IIRC, you can use poisons on voles. But moles eat bugs.
For moles, I've used the castor oil sprays with some success:
http://www.fertilome.com/ProductFiles/Molego%2010317.pdf
After applications over a few years, I had success. And funny as it seems, I followed some advice and stuck $1 pinwheels around the property - when they spin, they set up a subtle vibration that they say bothers the moles. I also tried the smoke bombs - not effective, but fun to use.
Anyway, I eradicated them in the main...they prefer my neighbors now.
The definitive cure is to trap 'em and bash 'em.
Link to a nationally-syndicated garden radio show, Ron Wilson's,originating in WKRC 550 radio in Cincinnati. Airs at 6 AM:
http://www.ronwilsononline.com/pages/ronW_...article=2140188