I'm so sorry for your loss, 3cats-and-a-dog.
You're in our thoughts and prayers during this sad time. What was your girl's name? 12 years is a long time to share together.
I never thought about the pesticide issue--so many people do get lawn service these days. It certainly is logical that it might contribute to the increase your vet is seeing! It's amazing how common this heartbreaking problem seems to be--before I joined up here, Priscilla's case was the only one I'd ever heard of.
Priscilla, however, was not exposed to many pesticides (I'm paranoid about them.) I just always chalked it up to the fact that dogs use their noses to explore, and who knows what all gets inhaled during a lifetime of sniffing...