Spruce Bud Scale

Pest Description

• 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

IPM Recommendations

• 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.