Wednesday, 20 November 2013

How To Identify A Powder Post Beetle Infestation - November 13, 2013

November 13, 2013

I spent an afternoon helping the Northville Farm Heritage Centre with identifying and isolating wooden artifacts infested with Powder Post Beetles.  I wrote about steps to take when dealing with an infestation and about infestation in general in the two previous posts so won't repeat that here.  This post has more pictures to help you search your own wooden artifacts.

Our objectives with the work at the farm centre was to:
  • identify anything infected and remove it,
  • place smaller artifacts in garbage bags to isolate them,
  • place the smaller artifacts for a minimum of two weeks in a freezer,
  • place larger artifacts that could safely be moved into a holding area,
  • identify areas of significantly larger objects and structural infestation for future spraying.
We searched three buildings for the evidence of sawdust laying about or holes in the wooden artifacts.  Some of the holes look recent with lighter colours and sawdust others look older with darker colours and no sawdust.  These photographs show what we found for recent activity and what you can look for:

Barrel header with sawdust

Saw handle with holes and dust.
Butter churn heavily infested

With the older holes that usually have no sawdust treatment is still necessary since the larvae can survive for many years within the wood.  We bagged and froze the smaller artifacts as well and documented the larger ones for spraying in the spring.  Here is an example of what appears to be older non-active holes with no recent sawdust evident:
Brush with older holes.
Wheel, painted with older holes
We identified several areas in two of the buildings where spraying with Timbor should be done in the spring.  I wrote about spraying in a previous post and steps to be taken with infestation.  Timbor is safe to use and can be effective over a longer period of time to reduce the population of beetles.  Spraying is recommended in the spring around second or third week in June when the beetles are most active.  Fresh sawdust is the clear sign of beetle activity so cleaning up the sawdust shortly after spraying and monitoring for more will let you know if you need to re-spray. The farm centre has been doing this already for the last few years by spraying the structure of their buildings but now they can spray the larger, individual items we have seen that are infected.  Here are photographs of most of the artifacts we found with beetle infestation:

Most importantly, they must isolate all wooden artifacts as they come in. Smaller ones can be frozen for  two weeks; larger ones sprayed.  In both cases they should be isolated from the rest of their collection and only returned to the general collection when they have been treated.

One area had a large amount of sawdust on a barrel header on the main floor.  After removing it and searching for further evidence we came across a wooden butter churn that was heavily infested sitting on a shelf above.  The sawdust fell down between the shelf boards onto the barrel header below.

Conservation Tip:  It is critically important that all wooden artifacts brought in be inspected for infestation and if there is any evidence isolate them and treat them as soon as possible.  Isolation can be as simple as bagging or keeping them outside or in a building without exposed wood and cement floors.  Spraying is most effective when the beetles are active in the spring when they emerge from the wood for mating.  If you have had an infestation it is necessary to spray each spring over a period of years to reduce the population to a manageable number.  Regular inspection of your wood collection is necessary.  Remember that painting and varnish will not discourage them, they live in the wood and will bore their way to the surface.

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