Soft, fleshy green galls often noticed in June and July at the bases of the twigs of different kinds of spruces, are the work of gall-making plant lice. The lice feed in chambers in the galls, which are often an inch long and half as wide, during the months named, but by August the galls crack open outside each cavity and turn brown, thus permitting the lice to escape. During the fall and winter these lice, in one stage or another, may be found on the tree, and the following spring eggs are laid, from which the gall inhabiting insects are produced.

The formation of a gall at the base of a twig nearly always causes the death of that twig, and a tree where the insects are abundant becomes thin, with many dead twigs showing brown galls, and as a whole is by no means the ornament it should be.

When the galls first appear on a tree, it is generally best to pick them off and destroy them. When they are abundant, this method becomes no longer practicable, and a thorough spraying with two pounds of soap dissolved in a gallon of water, applied about the third or fourth week in April, is the best treatment available.