Only two years after its discovery in a single town in Connecticut, a dreaded invasive insect that attacks ash trees has spread into five counties, a death sentence for tens of thousands of trees.
"It is exploding," said Kirby C. Stafford III, a scientist with the Connecticut Agricultural Experiment Station who also is the designated state entomologist. "We our going to lose our ash."
The insect, the emerald ash borer, native to Asia, was first discovered in Michigan in 2002 and has spread throughout the Midwest, parts of the South and the Northeast, already having killed millions of ash trees.
Once centered in New Haven County, the beetle has now spread to Fairfield, Hartford, Litchfield and Middlesex counties. With a new discovery in Bridgeport in recent days, the beetle has now been identified in 39 cities and towns in Connecticut, 24 of them this year.
Ash trees — white ash is the most common, but green ash also is found in Connecticut — make up between 4 percent and 15 percent of Connecticut forests. They are found throughout the state, but are especially numerous in a long south-to-north band in western Litchfield County and in northern Middlesex, eastern Hartford and southern Tolland counties,
Stafford said it is likely the beetle already is established in other towns. The state has a monitoring program to help identify newly affected forests. That it will be found in coming years in all 169 cities and towns in Connecticut appears inevitable.
White ash is a handsome tree with ash-colored bark in a distinctive, tight, diamond-like pattern. The wood is strong, light and pliable and has been used for baseball bats, tennis racquets and hockey sticks, among many other uses. In fall, the white ash is one of the distinctive components of the iconic New England fall foliage color, many of the trees displaying leaves of a light purple hue, rare in the foliage palette.
The emerald ash borer is a small insect, about 1/2-inch long and metallic green. Adults leave a D-shaped exit hole in the bark when they emerge in spring. Because woodpeckers like emerald ash borer larvae, heavy woodpecker damage to an ash tree can be a sign that it is infested.
While the beetle is expected to destroy many thousands of trees in Connecticut, a white ash planted as an ornamental near a home can be treated by an arborist and protected from damage. An untreated, infested tree can die within two or three years.
Peter Tyrell, an arborist with The Care of Trees company in Hamden, said it is important to treat ash trees before they are infested with the beetle, or at least treat them in the earliest stages of infestation, if it is to be successful.
Typically, an arborist would recommend fertilizing once or twice a year combined with an injection of what is known as a systemic pesticide, which travels through a tree's vascular system up to the canopy. A beetle chews on the tree, takes in pesticide, and dies.
The cost for an ash tree of perhaps 30 inches in diameter at chest height would be about $150 for the pesticide and $170 for the fertilizer, Tyrell said. That, he noted, is far less than the cost of removing a mature ash tree that has been killed by the beetle and becomes a hazard.
Affected states no longer hold any hope of eradicating the beetle. The goal now is to slow its spread. Claire Rutledge, another scientist at the experiment station, which is a state agency, is working with two biological controls, releasing parasitic wasps in Connecticut communities in hopes of reducing ash mortality.
The state already has imposed a quarantine regulating the movement of ash logs, nursery stock and firewood within the first four counties where it was identified. The state is now proposing that the quarantine be imposed statewide.
Detailed information about the quarantine and the beetle can be found at http://www.ct.gov/deep/eab. A fact sheet and additional information is available at http://www.ct.gov/caes. Also, information about the beetle and the biological control program can be found at http://www.emeraldashborer.info.
Contact Steve Grant at firstname.lastname@example.org