How Long Does It Take Emerald Ash Borers to Kill a Tree?
May 14, 2021
In 2002, a little green beetle was spotted in the United States. It was identified as the emerald ash borer, and it has wreaked havoc on ash trees in over 30 U.S. states. Unfortunately, Pennsylvania is one of those states. In 2015, scientists considered the emerald ash borer “the most destructive and economically costly forest insect to invade North America.” Unfortunately, Pennsylvania trees are vulnerable to several common tree diseases and parasites, so it’s important to know what to look for.
How to Identify Emerald Ash Borers
Emerald ash borers are parasitic; the emerald beetle lays its eggs and larvae in the tree, and it feeds on the inner tissue of the tree until it’s starved of nutrients. If you haven’t seen the insect before, you might struggle to identify it. The larvae are virtually invisible to the naked eye because they burrow deep into the bark.
If you do see larvae, they will be white and fat with distinct bell-shaped body segments. The adult emerald ash borer will look like many common beetles. It’ll have a shiny green shell and big, black eyes. Generally, the emerald ash borer is most active between June and August, but once signs of damage are evident, it’s important to act quickly before the tree must be removed.
Newer methods have been developed to detect emerald ash borer before the tree is considered a goner. It’s now known that trees affected by emerald ash borer show the earliest symptoms in the canopy. Bark cracks become apparent, especially near the first scaffold branch.
How Are Affected Trees Saved from Emerald Ash Borers?
If an emerald ash borer infestation is caught early, there are a number of different treatment options available to save the infected tree and protect surrounding trees. If applied correctly and within the right time frame, treatment of emerald ash borer is within 85-95% affected. To be treated, ash trees must be in good health. In straightforward terms, this means that the tree is structurally sound and has been assessed by a certified arborist.
There are four standard treatment options for eradicating emerald ash borer and protecting the surrounding trees. Soil and trunk injections are the most common treatments, while bark spray and canopy spray may be added to the treatment plan if the infestation is particularly bad. Injections are considered a systemic treatment option, and they address the larvae already inside the tree while sprays are applied to the tree’s exterior.
How Do You Know When It’s Time to Have an Affected Tree Removed?
The emerald ash borer is aggressive. Immature and smaller trees can advance beyond treatment in as little as 1 to 2 years, whereas more mature trees can be killed within 3 to 4 years. For this reason, it’s important to act quickly before your tree is in jeopardy.
As mentioned above, trees must be in good health to be considered a candidate for treatment. Similarly, the cost of treatment can be prohibitive as well. If your ash tree has lost more than half of its leaves, has the trademark S-shaped burrows and severe bark cracks, it’s likely time to remove your tree before its structural damage becomes a safety hazard. Many people will have to factor in the sentimental value of the tree, its aesthetic value, and the risk of damage to the surrounding area if that tree’s condition worsens. A tree with its canopy in solid condition will benefit from an aggressive treatment plan.