The Common Garden Pest That'll Do Major Damage To Your Trees

If you've recently spotted unusual-looking beetles on your trees, it's crucial to pay attention. They could potentially be Asian longhorned beetles, and their presence is often a silent alarm for impending damage. When the females of this species lay their eggs in a tree's bark, it marks the beginning of a destructive cycle. The eggs hatch into larvae that bore their way into the heartwood, disrupting the tree's essential systems for transporting nutrients and water. This invasion by the larvae is not just a surface issue; it attacks the tree's very core, leading to a gradual yet fatal weakening.

To properly eliminate them, you'll need to understand these beetles better — starting with proper identification. Originating from Korea and China, Asian longhorned beetles are also found in North America and Europe. They are relatively easy to identify, thanks to their distinctive appearance. They are large, ranging from 1 to 1.5 inches in length, and have white dots on their black exoskeletons. The most striking feature is their long antennae, often as long as their bodies. These beetles prefer to attack hardwood trees, such as maple, elm, willow, and birch. The variety in their choice of host trees makes them a widespread threat to different tree species in your garden. With this knowledge at hand, you can now begin to look for signs of their presence and take the necessary steps to protect your trees.

One of the first signs you might notice is the actual presence of the beetles themselves. You'll typically find them lounging on tree trunks or branches, especially during the warmer months. But it's not just the beetles you need to look out for. The damage they cause can also be quite telling. Keep an eye out for small, round depressions in the bark of your trees. These are the entry points the females have chewed to lay their eggs. These indentations are usually the size of a dime and can be a clear indicator of an infestation beginning to take hold.

Another classic sign is the presence of perfectly round exit holes in the tree, about the diameter of a pencil. These are created when the now-matured larvae tunnel their way out of the tree after feeding on its inner wood. These holes are a sure sign that the beetles have not only arrived but have been there long enough to complete a life cycle. Additionally, you might spot sawdust-like material, known as frass, accumulated at the base of affected trees. This is the by-product of the beetle larvae boring into the wood, and its presence often indicates a severe infestation. And lastly, keep an eye on the foliage. If you see leaves turning yellow or drooping when they seemingly shouldn't be, it could be a sign that the tree's vascular system has been compromised by these burrowing pests. 

The first, and often most drastic, measure is the removal and destruction of infested trees. It sounds harsh, but it's a necessary step to prevent these pests from spreading further. Professionals should carry out this task to ensure that every part of the tree is properly disposed of, leaving no room for the beetles to continue their life cycle. But what if you're keen on saving your trees? In that case, chemical treatments come into play. Among these, a specific insecticide called imidacloprid stands out. Imidacloprid acts as a systemic insecticide, meaning it's absorbed by the tree after application and distributed throughout its tissues. When Asian longhorned beetles or their larvae feed on the treated parts, they ingest the insecticide, which eventually leads to their demise. 

This method is especially effective because it attacks the pest at multiple stages of its life cycle. However, administering such treatments requires expertise, as they involve injections into the tree or soil applications around it. Professionals equipped with the right knowledge and tools can ensure the treatment is done safely and effectively. Another critical aspect of control is imposing quarantine and movement restrictions in affected areas. This means regulating the movement of firewood, lumber, and other materials that could harbor the beetles, preventing them from spreading to new areas.