graham law wrote:
Has anyone out there had similar experience with Bayvarol/Apistan
treatments?  If there is anything in this suspicion then Spring treatments
should be avoided if not absolutely necessary.

see

http://www.nalusda.gov/ttic/tektran/data/000009/21/0000092180.html

and

http://www.nalusda.gov/ttic/tektran/data/000009/83/0000098333.html