Emerald ash borer re-emerges in Maryland
Maryland officials recently confirmed the presence of the emerald ash borer (Agrilus planipennis) in ash trees located in the Clinton/Brandywine area of southern Prince George's County. The effected trees were discovered during survey and eradication efforts begun after the detection of the insect in Maryland in 2003, when a Michigan nurseryman shipped infested trees into a Prince George's County nursery.
“While we are disappointed to find the emerald ash borer after nearly three years of no detections, we are pleased that our surveillance efforts have proven to be effective and that we found the insect before it could spread further,” said Agriculture Secretary Lewis R. Riley. “Together with our federal, state and local nursery partners, we are beginning aggressive measures to control and eradicate this destructive pest.”
The Maryland Department of Agriculture (MDA) recently issued a quarantine that prohibits anyone from moving ash trees or any hardwood firewood into or out of Prince Georges's County until further notice. The results of the survey will determine the necessary course of action and scope of tree destruction and pest surveillance. The accepted protocol used in Maryland and the other impacted states is the removal and destruction of all ash trees in defined areas followed by on-going surveillance.
“DNR foresters together with MDA are proactively following this course of action to safeguard Maryland's trees on both private and public lands, neighborhood trees and the nursery industry,” said DNR Secretary of C. Ronald Franks.
Since 2003, efforts to eradicate the insect included the collection and destruction of all trees sent to Maryland from the Michigan nurseryman, destruction of all ash trees within a ½ mile radius of the introduction point and three years of surveillance, which produced no emerald ash borers until now. The insect, an exotic pest from Asia, feeds on and kills ash trees in one to three years after infestation.
The presence of the emerald ash borer typically goes undetected until the trees show symptoms of being infested — usually the upper third of a tree will thin and then die back. This is usually followed by a large number of shoots or branches arising below the dead portions of the trunk. Other symptoms of infestation include: D-shaped exit holes in the bark where adults emerge, vertical splits in the bark and distinct serpentine-shaped tunnels beneath the bark in the cambium, where larvae effectively stop food and water movement in the tree, starving it to death.
Maryland's nursery and greenhouse industry accounts for $303 million of the state's $1.4 billion agriculture industry. Ash is the most common tree in Baltimore with approximately 293,000 trees and accounts for about six million trees in the Baltimore metropolitan area. The U.S. Department of Agriculture has estimated losses could exceed $227,568,000 in the Baltimore area alone if the emerald ash borer were to become established.