An insidious metallic green menace known as the Emerald ash borer (EAB) continues its march westward…and eastward, and southward. The latest areas to join the federally regulated zone for the pest are Charlotte, Halifax, Lunenburg, Mecklenburg, and Pittsylvania Counties and the City of Danville, all in south-central Virginia. They are all at the other end of the state from areas in northern Virginia where the pest had been found previously.
But the pattern isn’t new. A look at the EAB map
of the pest’s spread reveals the “hopscotch” progression of the pest in all directions from the initial detection in southeastern Michigan. Outlying infestations are thought to have resulted from the borer hitching a ride on firewood, logs for lumber, and even nursery stock.
“For plant protection officials, conservation interests, and our industry alike, EAB is a sad case study,” said Craig Regelbrugge, vice president for government relations with the American Nursery & Landscape Association. Despite millions in federal and other funding for eradication, containment, and research, Regelbrugge explains that control efforts have been hampered by the lack of a good early detection method or a cost-effective and biologically effective area-wide treatment. Also good news: regulations are now in place requiring treatment of wood packaging, which is thought to have brought the borer to North America from Asia. But bad news too: non-compliance has been a recurring challenge.
Is there any hope? To date, there has been at least some success with strategies for protecting high-value landscape trees in the genus Fraxinus
. Yet, still, EAB is “pretty much a death sentence” for most ash trees in natural areas and most managed landscapes.
In the short term, beyond individual specimen trees, areas with ash trees that are contiguous to current infestations will continue to succumb. Long-term, the best hope is that biological controls for the borer itself can be found. Breeding for resistant trees might also be possible, though very long-term. Meanwhile, it may be possible to protect geographically isolated areas the pest might not spread to on its own, like cities in the mountain West and West Coast.
That’s where the federal regulations
come in. The interstate movement of EAB-host wood and wood products from infested areas is regulated, including firewood of all hardwood species, nursery stock, green lumber, waste, compost, and chips of ash species.
updated July 25, 2012
Last week the Connecticut Agricultural Experiment Station (CAES) confirmed the discovery of Emerald Ash Borer in Prospect, CT. This marks the first finding of this pest in the state. The confirmation came from EABs recovered from a native predatory wasp nest (Cerceris fumipennis
). The wasp collects the beetles to feed its wasp larvae. Discovering EAB in this manner suggests that the beetle is well established and at a significantly high density in the Prospect region. State officials believe that EAB is established in the nearby Naugatuck State Forest as well, an area spanning nearly 5000 acres. Surveys in CT will continue and likely expand but eradication seems unlikely. The state will focus its efforts on preventing and slowing the spread of EAB throughout the state. CAES estimates that ash species (Fraxinus
spp.) make up 4-15% of its forest cover and the tree is commonly used in its urban landscapes. This discovery brings the total number of states with EAB confirmations to fifteen.