Bronze Birch Borer on white birches
Bark-boring beetle that can severely harm birch trees. Usually spotted via d-shaped holes in bark with rusty fluid running down trunk. Also causes swollen trunks; dieback of leaders, branches and twigs; chlorotic leaves; and sparse foliage. Often attacks drought-stressed trees, so watering birches during hot summer months helps. Bark spray treatments, soil drenches and trunk injections may also help.