily from damage caused by other pests by the presence of slime trails. Feeding damage to foliage is removal of plant tissue between veins and on the edge of leaves. Slug damage tends to be heaviest along field margins. Weedy or grassy borders serve as excellent habitat for slugs. High populations build up in perennial legumes used for cover crops.
Cultural Controls
- Hand-pick and destroy individual rose slugs.
- Wash rose slugs off foliage with a strong stream of water.