I was asked to confirm the presence of bed bugs in a 100 year old 2 story home before a full gutting and renovation. I did note the presence of bed bug excrement in several places along baseboards which were mostly the 100 year old oak boards about 10 inches tall but there was also some modern baseboards consisting of modern spruce or pine 1x3s. The walls were mostly balloon framed rough cut fir with lath and plaster finish but there was also one wall with modern spruce framing and dry wall finish.
We removed the 100 year old oak baseboards and found very little evidence of bed bugs on that lumber despite evidence on the painted surface adjacent to the baseboards. On the other hand the one wall that was constructed with modern baseboards had considerable staining on that lumber. Also the vertical spruce studs behind the drywall had bug staining rising about 2 feet up from ground level. Other older lumber that was included in the wall did not have the staining – only the new lumber was stained.
The back side of the drywall was also unstained despite being in close proximity to the stained spruce lumber. The only part of the drywall that was stained was the paper gap between two pieces of drywall. The original lathe and plaster strips and the fir studs were not stained.
Once again we see that the bugs have very specific likes and dislikes for harbourage substrates. Older lumber, lathe and plaster and, interestingly enough in this setting, the back side of drywall, were not considered desirable. Only the smoother paper between the dry wall joints was stained. Of all the wood in the walls only the the new spruce (studs and plates) behind the drywall was stained.