The flat headed apple tree borer is groddy cambium feeding creep. Other than apples, this creep will affect young maple trees. While mainly a problem in the nursery, this boring menace can also be found on young maples in the landscape.
By feeding on the tree’s vascular system, this insect disrupts water and nutrient flow within the plant. This may lead to tree stress, and can contribute to the death of young trees. Look out for this creep in early spring.
Pic borrowed from: https://insects.tamu.edu/extension/publications/epubs/local_images/eee00027_flatheadedAppletreeBorer_larva.jpg