What's eating my colorado blue spruce?

Colorado Blue Spruce is attacked most severely by spruce spider mites, which cause needle bronzing and drop. Cooley spruce gall adelgid creates pineapple-shaped galls at shoot tips. White pine weevil kills the central leader. Deer and rabbits may browse young trees in winter when other food is scarce.

Needles turn yellow, then rusty-brown, starting on inner older growth; fine webbing visible; heavy infestations cause needle drop and thin canopy Spray dormant horticultural oil in early spring before bud break; apply insecticidal soap or miticide (bifenazate) during active infestations in cool weather (spring/fall); avoid drought stress

Pineapple-shaped galls form at the tips of new shoots in spring and early summer, distorting and killing shoot tips; heavy infestations reduce vigor Apply systemic imidacloprid soil drench in early spring before bud break, or dormant oil spray in late winter; prune and dispose of galls before they open in July

Adults girdle the terminal leader just below the tip in spring; the top 6–12 inches wilt, droop, and turn brown ('shepherd's crook'), creating a forked or bushy crown Prune and destroy infested leaders in June before larvae exit; apply pyrethroid spray to the terminal leader in early spring when adult weevils are active (late April–May)

Antler rubbing strips bark and cambium from the lower trunk; winter browse strips foliage from the lower 4–5 feet, leaving a sharp browse line Install wire mesh tree guards or sturdy fencing around trunks; apply deer repellent sprays (containing putrescent egg solids) repeatedly through winter; plant in groups to diffuse pressure