Emerald ash borers invade Missouri
July 07, 2009

After several years of visually surveying for this small invasive insect, the emerald ash borer (EAB), pictured right, has officially been found in Missouri. First found in Michigan and Windsor, Ontario in 2002, Missouri, the farthest south and west of any other known infestation, has become the tenth state to have a confirmed infestation. The others are Ohio, Indiana, Illinois, Maryland, Pennsylvania, Wisconsin, West Virginia and Virginia.

Officials with the USDA Animal and Plant Health Inspection Service confirmed the identity of the insect first discovered in traps at the US Army Corps of Engineers' Greenville Recreation Area in Wayne County. They have estimated that the insect has been present for about five years. The county has been placed under federal and state quarantines prohibiting the movement of all hardwood firewood, ash nursery stock and ash logs on which the pest is able to move long distances.

What should you do?

Ash trees (Fraxinus species) are unique from other trees because they exhibit opposite branching (unless branch is not present because of having broken off) and because their compound leaves are composed of seven to nine leaflets. Pictured is a young ash leaf with adult emerald ash borers present. It should be noted that the mountain ash (Sorbus) is not a true ash and consequently not affected by the EAB.

Damage to the North American ash species (Fraxinus sp.) that includes green, white, black and blue ash, is caused by the larvae of the borer that feed in tunnels in the phloem just below the bark. the serpentine tunnels disrupt water and nutrient transport eventually causing the entire tree to die. Adults that are roughly 3/8" to 5/8" long with metallic green wing covers and a coppery red or purple abdomen leave distinctive D-shaped exit holes in the outer bark of branches and the trunk. They are most commonly seen in June or July but may be present for a longer period of time.

In Missouri this summer federal and state officials will be expanding trapping efforts to detect the insect. The traps are purple, prism-shaped devices with sticky outer surfaces. The borers are attracted by the color and by the chemical scents that mimic a stressed ash tree. Insects landing on the traps are stuck and identified by periodic checking.

The Missouri Department of Conservation would like to know if anyone spots the insect. Collect a sample of it by trapping it in a zippered plastic bag. Place the bag in the freezer for several days to kill the insect then mail the sample in a sturdy container (35mm. film canisters work well) to Rob Lawrence, Forest Entomologist, Missouri Department of Conservation, 1110 S. College Ave., Columbia, MO 65201. Be sure to include your contact information and the date and location where you captured the sample.

For further information by e-mail contact Lawrence here or Colin Wamsley, state entomologist for the Missouri Department of Agriculture here.

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