I keep a vigilant eye on the ant population in my yard (4 acres) with all the rain this year in Sout Loosiana the ants have been pretty much left alone for most of the summer. I always tell myself I am going to count the mounds I treat but I always get side tracked. 30 to 70 is about the norm but I don't often have large mounds. I started using Bifenthrin last year but my favorite go to killer is Ortho... the white stuff when I am being lazy. Sometimes I treat large sections of yard if the ant population is increasing. Some of the 3 month ant killer I've used really does work but it doesn't kill the ants right away. I like dead ants by sundown. Ha ha.
So many people have ideas about how it should be done. I laugh when they tell me to treat the whole yard. Yea right 4 acres. So.... with Bifenthrin I take a stick with me, poke a hole deep into the mound and pour in a sufficient amount and then broadcast the mound and little around the perimeter.... Sometimes I have the spreader with me and I go 15 to 20 feet in all directions. Years ago, Once and Done used to really mean "Once and Done" that stuff was great but now... it is not the same so I don't use it. I am also careful not to use any ant killa that needs to be watered in. I am not carrying a bucket to water 50+ mounds.
So... Generally I cut the grass first. Wait a day for the ants to gather themselves and recover from the carnage of the mower.... then I strike. The mounds are easier to spot as the short grass more readily exposes enemy locations. At present the enemy is looming large in my thoughts and a significant offensive must be mounted soon but I am busy with other things. I like to strike in the evenings. I ride my Yamaha Zuma (see picture) around the yard with the weapons aboard. Search and Destroy. Muhaahahaa !!
Good Luck All,
Gene