Ash Trees in Ithaca

Ash trees grow fast and well in Ithaca. But they can die quickly, too, especially now that the emerald ash borer (EAB) beetle is here.  EAB has killed millions of trees in North America since its invasion began in the late 1990s. If you have ash trees on your property, it's time now to plan a defense against this lethal pest.   

Ash can grow to a large tall oval shape in an open field, with buds, leaves and branches opposite from each other; their bark ridges show diamond shapes once they're old enough, their fat brown buds sprout compound leaves, with 5-11 leaflets arranged in a line, one leaflet at the end. Their seeds grow in clusters of single thin paddle-shaped wings.

When EAB attack ash, their small (3/4-inch) metallic green adults lay eggs that grow into bark-burrowing larvae that chew S-shaped tunnels under the bark. The bark splits and can be peeled off to reveal these sideways-wandering tunnels as the tree dies. When the larvae mature they chew out of the bark leaving 1/8-inch D-shaped exit holes in a dying tree that will have plenty of thin, dead, leafless branches on it. One of the best ways to identify EAB-infested trees is in the winter to look for the light patches on the trunk that have been pecked away by woodpeckers.

Once a tree is severely infested, it will sprout leaves directly from its trunk, and become a dangerous source of falling limbs.  Such dead or nearly dead ash trees are hard to cut down, as the wood becomes brittle and apt to fall in winds or when arborists attempt to remove it. Proactive treatment with a pesticide is cheaper than tree removal, but the treatment needs to be reapplied every two-three years. Many homeowners opt to have their trees cut down by certified arborists, which presents a permanent option for addressing the inevitable hazard.

Please make sure you plan ahead, before your ashes become hazardous!  Applying an insecticide can keep EAB out of your tree. If they've just started to attack, it may not be too late. Please, don't travel anywhere with ash firewood, as the grubs travel much faster that way than the adult EABs can fly.

To learn more about identifying EAB, see this MSU EAB fact sheet at http://www.emeraldashborer.info/documents/E-2938.pdf 

A bulletin on EAB pesticide options may help you keep an ash you love, check: http://www.emeraldashborer.info/files/multistate_EAB_Insecticide_Fact_Sheet.pdf

Virginia Tech has a good EAB iBook, and an online course you can take that was funded by the USDA Forest Service; go to www.hort.vt.edu/eab 

From the Town of Ithaca Conservation Board, September 2018