by Joshua Palmer

Angie's List member Margaret Beerbower of Fishers, Ind., says she knew it was time to act when she noticed the upper canopy of her mature ash trees starting to thin in November. "We knew the emerald ash borer was around in Carmel and moving our way," she says.

Of approximately 30 trees on her property, she says EABs ruined six ash trees, and she hired highly rated Applied Tree Services in Fortville, Ind., to remove them. Although likely infested, she chose to treat several remaining mature ash trees with the hope of saving them. "It's not like getting a new car," Beerbower says. "When an 80-year-old tree is gone, it's gone."

The EAB, an exotic invasive beetle less than a half-inch long, threatens to eliminate Indiana's entire ash tree population. "The threat is imminent," says Rob Engledow, a manager with highly rated Complete Tree Care in Indianapolis.

Joshua Taflinger, co-owner of highly rated Simple Man's Tree Service in Indianapolis, says 2011 will be a critical year for homeowners with ash trees. "Even if they're not showing signs, we're assuming that most ash trees are infested," he says. "If you're seeing signs, it's probably too late."

First detected in Indiana in 2002, EABs likely arrived in the United States on wood products shipped from Asia to Detroit in the 1990s. Aided by firewood, wood products and nursery stock shipments, the insect has made inroads into the Indianapolis metropolitan area, including a large infestation along Hazel Dell Parkway in 2006.

"It's got a great foothold," says Jodie Ellis, exotic insects education coordinator for Purdue University. "If you don't treat your ash trees for it, there's a 100 percent chance they will eventually become infested, and the mortality rate is 100 percent." A successful treatment stops the tree's thinning canopy and it remains alive.

Preventive treatment options vary. Over-the-counter pesticides containing imidacloprid are the least expensive, generally starting around $20, but require at least annual soil-drench applications, depending on tree size. Taflinger says Tree-Ãge, a pesticide-injection treatment product, typically costs about $8 per inch of tree circumference but only needs to be applied every 2.5 years. He says imidacloprid products are less effective than Tree-Ãge.

Although removing a younger ash tree to prevent eventual infestation may cost less in the long run than treating it, removing a more mature ash tree too infested for treatment is almost always more expensive upfront. "You can expect to spend anywhere from $300 to $1,500 for removing a live tree, depending on the size," says Applied Tree Services owner Gregory Whisenand, who says he's treating more ash trees for EABs each year.

"Treat everything you want to live and expect that anything untreated will be dead in the next five to eight years," says Taflinger, who plans to branch out on his own this year with a new company, Indy Ash.