The Emerald Ash Borer
or EAB, is a highly destructive, invasive beetle that primarily attacks ash trees. It has killed millions of ash trees through North American and was recently found in Bedford, NS.
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The beetle is metallic green in color and usually around ½ inch long. The underside is a metallic green and the back is a bright emerald green. The body is long and elongated with a flat head and kidney shaped black eyes. They feed on leaves and lay eggs from June to August. The EAB larvae are white and flat with bell shaped segments that grow up to 1 inch long. They feed on the inner bark and cut off nutrient and water flow in the tree.
EAB was first detected in North America in 2002. It is native to Asia and it is thought to have been bought in on wood packaging or creating material. It has since spread to parts of Ontario, Manitoba, and Quebec. Most recently, EAB was found in Edmonton, New Brunswick in May of 2018 and Bedford, Nova Scotia in September of 2018.
Signs and symptoms of EAB
Symptoms of ash trees that are affected by EAB are canopy thinning, premature yellowing foliage, dead branches, bark cracks, heavy seeding, epicormic shoots on main stem or branches.
Another sign is physical damage to the tree resulting from EAB attack. Some examples of EAB are S-shaped larval galleries found underneath the bark, D-shaped beetle exit holes, and feeding notches in the leaves.
How to prevent spread?
The most common way EAB spreads is through people moving infested material such as firewood, logs, nursery stock, and wood chips. If going camping, it is best to get wood at the campsite rather than move wood. Also, if you have an ash tree that is showing signs or symptoms of EAB contact an authority such as the CFIA (Canadian Food Inspection Agency). By nature, adult EAB beetles can fly up to 10km, but they generally don’t go farther than the nearest ash tree.
Management of EAB
Species Selection. Plant other tree species besides ash. A landscape with a diverse mix of tree species will be less susceptible to the impacts of host-specific pest problems like EAB.
Removal, Pruning, and Sanitation. Branches removed from infested trees should be burned or properly disposed of as soon as possible to help prevent the borers from completing their life cycle and infesting other healthy trees. Dead trees should be removed before they become too rotten and hazardous.
Chemical Control. There have been a couple of pesticides that have had some success in protecting ash trees from EAB, such as Ima-jet by Arborjet. The product is directly injected into the trunk of the tree and moved throughout the tree by natural plant processes. Studies have shown, chemical control of EAB is most effective while the tree is still in good health and vigor. This is due to the fact that the plant protectant works systemically and is transported through the tree via the conducting tissues. Larval galleries from the EAB will interfere with translocation of the product throughout the tree which can reduce its efficacy in controlling EAB.