Black pineleaf scale
Nuculaspis californica
42 host plants
Last updated
Inspect pine needles closely for tiny black or dark brown scales clustered densely on surfaces, particularly lodgepole pine and western species. Heavy infestations make needles appear blackened or sooty. Look for scale populations building gradually over seasons, with damage more apparent on interior, lower canopy needles.
Prune and remove heavily infested branches; this is most practical control on landscape trees where chemical intervention is undesirable. Apply horticultural oil in March before new growth begins, coating thoroughly. If populations persist, repeat oil application in June during crawler stage when scales are mobile and vulnerable. Avoid broad-spectrum insecticides.
Quick Reference
Black pineleaf scale Emergence (est.) typically begins around 2990 GDD₃₂. As of April 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂, approximately 1809 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.) | 1,809 |
| Seattle / UW | 1,171 | Pre-season | Emergence (est.) | 1,819 |
| Kent / Auburn | 1,111 | Pre-season | Emergence (est.) | 1,879 |
| Olympia / Tumwater | 1,106 | Pre-season | Emergence (est.) | 1,884 |
| Bellingham / Whatcom | 1,101 | Pre-season | Emergence (est.) | 1,889 |
| Tacoma / Puyallup | 1,075 | Pre-season | Emergence (est.) | 1,915 |
| Sequim / Rain Shadow | 1,070 | Pre-season | Emergence (est.) | 1,920 |
Source: Herms (OSU) phenological tables: 1068 GDD₅₀ egg hatch, Dow Gardens MI 1985-1989 (Table 3). Exact match. MSU Extension GDD table corroborates. Updated 2026-04-03. About GDD₃₂ →
Cultural Controls
- biological control Larvae of green lacewings and other insects are aggressive predators of scale.
- A number of parasitic wasps will attack scale insects.
- However, biological control does not necessarily prevent significant scale infestations.
- Management-cultural control Scale can be rubbed off plants by hand with a glove or toothbrush.
- Major infestations can be pruned off.
- Tanglefoot, \"stickem,\" or a similar adhesive can be applied around infestations of adult scales to catch the crawler stage....