What's Eating Your Collection?

It can be difficult to determine whether damage is new or old and many hours and much money has been spent on treating old, dead infestations. Looking carefully at damage and/or insect finds will help to determine if the infestation is active or long dead and thus needs no treatment. 

The following checklist may be helpful.

Object record – Is the damage noted on the object’s record? Is it the same as the damage you have found?
IPM records – does this record previous insect activity in the area where you have found evidence of insects? Was anything done about it?
Frass – if you have found damage that you think has been caused by an insect, is there any frass? If there is damage but no frass, it is likely that the damage is old. Talk to the cleaners – they may be cleaning it up before you get to see it!
Bodies – Are there any dead insect larvae/adults or cast skins or webbing on or around the damage? If so, when was the object last checked? If it has been in a dark corner for many years and has not been looked at, you cannot be certain when the damage occurred. If it is regularly checked and the bodies have not been noticed before, they are probably new.
Live insects – Are there any live larvae or insects in the area? If so, any damage is likely to be new.
Time of year – What time of year is it? If you have found evidence of insect damage between March and November, then it is likely to be new as the insects are active during this time. If you have found the evidence during the winter, it is likely that the damage is old, although “old” in this case may mean that is was created during the active season just past.
Note that if your museum or store is heated at human comfort levels throughout the winter, the insects may not go into hibernation but be active all year round. If this is the case, then evidence found during the winter may be new.
Environment – What is the RH in the area where damage was found? If it is below 30%, insects will struggle to survive. If it is above 65%, insects will thrive and the damage is likely to be new.
Movement – Has the object been moved recently? Moving an object can shake frass out of an object, particularly from wooden objects. If frass seems to come from the building, has the building been shaken? Shaking can be caused by earth tremors, high winds or by lorries driving past.

If you are still uncertain, clean up any debris and monitor the object.
See Getting started with Integrated Pest Management for more information.