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Insects We Don't Want Here
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Contributed by Peter Goodwin
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Friday, March 27, 2009
We all know that we don't want Milfoil invading our lakes but we also must try to prevent exotic insects from arriving in our woods. As with invasive plants, knowing what the issues are and knowing what the insects look like can help prevent their spread. The first thing you should realize is that you should not bring firewood from outside the area. People coming to their summer homes often do this but the insects are in the wood and escape into our woods. Most of these exotic insects came to the United States in the wood that was used for packing crates for machines and the like made in Europe or Asia. They survived inside the wood for the trip across the ocean and then found lots of new things to eat when they arrived.
Below is an Asian Long-horned Beetle with its exit hole from the tree. They stay inside the tree or log until it is time to come out and mate. Information of USDA on the longhorn beetle is found at http://www.beetlebusters.info/home.php
We must avoid importing invasive insects to New Hampshire although the trip might be in the trunk of a car or the back of a pickup truck that comes from some other state. The dead tree cut for the firewood (or even a live one that was cut for some other reason) may have insects in it that either killed it or were starting to kill it. To repeat: DO NOT BRING FIREWOOD TO YOUR SUMMER HOME FROM OUT OF STATE
OR A LONG WAY AWAY. YOU MIGHT BE BRINGING UNWANTED TREE MUNCHERS.
Also, don't bring nursery stock from far away. Nursery stock can also
harbor unwanted insects.
There are three main threats at the present time: the Asian Long-Horned Beetle, the Emerald Ash Borer and the Hemlock Woolly Adelgid.
It is hard to know if you are bringing these insects to New Hampshire because they are hard to see. The problem with the first two insects is that they spend most of their lifetime inside the tree. The females lay their eggs in the trees, the larvae burrow into the wood and the adults only emerge briefly. For this reason, it is hard to know that a tree or log is infected. It is possible to see the exit holes of the adults but by that time, they have left. The Woolly Adelgids are also hard to see unless there is a real infestation because they are small and tend to stay on the bottom side of the small hemlock branches.
The Asian Long Horned Beetle is actually quite a neat looking beetle but its favorite tree seems to be the maple. It is also found in other trees but because maple trees are important to the New England maple syrup industry, this beetle is of special concern. One of the infested areas is in Worcester, Mass. so it is not far from our forests. Firewood brought from this area could be devastating to our forests.
 
The pictures show two long horned beetles mating which is done during their brief time spent outside the tree and then a female depositing eggs in tree bark.
The Emerald Ash Borer is bad for ash trees but seems to leave others alone. However, it kills ash trees and since its introduction into Ohio and Ontario, it has caused large amounts of damage to their forests. Ash trees are found in our area and are an important wood species so we should be worried about this beetle arriving in our state. It is a small beetle and is sometimes hard to see on trees. It eats the leaves with little damage in the adult stage but the larvae kill the tree by girdling the tree and preventing sap from traveling up to the branches and leaves. Below are pictures of these beetles.....
 
Another insect that is threatening our state, perhaps with more dire consequences than the Emerald Ash Borer is the Hemlock Woolly Adelgid. This bug kills hemlocks by sucking out the sap from the needles and small branches. It is spread by birds and the wind but it is also spread by people moving hemlock seedlings and also firewood or wood chips. Because the hemlock is an important tree in New Hampshire forests, we need to be particularly aware of this pest. There are some means to control it although they are not completely effective but the best way to save the hemlocks is to prevent their arrival. These pests are easy to spot if you turn small hemlock branches over. They are seen as white "fluff balls" because they have wrapped themselves in a fuzzy material for protection.
 
These pests are things that we would like to keep away from Lake Wentworth and if you know what the issues are, you can help prevent them from becoming part of our ecosystem. |
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