Invasive bugs toxic to trees on their way
Some harmful species already here in urban forest
SANTA FE — They’re coming. Some of them are already here.
With names that sound like they were lifted from a horror novel, different kinds of tiny insects seem to launch a new invasion threatening the urban forest every year in Santa Fe, around the state and across the country.
It was the airborne and awful ash whitefly two years ago. Then came the dreaded honey locust borer last year. Now, the evil European elm flea weevil is here, eating away at all species of elm trees in Santa Fe. Each one is a type of non-native invasive tree pest that has been identified as new to the area by Victor Lucero, who heads up city government’s Integrated Pest Management program.
In a recent report about “Pests of Concern,” Lucero writes that the weevil larvae “mine and feed inside the leaf tissue,” and adult weevils leave tree leaves with a “shot hole appearance.”
Invasive pests such as these can damage trees in a variety of ways, spread disease and in some cases kill them by choking off their water supply.
Lucero warns that the European elm scale, fruit lecanium scale and the elm leaf beetle are already here, and in large numbers can cause branches to die back and premature leaf senescence, destroying tree canopies.
It’s not just Santa Fe. Insect invasions to ash, elms, oaks and piñon trees in the City Different are no different than what’s happening elsewhere.
“Generally speaking, across the entire country, we’re seeing an invasion of all urban forest species,” says Jennifer Dann, manager of the state’s Urban and Community Forest Program.
And they come from all over the world.
Dann says some bugs cross oceans embedded in wood pallets or in shipping containers, arriving at seaports up and down the continent. They’ll then often hitch rides on trucks, so they invariably pop up along highway corridors.
They sometimes latch on to ornamental trees sold in nurseries or in firewood, leading The Nature Conservancy to create the website dontmovefirewood.org, which implores people to “buy it where you burn it,” to limit the spread of invasive pests.
“Some of them aren’t here yet, but we know they’re coming,” Dann said of the non-native intrusive pests, noting an interstate highway passes right by Santa Fe.
The ‘green menace’
One yet to arrive is the emerald ash borer, which in recent years has turned up six hours up the interstate in Boulder County in Colorado and next door in Texas.
The green invertebrate is the worst nightmare for city Parks Director Richard Thompson.
“It keeps me up at night,” he says of his fear of the bug.
Thompson says city workers are bound by ordinance to follow an Integrated Pest Management strategy that allows for pesticide use, though that’s a last resort.
But there appears to be no stopping the emerald ash borer, or EAB for short. He says trees infested by the bug have a 90 percent fatality rate. Once a tree is infested, it may be dead in two to four years.
Tom Zegler, the Forestry Division’s forest health program manager, says that when the emerald ash borer arrives — and it will arrive — it will bring devastation.
“We expect it will be the most damaging invasive pest since the chestnut blight in the early 1900s,” he said of the fungal infection believed to have been transported to this continent from Japan in nursery stock and that nearly wiped out the once plentiful American Chestnut tree.
Zegler says little can be done about the EAB except “try to slow its spread.”
“This insect has already devastated the native American ash population in the Northeast,” he said. “What it does is disrupt the flow of water through trees. There’s no genetic resistance to it in ash trees, so basically as soon as it arrives, it will kill any ash tree in our urban forest.”