You may have powderpost beetles if you find small holes in your wood with dust piles underneath. Getting rid of these pests will protect your wood from more damage.

Powderpost beetles can be identified by the accumulations of wood powder they leave under their exit holes. They are tiny, brownish, or reddish insects, but you’re unlikely to spot them crawling or flying around. To get rid of powderpost beetles, you have several options, including drying out your wood, heat treating it, spraying it with insecticides, fumigating, removing and replacing infested wood or waiting for them to leave on their own.

In my time as a pest control professional, I’ve helped many folks eliminate powderpost beetles. Read the rest of this article for my detailed tips about identifying these wood eaters and getting rid of them for good.

You might also be interested in reading these 3 related articles “How To Get Rid Of Bed Bugs“, “How To Get Rid Of Ladybugs/Asian Beetles” and “How To Get Rid of Carpet, Japanese & Cigarette Beetles Quickly Permanently“.

What Are Powderpost Beetles?

Powderpost beetle is a generic name for several small insects whose larvae eat wood and leave a powdery sawdust in their wake. They are brown to reddish and measure from 1/16 to 3/4 inch, but folks usually don’t see them, instead seeing evidence of their wood eating habits.

Adult beetles lay their eggs on or just under the surface of unfinished wood. After hatching, larvae make their way into the wood, carving out meandering tunnels as they feed. 

Interestingly, the larvae may spend one to five years living inside the wood. Once mature, the beetles chew a hole in the wood’s surface and restart their lifecycle by laying eggs.

Identifying Powderpost Beetle Infestations

The easiest way to identify a powderpost beetle infestation is the piles of fine sawdust, called frass, that accumulate under the wood where they live. Also, look for small holes on the wood’s surface that adults have emerged from.

The amount of time powderpost beetle larvae spend inside of wood depends on the starch content and moisture of the wood. As wood ages, these conditions become less hospitable for the larvae, and development takes longer.

Moreover, powderpost beetles might create new holes and emerge from wood for several years, but this doesn’t mean that the infestation is reoccurring. Instead, it simply means that the larvae from the initial infestation needed different amounts of time to mature.

Types Of Powderpost Beetle

Three types of powderpost beetle are most common in the USA, lyctids, anobiids, and bostrichids. Each can damage wood and leaves frass in its wake.

Your may never see an adult powderpost beetle, making their frass one of the best ways to differentiate between the three. Each type of beetle has a characteristic frass, which are:

• Lyctid Frass- Extremely fine, similar to flour or talc.
• Bostrichid Frass- Granular and sand like, which causes it to stick in exit holes.
• Anobiid Frass- Gritty and piles up below exit holes. Feels similar to soap flakes.

Lyctid Powderpost Beetle

This group of insects can also be called True Powderpost Beetles. They infest hardwoods, such as:

• Oak
• Walnut
• Mahogany
• Ash
• Hickory
• Cherry

This powderpost beetle type can tolerate lower moisture content woods than other types. They can live in wood with moisture content as low as eight percent, which makes indoor furniture susceptible to lyctid infestation.

Additionally, bamboo is susceptible to lyctid powderpost beetle infestation. Its large pores are a perfect egg-laying environment for these insects.

Anobiid Powderpost Beetles

The anobiid species of powderpost beetles are the most dangerous to homes because they can eat softwoods or hardwoods. Most structural lumber in houses is softwood.

They require higher moisture content wood, from 13 to 30 percent, for larval development. This makes it more likely to find anobiids in damp crawl spaces and unheated buildings.

Unlike the other two types of powderpost beetle, anobiids can digest cellulose in wood. Therefore they can infest wood of any age. Also, these powderpost beetles create varying-sized exit holes, while the other two common types create uniform-sized exit holes.  

Bostrichid Powderpost Beetles 

Unlike the other two types, Bostrichid powderpost beetles carve holes in wood where they lay eggs. The egg-laying holes don’t have frass near them. Exit holes might be filled with frass because it’s coarser and doesn’t fall out as easily as the other types of powderpost beetle frass.

Infestations are most common in hardwoods, but they are possible in softwoods. You’re most likely to find bostrichid powderpost beetles in imported tropical hardwoods.

Getting Rid Of Powderpost Beetles

The best method to get rid of powderpost beetles depends on the location of the infestation. Luckily, many powderpost beetle infestations go away on their own.

But, sometimes you need to take action to eliminate powderpost beetles. They can do serious damage to wood, and you can stop them. 

When To Let Infestations Go Away On Their Own

Powderpost beetle infestations in furniture or non-structural wood can go away on their own. Infestations most likely happened soon after the wood was cut down while it was in storage, and reinfestation in your home is unlikely.

It may take several years for all of the larvae to make their way out of the wood. If you choose this route, you may need to clean frass and new holes will occasionally appear during this time.

When To Take Action To Eliminate Powderpost Beetles

If powderpost beetles threaten any structural components of your home, such as beams or rafters, take immediate action to stop them. They could weaken these critical components and cause a dangerous situation.

Also, if the powderpost beetle activity damages wood of monetary or sentimental value, you should stop them. The holes they create cause a cosmetic change that alters the character of the wood.

Moisture Control To Eliminate Powderpost Beetles

The most likely powderpost beetle culprit of structural damage is the anobiid type. They need moist wood to survive, making moisture control an effective method to get rid of them.

Because powderpost beetles often infest beams in damp crawlspaces, this is a great place to start. You may need to install or repair a vapor barrier in your crawlspace to prevent moisture.

Also, increasing airflow by installing vents in the crawlspace helps carry moisture out. Finally, you might need to improve the drainage under your home to solve the moisture problem.

Residual Insecticides To Get Rid Of Powderpost Beetles

Borate insecticides are effective powderpost beetle killers. Sprays can penetrate wood and kill larvae inside, also killing beetles as they exit or enter the wood. 

Borates are safe for humans and nearly odorless. They work best on moist wood, making them perfect for stopping an anobiid powderpost beetle infestation.

Unfortunately, borates don’t work on painted, stained or coated wood. This fact makes them ineffective on most wood in living spaces.

Fumigation To Kill Powderpost Beetles

Fumigation is the most extreme method to kill powderpost beetles and can only be done by pest control professionals. Moreover, fumigation is reserved for infestations between floors and inside walls.

During fumigation, the entire home is sealed with tarps that look like a tent. Your home will stay under wraps and uninhabited for at least three days, then, it’s aired out before people can return.

Smaller items, like furniture, could be fumigated more easily and at a lower cost. Still, this is something that only pest control professionals should handle.

Heat Treatment For Powderpost Beetles

High temperatures kill powderpost beetles. Unfortunately, this method may only work for infestations in smaller objects that can fit into a heat chamber. 

The temperature must stay between 120 and 135°F for 24 hours to get rid of powderpost beetles with heat. This is similar to treatments for bedbugs.

Most lumber is heat treated this way in a kiln after its milled. But, powderpost beetles can still find a way to infest the wood after.

Remove and Replace Damaged Wood

In cases where powderpost beetles are limited to a small area, you could cut out the affected wood and replace it. Before getting out your saw and hacking away, be sure the wood you want to remove isn’t load-bearing.

You may want to consult a structural engineer for guidance if you’re not sure about the wood being load-bearing or not. Load-bearing beams or other boards require shoring to prevent further damage to the structure.

Take infested wood to the dump or burn it to stop the beetles from spreading to other parts of your house. Carefully inspect the wood you use to replace the bad wood for insect damage.

Preventing Powderpost Beetles

Most powderpost beetles enter homes through wooden items. Therefore, prevent them by closely inspecting any wooden item you bring home for exit holes.

Also, powderpost beetles won’t enter coated wood. Protect the wood in your home by applying paint, varnish or stain to prevent powderpost beetles from gaining a foothold.

Where Do Powderpost Beetles Come From?

Powderpost beetles normally enter homes inside furniture or other wooden objects. Only the anobiid powderpost beetles have a habit of flying into houses and infesting beams or other unfinished wood. 

The beetles were most likely in the wood before it became the item you purchased. The period between kiln drying and being made into a useful object is an opportune time for infestation.

Often, powderpost beetles come from tropical countries where they use improper wood curing or storage methods. However, they are native to most parts of the world.