UNITED STATES DEPARTMENT OF AGRICULTURE 



MISCELLANEOUS PUBLICATION No. 74 



WASHINGTON, D. C. 



MAY, 1930 



AN ANNOTATED LIST 



OF THE IMPORTANT NORTH AMERICAN 



FOREST INSECTS 



Compiled by F. C. Craighead, Principal Entomologist in Charge 



and William Middleton, Associate Entomologist 



Division of Forest Insects, Bureau of Entomology 



CONTENTS 



Page 



Government projects relating to forest insects 1 



Tree-killing bark beetles 1 



Insects injurious to forest products " 2 



Insects affecting forest management 3 

 Insects injurious to shade trees and 



ornamental shrubs _ 3 



The most important forest insects. 4 



Tree-killing bark beetles 4 



Insects boring in living trees 6 



Page 

 The most important forest insects— Con td 



Insects affecting forest products n 

 Insects affecting seeds, forest reproduc- 

 tion, and nursery plants 15 



Defoliating insects.... 13 



Literature cited 2 3 



Appendix '_"_ 07 



Index. "" oq 



GOVERNMENT PROJECTS RELATING TO FOREST INSECTS 



The investigations by the United States Government of the insects 

 affecting forest trees, forest products, and shade trees are centered in 

 the division of forest insects of the Bureau of Entomology The 

 investigations carried on by the division are grouped for administra- 

 tive convenience into projects, the most important of which are briefly 

 described m the following paragraphs. 



TREE-KILLING BARK BEETLES 



Several species of tree-killing bark beetles of the genlis Dendroc- 

 tonus destroy annually over 6.000,000,000 feet of timber valued at 

 from $15,000,000 to $20,000,000. Biological investigations of these 

 beetles and the associated cooperation with Federal and private 

 agencies in their control constitute one of the major activities of the 

 division. The biological studies relate not only to the seasonal 

 history and habits of the species, but also to the environmental fac- 

 tors governing the behavior of the insects in all stages of develop- 

 ment, such as the part played by predators, parasites, and other 

 associated insects; the effects of climate, forest type, and site- the 

 characteristics of the trees selected for attack; and the reaction of 

 the tree itself during and after attack. All these factors, to which 



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