Current status of the Emerald Ash Borer
Hailing from Eastern Asia, the Emerald Ash Borer (EAB) has had a steady incline to pest or invasive status across North America since 2002. There were strong and early eradication efforts, however, these were abandoned primarily due to the fact that it is difficult to detect EAB infestations in trees.
Current management efforts of EAB are centred around biological control, insecticide solutions with a focus on protecting important or high-value trees and various other integrated community efforts such as planting diverse tree species in rural and urban environments.
Susceptible species
All species of Ash trees across North America are susceptible to this invasive pest, including species of green, red and white varieties. The economic and ecological impact that this pest is having cannot be understated, with over 25-million trees in North America thought to be infected.
There are a variety of reasons why the EAB has been so successful
Treating your tree is an option, but perhaps it does not make financial sense for you. Infestation may take up to three years to appear with larger trees, which means by then it’s too late to save it by adjusting treatment levels. Therefore the remove and replace option becomes an interesting one. You must hire a tree professional for this method, as removing the tree is only half the battle.
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Having ideal conditions and tree species that are similar to their native environment.
Ash trees in North America provided the perfect host to this species which allowed them to flourish in an otherwise hostile environment.
Adults only require a one-week maturity phase before continued mating can begin.
Meaning that a short gestation cycle occurs and mating can happen at a rapid pace.
Some Long-lived females can lay up to 200 eggs at a time, leading to a high reproductive rate.
If all of these eggs live, then the population continues to grow at an exponential rate. Due to the ready supply of food for the EAB, this only supercharges the population and their mating habits even further.
It's very difficult to detect early infestations in trees.
Some populations can live inside a tree for up to 2 years before any side-effects on the tree are noticed, meaning that populations can be very advanced before the proper treatment is taken to manage their numbers.
EAB prepupae are intolerant of freezing, however, they can survive winter.
They do this by concentrating antifreeze compounds in their bodies such as glycerol which allow them to achieve low supercooling points and ride out the harsh winter temperatures. However, host availability and firewood spread in North America are bigger reasons for their spread than climate-related factors.
Emerald Ash Borer populations in North America were established for at least 3-9 years before they were even discovered for the first time, meaning that they had years to adapt and thrive to conditions.
This 3-9 year period of time allowed the populations to expand rapidly throughout North America.
There is no practical way to reduce EAB populations on a large scale with insecticides. Instead, specific treatment of trees is required.
Single-tree management plans are at present, the only method of containment. Wide-spread or large-scale insecticide solutions are not an option.
There are not any natural predators for the EAB, aside from the Woodpecker species of bird.
With only one notable predator, this is another factor allowing the population to spread rapidly.
