Obliquebanded Leafroller
Choristoneura rosaceana
171 host plants
Last updated
You will find green caterpillars rolling and tying leaves together into shelters for feeding and protection. Larvae thrash violently when disturbed and may drop suspended by silk threads. Adults are tan to brown bell-shaped moths with broad wing bands, reaching one inch long. Rolled leaves appear light brown and papery where larvae have fed. Host plants include ornamental cherries, apricots, and many rosaceous plants.
Remove rolled leaves by hand when populations are light. Time sprays for late June when first-generation adults lay eggs for the second generation. Spiders and parasitic wasps significantly reduce populations naturally. Avoid broad-spectrum insecticides that kill beneficial insects. Most plants tolerate moderate damage.
Quick Reference
Obliquebanded Leafroller Emergence (est.) typically begins around 1575 GDD₃₂. As of April 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂, approximately 394 units before the expected 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 | Pre-season | Emergence (est.) | 394 |
| Seattle / UW | 1,171 | Pre-season | Emergence (est.) | 404 |
| Kent / Auburn | 1,111 | Pre-season | Emergence (est.) | 464 |
| Olympia / Tumwater | 1,106 | Pre-season | Emergence (est.) | 469 |
| Bellingham / Whatcom | 1,101 | Pre-season | Emergence (est.) | 474 |
| Tacoma / Puyallup | 1,075 | Pre-season | Emergence (est.) | 500 |
| Sequim / Rain Shadow | 1,070 | Pre-season | Emergence (est.) | 505 |
Source: Standard OBLR phenology model (WSU Tree Fruit, UC Davis IPM): 350 DD base 43°F (6.1°C) for first larval hatch after biofix (first sustained adult moth catch). An alternate hazelnut model uses base 50°F with peak adult flight at 655 GDD₅₀. Previous profile listed base 50°F which was a BASE TEMPERATURE ERROR; CORRECTED 2026-03-20. Updated 2026-04-03. About GDD₃₂ →
Cultural Controls
- Naturally-occurring parasites and predators including birds and predacious ground beetles will help control leafroller populations.
- Pinch leaves to kill individual leafrollers.