Bolstering Biological Controls

Bolstering Biological Controls

The emerald ash borer beetle (Agrilus planipennis or EAB) is an exotic pest first discovered first in Detroit in 2002. It is thought that the borers arrived in the United States in solid wood packing on shipping containers from Asia. Since its initial discovery populations have been found in 20 additional states and in Ontario, Canada. EAB is real threat to ash trees which has led to the development of regulations and quarantines,  implemented by the USDA, are in place. However, all species of native ash trees are susceptible and the possibility that shade trees, lumber and woodlot trees may be lost still remains.

The parasitic wasp, Spathius galinae, is a natural predator of the emerald ash borer and may be released as a biological control mechanism.

The parasitic wasp, Spathius galinae, is a natural predator of the emerald ash borer and may be released as a biological control mechanism.

While research continues to more fully understand the life cycle of the emerald ash borer, find new methods for detection, control and containment, quarantines are in place to prevent spread through movement of firewood, logs or nursery stock. While adult beetles cause minimal damage with their leaf nibbling, larvae feed on the inner bark of ash trees inhibiting the tree’s ability to transport water and nutrients. To date millions of trees have been killed and have cost property owners, municipalities, nursery owners and wood product industries tens of millions of dollars.

Now the USDA is considering a new plan of attack, biological control of the borers using a natural predator, Spathius galinae. They propose to release the wasps into the continental U.S. to control EAB. In the meantime, this incredibly invasive and destructive pest continues is spread west, in spite of quarantines and protections currently in place. The USDA’s Animal and Plant Health Inspection Service (APHIS) recently expanded the quarantines to include portions of Wisconsin as well as the entirety of Massachusetts and Connecticut.