KALAMAZOO — It's been five years since emerald ash borer was first discovered in Kalamazoo County, and this summer, the toll is obvious.
Dead and dying trees line city streets, suburban backyards, golf courses and retail parking lots as one of the most popular landscape trees falls to the beetle and its larvae.
Linda Whitlock, consumer horticulturist at Michigan State University Extension, said her office has been receiving telephone calls daily from homeowners worried about their trees.
With good cause.
Since its introduction in the Detroit area in 2002, the insect has killed millions of ash trees in Michigan, and a quarantine of the entire Lower Peninsula bars transport of firewood to the Upper Peninsula in an effort to spare forests there.
The adult beetles nibble on ash foliage but cause little damage. The immature larvae feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients, and that's what kills the trees.
The good news— research in recent years has confirmed that treatment is effective in saving individual trees, Whitlock said, protecting against infestation, and reversing damages done by early infestations.
Various treatments are available at garden stores, and cost about $20 for a quart — at the recommended rate of one ounce per inch, capable of treeing a tree up to about 32 inches in circumference
The bad news— even the treatment won't work on trees displaying damage to half or more of their canopies. And untreated trees are generally being chalked up as losses across the county, Whitlock said.
MSU Extension send out a reminder Wednesday, advising that to determine if Emerald Ash Borer (EAB) is causing the decline or death of their trees, homeowners can visit its website for up-to-date research-based information.
Around Kalamazoo, the dieback of trees is most obvious on rights of way along city streets and retail businesses, Whitlock said. Retail owners may be less likely to notice the problem and treat for it, and then the insect spreads from that tree to others.
When the problem was first discovered in Kalamazoo in 2006, the infested trees were immediately removed to reduce the spread. Other trees were evaluated and either treated or monitored annually to determine infestation levels and to be removed if necessary.
County-wide educational programs were offered through the media and public meetings. This collaborative effort included Senator Thomas George’s office, Michigan State University Extension, the City of Kalamazoo and Kalamazoo County.
Whitlock said early containment efforts may have slowed the spread a bit, and alerted homeowners. "What we find is that people who knew they had an ash tree and began to monitor for the insects, they have protected their investment in those trees," she said. " In majority of cases, though, either A. people did not know they have ash trees or B. the tree looked healthy, maybe they thought 'I'm OK.'"
The city of Kalamazoo now monitors for its presence but does not routinely treat trees, she said. Nor do all homeowners wish to try to save their trees, she said. " It's inevitable it will spread in that situation. Everyone's got tight budgets, and they just don't have money to do that."
Whitlock said her office now helps callers weigh their options, which may come down to the costs of removal versus the cost to treat the trees.
Many whose trees have died haven't yet removed them, but once dead, the tree no longer harbors the insects and may be able to stand for years, providing habitat of another kind until homeowners choose, or can afford, to remove it.
Emerald ash borer was probably transferred from its native Asia to the United States on solid wood packing material carried in cargo ships or airplanes.