We use a product called Amdro. Its a granular you spread over the area. The ants, thinking its food carry it down into the nest and it kills the queen. It works great. We watch our dogs for awhile after spreading it but it doesn't stay above ground for long.

Here is a link that might be useful: Heres a link

A while back, did someone suggest urine for this? Or cornstarch? Did anyone try either? I did try the cornstarch, but results were kind of inconclusive -- my DH followed it up with a shot of Black Flag, and when next I looked, all ants were DEAD and have not returned to that spot.
Zill

Sam, I use the Amdro also, as you know I have pets, frogs, birds and lizards. I just sprinkle a small amount near the main activity, within 24 hours no more ants!

Thanks! Am on my way to Home Depot now. Hope they have Amdro. (Thanks Zill but I will pass on the cornstarch and urine) :) sam

Food- grade diatomaceous earth works pretty well, too- you can find it at feed stores (don't get the pool-grade DE, it has bigger, less-effective particles and is more likely to expose you to silicosis!) in 50-lb bags. You can't just sprinkle it on like it was Amdro (a good product but it's an insecticide), you have to really pound a bunch of it it down the hole and it helps if you sprinkle a bunch of ants thoroughly with it, too, but the tiny particles will pierce into insects and dehydrate them. I called the city sewer roach line one time to complain, and the man that answered told me that DE really works well on the sewer roaches (most of whom have never seen the inside of a sewer, having grown up inside a dying mulberry or leaf pile).

.... geez, Sam, you must be getting picky on us....

Just an FYI, for anyone who gets the sewer roaches who come from where they're supposed to, >grinAnd you still want these Mulberries, Eileen? They're still on my porch, awaiting your loving touch. I just chopped mine down this last weekend. Whatta mess.

Mein Gott! I'm sorry, PC, I totally forgot about them what with all the sturm und drang surrounding me lately! Yes, I do! I'll email you separately...