About the Invasive Species Gallery

About Forest Pests

The dangers of exotic forest pests in North America first became evident when gypsy moth quickly became a problem after its release in 1869 (Howard, 1898). Over the years, hundreds of species of insects and plant pathogens have been introduced to North America (Mattson et al., 1994; Liebhold et al., 1995). While only a portion of them cause dramatic damage to forests or threaten specific species, the results have been devastating.

Use our common name or latin name photo galleries below to learn more about forest pests, what they look like, and about the damage they cause.

If, after visiting our photo galleries, you are concerned you’ve discovered a new infestation of a forest pest- please visit our Report a Pest page to contact the appropriate local authority.

Please note that a few of the invasive species listed in the Gallery of Pests are not considered pests that can be transported in or on firewood. All pests that are considered to be extremely low risk, or no risk, to spread in or on firewood have a brief note at the top of their Gallery profile page. They are included for general information purposes only.



The introduction was written by Faith T. Campbell, The Nature Conservancy.

The Nature Conservancy’s Forest Health Protection Program staff would like to thank in particular the many photographers that contribute to the image archives at http://www.forestryimages.org. Many of their images are used throughout these webpages.


Sources for the introduction on the front page of the Gallery

Howard, L. O. 1898. Danger of importing insect pests. 1898. In: Yearbook of the United States Department of Agriculture. 1897. G. M. Hill, Editor. Government Printing Office, Washington. Pp. 529 552.

Liebhold, A. M., W. L. MacDonald, D. Bergdahl, and V. C. Mastro. 1995. Invasion by exotic forest pests: a threat to forest ecosystems. Forest Sci., Monograph 30. 49 pp.

Mattson, W. J., P. Niemela, I. Millers, and Y. Ingauazo. 1994. Immigrant phytophagous insects on woody plants in the United States and Canada: an annotated list. USDA For. Ser. Gen. Tech. Rep. NC-169, 27 pp.