Yeah, it takes some diligence to get rid of them. Actually, I can only say that I have controlled them with DE. But it is a lot of fun to put the DE on a mound and watch the little buggers writhe and die. If you do a search on DE and fireants you will see directions on pressure spraying into the bed. This is more effective that just sprinkling the bed with De. But, I like dealing with the pests in a way that will not harm the other animals.
Yeah, if you have acres to treat, you might want to try another method. But even the poisonous broadcast methods take some time and diligence to get rid of them. So, I will still use DE.
Also, as far as the bites are concerned, I used to use bleach. My oldest son (31) is allergic and we always just rubbed bleach on the bites, until I discovered Bert's Bees Res-Q-Ointment. If you get that stuff on a fire ant bite or a mosquito bite within 20 minutes , you will not see a mark where you were bitten the next day. I buy it in a small metal container, and I keep one in my purse, one in the kitchen, one in the bathroom, one in the barn, one in each vehicle, and an extra one to give away. My daughter and I were in the grocery store one day and a friend of hers was looking for some kind of cream for treating a new tattoo and I gave him a tin of Res-Q-Ointment. He told Madalyn it was the best he had used. Also very good for burns. My son ran over a bed of coals one spring with his Rainbow flip-flops. He had to sleep with his foot in a bowl of chilled water. I put the ointment on his burn until I could get him to the pediatrician three days later. No infection. He couldn't even tolerate a shoe for a week. Ointment and socks only. This stuff is Good for any "boo-boo". Even bruises. I used to always use triple-antibiotic cream. I haven't even needed it since I found out about the Res-Q Ointment. That dadgum rooster that spurred me three times (and is now no longer with us); I treated all those scratches with Res-Q ointment and never had a problem.