Pest Alert: Emerald Ash Borer
The next time you walk through your neighborhood, take note of the ash trees (Fraxinus spp.) you see. They are popular shade trees that comprise approximately 20% of our urban forest. Now consider this: due to the arrival of the emerald ash borer, a destructive invasive insect originating from Asia, each of the ash trees you noticed is in danger.
Adult emerald ash borers (Agrilus planipennis Fairmaire) – also known as EAB – move quickly and the larvae eat ravenously. The borer’s North American presence was first discovered in Michigan in 2002, where tens of millions of ash trees have since been lost. Today, the borer has established itself in many states across the US.
Emerald ash borer is not the first pest to wreak havoc on our continent. Rather, it is the most recent addition to a list of notorious pest and disease issues introduced via human intervention. Chestnut blight, gypsy moth, Dutch elm disease, Asian longhorn beetle: each has left an undeniable mark on the North American landscape. These insects became pests and fungi became diseases when they found an ample supply of vulnerable host trees.
For example, the American chestnut (Castanea dentata) once comprised approximately 25% of the Eastern Deciduous Forest; today the tree has practically vanished. The American elm (Ulmus americana) once typified the hallowed All-American streetscape; now the remaining elms are cherished relics. Ash trees could meet a similar fate.
Because the emerald ash borer evolved in Asia and was only recently introduced to North America, the methods typically employed by Nature to keep predators and prey in balance are not in place. To remedy the situation, arborists and property owners must work together to control the pest and preserve our urban forest while Nature strives to regain its balance. Fortunately, there are ways you can help.
Know Your Trees
It is very likely that you have an ash tree growing on your property. If you donʼt know how to identify an ash tree, contact your trusted SavATree arborist. He or she will be happy to identify your ash trees and inspect the trees for early warning signs of an EAB infestation.
Remove the Ash Trees You Do Not Need
If any of the ash trees on your property exhibit signs of decline, consider removing those trees now before they are infested with EAB or become a hazard to your property. When replacing the trees you remove, select nonash species to help diversify the urban forest.
Cooperate With State and Regional Regulations
Current quarantine restrictions are in place to limit the spread of EAB by means of firewood or nursery stock transportation. Please adhere to the quarantine restrictions to help prevent the accelerated spread of the pest.
Treat the Ash Trees You Want to Keep
There is no simpler way to say it. If you want to preserve an ash tree, it is imperative that you employ systemic applications to protect it against future EAB infestation.
Of the treatments currently approved for use to combat emerald ash borer, systemic applications are particularly promising. These treatments are dispersed by means of the treeʼs vascular system. Speak with your SavATree arborist for additional information about these treatment methods to determine which is best for your specific landscape.
The arrival of the emerald ash borer in North America and its subsequent impact on our environment offers countless lessons, such as the importance of biodiversity and the unexpected impacts of globalization. Most importantly, though, emerald ash borer speaks to the essential role that arborists and residents play as stewards of the urban forest. If we do nothing, the ash tree will certainly follow a course similar to that of the American chestnut or American elm. To preserve ash trees – and our landscape – we must each accept responsibility for nurturing our environment.
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