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Forest Health > Insects and Diseases publication
INSECTS of... Conifer/Hardwood Branch and Stem
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FLATHEADED BORERS
Typical larva of FLATHEADED BORER. |
Other: |
Metallic beetles
Wood borers |
| Species |
Hardwoods: Brachys spp., Chrysobothris spp.
Softwoods: Acmaeodera sp., Chalcophora spp., Chrysobothris spp. |
| Common Hosts: |
Hardwoods
Softwoods
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Description |
Adult -- approximately 6-33 mm long; head and body with flattened appearance; coloration variable; often a metallic blue, green, copper, or red; sometimes distinctive banding.
Pupa -- similar to adult; white.
Larva -- size variable, approximately 8-50 mm long when mature; head and body yellowish to creamy white; mouthparts dark and prominent; neck region greatly expanded, flattened; legless. |
Importance |
The majority of flatheaded borers, like roundheaded borers, infest dead, dying, or high stressed or weakened trees. A few species do attack healthy trees. All tree parts are susceptible to flatheaded borer infestation. Seasoning timber is highly susceptible to borer infestation. A common occurrence in Florida is the emergence of adult beetles from newly constructed log houses; a result of improper log treatment prior to construction. Fortunately, the beetles will not reinfest the wood. The holes, however, should receive treatment to minimize decay. |
Biology
and Habits |
Adult beetles emerge year-round from infested trees or material, mate, and the females lay eggs in protected sites; in bark crevices, under bark flaps, or in wounds. Larvae first feed on tree's inner bark, then bore into the sapwood and heartwood. Pupation occurs in a chamber made by the mature larva. Overwinters as larva, pupa, or adult. |
Number
of Generations |
Variable - several generations per year to 2-3 years for just one generation. |
Signs
of Infestation |
Foliage discoloration and/or wilting. Some metallic beetles are leaf miners. Flattened holes (more than 4 mm wide) in bark and into sapwood. Sapstaining of bark around holes. |
Control |
Promote tree vigor and health to minimize the possibility of borer infestation. Avoid injury of trees. Promptly dispose of material infested by borers. Remove and destroy trees severely infested by borers. Use an approved insecticide to prevent infestation of susceptible trees or material. Use an approved insecticide to prevent complete emergence of adult beetles from infested material.
NOTE: Galley fumigation is difficult for this group of wood boring insects because the galleries are tightly packed with their frass, thus inhibiting fumigant penetration. |
Bulletin No. 196-A | Printed October, 1983 |
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