What insect deposits eggs in cells at the base of spruce buds?

The correct choice is the Spruce Gall Adelgid, which is known for its specific behavior of depositing eggs in the cells at the base of spruce buds. This insect is a small, sap-sucking pest that affects spruce trees by laying its eggs within the buds, which can lead to the formation of galls. These galls can interfere with normal growth and development of the spruce, potentially causing stunted growth or even dieback of the affected branches.

In contrast, the White Pine Weevil is primarily associated with white pines and does not exhibit the same egg-laying behavior as the adelgid. The Pine Sawfly larvae feed on the needles but do not deposit eggs in the spruce buds. Cedar Apple Rust, while a significant pathogen affecting certain trees, particularly apples and junipers, is a fungus and does not have any involvement with insect egg deposition in spruce buds. Thus, the behavior and life cycle of the Spruce Gall Adelgid make it the distinct and correct answer in this context.