Ah, Mother Nature! She is complicated! This is a very good question and important topic to bring up.
I'd suggest that you say what pesticides you use under the section of other things that guests should know. For many people, pesticides are much more of a problem than the occasional insect or spider. I'd think it really important to let prospective guests know - in several locations in your listing - that you use such a professional service, how often, and what chemicals they apply. Some may appreciate that you do this pest control, others may not. It would seem to me an important disclosure, especially if you allow pets or children. We personally would need to avoid any housing that used pesticides, and would need to know what they are, how often applied as the ultimate deciding factor in their potential toxicity to humans.
About our own listing, since you asked:
We are very upfront about coexisting with Mother Nature. Our guests come here for being in a natural setting, to experience and appreciate wilderness, for birding, nature study and hikes. We are up front in our listing and followup communications about large and small wildlife, poison oak, ticks, etc. Spiders are relocated gently from the guest suite to our personal living spaces. Our 180 forested acres and popular garden tour gardens are free from pesticides and poisons of every kind, but do include many naturally toxic plants, plus our large cactus garden. Spiders, lizards and birds take care of any mosquitoes that could bother us, opossums eat ticks, foxes, snakes and bobcats eat the ubiquitous field mice. We recommend that folks with insect/spider phobias choose a motel in town where nature does not encroach. When we managed a wilderness resort we did the same thing.
We are, of course, meticulous about surgically cleaning the guest suite, and doing a last minute check for spiders and such - but we leave the forest ecosystem to regulate itself.