Colorado Keeps a Watchful Eye Out for Emerald Ash Borer and Gypsy Moth

The Colorado State Forest Service, U.S. Department of Agriculture Animal Plant Health Inspection Services-Plant Protection and Quarantine and the Colorado Department of Agriculture are carrying out a statewide plan to monitor two non-native insects that may be damaging to Colorado’s forests. Gypsy moth and emerald ash borer have not yet been found in Colorado; however, if they are transported into the state, infestations would severely affect the tourism industry and urban and rural areas that rely on forests to produce forest products and services.

"Monitoring will occur where the potential of introduction exists, including areas where trees provide an opportunity for the insects to feed and develop, and where human activities unwittingly allow insects to spread," said Ingrid Aguayo, forest entomologist for the Colorado State Forest Service, a division of the Warner College of Natural Resources at Colorado State University. "In general, this means urban areas and recreation sites near firewood sources and campgrounds."

Gypsy moth larvae feed on the leaves of more than 200 tree species. This moth is known to be established in eastern states, from Wisconsin to Virginia. Females lay eggs on cars, trucks, RVs and nursery stock such as trees and shrubs. That means they can be accidentally – and easily – introduced to Colorado from infested areas of the country. Gypsy moth was first detected in Colorado in 1984 and then in 2004. In both cases, Colorado has been successful in eradicating this pest. Since then, the Colorado State Forest Service, U.S. Department of Agriculture Animal Plant Health Inspection Services-Plant Protection and Quarantine and the Colorado Department of Agriculture have coordinated efforts to detect and restrict this exotic pest in Colorado.

Emerald ash borer is killing millions of ash trees in the Great Lakes area. This insect feeds in the inner bark of any type of ash tree. Several years of continuous infestation will cause trees to die. The larvae can be transported in ash firewood and nursery stock from infested areas of the country. To date, emerald ash borer has not been detected in Colorado.

Monitoring and detection of both insects is carried out with special traps that will be located on federal, state and private lands throughout Colorado. The gypsy moth trap is a small green container lined with a sticky substance inside that captures male gypsy moths with attractant bait.

The emerald ash borer trap is purple, coated with a sticky substance on the outside and baited with manuka oil as attractant. These traps will be placed out of public reach, when possible. The traps are currently being deployed and will be collected in September and October.

The trapping effort will help the agencies confirm that Colorado is free of gypsy moth and emerald ash borer. For more information on gypsy moth and emerald ash borer, visit http://www.ext.colostate.edu/pubs/insect/exotic.html. If you see a trap that appears to be in need of service, contact Ingrid Aguayo at (970) 491-7282 or iaguayo@colostate.edu.

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