The insects will fall off onto the paper like small greenish specks. If a determined gardener wishes to grow spruce and wants to get some control for the spruce aphid problem, the WSU recommendation is to spray during winter when the insects are active. The least-toxic materials registered for the problem are horticultural oils or insecticidal soaps. Be sure to get thorough coverage of all needles, and apply on a dry day. Also, be aware that horticultural oils will discolor the blue needles of Colorado blue spruce, turning them a muddy green.
Spruces are also susceptible to other insect problems.
White, cottony tufts on the undersides of Douglas fir and spruce needles in early spring hide the adelgids. These are aphid relatives which cause needle drop and needle distortion. The new growth can be so twisted and misshapen that it resembles a cone-like structure. Check with your local nursery for others equally suited to western Washington and free from the problems associated with growing spruce.