This field guide describes insects and diseases of balsam fir and spruce trees, which are often used as Christmas trees. It highlights pest insects, including balsam fir sawfly, balsam twig aphid, and spruce budworm, and beneficial insects such as red-eyed bee, tachinid fly, and stink beetle. Diseases covered include needle rusts of balsam fir and yellow witches broom. The guide outlines seasonal history, damage, detection and monitoring, and control for each item.