Questions about permanent mulched garden beds

I have about 4000 sqft of Emilia Hazelip inspired raised beds.  Overall I really like them but I've run into a few issues.  Moles and fire ants seem to love them.  I know this is good since it means that the soil is loose and full of worms.  A huge improvement over the red heavy clay I had before.  I've been trying to live with the moles but the fire ants are simply not something I can abide anymore.  I've planted some of the native plantain of the area in the garden to have ready access to sting relief, but I really need to control them.  Unfortunately, our chickens and guineas seem to have no intrest in eating them.

Has anyone else had similar issues with permanent beds that knows some controls for moles and fire ants?  I'm not sure I want to use boric acid.

Question 2: I planted sweet potato in a bed but don't know if it will grow well with mulch. I've always used sweet potato as a ground cover for bare spots. Anyone tried?

Boric acid formulated as a bait and put into bait stations to protect against rain/dew is one of the safest ways of controlling ants. The boric acid supplies boron, which can be very beneficial in many soils (especially warm/wet areas where boron is depleted). Even if the amount of boron in your soils is high, baiting does not add much to the total. 

Microscopic parasitic wasps that do not sting humans have been released as a natural pest of the fire ant, and seem to be doing a modest job of reducing fire ants, but cutting the population in half still leaves lots of nasty stinging monsters.

Thanks for the reply.  I have used boric acid in conjunction with sugar and grits before.  I'm just worried about the watershed.  south central TN receives about 50 inches of rainfall a year, so I assume I'm boron deficient but I don't know as I do use some commercial feed for my poultry which is usually high in boron as I understand.

protect the plants and then with a teakettle so you can control where the water goes put on boiling water..right down the ant holes..keep it restricted as it will kill the plants..repeat if they come back..try to do it when everyone is home..probably at night

I've been using orange oil on my fire ants, a couple tablespoons to a gallon of H2O. Works great!

Can you make orange oil by just simmering orange peels in water or do they need to be processes in oil or alcohol?

Orange oil. 

I made it with some students one time.  We used distillation apparatus and boiled the orange peel with water.  Collected the evaporating water and cooled it, condensed it using a Leibig condenser.  Then poured the liquid distillate into a burette.  The oil floated, and we ran the water out the bottom of the burette and were left with the oil. 

We produced less than 1ml in a 2 hour class. 

Could you use vinegar?

This site has a lot of info on fire ants:

http://fireant.tamu.edu/