We're looking to freshen the mulch on our property and our pest control company is asking us to only use termite-resistant mulch. The closest alternative the landscaper has is a top grade bark mulch. Will that help termite resistance?
That is funny “top grade mulch” as termite resistant. I say this as I have worked in the lumber and plywood industry for a few years. My plant specializes in small log recovery (old logs have more bugs) and you find termites time to time but the process usually kills them.
The bark is scraped off the trees then it goes through a machine called a hammer hog where it is reduced to mulch then put in huge bins. Then transferred to trucks, dumped in piles and pushed in mounds by heavy equipment and then loaded in trucks. Yes, some could survive if they are in the bark as larva but it is more likely for them to be in the wood chips not the bark mulch or Hog fuel.
Possibly what they call high quality is a finer product. But termites don’t live in the bark they live in the wood. This is where we see them and usually in the older trees or dead trees (we do have a large log mill also so I see both.) I can say I see more chance of termites by swarms than bark mulch in the Pacific Northwest.
According to the pest-control company Terminix, termites don't really feed on wood mulch but like the fact that it causes a moist environment, which they then use for cover to explore for a wood source. Terminix, because it wants to sell you their services, rather dramatically states that "Mulch doesn't necessarily attract termites, but can serve as an invite for them to feast on your house." The fact that termites like "cover" while foraging would equally apply to stone and rubber mulches as it does to wood mulch.
Terminix also states that termites are unlikely to survive going through a chipper. Remember, termite colonies require a queen, so random termites in a load of wood mulch would NOT be enough to start a colony unless one of them happened to be the queen.
Now, there are termite-resistant woods that could be used for mulch (the web site states that cypress is one of them, but please don't use cypress as entire forests are being cut down and chipped for mulch), but cedar, such as Thuja species, is also listed. Perhaps those trees could be what your pest control company means by "termite resistant" mulch.
To conclude - chipped wood products would be highly unlikely to transplant a termite colony to your home, most chipped wood products are unlikely to be fed upon by termites - especially chips from trees like arbor vitae, and all mulches may provide cover for termites to explore for wood sources.