Spruce Bud Scale
- adults: highly variable; females ~ 1/8 inch; globular; yellowish to dark brown with light, white dusting
- adults: often aggregate at the base of new growth; look very similar to spruce buds
- immatures: crawlers (mobile stage); tiny (3/64 inch), yellow orange and wingless
- immatures: nymphs are smaller, flattened and oval to globose; brownish yellow to dark brown
- most common on lower branches
Host Plants, Diet & Damage
- spruce; occasionally pine
- feed on plant sap from twigs, needles and scales
- can cause tree stress, decline, and branch death
- copious honeydew may lead to sooty mold
Biology, Life Cycle & Damaging Life Stage
- overwinter as 2nd instar nymphs on needles or bud scales
- in spring, overwintering nymphs migrate to twigs to feed
- around May, females reach maturity and mate
- can reproduce without mating (parthenogenetic)
- eggs are laid under the female body
- egg hatch occurs from mid-June through late-July
- crawlers migrate to needles, scales or twigs and feed
- one generation per year
- nymphs and adults are the damaging stages
- Manage trees to improve or maintain health.
- Monitor scale populations host plants.
- Apply an insecticide (carbamate; horticultural oil; insecticidal soap; organophosphate; pyrethroid) to coincide with scale crawler activity.
- Apply a systemic neonicitinoid in spring after new needles have expanded.
For more information, see our Soft Scales in Utah Landscapes fact sheet.