As Turf recently reported, August is “Tree Check Month” for Asian longhorned beetle (ALB) since adult activity peaks this month for the invasive wood-boring beetle that attacks and kills 12 types of North American hardwood trees. But alongside public education efforts to spot and control ALB, the USDA and its partners may soon have another tool in its arsenal in the 25+ year battle, reported Sharon Lucik in Plant Protection Today, a USDA publication.
Scientists from the USDA’s Plant Protection and Quarantine (PPQ) program announced in late July that they are evaluating a stingless parasitoid wasp, or Ontsira mellipes, for its potential to attack and kill ALB larvae. The wasp is native to North America, abundant, and widely distributed across the continent. Ontsira mellipes attacks larvae of native longhorned wood-boring beetles and ALB—a non-native—in laboratory tests. For this reason, scientists are hopeful that the wasp can aid ALB eradication efforts and conducting field studies in the ALB quarantine area in Worcester, MA. The team will conduct an 18-week study on conservation property in woodlots where public usage is limited, and ALB quarantine regulations are in place. “We’re already out in the field setting up our test and control plots,” said PQ’s Science and Technology researcher Juli Gould.
If scientists do prove Ontsira mellipes is an effective biocontrol agent for the ALB, it would provide the ALB staff with a new tool to use in sensitive areas where traditional eradication methods may not be suitable, and also in wetlands and rugged terrain inaccessible to the staff.
At the same time, foreign exploration for parasitoids that attack the ALB is ongoing in China and Korea. ARS researchers have collected one species in the genus Spathius and are rearing it in their Delaware laboratory. Next, they will conduct host-specificity testing to ensure that the parasitoid does not attack native cerambycid beetles.
In a similar eradication effort, Turf reported this past June about PPQ scientists fighting emerald ash borer with four stingless wasp species, specifically the Tetrastichus. Shipments of the wasps are already being made in EAB-infested states.
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