Asian Longhorned Beetle

An exotic pest that we do not want in Michigan
(The following excerpts taken from MSU Extension Bulletin E-2693)

The Asian Longhorned Beetle is a large wood-boring insect native to China and other Asian countries. It is not currently known to be in Michigan. New York City (since 1996) and Chicago (since 1998) are attempting to eradicate this pest. Thousands of trees have been removed and destroyed. Large tunnels created by larvae can cause branches or stems to break and can eventually lead to tree death. Because this beetle is not native to North America, it has no known natural enemies, and our trees have low resistance to this pest. Learn more…

 

Asian Longhorned Beetle adults are >1 inch from eyes to stern with antennae longer than the body. Notice white & black banded antennae, white marks on hardened wing covers (called elytra) and bluish tint on “feet” (called tarsi).

 

Asian Longhorned Beetles from different angles.

How did the the Asian Longhorned Beetle get into Michigan?

Most experts believe that the Asian Longhorned Beetle came from China
in wood crating, pallets or wooden logs and braces used to support cargo during shipping. Once established, beetles are moved when infested tree parts are taken to new areas. The adult beetles are poor fliers, generally flying short distances to neighboring trees.

Life Cycle

Adult beetles are usually active from May to October, with peak activity in midsummer. Females chew pits in the bark used for depositing eggs. Eggs hatch in 1-2 weeks, and the young larvae begin feeding and boring into the wood. Older, larger larvae tunnel deep into the wood, periodically pushing coarse sawdust out of entrance holes. The larvae spend the winter in the tree, emerging as adults in late spring. It usually only takes one year to go from egg to adult.

Infested tree damaged by ALB. Upper crown is attacked first.

 

Close up of infested upper crown branches showing large, round beetle emergence holes.

Similar Native Beetles

There are many species of longhorned beetles in North America. They feed in both conifers and evergreens. These beetles have evolved with native forests and pose little threat to forest health and productivity.

These native pine sawyer beetles do not damage healthy trees.
They infest dead trees, speeding up the recycling of nutrients.

 

Cottonwood borer is common in Michigan and is often mistaken for the Asian Longhorned Beetle.

Managing the Problem

Federal and state regulatory agencies inspect cargo entering the country.
Inspections are designed to detect exotic pests to prevent entry. New regulations require crates and dunnage shipped from China to be free of bark and kiln-dried or fumigated to reduce the risk of undetected introductions. Importantly, if after review this information you believe you have found the Asian Longhorned Beetle in Michigan, report you finding here or at any Department of Agriculture office or at your county MSU Extension office.