How do trees infested by the bronze birch borer die?

How do trees infested by the bronze birch borer die?

• A. From the top down
• B. From the roots
• C. From the base up
• D. Evenly throughout

Answer: (A)

The trees die from the top down. Bronze birch borer larvae feed under the bark in the upper trunk and branches, tunneling through the phloem and cambium and effectively girdling the tissue that moves nutrients and water toward the crown. When this upper portion is damaged, the canopy can no longer receive what it needs, so leaves yellow, wilt, and die first in the crown. The injury then progresses downward as more of the trunk is girdled. Roots and the lower parts aren’t the initial failure points, and death doesn’t start evenly throughout the tree, which is why the top-down pattern is characteristic of this pest.

The trees die from the top down. Bronze birch borer larvae feed under the bark in the upper trunk and branches, tunneling through the phloem and cambium and effectively girdling the tissue that moves nutrients and water toward the crown. When this upper portion is damaged, the canopy can no longer receive what it needs, so leaves yellow, wilt, and die first in the crown. The injury then progresses downward as more of the trunk is girdled. Roots and the lower parts aren’t the initial failure points, and death doesn’t start evenly throughout the tree, which is why the top-down pattern is characteristic of this pest.