Depending on the temperature, region, and host, the life cycle of A. anxius can be one or two years; colonies in warmer climates typically show a one-year life cycle while those in colder regions often have a two-year cycle (Katovich et al). Insect development is hastened with increased stress level of the host.
Adult A. anxius emerge in early summer and live three weeks. Females lay up to 75 eggs, singly or in clusters, in bark crevices (Katovich et al)(EPPO1). Larvae hatch two weeks later and immediately bore into cambium. Larvae overwinter inside host trees(EPPO1).
Prefers weakened hosts
A. anxius larvae feed on phloem and cambium of affected trees. Affected trees may show the following symptoms manifesting from the upper crown, moving downward:
North American native Betula species under stress (drought, old age, poor site selection, injury, elevated soil temperature, pollution)
Non-native Betula species, even when healthy (EPPO2)(Katovich et al)
Planting resistant birch varieties on sites that are appropriate for the species is the best way to avoid attack of A. anxius.
Maintain tree health and minimize stress with proper watering, mulching, and care for roots.
Chemical treatments: Should be used only when decline is in initial stages. Systemic insecticides are applied to soil as a drench or in granulated form, and are taken up to larval galleries through the xylem. Insecticidal sprays are not advised due to the timing considerations required to avoid disrupting pollinator activity.