Bronze Birch Borer (Agrilus anxius) is a North American insect pest that has damaged and killed tens of thousands of birch trees in Canadian landscapes. The larvae remain in these galleries through winter until they pupate in spring. Life cycle of the bronze birch borer. A sure sign of bronze birch borer damage is raised bark welts or ridges on the bark, caused by larvae tunneling beneath the bark. The larvae feed through the summer, overwinter as larvae, and pupate in the cambium area in spring. Welts appear on the surface of the stem above borer galleries (a). Although the life cycle can be completed in 1 year, a 2-year life cycle … The larvae then feed on the phloem and the cambium of the tree and create galleries. Larvae hatch June through July and tunnel into birch tree cambium. Adults are dark green-bronze or copper-bronze and about 3/8 inch long. Biology and life history The insect overwinters as a larva in the tree. The life cycle of bronze birch borer can be annual or biennial depending on climate and host condition, with 2-yr life cycles more prevalent in cooler climates and on more vigorous hosts (Slingerland 1906, Balch and Prebble 1940, Anderson 1944, … The bronze birch borer (Agrilus anxius) is found throughout the birch range in the U.S. and Canada. Life Cycle: Adults emerge in late May through June. Life Cycle: It takes one to two years to complete development. The larvae excavate tunnels under the tree bark, eating the cambium and phloem until the weather cools in the fall. Bronze birch borer’s life cycle can last one or two years. Bronze Birch Borer. The adults live for two to five weeks, feeding on leaves, mating and laying eggs in branch or bark crevices. Start to emerge as adults in early June. It attacks several species of birch (Betula sp. Fully grown larvae are about 1 inch long. The eggs hatch about 14 days later. ), but is especially devastating on exotic birch species including European white birch (Betula pendula). Bronze birch borer larvae are elongate, white, and flattened, with obvious beadlike segments. The adults (beetles) emerge from pupation under the bark of the host tree from May to mid-July, depending on climatic conditions. Adult emergence holes are D-shaped and about 1/8 inch long. Bronze birch borers live through the winter as larvae under the bark of trees in pupal chambers. The bronze birch borer life cycle begins when eggs are laid in branch crotches or bark crevices of host trees. Bronze birch borers attack trees weakened by age, environmental stresses, or previous insect attacks. It attacks and breeds in paper birch, yellow birch, gray birch, western birch, water birch, and sweet birch, and has been found in stands of beech and aspen. 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