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A Japanese beetle on a leaf. Thinkstock photo

As emerald ash borer beetle approaches, an update on invasive insects

When it was first reported that the ravenous Japanese beetle had entered North Dakota and Minnesota, and the tree-killing machine called emerald ash borer was feeding its way toward us, it seemed insect invasions were getting steadily worse. Sort of like the locust troubles of the ancient Egyptians who didn't follow Moses' control recommendations.

Insect invasions aren't new. I remember five decades ago how the elm bark beetle began spreading Dutch elm disease into our region that devastated our elms. Beautiful elms remain, but fewer. I recall my mother relating the difficulties of growing gardens in the 1930s when plants carefully tended during the drought years were hungrily consumed by hordes of grasshoppers.

Insects will probably always come and go, but when a new wave is marching toward us, it's concerning. I contacted Charles Elhard, plant protection officer with the North Dakota Department of Agriculture's Plant Industries Division, for an update on two high-profile insects hovering around the region's doorstep. Charles provided information for the following updates:

Japanese beetle

The insect is extremely devastating because it devours more than 300 species of plants, including trees, shrubs, perennials, annuals, fruits, vegetables and turf grass. Farmers have reason for concern because Japanese beetles consume soybeans and corn.

The state Department of Agriculture has monitored for the Japanese beetle since the 1960s, catching two beetles in 2001, but not again until 2012. Since then, the beetles have been caught in monitoring traps each year. In 2017, a wholesale nursery from an infested area accidentally introduced live Japanese beetle larva in container nursery stock and shipped potentially infested stock to nearly 80 nurseries across North Dakota. The Department of Agriculture placed 1,200 traps statewide and caught 1,467 beetles in 22 counties last year.

Monitoring continues in 2018, with approximately 800 traps statewide, but it's hoped that this region's past cold, dry winter might have prevented Japanese beetles from overwintering. Traps will be monitored throughout the flight period of the species, which is from June 1 to Sept. 30.

The adult Japanese beetle is rounded-fat, half an inch long and metallic green in color with copper-bronze wing covers.

Emerald ash borer

First discovered around Detroit in 2002, the emerald ash borer (EAB) was likely imported into the United States from China in wood packing material. Since then, it has killed hundreds of millions of ash trees in the U.S., which is the only tree type it attacks.

EAB has now been found in 34 states and three Canadian provinces, but hasn't been detected in North Dakota to date. The closest since 2009 had been the Minneapolis-St.Paul area in Minnesota, but in December 2017, EAB was discovered in Winnipeg, Manitoba, 70 miles from the North Dakota border, and most recently in Sioux Falls, S.D., in May 2018.

The Department of Agriculture, along with partners the North Dakota Forest Service and city foresters across the state, will place more than 250 EAB traps across North Dakota at high-risk sites, including state parks, rest areas and campgrounds.

The adult EAB is a narrow beetle about half an inch long, with metallic-green wing covers with coppery reflections. When the wing shields are spread, the bright metallic-red upper surface of the abdomen is visible.

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