Flatheaded Borer in White Alder Landscape Trees

Abstract

Flight of a flatheaded borer (Agrilus burkei)begins in late March or the beginning of April and lasts for 35 to 62 days. After emergence through D-shaped holes in the bark, the adults feed for one week on the foliage; they live about 12 days. The first egg mass is oviposited 7 days after emergence. Hatched larvae penetrate the bark surface directly into the phloem tissues. The larval stage lasts from April to February of the next year. In March a pupa is formed beneath the bark and the new imago emerges. The apparent propensity of A. burkei to attack poorly growing alder trees suggests that white alders, Alnus rhombifolia, should be planted only in landscapes where moisture stress can be avoided or minimized.