What is an Asian Longhorned Beetle?

The Asian longhorned beetle (ALB) is an exotic invasive wood-borer beetle in the family Cerambycidae that feeds on a wide variety of trees encompassing 12 genra in 9 plant families with Maples (Acer spp.) being the most ecologically and economically significant in the United States, eventually killing them. The beetle is native to China and the Korean Peninsula and was most likely brought to the United States in wood packing material such as crates or pallets. Adult beetles are large, distinctive-looking insects measuring 1 to 1.5 inches in length with long antennae. Their bodies are black with small white spots, and their antennae are banded in black and white. Checking your trees regularly for this insect and looking for the damage it causes and reporting any sightings can help prevent the spread of the beetle. If not eradicated, ALB poses a severe threat to natural and urban North American Forests if it becomes widespread.

History of ALB in the United States

First detected in North America in 1996 in New York City, additional infestations have since been detected in New York, New Jersey, Illinois, Massachusetts, Ohio, and Ontario, Canada. The beetle has been successfully eradicated in Illinois, New Jersey, and parts of New York and Ontario. Eradication efforts continue in other states and Ontario where ALB has been found.

Ohio was the fifth state to find ALB. In Ohio, ALB was discovered in Tate Township in Clermont County in June 2011, and the Ohio ALB Cooperative Eradication Program was established with the goal of eradicating the infestation. Participating agencies include United States Department of Agriculture (USDA) Animal Plant Health Inspection Service (APHIS), Ohio Department of Agriculture (ODA), Ohio Department of Natural Resources (ODNR), Ohio State University Extension, USDA’s Agricultural Research Service and USDA Forest Service. Quarantines were established in Clermont County to prevent the spread of ALB. The removal of regulated items that could spread the beetle, such as logs, trees, tree trimmings, chipped wood with pieces larger than 1 inch in two dimensions, and firewood, from the quarantined area is restricted by law. This invasive beetle has no known natural predators and poses a threat to Ohio's hardwood forests (more than $2.5 billion in standing maple timber) and the state's $5 billion nursery industry which employs nearly 240,000 people.

What is ALB Host Range?

ALB has a broad host range that includes trees representing multiple species from 12 genera: maples (Acer spp.); horsechestnuts and buckeyes (Aesculus spp.); elms (Ulmus spp.); willows (Salix spp.); birches (Betula spp.); sycamore and planetrees (Plantanus spp.); poplars (Populus spp.); mimosa (Albizia julibrissin); katsura (Cercidiphyllum japonicum); ash (Fraxinus spp.); golden raintree (Koelreuteria paniculata); and mountainash (Sorbus spp.)

What is The Life History of ALB?

Adult females chew depressions known as "oviposition pits" into the bark of various hardwood tree species. They lay an egg—about the size of a rice grain—under the bark at each site. (Females can lay up to 90 eggs in their lifetime.) Within 2 weeks, the egg hatches, and the white larva bores into the tree, feeding on the living tissue (xylem & phloem) that carries nutrients and the layer responsible for new growth under the bark. After several weeks, the larva tunnels into the woody tree tissue, where it continues to feed and develop over the winter. Larvae molt and can go through as many as 13 growth phases. As the larvae feed, they form tunnels or galleries in tree trunks and branches. Sawdust-like material, called frass, from the insect’s burrowing can be found at the trunk and branch bases of infested trees.

Feeding by ALB larvae damages the xylem, which moves water from the roots to the canopy of the tree. As larval feeding continues over time, damage to the xylem slowly accumulates causing structural weakening in tree branches. Branches often break, especially during storms. Eventually, larval feeding kills the tree. The larvae feed through the summer and fall until pupation; occasionally, pupation occurs in the spring.

Over the course of a year, beetle larvae develop into adults. The pupal stage lasts 13 to 24 days. Adults emerge in late spring through late summer with peak emergence typically occurring in late June to early August; however, adults can be present in the fall. Mating begins 2 to 3 days after emergence. ALB can overwinter in the egg, larval or pupal stage, but adults do not survive the winter, dying after the first fall freeze. There is one generation per year. After adult beetles emerge from the pupae, they chew their way out of the tree, leaving round exit holes approximately three-eighths of an inch in diameter. Once they have exited a tree, they feed on its leaves and bark for 10 to 14 days before mating and laying eggs.

Because ALB can overwinter in multiple life stages, adults emerge at different times. This results in their feeding, mating, and laying eggs throughout the summer and fall. While adult beetle activity is most obvious during the summer and early fall, adults have been seen from April to December. Adult beetles can fly for 400 yards or more to search for a host tree or mate. However, they usually remain on the tree from which they emerged, resulting in infestation by future generations.

Signs of ALB start to show about 3 to 4 years after infestation, with tree death occurring in 10 to 15 years depending on the tree’s overall health and site conditions. Infested trees do not recover, nor do they regenerate. Foresters have observed ALB-related tree deaths in every affected state.

Prevent The Spread

ALB has the potential to become a catastrophic pest of hardwood trees in North America due to a wide range of suitable hosts and difficulties in detection and monitoring. If the spread of this beetle is not stopped, ALB will cause significant ecological and economic impacts. The forest products and nursery industry in Ohio and elsewhere would be threatened by the loss of trees. Tree mortality caused by ALB will also impact biodiversity and ecosystem services in urban and natural forests. The eastern and southern half of Ohio is dominated by hardwood forests, and damage to trees will impact homeowners, parks and recreation, and maple syrup processors. Additionally, the state tree of Ohio, the buckeye, is a host for ALB.

Eradication efforts in some areas of North America have been successful and those efforts continue in Ohio. However, if ALB is allowed to spread, those efforts will be undermined. To prevent the spread of ALB, quarantines are established in areas where the beetle has been detected. Removing infested trees or high risk host trees in the surrounding area are essential to stop the spread of ALB and save millions of trees.  Do not transport living or dead trees, including firewood, branches, roots, stumps, or other debris from quarantined areas. Larvae often go unnoticed because feeding occurs under the bark, and this is why transporting wood is a major problem. It is particularly important to purchase firewood where you plan to burn it to avoid spreading ALB or other pests, such as emerald ash borer, gypsy moth, and walnut twig beetle.

Early detection of ALB infestations is critical to the success of eradication efforts in terms of time and money. Most infestations have been identified by alert citizens that find the beetle, but careful monitoring for tree damage will also help catch an infestation early. If signs or symptoms of ALB are found, report the infestation to the ODA by phone at (614) 728-6201 or online at agri.ohio.gov. Citizens in Ohio or other states may also report a suspected ALB infestation to USDA APHIS by accessing their ALB website and clicking on “Have You Seen The Beetle” at: asianlonghornedbeetle.com

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Asian longhorned beetle. Photo credit: Joe Boggs, The Ohio State University

About Our Parks

Our parks and staff are dedicated to education, enjoyment and preservation of Richland County's natural areas and inhabitants. Our goal is pursued by preserving natural areas for people to experience, and by providing opportunities for people of all ages to learn about the rich diversity of life and habitats in our county.

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Gorman Nature Center
2295 Lexington Avenue
Mansfield, Ohio 44907

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(Closed Sunday-Monday and Federal Holidays. Trails are open daily from dawn to dusk.)

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