UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 437 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



January 16, 1917 



FLAT-HEADED BORERS AFFECTING FOREST TREES 

 IN THE UNITED STATES. 



By H. E. Burke, Specialist in Forest Entomology, Forest Insect Investigations. 



CONTENTS. 



Page. 



Importance of flat-headed borers 1 



Food plants 2 



Character of the work 2 



Life history 2 



Seasonal history 2 



Special habits 3 



Special structural characters 3 



Agreement of adult and larval classifications. 4 



Distinguishing characters 4 



Key to genera of buprestid larvae 5 



List of genera, distribution, common habits, 



and host trees 6 



References to imj)ortant literature 8 



IMPORTANCE OF FLAT-HEADED BORERS. 



Flat-headed borers (buprestid larvae) are among the most important 

 of the borers infesting forest trees in the United States. Some mine 

 the leaves, one burrows into the cones, a number bore into the inner 

 bark and outer wood of the triuik, branches, and roots, while the 

 majority excavate oval winding "wormholes" throughout the sound 

 or decaying sapwood and heartwood. 



At present the leaf-miners and the cone-burrower are not common 

 enough to be important. The bark-borers often girdle and kill healthy 

 trees or those injured by fire, floods, droughts, diseases, other insects, 

 or careless lumbering, and at other times weaken trees so that they 

 become easy victims of diseases, other insects, or unfavorable environ- 

 ment. vSometinies when they do not kill the tree outright their work 

 causes dead limbs or twigs, or serious defects, checks, or gum spots 

 to form in the wood, or swollen gaUs to form on the branches. The 

 wood-borers mine the sapwood and heartwood of the trunk, top, and 

 larger branches and thus destroy or seriously injure a large amount 

 of the tree's most valuable product, its timber. Wormholes will cause 

 tlic finest grade clear lund^or to become unfit for the higher grade 

 uses and therefore unsalable at the higher prices. 



57160'— Bull. 4.",7 17 



