Spruce aphid

Yellow patches appear on spruce needles in late winter or early spring (February-March) in Western Washington; this discoloration intensifies and eventually turns brown as needles drop prematurely. Black fungal growth resembling soot develops on affected needles. The green spruce aphid begins infestations in shaded lower crown portions; epidemics occasionally affect upper crown and leaders.

Green aphids overwinter as wingless females. Strong winter oil spray targets females and reduces spring populations. In wet years, parasitic wasps and predators provide natural suppression. Improve air circulation through selective pruning. Avoid excessive nitrogen fertilization.