Injury to buds and shoots may be caused by caterpillars, weevils, bark beetles, midges, aphids, or scale insects. Some of these insects also feed on other plant parts such as foliage, cones, and branches. By far the most frequently observed damage to pine shoots is caused by tip moths and shoot borers belonging to the order Lepidoptera (moths and butterflies).

Shoot insects affect trees by damaging terminal or lateral shoots. Such damage typically reduces height growth and deforms the tree. Forked branches or multiple leaders often result from a previous year’s insect damage. Seedlings and saplings are most susceptible to damage by shoot insects. Trees above 2 m in height rarely sustain significant injury. Young seedlings are often prevented from growing taller than herbaceous competitors, resulting in mortality.

Most of these shoot insects are important in young, intensively managed stands or replanted forested areas. The susceptible stage of hosts is predictable and managers can plan accordingly to minimize impacts caused by shoot insects.

References:  24, 41, 44, 109