Life Cycle

The life cycle (see diagram below) of the insect is two years with synchronous emergence of adults occurring in odd-numbered years. Adult flight is from late June through early August (1). After mating females oviposit up to 200 eggs on the bark of living oak trees (2). After hatching, small larvae burrow through the bark, forming small attack holes (3). They enter the inner phloem and excavate feeding galleries where they also over-winter (4). Larvae feed within the phloem/cambial/xylem tissue the following summer (5) and simultaneously excavate vertical ~18 cm heartwood galleries (6). Larvae pupate within the heartwood gallery behind a frass plug (7) before finally emerging via an oblong exit hole (8).