Hitchhiking Bugs

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Published on: Mar. 2, 2007

Last revision: Nov. 30, 2010

as possible. Reducing firewood movement and thinking about other ways that pests might hitchhike into our forests will go a long way toward preventing the arrival of the next new pest.

Help Stop Invasive Bugs

  • Do not bring firewood from other states. Use local sources.
  • Examine vehicles and outdoor gear for gypsy moth egg masses after summer visits to Great Lakes states or the northeastern U.S. If you find egg masses, destroy them.
  • Start replacing ash trees in urban landscapes with other tree species to avoid having to replace them all later at one time.
  • Plant a diversity of trees and shrubs (no more than 10 percent of any one species).
  • Use proper planting, mulching and pruning methods to improve plant health. See
  • Do not use insecticides to prevent emerald ash borer attacks where borer populations have not been detected.
  • If you find what you suspect is a non-native pest, contact your local Department of Conservation forester.

Is It Emerald Ash Borer?


Is the tree an ash species?

  • Emerald ash borers only attack ash trees.
  • For help identifying ash trees visit online or you can purchase the Trees of Missouri Field Guide. The book includes easy-to-understand descriptions and color illustrations for 147 native and 27 non-native tree species found in Missouri. This item is available for $7.50 plus shipping and handling, and sales tax (where applicable). To order, call toll free 877/521-8632 or visit


Is the tree in poor health?

The following symptoms can be caused by native pests, emerald ash borers or other stresses:

  • Branch dieback in upper crown
  • Sparse leaves
  • Splits in bark
  • New sprouts on trunk or limbs


Do you see any of the following?

  • 1⁄2-inch-long, metallic-green, bullet-shaped beetles
  • 1/8-inch-wide, D-shaped holes in bark
  • Tapeworm-like larvae with bell-shaped segments under bark
  • S-shaped larval tunnels under bark

It’s NOT Emerald Ash Borer if you see:

  • Round or oval holes in bark
  • Brown papery insect “skins” in bark holes (clearwing moths)
  • Round holes in rows on bark (yellowbellied sapsucker)
  • Larval tunnels deep into wood or not S-shaped

Check the links listed below to be sure.

Other Invasive Insects

Gypsy Moths

  • Caterpillars feed on leaves of oaks and other woody plants and can kill trees during outbreaks.
  • Velvety-brown egg masses (1 to 2 inches wide) can be deposited on vehicles, outdoor equipment, firewood and nursery stock in July and August.
  • Species is spreading from Wisconsin, northern Illinois, Indiana, Ohio and northeastern U.S.

Asian longhorned Beetles

  • Larval tunneling in trunk and branches kills maples, elms and other deciduous trees.
  • Species can spread when firewood and logs are taken from infested areas.
  • They have entered North America multiple times in international shipments.

Sirex Woodwasps

  • Female injects a fungus and toxic mucus that kill pines while her offspring tunnel in the wood.
  • The species can be spread by moving infested logs.
  • They are present in New York, Pennsylvania and Ontario, but the extent of their range is unknown.

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