Asian longhorned beetle

Departments - Under the Microscope

USDA scientists are evaluating a wasp's ability to detect and attack the Asian longhorned beetle.

September 7, 2021

The Asian longhorned beetle is a threat to America’s hardwood trees. With no current cure for infested trees, early identification and eradication are critical to prevent the loss of more trees.

August is the most critical time of year to spot ALB as adult activity peaks. That’s why the U.S. Department of Agriculture (USDA) declared August as “Tree Check Month” for this invasive pest. Checking trees for the beetle and the damage it causes is how everyone can help USDA and its partners eliminate the beetle from the U.S. and protect more trees. USDA and its partners are working to eradicate the tree-killing beetle in Massachusetts, New York, Ohio and South Carolina. However, residents in all states should keep an eye out for any new incursions.

ALB is an invasive wood-boring beetle that attacks 12 types of hardwood trees in North America, such as maples, elms, buckeyes, birches, and willows. Infested trees do not recover and eventually die. Infested trees also become safety hazards since branches can drop and trees can fall over, especially during storms. In its larval stage, the insect feeds inside tree trunks and branches, creating tunnels as it feeds, then adults chew their way out in the warmer months, leaving about ¾-inch round exit holes.


Native stingless wasp may benefit ALB eradication efforts

For 25 years, the USDA-APHIS Plant Protection and Quarantine program's Asian longhorned beetle (ALB) eradication program has successfully battled back against the pest to significantly reduce its footprint. PPQ experts have established a solid response plan to eliminate the ALB and prevent its spread to other locations. As part of PPQ’s ongoing efforts, scientists are evaluating a biological control (biocontrol) agent—Ontsira mellipes—for its potential to attack and kill ALB larvae.

This stingless parasitoid wasp is native to North America, abundant, and widely distributed across the continent. Ontsira mellipes attacks larvae of native woodboring cerambycids (longhorned wood-boring beetles) and the ALB—a non-native cerambycid—in laboratory tests. For this reason, scientists are hopeful that the wasp can aid ALB eradication efforts. To prove it, they have teed up biocontrol field studies in the ALB quarantine area in Worcester, Massachusetts.

PPQ’s Science and Technology researchers Juli Gould, Carrie Crook, Mandy Furtado, and Theresa Murphy are working with colleagues from USDA’s Agricultural Research Service (ARS), the University of Massachusetts Amherst, and PPQ’s ALB response team to evaluate Ontsira mellipes as an effective biological control agent. They will conduct their 18-week study off the beaten path on conservation property in woodlots where public usage is limited, and ALB quarantine regulations are in place.

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