What's eating my ezo spruce?

Ezo Spruce (Picea jezoensis) is attacked by spruce aphids and adelgids, which cause needle yellowing and pineapple-shaped galls at shoot tips. Spider mites are a significant threat during hot, dry summers, especially on bonsai. Spruce bark beetle can kill weakened trees. Red squirrels and deer damage young specimens in garden settings.

Green aphids on undersides of needles through autumn and spring; needles turn yellow then brown and drop; interior and lower crown loses needles first Apply insecticidal soap or pyrethrum in late winter/early spring before populations build; encourage natural predators; a systemic insecticide (acetamiprid) for severe outbreaks on bonsai

Distinctive pineapple-shaped green then brown galls at shoot tips in spring; galled shoots are distorted and die; galls open in summer releasing winged insects Remove and destroy galls before they open in midsummer; apply horticultural oil in late winter when the nymphs are at the needle base; galls do not re-form on removed shoots

Fine stippling then bronze or grey discolouration of needles, especially on inner branches; webbing visible under a hand lens; heavy infestations cause mass needle drop Increase humidity around bonsai; spray with water to dislodge mites; use predatory mite sachets (Phytoseiulus or Amblyseius) for bonsai; miticide (bifenazate or abamectin) for severe cases

Resin bleeding on the lower trunk; excavated galleries under bark; pitch tubes with frass; affected bark dies; trees weaken and may be killed Keep trees well-watered to maintain resin flow (natural defence); remove infested material immediately; biological control (Rhizophagus grandis predatory beetle) is used in forestry — not practical for bonsai