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DNRC Headquarters
1539 Eleventh Ave. Helena, MT 59601
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Surveillance for Invasive Forest Pests



The potential ecological damage and financial losses due to invasive or introduced insects and diseases is incalculable.  Historical examples include gypsy moth, white pine blister rust, chestnut blight, Phytophthora spp., and Dutch elm disease.  Recent examples include Asian long-horned beetle, emerald ash borer, laurel wilt, thousand-cankers disease of walnut, and various conifer bark and shoot beetles.

Non-native pests can be transported to Montana from overseas or within North America via cargo containers, wood pallets and dunnage, nursery stock, firewood, recreation vehicles, boats, outdoor furniture, or any other items stored outside and then moved long distances.

Montana DNRC Forest Pest Management works cooperatively with the Montana Department of Agriculture, USDA Forest Service, and the USDA Animal Plant Health Inspection Services to survey and monitor for non-native invasive pests in Montana.  Please report any suspicious findings to your local extension agent

Potential invasive pests currently of most concern in Montana

Emerald Ash Borer -- Thus far not detected in Montana.                      

Emerald ash borer (EAB), Agrilus plannipennis, is a wood-boring insect that attacks and slowly kills ash trees (Fraxinus spp.).  It has spread to and killed much of the ash in urban and natural forests in the midwestern and eastern United States and was most recently detected in Boulder, Colorado.  The suspected means of long-distance transport is firewood cut from infested trees.

Ash distribution is limited in Montana but it is a key component of riparian corridors, shelterbelts, and community plantings.  Early detection of EAB is critical yet difficult.  Cooperators, including the Montana DNRC, have been placing detection traps throughout the state.  The Montana Urban and Community Forestry Association also coordinates a sampling project to detect larvae in branches pruned during regular tree maintenance.

To learn more about EAB, visit:


Asian Longhorned Beetle  -- Thus far not detected in Montana.

Asian longhorned beetle (ALB), Anoplophora glabripennis, is a wood-boring insect that attacks a wide range of hardwood hosts including maple, elm, and willow.  These species, especially maple, are commonly planted in many Montana communities.  The insect originates from Asia and was likely transported to North America in infested shipping material.  It has been detected in Massachusetts, Ohio, and New York. 

To learn more about ALB, visit:


Lymantria dispar – Occasional, localized introductions into Montana have been detected and eliminated.

Lymantria dispar (formerly known as Gypsy moth), feeds on array of tree species, both conifer and hardwood.  Although trees are not killed outright, the insects can completely defoliate and severely weaken trees. L. dispar is well-established in the eastern U.S. and currently extends as far west as Minnesota.  Egg masses laid by females are notorious for being transported long distances on RVs, firewood, and (or) any item that has been stored outside.  Introductions occur when an egg mass is moved and the larvae emerge and infest nearby trees.  In order to detect introductions, cooperative agencies set over 1000 traps annually in Montana.   

Learn to identify Lymantria dispar.


2705 Spurgin Road, Missoula, MT 59804
Phone: (406) 542-4300
Fax: (406) 542-421