The emerald ash borer beetle was first identified in the US in Allamakee County, northeast Iowa in 2010 to the alarm of environmentalists. The deceptively pretty little creature with its glittering, iridescent emerald green carapace is responsible for the deaths of millions of ash trees across 18 states according to the Iowa Department of Natural Resources and is rapidly becoming a world-wide menace.
It was hoped that the destructive borer could be contained and eradicated but larvae have now been discovered by officials in two additional areas in Allamakee County. The find in the Black Hawk Point Wildlife Area, New Albin came as a result of a state-wide monitoring initiative and has been described by the DNR as significant. Tivon Feeley, DNR Forest Health Program Leader explained that this spot is especially important because it is the furthest west in Iowa that the emerald ash borer has been found. Observations in others states have shown that the insect is usually well-established before it is discovered which means that the damage to the ash trees has already been done and it’s too late to save them.
Feeley’s concern is justified. Several years ago a small number of borers were discovered in Indiana in two counties but in just three years they were widespread across the whole state. Unfortunately, budget constraints have meant that a ‘wait and see’ policy has been adopted rather than investment in controlling the insect. It is hoped that some ash trees may develop a certain tolerance to the insect and experiments are underway in some states using a special parasitic wasp to help control the borer.
It’s important that landowners begin to diversify their planting and replace ash trees with other species which are resistant to the borer. If homeowners are concerned about the health of an ash tree on their land, Feeley advises that they consult a qualified arborist for guidance. There is an effective insecticide available although the treatment would be ongoing and would thus incur not inconsiderable expense, especially as reapplication is required every three years.
The state-wide monitoring program set up to keep track of the spread of the troublesome insects entails the regular review of specially prepared sentinel trees to see if any white larvae can be found. The larvae feed on the outer layers of the host tree’s wood. This deprives the tree of water and nutrients and quickly brings about the demise of the branches and ultimately the whole tree. The adult beetles have a short life span of just a few weeks but just one female can produce over 200 eggs and the larvae quickly wreak havoc on their host tree as they munch their way through the wood.
Hikers and park users across northeast Iowa are encouraged to report any ash tree they come across which appears to be dying to the DNR via their website http://www.iowadnr.gov/ContactIowaDNR.aspx
The following video clip explains how to identify EAB activity in your ash trees.