People have speculated about a possible pesticide nexus for White Nose Syndrome since WNS was first observed back in 2007. The US Fish and Wildlife Service funded a three year study, but no evidence has ever been presented that pesticides are a factor in bats getting WNS.
Do pesticides harm bats, as they do other living things? Yes, but so far there is no tie that I'm aware of to WNS. Blog after blog and members of the public ask and wonder and offer opinion, but so far I've seen no studies to support any connection.
The only comparative study I've ever seen of various environmental toxins was done back in 2008, and has occasionally been cited by writers. This analyzed a number of Little Brown bats taken from NY sites and compared them with reference bats from Kentucky, a non-WNS region at that time. Elevated levels were found in both samples, which would imply that environmental exposure was not key to WNS. The study was inconclusive in terms of any cause and effect for WNS, but at least researchers did the study:
http://www.sciencedirect.com/science/article/pii/S0045653510005084
In addition, this rather comprehensive analytical piece cites circumstances where pesticides or other environmental toxins can or may cause immunosuppressive reactions, which "might" make a bat more susceptible to infection or other disease, but it is not a scientific study demonstrating cause and effect, rather a discussion of possibilities:
http://www.birc.org/JunJul2013.pdf
Bottom line: to date I know of no scientific study demonstrating a cause and effect relationship between pesticides and WNS. If anyone has information to the contrary, please point us to it. Thank you.