What insect would do this?

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Forum topic by greatview posted 08-02-2011 08:35 PM 1926 views 0 times favorited 10 replies Add to Favorites Watch
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131 posts in 3153 days

08-02-2011 08:35 PM

Topic tags/keywords: question insects

Here’s a piece of exterior trim board from my house in New Hampshire

And, here I’ve split the board with a band saw. What insect would do this?

-- Tom, New London, NH

10 replies so far

View DaddyZ's profile


2475 posts in 3036 days

#1 posted 08-02-2011 08:42 PM

My guess some sort of wood beetle

-- Pat - Worker of Wood, Collector of Tools, Father of one

View Tim Kindrick's profile

Tim Kindrick

369 posts in 2550 days

#2 posted 08-02-2011 08:45 PM

I was in the pest control business for about 20 years. My best quess is Long-horned Beetle.

Long-horned Beetles or Round-headed Borers (Coleoptera: Cerambycidae)

Adults of this family are called long-horned beetles because their antennae are usually long. Larvae (round-headed borers) tunnel underneath bark and into the wood. The tunnels are oval to almost round in cross section, conforming to the cylindrical shape of the larvae. Larvae of some species are legless, but most have three pairs of small legs. While tunneling, larvae continually pack their tunnels with frass, which looks like compressed wood fibers, or push frass out of the holes they make. This frass, along with the sap exuded by the plant in response to the damage, is often visible on the outside of infested trunks or branches.

Credits: L. J. Buss, University of Florida

-- I have metal in my neck but wood in my blood!!

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Tim Kindrick

369 posts in 2550 days

#3 posted 08-02-2011 08:54 PM

More specifically the Old House Borer…. in my opinion.

Old House Borer

Hylotrupes bajulus


The old house borer is one of the most injurious wood-boring insects inhabiting Pennsylvania. The name is somewhat misleading since a large number of infestations are noticed in homes just four to seven years after construction. The larva bores through wood and also feeds on it. Tunnels made by the larva weaken structural timbers. The borers feed only in pine, spruce, and other coniferous woods.

The old house borer is native to North Africa and is believed to have arrived in North America around 1875. The beetles currently range from Maine to Florida and west to Michigan and Texas.


An infestation of old house borers is evidenced by the presence of the adults their emergence holes, or by the larvae and larval tunnels in the wood. The black to gray beetles are 5/8 to 1 inch in length and possess long antennae. Fine, gray hairs are present on the thorax with two shiny raised areas on each side. Patches of gray hairs are visible on the wing covers in irregular lateral bands. The pointed abdomen of the females will typically extend beyond the ends of the wing covers. Emergence holes made by the adult beetles are somewhat oval and 1/4 inch in diameter. The cream-colored larvae are up to 1-1/4 inch in length. On each side of the head are three distinct, dark eyes (ocelli) arranged vertically behind the mouthparts. The larval body tapers towards the posterior end. Tunnels made by the larvae contain a sawdust-like material known as frass. The tunnel walls are sculptured (showing where the mandibles scraped away the wood), and the frass is barrel-shaped. The larva, while chewing with its hard jaws, emits a rasping or clicking sound (very similar to the sound produced by clicking fingernails), are often audible to the householder.

Life History

The adult beetles emerge mainly during July and August. They mate, then the female deposits her eggs in the natural cracks and crevices of the bark of felled logs and in wood stored in lumberyards. Subsequently, infested timber may be used in newly constructed buildings. In wood, the larval stage may last from three to fifteen years. The average time for the borers to reach maturity in Pennsylvania (in structures heated year long) appears to be from five to seven years. The majority of borers are secreted in the thicker timbers of a building. Very few ever have been located in wood less than one-inch thick. Nearly all the structural infestations in Pennsylvania are started by old house borer larvae in some of the original construction timber. Most infestations remain localized. However, where excessive wood moisture is found, such as poorly vented attics and leaky roofs, beetles will flourish, spread to other structural items and cause much damage in a short period of time.


The following points should aid in discouraging old house borer infestations:

1. Rough-cut lumber should be kiln-dried to kill all stages of the beetle.

2. Uninfested wood which is sanded and varnished will not normally be attacked by the adult beetles because they cannot find crevices in the wood surface into which they would deposit their eggs.

3. Surface sprays containing borates will prevent newly hatched larvae from entering the wood. However, this technique is not effective on wood which has been varnished, waxed or otherwise sealed from attack by moisture. The borates will last indefinitely, provided the treated wood is kept dry to prevent water from leaching the material.

4. Fumigation of lumber or structures is the only absolute method of eliminating old house borer infestations, particularly in structures. Fumigations are the use of volatile, poisonous gases which will readily penetrate wooden items and can only be contained within a gas-impervious tarp. Fumigations, however, are very expensive and do not provide lasting protection from re-infestation. Fumigations must be performed by certified, professional pest control individuals specifically licensed to do this type of procedure. The most commonly utilized fumigants contain either methyl bromide or sulfuryl fluoride.


Pesticides are poisonous. Read and follow directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams, or ponds.

Authored by: Steve Jacobs, Sr. Extension Associate Revised August 2007

-- I have metal in my neck but wood in my blood!!

View greatview's profile


131 posts in 3153 days

#4 posted 08-02-2011 08:55 PM

OK, that makes sense. I looked up a picture of the long horned beetle and we see them around here frequently. Now, how do I prevent them from attacking?

-- Tom, New London, NH

View chrisstef's profile


17381 posts in 3002 days

#5 posted 08-02-2011 09:01 PM

id say it could be from a wood boring bee … the look like huge bumblebees, ive got a ton at my house and they chew up the fascias pretty good. Is there sawdust around the holes?

-- Its not a crack, its a casting imperfection.

View Tim Kindrick's profile

Tim Kindrick

369 posts in 2550 days

#6 posted 08-02-2011 09:03 PM

Oh yeah, That is the exit hole and NOT the entry hole in your first pic…..

-- I have metal in my neck but wood in my blood!!

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Tim Kindrick

369 posts in 2550 days

#7 posted 08-02-2011 09:09 PM

Chris: It’s not a wood boring bee… wood boring bees make holes that are almost exactly 5/8” in diameter.

The usual course of action is to simply replace the damaged area with wood that is treated with borates…. If the house has a large infestation (unlikely) then it will need to be fumigated by a professional.

-- I have metal in my neck but wood in my blood!!

View will delaney's profile

will delaney

326 posts in 2631 days

#8 posted 08-03-2011 01:14 AM

Carpenter bee they should be called forstner bit bee.This bee makes a perfect hole. They love my ceder deck.Big but harmless unless you wood. I even was able to pet it.

View Grandpa's profile


3259 posts in 2671 days

#9 posted 08-03-2011 01:37 AM

I have carpenter bees also. I spray them and I think I have gotten them for the mean time. They bore that hole like described above. I would say half inch dia. they are quick and destroy the wood. I had a split rail fence that they really worked over before I knew it. They prefer untreated wood. Paint helps a lot. Now we have solved 2 problems. Long horns and carpenter bees.

View tnwood's profile


258 posts in 3082 days

#10 posted 08-03-2011 08:37 PM

Carpenter Bees. They are a major problem down south but my son in NY has been complaining about them this year up there. I never saw one in NH in the 12 years I was there but I think that is what you have.

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