Borer and termites are two of the biggest problems for museums in caring for their wooden materials. Find out how to deal with these pesky insects in your wooden objects!
What are tunnelling insects?
The two main types of tunnelling insects that I see the most in wooden objects are borer (larval stage of a beetle) and termites (winged insect of its own biological order). There are lots of other species that can cause damage and can also damage different materials )(such as paper), but they can mostly be treated in similar ways.
How do I know if they are active?
Objects will often have evidence of active infestation in the form of a powder appearing on surfaces where the object is placed, known as frass. You will likely also see small holes in the surface of the wood. If you are not sure and the object is small enough, you can place the object in an enclosed bag. Leave the object enclosed for 1-4 weeks. You should then notice if there are any residues, powders or webs on the object or contained in the bag. Some museums automatically ‘quarantine’ an object this way or immediately freeze it before allowing in with the rest of the collection.
Can they spread?
This is the biggest problem with tunnelling insects is that they can spread to other objects and to your building. If you are concerned about a broader infestation, it may be worth talking with a pest management company to also try to eliminate avenues of entry for future borer and start an annual treatment plan for your building.
How are they treated?
The traditional way of treating tunnelling insects was to apply diesel, turpentine or kerosene to the surface of the wood. This can be effective for a short time, but it is not recommended for museum objects due to the residues and odours. Please note the methods below do not continue to kill the insects after treatment. It is to stop the infestation. Care must be taken to place the object back into an insect-free environment.
Also, this advice is meant as a general guide and each object may react differently. We are not responsible if you attempt this treatment on your own unsuccessfully.
Depending on the size of your object, you may be able to treat an infestation using one of the following techniques:
Do not freeze these materials: paintings, photographic materials, electronic media.
Materials: Freezer that is capable of maintaining -29C*, plastic bag or wrap depending on the size, freezer proof tape if not using a bag.
Process: Using a standard, commercially-available chest or standing freezer, place the object in a bag or wrap it in plastic being sure to seal it with freezer proof tape. Place into the freezer and leave 1-4 weeks. Remove the object and allow to thaw for 24 hours before opening.
*Most commercial freezers only go down to -18C. You may need to leave the object in longer or obtain a thermostat to reduce the temperature even further. You can also contact larger museums as they often have freezers as part of their pest management plan.
2.0 Liquid Insecticide
This process is only for wood that has no surface treatment and is NOT painted or varnished.
Process: Place the object in a well ventilated area and lay a drop cloth or plastic underneath the object. Prepare the chemical as directed. Using personal protection, apply the product with a paint brush. A second coat may be needed. Allow the object to ventilate for at least 24 hours.
This technique could be good for painted or varnished surfaces of furniture. Chemicals such as arsenic and formaldehyde have been used in the past on museum collections which have led to highly toxic environments for museum staff and huge remediation programs. It is very important to select the correct fumigant and consider it for only extreme cases.
Materials: Thick plastic sealable bags or wrap, duct tape or other thick tape if not using a sealable bag, fumigant (No Bugs Super Fumigator 20g in NZ) , nitrile gloves, respirator with a gas and vapour cartridge (consider investing in a half face mask), clothes protection.
Process: In a highly ventilated environment (preferably outside and away from people or animals where it can left safely) and using personal protection, loosely wrap the object in thick plastic being sure to seal any joins thoroughly with duct tape or a thick tape. Prepare the fumigator product as described. Place fumigator inside of the bag on a flat surface and seal the entrance well. Leave for 3-12 hours. Unwrap and allow the object to off-gas in a well ventilated area.
4.0 Other Treatments
There are other options for treating tunnelling insects depending on your budget. These can include the use of gas to create an anoxic environment or oxygen scavengers. Contact us with further questions if this is a direction you want to explore!
- Be sure to note in the object record that it was treated and put specific details about the process used.
- Make observations and take images at periodic times after the treatment to note any new activity or any changes that may have taken place to the wood.
- Lay down traps or glue boards to identify what other pests may be in the collection. Try these available at Bunnings: https://www.bunnings.co.nz/the-buzz-pest-glue-traps-4-pack_p00250488.
- Create an integrated pest management plan for your museum.
- Ensure the humidity in your storage or display areas is 50% or less.