Forest Pest Insects in North America: a Photographic Guide

Flatheaded appletree borer

Chrysobothris femorata (Olivier) (Coleoptera: Buprestidae)

Orientation to pest

Flatheaded appletree borer, Chrysobothris femorata (Olivier), is a common, well known native borer affecting many species of hardwood trees in North America. Adults emerge in summer and feed on foliage of their host trees. Eggs are deposited under bark scales or in crevices on the main trunk or larger branches. The larvae bore into the bark and feed in the phloem and outer sapwood. In older trees, tunnels are most often in the thick inner bark. Mature larvae build pupation cells in the outer wood in late summer, where they pass the winter and pupate the following spring. There is one generation per year. This borer is especially damaging to newly planted trees and trees stressed by drought or other factors. Young trees may be girdled and killed. Larger trees may show injuries through loss of large patches of bark on trunks.

Hosts commonly attacked

This species attacks a wide range of trees species, including sycamore (Platanus occidentalis L.), silver maple (Acer saccharinum L.), boxelder (Acer negundo L.), black walnut (Juglans nigra L.), willow (Salix), white oak (Quercus alba L.), black oak (Quercus velutina Lamb.), yellow-poplar (Liriodendron tulipifera L.), elm (Ulmus), American beech (Fagus grandifolia Ehrh.), hickory (Carya), hackberry (Celtus), apple (Malus domestica Borkh.), and pear (Pyrus).

Distribution

This species is found throughout most of Canada and the United States.

Images of flatheaded appletree borer

Adult of the flatheaded apple tree borer Joseph Berger, Bugwood.org 768x512 / 1536x1024
Mature larva of flatheaded apple borer James Solomon, USDA Forest Service, Bugwood.org 768x512 / 1536x1024
Sap spot over feeding site of flatheaded apple borer larva in Nuttall oak James Solomon, USDA Forest Service, Bugwood.org 768x512 / 1536x1024
Damage to red maple from flatheaded apple borer John Ruter, University of Georgia, Bugwood.org 768x512 / 1536x1024
Figure 1. Adult of the flatheaded apple tree borer, Chrysobothris femorata Figure 2. Mature larva of flatheaded apple borer Figure 3. Sap spot over feeding site of flatheaded apple borer larva in Nuttall oak (Quercus texana Buckl.) Figure 4. Damage to red maple (Acer rubrum L.) from flatheaded apple borer

Important biological control agents related to this pest species

Natural enemies known to attack the flatheaded apple borer include the ichneumonids Labena grallator Say and Crytohelcostizus chrysobothridis Cushman, the chalcid Phasgonophora sulcata Westwood, and the braconid Atanycolus rugosiventris Ashmead. Predators include the clerids Chariessa pilosa (Foster) and Chariessa pilosa onusta Say, the asilid Andrenosoma fulvicauda Say, and various woodpeckers.

Web links for information on flatheaded appletree borer

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