Emerald ash borer on the move: Four new counties positive for the tree-killing beetle

by | Jul 27, 2016


Across the state, North Carolinians are packing their bags and going on their summer vacations. Roads are full of families driving to the beautiful N.C. beaches, charming Piedmont destinations and the awe-inspiring mountains. But vacationers aren’t the only ones on the move in the state this year. The invasive, tree-killing emerald ash borer has shown it can be quite the tourist as well and has already visited several new counties in North Carolina this summer. Unlike most tourists though, the emerald ash borer doesn’t go back home after a week!

The emerald ash borer is on a true vacation and eating as much as it wants while it’s at it — in this case, ash trees. Last September, the total number of N.C. counties known to have emerald ash borer skyrocketed to 18, giving the department’s Plant Industry Division the incentive to quarantine the entire state for the pest. This summer, four additional counties – Davidson, Forsyth, Swain and Yancey – have already been added to that list, and more are expected as surveys are conducted statewide. The N.C. Forest Service and their cooperators have set nearly 50 traps across the state in an effort to detect new infestations of emerald ash borer as quickly as possible.

While many hope biocontrol efforts become effective in the future, the only sure way to protect ash trees now is through the use of insecticides. There are many options available to homeowners to protect or save lightly infested trees, with do-it-yourself applications of imidacloprid and professionally applied emamectin benzoate being the most popular.

Imidacloprid is less expensive but may not be as effective as other options. In addition, it cannot be applied in all settings because of its potential to harm pollinators if applied incorrectly. Imidacloprid soil drenches are most successful on trees less than 20 inches in diameter that are lightly or uninfested with the emerald ash borer. Trunk injection of emamectin benzoate is typically more expensive, but provides greater effectiveness and has fewer potential environmental impacts. It is recommended when trees are larger than 20 inches in diameter and when losing the tree isn’t an option.

So, don’t take a vacation from monitoring ash trees in your yard. It’s not too soon to consider the options of protecting your tree or losing it, no matter where you live in the state. Emerald ash borer is on the move and likely to come to your neighborhood soon, if it hasn’t already. The N.C Forest Service’s emerald ash borer range map is constantly updated to provide the most up-to-date known whereabouts of this tree killer and help you make the decision. This traveling terror doesn’t need an ocean view to be lured to your backyard.

Counties in which the emerald ash borer is known to occur are in red. Map current as of 25 July 2016. Map created by K. Oten, NCFS.

Counties in which the emerald ash borer is known to occur are in red. Map current as of 25 July 2016. Map created by K. Oten, NCFS.