Pest profile

Flatheaded Appletree Borer

Chrysobothris femorata · Coleoptera: Buprestidae[2]

Flatheaded appletree borer larvae bore into the trunk and main branches of young or stressed apple trees and can girdle them.[1]

Flatheaded appletree borer, a flattened, mottled gray-bronze metallic beetle on tree bark
Flatheaded appletree borer, a flattened, mottled gray-bronze metallic beetle on tree bark. (c) Katja Schulz, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Adults are somewhat flattened beetles about 1/2 inch long, dark metallic brown to dull gray.[1]
  • Larvae are legless and yellowish-white with a broad flat area behind the head, reaching 1 1/2 inches.[1]
  • Infested trees have bark cracks that ooze sap, and galleries are packed with sawdust-like frass.[1]

Where it lives

HGIC covers it on apple trees in South Carolina.[1]

US map: public records from 25 states since 1990 (GBIF).

Biology and life cycle

Adults are present from late spring to November, and there's one generation a year.[1]

First attacks are usually on the sunny side of the tree.[1]

Damage and signs

  • Trees stressed by recent planting or drought are attacked; galleries can girdle and kill the tree.[1]

Health risk

It feeds on plants; Clemson HGIC mentions no risk to people.[1]

Control

Prevention

Keep trees healthy and vigorous, watering weekly during heat and drought; vigorous trees can drown larvae in sap.[1]

Common questions

Why is sap oozing from cracks on my young apple tree?
Flatheaded appletree borer larvae tunneling under the bark can cause sap-oozing cracks.[1]
How do I protect a newly planted tree from borers?
Keep it vigorous, watering weekly in heat and drought; stressed young trees are the targets.[1]

Sources

  1. Clemson Cooperative Extension, Home & Garden Information Center, “Apple & Crabapple Insects (HGIC 2001).” hgic.clemson.edu/factsheet/apple-crabapple-insects/ (accessed 2026-10-06)
  2. iNaturalist, “Chrysobothris femorata taxon page (order and family).” www.inaturalist.org/taxa/1308752 (accessed 2026-10-06)

Updated 2026-10-14. Built from sourced records. Spot an error? Tell us.