Emerald Ash Borer in Colorado
The Denver Post
Emerald ash borer’s discovery in Boulder is cause for condolences and maybe cursing, but not panic and certainly not profit at this point.
The insect that has devastated urban and wild forests in the Midwest and two Canadian provinces spreads slowly on its own.
“When you have the pest come in, it takes three to five years to build up the population to where it kills a tree,” said Carol O’Meara, horticulture extension agent in Boulder County.
“The adults, they’re noshing on the leaves, they’re makin’ the love, and eventually, exponentially more eggs are laid on that tree. But they’re not fast fliers” — and they don’t have vast, contiguous forests of ash trees to feed on, as they do in the northern Midwest, she said.
But the bug can move quickly when it’s aided by humans moving infested firewood or trees.
“Every city is just one truckload, one bundle of firewood away, and it will always be one truckload away,” said Whitney Cranshaw, CSU Extension entomology specialist. “If you move firewood, you’re causing other people to have very expensive problems.”
About the only thing homeowners should be doing now is identifying their trees and then giving them good general care, O’Meara said.
In Boulder, a league of city, county, state experts and other plant scientists are surveying trees surrounding the known infestation on the city’s northeast side, said Keith Wood, community forester with the Colorado State Forest Service.
Every ash tree near the tree that emerald ash borers killed has been visually inspected. In the coming months, the city will be divided into a square mile grid and a few trees in each square mile will be branch-sampled to try to find the infestation’s boundaries, said John Kaltenbach of the Colorado Department of Agriculture.
The protocol is determined federally and involves the state Department of Agriculture because the pest itself is federally regulated. Any infestation in a new county has to be confirmed at three agency levels: locally, meaning usually Colorado State University; then a lab in Michigan; then at the Smithsonian Institution.
The likely outcome of the Boulder survey, said Kaltenbach, will be a quarantine of almost all ash products, which would not be allowed to move out of Boulder County. A temporary quarantine could come as soon as Oct. 31.
To know if the problem could affect you, all you have to do is be able to identify an ash tree. That’s easier when leaves are on.
Detecting emerald ash borer itself, though, is another story, said entomologist Cranshaw. A highly effective trap eludes scientists. The thinning crown and dying limbs that are a fairly sure sign of the borer in the Midwest?
“Here, that’s a normal-looking ash tree,” Cranshaw said. “We’re a much harder place to be a tree.”
Ash species, while they can grow 30 to 70 feet tall and provide great shade, are also plagued by several other borers and some nuisance insects. They can also be affected by drought, compacted soils and machine injuries.
Treatments to save an ash tree from emerald ash borer involve soil sprays, trunk sprays or trunk injections; can cost up to $200 per year; and have to be continued as part of the tree’s regular maintenance. Assuming no other infestations are found, decisions about treatment could be years, even a decade or more, away for most homeowners, Cranshaw said.
But if you needed another reason to spend some time appreciating your local trees, this is it.
“Ash is not part of Colorado’s natural forest, but it’s what we live and play under,” said O’Meara. “Never mind that baseball bats are made out of ash.”
Susan Clotfelter: 303-954-1078, firstname.lastname@example.org or twitter.com/susandigsin
What you can, should do now
1. Don’t move firewood. Ever. Burn it where you buy it and spread that message. Human-moved firewood is the most likely way emerald ash borer traveled to Boulder, officials say, and it’s the most likely way it would spread across the many natural geographical barriers that cut up Colorado.
2. Identify the trees in your yard and your nearby public spaces. Ash trees have compound leaves with 5 to 11 leaflets, and the leaflets, buds and branches grow opposite from one another. No ash trees? No emerald ash borers. All ash trees —genus Fraxinus — are susceptible; mountainash (Sorbus aucuparia) is not.
3. Give all your trees good care. Check on them regularly. Keep them well-pruned and water them in dry winter months. Mulch them. Avoid injuring them with lawnmowers and trimmers.
4. Get informed. Ash trees are affected by several other borers, especially lilac ash borer. Get to know these pests, too. If you truly see signs of emerald ash borer damage, notify your county’s Colorado State University Extension Office (find each county’s phone numbers, websites and e-mail addresses at www.ext.colostate.edu/cedirectory/countylist.cfm). You can also report sightings to the Colorado Department of Agriculture at email@example.com
5. If you have ash trees and are near affected areas, investigate replacement species. But this fall, there will likely be no reason to treat with pesticides (they’re best applied in April) or remove unaffected trees.
Read more: Emerald ash borer in Colorado: What homeowners can, should do now – The Denver Post http://www.denverpost.com/homegarden/ci_24289766/emerald-ash-borer-colorado-what-homeowners-can-should#ixzz2rKzkZKe7