Insects That Bore Holes in Trees

Several types of insects bore holes in trees. The observable holes are just a little area of the harm; beneath the bark, you’ll probably find tunnels and grooves cut into the tree. Healthy trees are normally able to withstand occasional attacks by wood-boring insects. However, unhealthy, stressed or newly planted trees may be severely damaged or killed as a result of an infestation.

Bark Beetles

America is home to hundreds of bark beetle species (Scolytidae family). Even though the tiny beetles are just about the size of a grain of rice, they could cause significant damage to trees. They may kill twig ends, weaken branches as well as kill the whole tree. Bark beetles may also spread Dutch elm disease between trees. The damage starts when adult female bark beetles lay eggs beneath the tree bark. The eggs hatch into larvae that chew tunnels throughout the bark. The larvae pupate before emerging as adult beetles. The emerging beetles bore holes in the bark in order to attain the outside of the tree. The little evolution holes resemble a buckshot pellet pattern. After emerging, the beetles may continue the cycle to precisely the identical tree or transfer to other vulnerable trees.

Clearwing Moths

Several clearwing moth species (Sesiidae family) develop in wood-boring larvae. Some species of clearwing moths could possibly be mistaken for wasps, as they have black and yellow bodies, and they fly during the day. Other species may have red or orange coloring on dark blue or black. Clearwing moths are known for their mainly clear hind wings. Mature female moths lay eggs in cracks and crevices of bark; they are especially attracted to wounded bark, such as from injuries or vandalism from lawn equipment. The eggs hatch into larvae that tunnel holes into the heartwood of the tree. The tunnels tighten the tree. Infestations in divisions can cause branch breakage, while trunk infestations may kill the tree. The larvae pupate beneath the bark, eventually emerging as adult clearwing moths. Signs of infestation include bark which looks tough or gnarled, dying limbs and the presence of frass — sawdust mixed with excrement.

Flathead Borers

Metallic woodboring beetles (Buprestidae family) are flathead borers. The beetles are recognizable by their shiny, metallic-colored shell in shades of pink, blue, green and bronze. Female beetles lay eggs in the cracks and crevices of bark. The eggs hatch into grub-like seams that tunnel through the inner bark and sapwood. The larvae have wide, flat bodies behind their heads, and their tunnels are typically oval shaped. The larvae pupate into adult beetles that chew their way out of this tree, leaving oval or “D” shaped holes at the tree. Infested trees may have one or more dead branches, sections of bark which appear wet or greasy-looking, or regions in which the bark has fallen from the tree. You might also see places of sawdust or frass around the tree bark or in the base of this tree. Flathead borers can ruin young, stressed or trees that are weak.

Roundhead Borers

Also called long-horned borers, roundhead borers (Cerambycidae family) are beetles with different differences from flathead borers. Roundhead borers are bigger, not as brightly coloured and have more antennae than flathead borers. As their name suggests, the larvae of the beetles have round heads. The tunnels and exit holes of roundhead borers are oval to round. The life cycle of roundhead borers is very similar to flathead borers, and trees show the same signs of infestation. Significant infestations of roundhead borers may kill trees, but those beetles typically only attack damaged or unhealthy trees.

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