|scientific name Agrilus anxius |
common name Bronze Birch Borer
June, July and August.
This species along with A. liragus are virtually identical in external appearance. The pronotum and top of the head often have brassy to coppery reflections. On beetles of liragus, there may be two pale pub sent spots on the elytra. Characters of the male genital apparatus will separate the species. The easiest diagnostic character if available is host association. These beetles are found on birch.
The adults first start to emerge in late June and live about 3 weeks. Females oviposit on damaged or weakened trees, in crevices in the bark. Preference is given to exposed, open growing trees, often drought stressed. Eggs are deposited on branches or on the trunk, (usually larger than 25 mm in diameter). Larvae bore into the cambial area. If the tree is healthy it may overgrow the damage, if not the larval tunnelling may kill the branch. The larvae feed under the bark, entering the wood to moult. Pupation occurs in the wood just beneath the bark. Adult exit holes are "D" shaped (Ives and Wong, 1988).
Common; serious pest of ornamental plantings of birch in our area (Baker 1972).
Restricted to birch trees, including paper birch, weeping birch and water birch.
North America, anywhere birch grows (Baker 1972).
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